Bottlebrush polymers

Abstract

Provided herein are bottlebrush polymers and macromolecules including such polymers, comprising: a monodisperse polymer backbone; and defined bottlebrush sidechains. The polymer backbone is a polypeptide comprising amino acid residues with an amine moiety on the sidechain of each amino acid residue. Each of the defined bottlebrush sidechains is attached to the polymer backbone at the amine moiety of each of the respective amino acid residues; and the defined bottlebrush sidechains comprise at least two blocks of polypeptide or similar, wherein, in each said block, the polypeptide, polypeptoid or polypept(o)ide is functionalised proximate to the end of its chain with a reactive group or ligand, wherein adjacent blocks of the at least two blocks do not comprise the same reactive group or ligand. Also provided are methods of making such bottlebrush polymers, as well as methods of forming bottlebrush polymers with a longer or branched backbone, macromolecules comprising such bottlebrush polymers made by such methods, and uses thereof.

Description

Bottlebrush Polymers

[0001] This invention relates to monodisperse bottlebrush polymers comprising a sequence defined polymer backbone and polymer side chains. The invention also relates to method of preparing such polymers. BACKGROUND

[0002] Polymer-based materials have shown revolutionary potential for multiple biomedical applications, including drug or vaccine delivery, tissue engineering and biosensors. In nature, the importance of perfect spatial arrangement of functionality in natural polymers (such as oligonucleotides and proteins) is evident. For example, in antibodies, the final scaffold architecture and stable 3-dimensional structure is of supreme importance for the recognition of specific receptor patterns on cell or pathogen surfaces. Preserving receptor patterns in space requires stable nanostructures with precise control over morphology and local arrangement of surface functionality. While a certain control over particle morphology or surface properties can be achieved by several synthetic approaches (Schacher et al., Angew Chem. Int. Ed. Engl., 2012, 51 (32); 7898-7921; Liao et al, Chem, 2023, https: / / doi.org / 10.1016 / j.chempr.2023.03.012) precise and independent control of size, shape and local surface functionality is still impossible in polymer-based synthetic nanomaterials.

[0003] Cylindrical bottlebrush polymers (CPBs) or molecular bottlebrushes represent an important class of graft-copolymers with high side chain densities and high molecular weights, in which one or more polymeric side chains are tethered to each repeating unit of a linear polymer backbone, such that the resulting macromolecule resembles a “bottlebrush”. Steric repulsion between the densely grafted side chains enhances stiffness of the backbone, hinders overlapping and entanglement with neighbouring macromolecules, and promotes ordering. The synthesis of bottlebrush polymers can take place by grafting-from (polymer backbone acts as initiator), grafting-onto (preformed polymers are attached to a polymer backbone) or grafting- through (polymerization of macromonomers).

[0004] Unlike linear polymers which tend to form random coils, the densely grafted side chains on the polymer backbone of bottlebrush polymers stretch the main chain into an elongated worm-like structure, in which nanoparticle size and shape are controlled by the length of backbone and side chains (Feng et al. Accounts of Chemical Research, 2018, 51 (9), 2314- 2323; Müllner et al., Polymer, 2016, 98, 389-401). The length and polydispersity are governed by the backbone polymer.

[0005] Monodisperse synthetic polymers, however, have not been applied to the synthesis of bottlebrush polymers. So far, only Weil et al. reported the use of exfolded human serum albumin to grow polymers by controlled radical polymerization. However, the reduced grafting density,yielded spherical graft copolymers which did not offer shape persistence (Weil et al., J Am Chem Soc, 2020, 142 (3), 1332-1340). Moreover, the chemical flexibility is limited when natural protein scaffolds are applied.

[0006] Accordingly, there is a need in the art for scalable methodology which achieves more precise control over the size, shape and localisation of surface functionality in the synthesis of nanoparticles. BRIEF SUMMARY OF THE DISCLOSURE

[0007] The invention provides bottlebrush polymers comprising a monodisperse polymer backbone and defined bottlebrush side chains comprising a polypeptide, polypeptoid or polypept(o)ide (polypeptide-co-polypeptoid copolymer). The invention also provides branched bottlebrush polymers (e.g. macromolecules) comprising three or more bottlebrush polymer moieties linked to a branching unit.

[0008] Typically, the macromolecules and bottlebrush polymers of the invention are produced by the combination of solid phase peptide synthesis of the polymer backbone and controlled living ring opening polymerization for the bottlebrush side chains. In particular, each side chain segment tethered to the polymer backbone may be introduced by sequential deprotection, and subsequent polymerization, followed by differential end-capping on individual side chain polymers to allow the conversion of any specific sequence of the polymer backbone to functional patches on the surface of the bottlebrush polymers. These patches enable specific ligand attachment for the desired specific interactions with other molecules or surfaces.

[0009] Without wishing to be bound by theory, it is thought that the provision of the macromolecules and bottlebrush polymers of the invention allows for precise control of size, shape and surface functionality, yielding uniform nanostructures.

[0010] Additionally, without wishing to be bound by theory, it is thought that the use of a polypeptide, polypeptoid or polypept(o)ide (e.g. polysarcosine) in side chains produces nanoparticles with non-immunogenic, non-toxic, protein-resistant surface.

[0011] Furthermore, the macromolecules and bottlebrush polymers of the invention demonstrate additional advantageous properties, such as good thermal stability. This allows them to be useful in environments where cold storage is not available.

[0012] In a first aspect of the present invention, there is provided bottlebrush polymers, comprising: a monodisperse polymer backbone; and defined bottlebrush side chains; wherein the polymer backbone is a polypeptide comprising amino acid residues with an amine moiety on the sidechain of each amino acid residue; wherein each of the defined bottlebrush sidechains is attached to the polymer backbone at the amine moiety of each of the respective amino acid residues; and wherein the defined bottlebrush sidechains comprise at least one block of polypeptide, polypeptoid or polypept(o)ide, (for example at least two blocks) wherein, in eachblock of polypeptide, polypeptoid or polypept(o)ide, the polypeptide, polypeptoid or polypept(o)ide is functionalised proximate to the end of its chain with a reactive group or ligand, wherein when there are at least two blocks the adjacent blocks of the at least two blocks do not comprise the same reactive group or ligand.

[0013] In a second aspect of the present invention, there is provided a (branched) macromolecule comprising three or more bottlebrush polymers as defined in the first aspect, wherein at least three of the three or more bottlebrush polymers are covalently linked to one another via the C-terminus or N-terminus of each bottlebrush polymer.

[0014] In a third aspect of the present invention, there is provided monodisperse bottlebrush polymers of formula (I): CH3C(O)-[Z]r-NH2(I) wherein: r is 1-20, and each instance of Z is:wherein: R1zis independently for each Z selected from H and C1-4alkyl; R2zis independently for each Z selected from H and C1-4alkyl; R3zis independently for each Z selected from H and C1-4 alkyl; Rais independently for each Z selected from H and CH3; Rbis independently for each Z selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andL is independently for each Z selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; n is independently for each Z selected from 5-100;p is independently at each occurrence selected from 0-100; and X is independently at each occurrence selected from a reactive group or a ligand, with the proviso that the X moieties on adjacent Z groups are different; or a salt or solvate thereof.

[0015] In embodiments of the third aspect, y is 2, 3, 4, or 5.

[0016] In a fourth aspect of the present invention, there is provided a macromolecule having a structure of formula (II-a) or (II-b):wherein G comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue, wherein each of Y1, Y2, Y3and Y4is independently a bottlebrush polymer moiety of formula (Ib) or (Ic): -C(O)-[Z]r-NH2(Ib) CH3C(O)-[Z]r-NH- (Ic), wherein each of Y1, Y2, Y3and Y4is independently attached to G via the terminal - C(O)- or terminal -NH- group of formula (Ib) or (Ic), wherein: each r is independently an integer selected from 1-20; and each instance of Z is:wherein: R1zis independently for each Z selected from H and C1-4 alkyl; R2zis independently for each Z selected from H and C1-4 alkyl;R3zis independently for each Z selected from H and C1-4 alkyl; Rais independently for each Z selected from H and CH3; Rbis independently for each Z selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andL is independently for each Z selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; n is independently for each Z selected from 5-100; p is independently at each occurrence selected from 0-100; y is 2, 3, 4 or 5; and X is independently at each occurrence selected from a reactive group or a ligand, with the proviso that the X moieties on adjacent Z groups are different; or a salt or solvate thereof

[0017] In a fifth aspect of the present invention, there is provided a method of preparing a bottlebrush polymer, comprising: (a) forming a polymer backbone by extending a polypeptide comprising protected amino acid residues, the formed polypeptide backbone comprising at least one block of the protected amino acid residues, wherein in each specific block the protected amino acids: i) comprise an equivalent protecting group; and ii) when at least two blocks of protected amino acid residues are present, the equivalent protecting group is orthogonal to at least the protecting group of any adjacent specific block; (b) forming a functionalised specific block by: i) deprotecting the protected amino acid residues of a first of the specific blocks, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; wherein, when at least two blocks of protected amino acid residues are present, the method further comprises (c) forming a subsequent functionalised specific block by: i) deprotecting the protected amino acid residues of a second specific block, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i); ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; andiii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0018] In a sixth aspect of the present invention, there is provided a method of preparing a macromolecule comprising three or more bottlebrush polymers, comprising: (a) forming a polymer backbone by extending a branched polypeptide comprising three or more branches of protected amino acid residues, the formed branched polypeptide backbone comprising at least one block of the protected amino acid residues in each branch of the branched polypeptide backbone, wherein in each specific block of each branch of branched polypeptide backbone, the protected amino acids: i) comprise an equivalent protecting group; and ii) when at least two blocks of protected amino acid residues are present, the equivalent protecting group is orthogonal to at least the protecting group of any adjacent specific block; and (b) forming a functionalised specific block in each branch of the branched polypeptide by: i) deprotecting the protected amino acid residues of a first of the specific blocks in each branch, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; wherein, when at least two blocks of protected amino acid residues are present in each of the branches of the branched polypeptide, the method further comprises (c) forming a subsequent functionalised specific block in each branch of the branched polypeptide by: i) deprotecting the protected amino acid residues of a second specific block in each branch, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i); ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0019] In a seventh aspect of the present invention, there is provided a method of preparing a bottlebrush polymer, comprising: (a) forming a polymer backbone of formula (II) by extending a polypeptide comprising protected amino acid residues: CH3C(O)-[Z’]r-NH-X’’ (III) wherein: r is 1-20 and each instance of Z’ is:wherein R1zis independently for each Z’ selected from H and C1-4 alkyl; R2zis independently for each Z’ selected from H and C1-4 alkyl; Rais independently for each Z’ selected from H and CH3; Rbis independently for each Z’ selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2 andn is independently for each Z’ selected from 5-100; L is independently for each Z’ selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; X’ is independently for each Z’ is a protecting group, with the proviso that the X’ protecting group for each Z’ is an orthogonal protecting group to the X’ of any adjacent Z’ and X’’ is a solid support; or a salt or solvate thereof; (b) forming a functionalised specific block by: i) removing a first X’, thereby deprotecting the amino acids in at least a first Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block by:i) removing a second X’, that comprises an orthogonal protecting group to the first X’, thereby deprotecting the amino acids in at least a second Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0020] In embodiments of the seventh aspect, y is 2, 3, 4, or 5.

[0021] In an eighth aspect of the present invention, there is provided a method of forming a bottlebrush polymer with a longer polymer backbone, comprising: (a) obtaining at least two bottlebrush polymer of the first or third aspect, or performing the method of the fifth or seventh aspect at least twice to obtain at least two bottlebrush polymers; and (b) ligating the polymer backbones of the at least two bottlebrush polymers.

[0022] In a ninth aspect of the present invention, there is provided a method of preparing a macromolecule comprising (a) forming a polymer backbone of formula (IVa) or (IVb) by extending a branched polypeptide comprising protected amino acid residues:wherein G’ comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue, wherein each of Y1’, Y2’, Y3’and Y4’is independently a moiety of formula (Ib’) or (Ic’): -C(O)-[Z’]r-NH2 (Ib’) CH3C(O)-[Z‘]r-NH- (Ic’), wherein each of Y1’, Y2’, Y3’and Y4’is independently attached to G’ via the terminal -C(O)- or terminal -NH- group of formula (Ib’) or (Ic’), wherein: each instance of r is independently an integer selected from 1-20 and each instance of Z’ is:wherein R1zis independently for each Z’ selected from H and C1-4 alkyl; R2zis independently for each Z’ selected from H and C1-4 alkyl; Rais independently for each Z’ selected from H and CH3; Rbis independently for each Z’ selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2 andn is independently for each Z’ selected from 5-100; y is 2, 3, 4, or 5; L is independently for each Z’ selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; X’ is independently for each Z’ is a protecting group, with the proviso that the X’ protecting group for each Z’ is an orthogonal protecting group to the X’ of any adjacent Z’; or a salt or solvate thereof wherein the branched polypeptide is attached to a solid support where chemically possible; (b) forming a functionalised specific block in each branch of the branched polypeptide by: i) removing a first X’ in each branch, thereby deprotecting the amino acids in at least a first Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing a second X’ in each branch, that comprises an orthogonal protecting group to the first X’, thereby deprotecting the amino acids in at least a second Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; andiii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0023] In a tenth aspect of the present invention, there is provided a bottlebrush polymer obtainable by or obtained by the methods of the fifth, seventh and eighth aspects.

[0024] In an eleventh aspect of the present invention, there is provided a polymer obtainable by or obtained by the methods of the sixth or ninth aspects.

[0025] In a twelfth aspect of the present invention, there is provided a bottlebrush polymer of the first, third or tenth aspect for use as a medicament.

[0026] In a thirteenth aspect of the present invention, there is provided a macromolecule of the second, fourth or eleventh aspect for use as a medicament. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 shows the production of the polymer backbones of bottlebrush polymers of the invention via solid phase (flow) synthesis. Orthogonal protecting group patterns enable stepwise controlled graft polymerization of different brush patches. Figure 2 shows the synthesis of an exemplary bottlebrush polymer of the invention via solid phase synthesis, where the brush polymer is a tri-block polymer in which the first and third blocks are the same and the second block is different (A-B-A). a) Solid phase synthesis of the sequence defined polymer backbone with a Fmoc-based protocol. b) LCMS trace showing the successful synthesis of sequence defined, specific [Lys(Alloc)]10Lys40[Lys(Alloc)]10peptide. c) ‘Grafting-from’ polymerization of sarcosine and associated end-capping strategy using pentafluorophenyl esters, followed by Alloc removal, second polymerization and differential end- decoration. d) The removal of Alloc from the polymer backbone via Tsuji-Trost reaction, as shown by1H NMR. e) Comparative weight distribution analysis of a sequence defined triblock brush polymer of the invention compared to mono- or triblock brushes produced with other technologies, defined in terms of the polydispersity index (PDI). Figure 3 shows the synthesis of a bottlebrush polymer of the invention via solid phase synthesis, where the brush polymer is a tri-block polymer having three different blocks (A-B-C). Figure 4 shows exemplary orthogonal protecting group schemes and peptide synthesis resins that may be employed in the preparation of the bottlebrush polymers of the invention. a) Lysine protecting groups that can be removed orthogonally to each other. b) Examples of peptide synthesis resins that require diverse conditions for peptide release.Figure 5 shows examples of conjugation strategies that enable access to longer polymer backbones. Figure 6 shows the chemical structure of an exemplary bottlebrush polymer of the invention and a corresponding LCMS trace of said polymer. Figure 7 shows the measured homogeneity of an exemplary sequence defined triblock polypeptide backbone transferred into a bottlebrush polymer of the invention (having three distinct domains on the particle surface) compared to that of a homo polymer brush and a triblock polypeptide backbone synthesized by conventional NCA polymerization. As depicted, the brush of the invention achieves a lower polydispersity index than those of the prior art. Figure 8 shows dynamic light scattering analysis of a Y-shaped peptobody brush of the invention compared to a aPD-L1 antibody. As depicted, both the hydrodynamic diameter and the polydispersity index of the peptobody of the invention were analogous to that of the known antibody. DETAILED DESCRIPTION

[0028] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers, or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0029] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0030] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and whichare open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. DEFINITIONS

[0031] The following explanations of terms and methods are provided to better describe the present disclosure and to guide those of ordinary skill in the art in the practice of the present disclosure

[0032] The term “alkyl” refers to a straight or branched hydrocarbon chain that is fully saturated.

[0033] The term “monodisperse” in relation to polymers of the disclosure refers to uniform bottlebrush polymers, in which all polymeric nanoparticles have the same size and shape. Variation in size and width may be less than 20% of the average. The dispersity of the bottlebrush polymers may be determined by measurement of the polydispersity index (PDI or Ð) by size exclusion chromatography (relative to PEG or protein standards or combination of absolute methods). In the context of the disclosure, a polymer or portion of a polymer may be described as ‘monodisperse’ if it has a PDI of less than 1.4, less than 1.2 or less than 1.1. The monodispersity of a sample may be confirmed by performing microscopy on a sample of at least 100 particles and measuring the PDI of the sample. The PDI is calculated by dividing the weight average molecule weight of the polymer (Mw) by the number average molecule weight of the polymer (Mn).

[0034] The term “monodisperse” in relation to the polymer backbone of a bottlebrush polymer refers to uniform polymer backbones, in which substantially all of (e.g.90% or more, 95% or more of or 99% or more of) the polymer backbones have substantially the same number of amino acid residues. “Substantially the same” in this context may mean + / - 0 to 3 amino acid residues, for example + / - 0, 1, 2, or 3 amino acid residues.

[0035] The term “sequence defined” in relation to the polypeptide backbone of the disclosure refers to a specific sequence and defined molecular weight of the polypeptide derived by solid phase chemistry. These properties are commonly ensured by the coupling protocol, and the sequences may be confirmed using analytical techniques, such as mass spectrometry, NMR, electron microscopy, or a combination thereof.

[0036] The term “protecting group” as used herein is given its ordinary meaning which is readily understandable to those of skill in the art. It is used herein to refer to a group suitable for protecting an amino acid side chain. Exemplary protecting groups which may be employed include: N-Fluorenylmethoxycarbonyl (Fmoc), 2-(4-Nitrophenylsulfonyl)ethoxycarbonyl (Nsc), 1- (4,4-Dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde), 1-(4,4-dimethyl-2,6-dioxocyclohex-1- ylidene)isovaleryl (ivDde), allyloxycarbonyl (Alloc), benzyloxycarbonyl (Cbz), phthalimide, sulfonamide, 2,4,6-Triisopropylsulfonamide (Trs), tert-butoxycarbonyl (Boc), 2-(4-biphenylyl)-2- propyloxycarbonyl (Bpoc), monomethoxytrityl (MMT), dimethoxytrityl (DMT), 2,4-Dimethoxybenzyl (DMB), N-Diphenylmethyleneamine, 2-(Trimethylsilyl)-ethoxycarbonyl (Teoc), 2-Trimethylsilylethoxymethyl (SEM), 6-nitroveratryloxycarbonyl (NVOC), 2,2’-bis(2- nitrophenyl)ethoxycarbonyl (diNPEOC), benzoyl, benzyl, tetrahydropyran (THP), dimethoxybenzyl, monomethoxymethyl (MOM), acetyl, Levulinate (Lev), 2,2,2- Trichloroethoxycarbonyl (Troc), tert-Butyldimethylsilyl (TBDMS), tert-Butyldiphenylsilyl (TBDPS), Trimethylsilyl (TMS), Triisopropylsilyl (TIPS), Pivaloyl (Pv), allyl, and 4-Azido-3-chlorobenzyl (ClAzb).

[0037] The term “orthogonal” in relation to protecting groups means that each said protecting group is removed using reaction conditions that do not remove the other said protecting groups.

[0038] The term “equivalent protecting group” refers to a protecting group that can be removed using the same deprotecting chemistry used for the removal of another protecting group.

[0039] The term “peptide” refers to polymer a chain of amino acids linked by peptide bonds. The peptide may also comprise one or more non-amino acid building blocks and / or non-peptide linkages. Peptides are distinguished from proteins or polypeptides on the basis of size, and comprise no more than 50 amino acid residues.

[0040] The term “peptoid” refers to a chain of N-substituted glycines linked by peptide bonds, wherein the nitrogen of each glycine residue is substituted with a side chain. The peptoid may also comprise one or more non-glcyine building blocks and / or non-peptide linkages.

[0041] The term “amino acid” refers to an organic compound composed of amine and carboxylic acid functional groups and optionally a side-chain specific to each amino acid. The amino acids may be proteinogenic or non-proteinogenic amino acids. The term amino acid typically refers to α-amino acids, i.e. having the generic formula H2NCHRC(O)OH. The amino acids may also refer to beta-, gamma-, and delta-amino acids, i.e. that contain multiple carbon atoms between the amine and the carboxylic acid.

[0042] The term “amino acid residue” in the context of the invention refers to an individual amino acid that has been attached to one or more other moieties via the N-terminus and / or C- terminus of the amino acid.

[0043] The term “polypeptide” refers to a polymeric chain of amino acids linked by peptide bonds. The polypeptide may also comprise one or more non-amino acid building blocks and / or non-peptide linkages. Polypeptides typically comprises more than 50 amino acid residues.

[0044] The term “polypeptoid” refers to a polymeric chain of N-substituted glycines linked by peptide bonds. The polypeptoid may also comprise one or more non-glycine building blocks and / or non-peptide linkages. Polypeptoids typically comprises more than 50 amino acid residues.

[0045] The term “polypept(o)ide” as used herein refers to a copolymer comprising peptides and peptoids.

[0046] The term “macromolecule” as used herein may refer to a polymeric structure comprising a plurality of smaller polymers (e.g. bottlebrush polymers of the invention) attached to one another. For example, the macromolecule may be a branched bottlebrush polymer, i.e. comprising a plurality of bottlebrush polymer branches attached to one another at one or more branching points. The branching points may comprise a core moiety to which 3 or more (e.g.3, 4, 5, or more) smaller moieties (such as bottlebrush polymers described herein) are attached.

[0047] The term “solid support,” as used herein, refers to a material that is substantially insoluble in a selected solvent system, or which can be readily separated (e.g., by precipitation) from a selected solvent system in which it is soluble. Solid supports of use in the present disclosure may be any solid support that is useful in solid-phase peptide synthesis (SPPS).

[0048] The term “reactive group” refers to a group that is capable of reacting with another chemical group to form a covalent bond, i.e. is covalently reactive under suitable reaction conditions, and generally represents a point of attachment for another substance. As used herein, reactive groups refer to chemical moieties generally found in biological systems and that react under normal biological conditions. The reactive group is a moiety (such as an amine, an azide, a carboxylic acid, an alkyne, an activated alkyne, phosphite, phosphine, thiol, transcyclooctene, and tetrazine) on the bottlebrush side chain of a bottlebrush polymer of the invention that is capable of chemically reacting with a functional group on a different compound to form a covalent linkage. Reactive groups generally include nucleophiles, electrophiles and photoactivatable groups.

[0049] The term ‘click chemistry’ refers to the Huisgen cycloaddition or the 1,3- dipolar cycloaddition between an azide and a terminal alkyne to form a 1,2,4-triazole.

[0050] The term ‘Pictet-Spingler’ refers to the reaction in which a β-arylethylamine undergoes condensation with an aldehyde or ketone followed by ring closure

[0051] The term ‘native chemical ligation’ refers to the transthioesterification reaction between an ionised thiol group of an N-terminal cysteine residue of a first peptide with a C-terminal thioester of a second peptide, resulting in the formation of a thioester-linked intermediate, which rapidly rearranges by an intramolecular S,N-acyl shift to produce a peptide bond between the first peptide and second peptide.

[0052] As use herein, the term “proximate to the end of its chain” may refer to a position 0, 1 or 2 residues away from the terminal residue of the chain. It may be that the term “proximate to the end of its chain” may refer to being at the end of the chain, i.e. on the terminal residue of the chain.

[0053] As the skilled person would appreciate, any alkyl, cycloalkyl, heterocycloalkyl, phenyl, heteroaryl, or alkylene referred to herein may be optionally substituted, where chemically possible, by 1 to 4 substituents which are each independently selected at each occurrence fromthe group consisting of: =O; =NRa, =NORa, C1-C4-alkyl, halo, nitro, cyano, C1-C4-haloalkyl, C2- C4-alkenyl, C2-C4-alkynyl, NRaRb, S(O)2Ra, S(O)Ra, S(O)(NRa)Ra, S(O)2NRaRa, CO2Ra, C(O)Ra, CONRaRa, ORaand SRa; wherein Rais independently selected from H and C b 1-C4-alkyl; and R is independently selected from H, C1-C4-alkyl, C(O)-C1-C4-alkyl and S(O)2-C1-C4-alkyl. BOTTLEBRUSH POLYMERS

[0054] In the first aspect, the invention provides bottlebrush polymers, comprising: a monodisperse polymer backbone; and defined bottlebrush side chains; wherein the polymer backbone is a polypeptide comprising amino acid residues with an amine moiety on the sidechain of each amino acid residue; wherein each of the bottlebrush sidechains is attached to the polymer backbone at the amine moiety of each of the respective amino acid residues; and wherein the defined bottlebrush sidechains comprise at least two blocks of polypeptide, polypeptoid or polypept(o)ide wherein, in each block of polypeptide, polypeptoid or polypept(o)ide, the polypeptide, polypeptoid or polypept(o)ide is functionalised proximate to the end of its chain with a reactive group or ligand, wherein adjacent blocks of the at least two blocks do not comprise the same reactive group or ligand.

[0055] In embodiments, each of the at least two blocks of polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4alkylglycine), poly(glycine), poly(N-C1-4alkylalanine), poly(alanine), (protected) poly(lysine), (protected) poly(glutamic acid) or esters or amides thereof, or copolymers thereof. In embodiments, each of the at least two blocks of polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4alkylglycine) and poly(glycine). In embodiments, each of the at least two blocks of polypeptide, polypeptoid or polypept(o)ide is poly(N-C1-4alkylglycine).

[0056] In embodiments, the poly(N-C1-4alkylglycine) is selected from poly(N-methylglycine), poly(N-ethylglycine) or poly(N-isopropylglycine). In embodiments, the poly(N-C1-4alkylglycine) is selected from poly(N-methylglycine) and poly(N-ethylglycine). In embodiments, the poly(N-C1-4alkylglycine) is poly(N-methylglycine).

[0057] In embodiments, the poly(N-C1-4 alkylalanine) is selected from poly(N-methylalanine), poly(N-ethylalanine) or poly(N-isopropylalanine). In embodiments, the poly(N-C1-4 alkylalanine) is selected from poly(N-methylalanine) and poly(N-ethylalanine). In embodiments, the poly(N- C1-4 alkylalanine) is poly(N-methylalanine).

[0058] In embodiments, the polymer backbone substantially comprises (or consists of) amino acid residues with an amine moiety on the sidechain of each of the respective amino acid residues. The sidechain may be interrupted up to several times by at least one amino acid residue which lacks an amino moiety on its sidechain. For the avoidance of doubt, the defined bottlebrush sidechains attach to the polymer backbone at the amine moiety of each of therespective amino acid residues such that an amide bond is formed between the amine moiety and the bottlebrush sidechain.

[0059] In embodiments, the amine moiety on the sidechain is a primary or secondary amine.

[0060] In embodiments, the amino acid residues with an amine moiety on the sidechain are all the same.

[0061] In embodiments, the amino acid residues with an amine moiety on the sidechain are selected from lysine, ornithine, diaminobutyric acid, and diaminopropionic acid.

[0062] In embodiments, each of the amino acid residues with an amine moiety on the sidechain is lysine.

[0063] In embodiments, the at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycine, alanine, protected lysine, protected or unprotected glutamic acid, protected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine. Where the at least one amino acid is protected, the at least one amino acid is protected by a protecting group as defined herein. In embodiments, the at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycine, alanine.

[0064] It may be that the at least one amino acid residue which lacks an amino moiety on its sidechain comprises from 1 to 10 said amino acids.

[0065] In embodiments, the polypeptide, polypeptoid or polypept(o)ide of the bottlebrush sidechain comprises a degree of polymerisation (DP) of about 5 to about 100. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 10 to about 60. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 30 to about 50. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 35 to about 45. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 20 to about 40. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 20 to about 30. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 30. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 20. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 10. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 40. In embodiments, the polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 25.

[0066] In embodiments, the polymer backbone comprises a polypeptide that is no more than about 300 amino acids in length, no more than about 250 amino acids in length, no more than about 200 amino acids in length, or no more than about 150 amino acids in length.

[0067] In embodiments, the polymer backbone comprises a polypeptide that is at least 10 amino acids in length, at least 15 amino acids in length, at least 20 amino acids in length, at least 25 amino acids in length, or at least 30 amino acids in length.

[0068] In embodiments, the polymer backbone comprises a polypeptide that is from about 10 to about 300 amino acids in length. For example, the polymer backbone may be from about 20 to about 200 amino acids in length, or from about 30 to about 150 amino acids in length.

[0069] In embodiments, the bottlebrush polymers have a monodisperse polymer backbone such that substantially all of (e.g. at least 98% or at least 99% of) the bottlebrush polymers have substantially the same number of (e.g. the mode No.+ / - 0, 1, 2 or 3) amino acid residues.

[0070] In embodiments, each reactive group is independently selected from a nucleophile, an electrophile and a photoactivatable group.

[0071] In embodiments, each reactive group is independently selected from a moiety comprising an amine, an azide, a carboxylic acid, an alkyne, an activated alkyne, phosphite, phosphine, thiol, transcyclooctene, and tetrazine.

[0072] In embodiments, each ligand is independently selected from an amino acid, a peptide, a protein, a polysaccharide, a nucleoside, a nucleotide, an oligonucleotide, a nucleic acid, a hapten, a psoralen, a drug, a hormone, a vitamin, a lipid, a lipid assembly (such as a biological membrane or liposome), a synthetic polymer, a polymeric nanoparticle or microparticle, a biological cell, a virus derived component (such as a viral derived protein, nucleic acid, lipid or carbohydrate, or combination thereof), a chromophore, a fluorophore, a dye, a radioisotope and a capping group (e.g. an acetyl group).

[0073] In an aspect, the invention provides monodisperse bottlebrush polymers of formula (I): CH3C(O)-[Z]r-NH2 (I) wherein: r is 1-20, and each instance of Z is:wherein: R1zis independently for each Z selected from H and C1-4alkyl; R2zis independently for each Z selected from H and C1-4alkyl; R3zis independently for each Z selected from H and C1-4alkyl; Rais independently for each Z selected from H and CH3; Rbis independently for each Z selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andL is independently for each Z selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; n is independently for each Z selected from 5-100; p is independently at each occurrence selected from 0-100; y is 2, 3, 4 or 5; and X is independently at each occurrence selected from a reactive group or a ligand, with the proviso that the X moieties on adjacent Z groups are different; or a salt or solvate thereof.

[0074] In embodiments, monodisperse means that, for the population of bottlebrush polymers, for each instance of Z in substantially all of (or all of) the population, n is + / - 0, 1, 2 or 3 from the mode, preferably n is + / - 0 or 1 from the mode; and / or for the population of bottlebrush polymers, in substantially every one of (or in every one of) the population the sum total of all of the n for each instance of Z for said one of the population is + / - 0, 1, 2 or 3 from the mode, preferably + / - 0 or 1 from the mode.

[0075] In embodiments, r is 2-20. For example, r may be 2-15, 2-10, 2-8, or 2-6. For example, r may be 3-20, 3-15, 3-10, 3-8, or 3-6. r may be 4-20, 4-15, 4-10, 4-8, or 4-6.

[0076] r may be 2. r may be 3. r may be 4. r may be 5. r may be 6. r may be 7. r may be 8. r may be 9. r may be 10. r may be 11. r may be 12. r may be 13. r may be 14. r may be 15. r may be 16. r may be 17. r may be 18. r may be 19. r may be 20.

[0077] In embodiments, R1zis C1-4 alkyl, e.g. methyl. In embodiments, R1zis H.

[0078] In embodiments, R2zis C1-4 alkyl, e.g. methyl. In embodiments, R2zis H.

[0079] In embodiments, R3zis C1-4 alkyl, e.g. methyl. In embodiments, R3zis H.

[0080] In embodiments, the compound of formula (I) is a compound of formula (I-a)::wherein: each of R1, R2, R3, R4and R5is independently selected from H and C1-4 alkyl; each of R6, R7, R8, R9and R10is independently selected from H and C1-4 alkyl; each of R11, R12, R13, R14and R15are independently selected from H and C1-4 alkyl; each Rais H or CH3; each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach of L1, L2, L3and L4is independently selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; m is 2, 3, 4, or 5; each of n1and n2is independently selected from 5-100; each of n3, n4and n5are independently selected from 0-100; each of p1, p2, p3, p4and p5are independently selected from 5 to 100; each of A, B, C, D and E are independently selected from a reactive group or a ligand, with the proviso that A and B are different; or a salt or solvate thereof.

[0081] In embodiments, the compound of formula (I) is a compound of formula (I-a1):wherein each of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5is 0. It may be that n4and n5are 0.

[0082] In embodiments, the compound of formula (I) is a compound of formula (I-a2):wherein each of R11, R12, R13, R14, R15, Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5is 0. It may be that n4and n5are 0.

[0083] In embodiments, the compound of formula (I) is a compound of formula (I-a3):wherein each of R11, R12, R13, R14, R15, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0084] In embodiments, the compound of formula (I) is a compound of formula (I-a4):wherein each of R1, R2, R3, R4, R5, Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0085] In embodiments, the compound of formula (I) is a compound of formula (I-a5):and E are as defined in formula (I-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0086] In embodiments, the compound of formula (I) is a compound of formula (I-a6):wherein each of R6, R7, R8, R9, R10, Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0087] In embodiments, the compound of formula (I) is a compound of formula (I-a7):wherein each of R6, R7, R8, R9, R10, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0088] In embodiments, the compound of formula (I) is a compound of formula (I-a8):wherein each of Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5is 0. It may be that n4and n5are 0.

[0089] In embodiments, the compound of formula (I) is a compound of formula (I-a9):Wherein each of L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0090] In embodiments, the compound of formula (I) is a compound of formula (I-a10):wherein each of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, L1, L2, L3, L4, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5is 0. It may be that n4and n5are 0.

[0091] In embodiments, the compound of formula (I) is a compound of formula (I-a11):wherein each of L1, L2, L3, L4, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-a). It may be that n5is 0. It may be that n4and n5are 0.

[0092] In embodiments, the compound of formula (I) is a compound of formula (I-a12):p3, A, B and C are as defined in formula (I-a), wherein A and C are the same.

[0093] In embodiments, R1is C1-4 alkyl, e.g. methyl. In embodiments, R1is H.

[0094] In embodiments, R2is C1-4 alkyl, e.g. methyl. In embodiments, R2is H.

[0095] In embodiments, R3is C1-4 alkyl, e.g. methyl. In embodiments, R3is H.

[0096] In embodiments, R4is C1-4 alkyl, e.g. methyl. In embodiments, R4is H.

[0097] In embodiments, R5is C1-4 alkyl, e.g. methyl. In embodiments, R5is H.

[0098] In embodiments, each of R1, R2, R3, R4and R5is H or methyl. In embodiments, each of R1, R2, R3, R4and R5is H.

[0099] In embodiments, R6is C1-4 alkyl, e.g. methyl. In embodiments, R6is H.

[0100] In embodiments, R7is C1-4 alkyl, e.g. methyl. In embodiments, R7is H.

[0101] In embodiments, R8is C1-4 alkyl, e.g. methyl. In embodiments, R8is H.

[0102] In embodiments, R9is C1-4 alkyl, e.g. methyl. In embodiments, R9is H.

[0103] In embodiments, R10is C1-4 alkyl, e.g. methyl. In embodiments, R10is H.

[0104] In embodiments, each of R6, R7, R8, R9and R10is H or methyl. In embodiments, each of R6, R7, R8, R9and R10is H.

[0105] In embodiments, R11is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R11is H.

[0106] In embodiments, R12is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R12is H.

[0107] In embodiments, R13is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R13is H.

[0108] In embodiments, R14is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R14is H.

[0109] In embodiments, R15is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R15is H.

[0110] In embodiments, each of R11, R12, R13, R14and R15is independently selected from methyl and ethyl.

[0111] In embodiments, each of R11, R12, R13, R14and R15is ethyl or methyl. In embodiments, each of R11, R12, R13, R14and R15is methyl.

[0112] In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H.

[0113] In embodiments, each of R1, R2, R3, R4and R5is H or methyl, and each of R11, R12, R13, R14and R15is ethyl or methyl. In embodiments, each of R1, R2, R3, R4and R5is H or methyl, and each of R11, R12, R13, R14and R15is H. In embodiments, each of R1, R2, R3, R4and R5is H, and each of R11, R12, R13, R14and R15is methyl.

[0114] In embodiments, each of R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is ethyl or methyl. In embodiments, each of R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is H. In embodiments, each of R6, R7, R8, R9and R10is H, and each of R11, R12, R13, R14and R15methyl.

[0115] In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is ethyl or methyl. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is H. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is methyl. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H, and each of R11, R12, R13, R14and R15is methyl.

[0116] In embodiments, each Rais H. In embodiments, each Rais CH3.

[0117] In embodiments, each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rbis independently selected from H or CH3. In embodiments, each Rbis H or CH3. In embodiments, each Rbis H.

[0118] In embodiments, each Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rcis independently selected from H or CH3. In embodiments, each Rcis H or CH3. In embodiments, each Rcis H.

[0119] In embodiments, each Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rdis independently selected from H or CH3. In embodiments, each Rdis H or CH3. In embodiments, each Rdis H.

[0120] In embodiments, each Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Reis independently selected from H or CH3. In embodiments, each Reis H or CH3. In embodiments, each Reis H.

[0121] In embodiments, each Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rfis independently selected from H or CH3. In embodiments, each Rfis H or CH3. In embodiments, each Rfis H.

[0122] In embodiments, each instance of Ra, Rb, Rc, Rd, Reand Rfis H or CH3. In embodiments, each instance of Ra, Rb, Rc, Rd, Reand Rfis H.

[0123] In embodiments, L1 is a bond. In alternative embodiments, L1 is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0124] Where L1 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0125] In embodiments, where present, L2 is a bond. In alternative embodiments, L2 is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0126] Where L2is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0127] In embodiments, where present, L3is a bond. In alternative embodiments, L3is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0128] Where L3is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0129] In embodiments, where present, L4is a bond. In alternative embodiments, L4is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0130] Where L4is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0131] In embodiments, if present, each of L2, L3 and L4 is a bond. In alternative embodiments, if present, one, two or three of L2, L3 and L4 is at least one amino acid residue which lacks an amino moiety on its sidechain. The at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids.

[0132] In embodiments, any of said at least one amino acid which lacks an amino moiety on its sidechain is selected from glycine, alanine, protected lysine, protected or unprotected glutamic acid, protected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine. Where the at least one amino acid is protected, the at leastone amino acid is protected by a protecting group as defined herein. In embodiments, the at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycine, alanine..

[0133] In embodiments, m is 2. In embodiments, m is 3. In embodiments, m is 4. In embodiments, m is 5.

[0134] In embodiments, m is 2, 3 or 4, and / or each Rb, Rc, Rd, Reand Rfis H or CH3. In embodiments, m is 2, 3 or 4, and / or each Rb, Rc, Rd, Reand Rfis H. In embodiments, m is 4, and / or each Rb, Rc, Rd, Reand Rfis H.

[0135] In embodiments, n1is selected from 5 to 90, from 5 to 80, from 5 to 70, from 5 to 60, from 5 to 50, from 5 to 40, from 5 to 30, from 5 to 20, or from 5 to 10.

[0136] In embodiments, n2is selected from 5 to 90, from 5 to 80, from 5 to 70, from 5 to 60, from 5 to 50, from 5 to 40, from 5 to 30, from 5 to 20, or from 5 to 10.

[0137] In embodiments, n3is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n3 is 0.

[0138] In embodiments, n4is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n4is 0.

[0139] In embodiments, n5is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n5is 0.

[0140] In embodiments, n4and n5are 0. In embodiments, n3, n4and n5are 0.

[0141] In embodiments, each of p1, p2, p3, p4and p5are independently selected from 10 to 60. In embodiments, each of p1, p2, p3, p4and p5are independently selected from 30 to 50. In embodiments, each of p1, p2, p3, p4and p5are independently selected from 35 to 45.

[0142] Each of A, B, C, D and E are independently selected from a reactive group or a ligand, with the proviso that A and B are different.

[0143] In embodiments, each of A, B, C, D and E are different. In embodiments, at least two of A, C, D and E are the same.

[0144] In embodiments, A, B, C and D are different. In embodiments, A and C are the same, and / or B and D are the same.

[0145] In embodiments, A, B and C are different. In embodiments, A and C are the same.

[0146] In embodiments, each reactive group is independently selected from a nucleophile, an electrophile and a photoactivatable group. For example, each reactive group may be independently selected from a moiety comprising an amine, an azide, a carboxylic acid, an alkyne, an activated alkyne, phosphite, phosphine, thiol, transcyclooctene, and tetrazine.

[0147] In embodiments, each ligand is independently selected from an amino acid, a peptide, a protein, a polysaccharide, a nucleoside, a nucleotide, an oligonucleotide, a nucleic acid, a hapten, a psoralen, a drug, a hormone, a vitamin, a lipid, a lipid assembly (such as a biologicalmembrane or liposome), a synthetic polymer, a polymeric nanoparticle or microparticle, a biological cell, a virus derived component (such as a viral derived protein, nucleic acid, lipid or carbohydrate, or combination thereof), a chromophore, a fluorophore, a dye, a radioisotope and a capping group (e.g. an acetyl group).

[0148] In embodiments, the bottlebrush polymers have a polydispersity index (Ð) of less than about 1.4. The bottlebrush polymers may have a polydispersity index (Ð) of less than about 1.2. The bottlebrush polymers may have a polydispersity index (Ð) of less than about 1.1. MACROMOLECULES

[0149] In another aspect, the invention provides a (branched) macromolecule comprising three or more bottlebrush polymers of the first aspect, wherein at least three of the three or more bottlebrush polymers are covalently linked to one another via the C-terminus or N- terminus of each bottlebrush polymer.

[0150] For the avoidance of doubt, as the bottlebrush polymers in the macromolecule are covalently linked to one another via their C-terminus or N-terminus, the bound structures of the bottlebrush polymers in the macromolecules may differ from the unbound structures of said bottlebrush polymers of the first aspect in that the bound structures will include a -C(O)-R at the C-terminus or a -NH-R at the N-terminus (where R is the rest of the bottlebrush polymer structure), i.e. in which the methyl group or the like on the C-terminus or an H atom on the N- terminus has been displaced to facilitate covalent binding with another moiety in the macromolecule.

[0151] In embodiments, the macromolecule comprises four or more bottlebrush polymers linked together. In embodiments, the macromolecule comprises five or more bottlebrush polymers linked together. In embodiments, the macromolecule comprises six or more bottlebrush polymers linked together. In embodiments, the macromolecule comprises seven or more bottlebrush polymers linked together. In embodiments, the macromolecule comprises eight or more bottlebrush polymers linked together.

[0152] In embodiments, at least four of the bottlebrush polymers are covalently linked to one another via the C-terminus or N-terminus of each bottlebrush polymer. In embodiments, at least five of the bottlebrush polymers are covalently linked to one another via the C-terminus or N- terminus of each bottlebrush polymer. In embodiments, at least six of the bottlebrush polymers are covalently linked to one another via the C-terminus or N-terminus of each bottlebrush . In embodiments, at least seven of the bottlebrush polymers are covalently linked to one another via the C-terminus or N-terminus of each bottlebrush polymer. In embodiments, at least eight of the bottlebrush polymers are covalently linked to one another via the C-terminus or N-terminus of each bottlebrush polymer.

[0153] The macromolecule may be described as having a branched polymeric structure. For example, the macromolecular may be a branched polymer in the form of: a Y-shaped polymer (i.e. at least 3 branches), a X-shaped polymer (i.e. at least 4 branches), a star-shaped polymer (i.e. at least 3 branches connected to a core moiety), or a dendrimer (i.e. a plurality of branches emanating from a core moiety).

[0154] In embodiments, the macromolecule comprises three or four bottlebrush polymers linked together. In embodiments, the macromolecule is formed from three bottlebrush polymer units. For the avoidance of doubt, where the macromolecule is formed from three bottlebrush polymers, it may resemble the structure of an antibody, i.e. having a ‘Y-shape’. Thus, such a structure may be referred to as a “synthetic antibody” or a “peptobody”.

[0155] In embodiments, two of the three bottlebrush polymers are the same as one another. In these embodiments, said two bottlebrush polymers may differ only in their end group functionalities. Alternatively, in these embodiments, said two bottlebrush polymer may be substantially identical.

[0156] In embodiments, the at least three of the three or more bottlebrush polymers are covalently attached to one another via a core moiety, wherein each bottlebrush polymer is independently linked to the core moiety at the (optionally modified) C-terminus or N-terminus of the polymer backbone of the bottlebrush polymer.

[0157] In embodiments, the core moiety comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue. In embodiments, the core moiety comprises an aryl ring or an amino acid residue. In embodiments, the core moiety comprises an aryl ring, e.g. a phenyl ring. In embodiments, the core moiety comprises an amino acid residue.

[0158] In embodiments, the core moiety comprises an amino acid residue having an amine moiety on its sidechain. For example, the amino acid residue may be selected from: lysine, ornithine, diaminobutyric acid, and diaminopropionic acid. In embodiments, the amino acid residue is lysine.

[0159] In embodiments, the covalently linked to one another comprises covalent attachment of the at least three bottlebrush polymer units to the core moiety (e.g. the amino acid residue) via one or more peptide bonds. In embodiments, each of the at least three bottlebrush polymer units is attached to the core moiety (e.g. the amino acid residue) via a peptide bond.

[0160] For the avoidance of doubt, it may be that each peptide bond is formed between a - C(O)- group present on the core moiety and the -NH- group at the N-terminus of the polymer backbone of the bottlebrush polymer unit, or between a -NH- group present on the core moiety and the -C(O)- group at the C-terminus of the polymer backbone of the bottlebrush polymer unit.

[0161] In embodiments, where the core moiety is an amino acid residue, each of the at least three bottlebrush polymer units may be attached to the amino acid residue via (i) a peptide bondbetween the N-terminus of the amino acid residue and the C-terminus of the polymer backbone of the bottlebrush polymer, (ii) a peptide bond between the C-terminus of the amino acid residue and the N-terminus of the polymer backbone of the bottlebrush polymer, or (iii) a peptide bond between an amino group on the side chain of the amino acid residue and the C-terminus of the polymer backbone of the bottlebrush polymer.

[0162] In embodiments, each of the three or more bottlebrush polymer units may be further defined according to any of the embodiments relating to the bottlebrush polymer of first aspect.

[0163] In an aspect, the invention provides a macromolecule having a structure of formula (II-a) or (II-b):wherein G comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue, wherein each of Y1, Y2, Y3and Y4is independently a bottlebrush polymer moiety of formula (Ib) or (Ic): -C(O)-[Z]r-NH2(Ib) CH3C(O)-[Z]r-NH- (Ic), wherein each of Y1, Y2, Y3and Y4is independently attached to G via the terminal - C(O)- or terminal -NH- group of formula (Ib) or (Ic), wherein: each r is independently an integer selected from 1-20; and each instance of Z is:wherein: R1zis independently for each Z selected from H and C1-4 alkyl; R2zis independently for each Z selected from H and C1-4 alkyl;R3zis independently for each Z selected from H and C1-4 alkyl; Rais independently for each Z selected from H and CH3; Rbis independently for each Z selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andL is independently for each Z selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; n is independently for each Z selected from 5-100; p is independently at each occurrence selected from 0-100; y is 2, 3, 4, or 5; and X is independently at each occurrence selected from a reactive group or a ligand, with the proviso that the X moieties on adjacent Z groups are different; or a salt or solvate thereof.

[0164] For the avoidance of doubt, the formula: -C(O)-[Z]r-NH2(Ib) means that this moiety is attached to G via the -C(O)- group.

[0165] Similarly, for the avoidance of doubt, the formula: CH3C(O)-[Z]r-NH- (Ic) means that this moiety is attached to G via the -NH- group.

[0166] In embodiments, the polymer has a structure of formula (II-a):

[0167] In embodiments, each of Y1, Y2, Y3and Y4are different from one another. In embodiments, two or more of Y1, Y2, Y3and Y4are the same as one another. In embodiments, three of Y1, Y2, Y3and Y4are the same as one another. In embodiments, each of Y1, Y2, Y3and Y4are the same as one another.

[0168] In embodiments, each of Y1, Y2and Y3are different from one another. In embodiments, two of Y1, Y2and Y3are the same as one another (e.g. Y2and Y3are the same as one another). In embodiments, each of Y1, Y2and Y3are the same as one another.

[0169] In embodiments, two of Y1, Y2and Y3are attached to G via their C-termini and the other one of Y1, Y2and Y3is attached to G via their N-terminus.

[0170] In embodiments, Y2and Y3are the same as one another. In these embodiments, Y2is attached to G via its N-terminus, and Y1and Y3are attached to G via their C-termini.

[0171] In embodiments, G comprises a C6-10 aryl, a 5- to 10-membered heteroaryl, a C3-8 cycloalkyl, a 5- to 10-membered heterocycloalkyl ring, or an amino acid residue. In embodiments, G comprises a C6-10 aryl, a 5- to 10-membered heteroaryl, or an amino acid residue. In embodiments, G comprises a C6-10 aryl or an amino acid residue. In embodiments, G comprises a phenyl or an amino acid residue. In embodiments, G comprises a C6-10 aryl (e.g. a phenyl. In embodiments, G comprises an amino acid residue (e.g. lysine, ornithine, diaminobutyric acid, or diaminopropionic acid).

[0172] In embodiments, G is selected from the group comprising:, wherein Q is independently selected at each occurrence as a functional group capable of forming a bond (e.g. a peptide bond) with the N-terminus or C-terminus of the polymer backbone of a bottlebrush polymer of the invention.

[0173] In embodiments, G is selected from the group comprising:, wherein Q is independently selected at each occurrence as a functional group capable of forming a bond (e.g. a peptide bond) with the N-terminus or C-terminus of the polymer backbone of a bottlebrush polymer of the invention.

[0174] In embodiments, G is:wherein Q is a functional group capable of forming a bond (e.g. a peptide bond) with the N-terminus or C-terminus of the polymer backbone of a bottlebrush polymer of the invention.

[0175] In embodiments, G is selected from the group comprising:

[0176] In embodiments, G is selected from the group comprising:

[0178] In embodiments, G is selected from:

[0180] Thus, it may be that the polymer is of formula (II-a1):

[0181] In embodiments, each of the bottlebrush polymer moieties are of formula (I-d) or (I-e):wherein each bottlebrush polymer moiety is independently further defined as follows: each of R1, R2, R3, R4and R5is independently selected from H and C1-4 alkyl; each of R6, R7, R8, R9and R10is independently selected from H and C1-4 alkyl; each of R11, R12, R13, R14and R15are independently selected from H and C1-4 alkyl; each Rais H or CH3; each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach of L1, L2, L3and L4is independently selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; m is 2, 3, 4, or 5; each of n1and n2is independently selected from 5-100; each of n3, n4and n5are independently selected from 0-100; each of p1, p2, p3, p4and p5are independently selected from 5 to 100; each of A, B, C, D and E are independently selected from a reactive group or a ligand, with the proviso that A and B are different; or a salt or solvate thereof.

[0182] In embodiments, each of the bottlebrush polymer moieties of Y1, Y2, Y3or Y4may be independently defined according to any of the embodiments relating to the bottlebrush polymer of third aspect, as provided for in the following paragraphs.

[0183] In embodiments, monodisperse means that, for the population of bottlebrush polymers, for each instance of Z in substantially all of (or all of) the population, n is + / - 0, 1, 2 or 3 from the mode, preferably n is + / - 0 or 1 from the mode; and / or for the population of bottlebrush polymers, in substantially every one of (or in every one of) the population the sum total of all of the n for each instance of Z for said one of the population is + / - 0, 1, 2 or 3 from the mode, preferably + / - 0 or 1 from the mode.

[0184] In embodiments, r is 2-20. For example, r may be 2-15, 2-10, 2-8, or 2-6. For example, r may be 3-20, 3-15, 3-10, 3-8, or 3-6. r may be 4-20, 4-15, 4-10, 4-8, or 4-6.

[0185] r may be 2. r may be 3. r may be 4. r may be 5. r may be 6. r may be 7. r may be 8. r may be 9. r may be 10. r may be 11. r may be 12. r may be 13. r may be 14. r may be 15. r may be 16. r may be 17. r may be 18. r may be 19. r may be 20.

[0186] In embodiments, R1zis C1-4 alkyl, e.g. methyl. In embodiments, R1zis H.

[0187] In embodiments, R2zis C1-4 alkyl, e.g. methyl. In embodiments, R2zis H.

[0188] In embodiments, R3zis C1-4 alkyl, e.g. methyl. In embodiments, R3zis H.

[0189] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d1)wherein each of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0190] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d2) or (I-e2):wherein each of R11, R12, R13, R14, R15, Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0191] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d3)wherein each of R11, R12, R13, R14, R15, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0192] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d4)wherein each of R1, R2, R3, R4, R5, Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0193] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d5)wherein each of R1, R2, R3, R4, R5, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5 is 0. It may be that n4 and n5 are

[0194] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d6) or (I-e6):wherein each of R6, R7, R8, R9, R10, Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0195] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d7)wherein each of R6, R7, R8, R9, R10, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5is 0. It may be that n4and n5are 0.

[0196] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d8)wherein each of Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0197] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I-d9)Wherein each of L1, L2, L3, L4, m, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5is 0. It may be that n4and n5are 0.

[0198] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I- d10) or (I-e10):wherein each of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, L1, L2, L3, L4, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0199] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I- d11) or (I-e11):wherein each of L1, L2, L3, L4, n1, n2, n3, n4, n5, p1, p2, p3, p4, p5, A, B, C, D and E are as defined in formula (I-d) or (I-e). It may be that n5is 0. It may be that n4and n5are 0.

[0200] In embodiments, the compound of formula (I-d) or (I-e) is a compound of formula (I- d12) or (I-e12):wherein each of R1, R2, R3, R6, R7, R8, R11, R12, R13, Ra, Rb, Rc, Rd, L1, L2, m, n1, n2, n3, p1, p2, p3, A, B and C are as defined in formula (I-d) or (I-e), wherein A and C are the same.

[0201] Each of the following embodiments may apply independently to each of the three or more bottlebrush polymers in the macromolecule.

[0202] In embodiments, R1is C1-4 alkyl, e.g. methyl. In embodiments, R1is H.

[0203] In embodiments, R2is C1-4 alkyl, e.g. methyl. In embodiments, R2is H.

[0204] In embodiments, R3is C1-4alkyl, e.g. methyl. In embodiments, R3is H.

[0205] In embodiments, R4is C1-4alkyl, e.g. methyl. In embodiments, R4is H.

[0206] In embodiments, R5is C1-4alkyl, e.g. methyl. In embodiments, R5is H.

[0207] In embodiments, each of R1, R2, R3, R4and R5is H or methyl. In embodiments, each of R1, R2, R3, R4and R5is H.

[0208] In embodiments, R6is C1-4alkyl, e.g. methyl. In embodiments, R6is H.

[0209] In embodiments, R7is C1-4alkyl, e.g. methyl. In embodiments, R7is H.

[0210] In embodiments, R8is C1-4alkyl, e.g. methyl. In embodiments, R8is H.

[0211] In embodiments, R9is C1-4alkyl, e.g. methyl. In embodiments, R9is H.

[0212] In embodiments, R10is C1-4alkyl, e.g. methyl. In embodiments, R10is H.

[0213] In embodiments, each of R6, R7, R8, R9and R10is H or methyl. In embodiments, each of R6, R7, R8, R9and R10is H.

[0214] In embodiments, R11is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R11is H.

[0215] In embodiments, R12is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R12is H.

[0216] In embodiments, R13is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R13is H.

[0217] In embodiments, R14is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R14is H.

[0218] In embodiments, R15is C1-4 alkyl, e.g. methyl or ethyl. In embodiments, R15is H.

[0219] In embodiments, each of R11, R12, R13, R14and R15is independently selected from methyl and ethyl.

[0220] In embodiments, each of R11, R12, R13, R14and R15is ethyl or methyl. In embodiments, each of R11, R12, R13, R14and R15is methyl.

[0221] In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H.

[0222] In embodiments, each of R1, R2, R3, R4and R5is H or methyl, and each of R11, R12, R13, R14and R15is ethyl or methyl. In embodiments, each of R1, R2, R3, R4and R5is H or methyl, and each of R11, R12, R13, R14and R15is H. In embodiments, each of R1, R2, R3, R4and R5is H, and each of R11, R12, R13, R14and R15is methyl.

[0223] In embodiments, each of R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is ethyl or methyl. In embodiments, each of R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is H. In embodiments, each of R6, R7, R8, R9and R10is H, and each of R11, R12, R13, R14and R15methyl.

[0224] In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is ethyl or methyl. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is H. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl, and each of R11, R12, R13, R14and R15is methyl. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H, and each of R11, R12, R13, R14and R15is methyl.

[0225] In embodiments, each Rais H. In embodiments, each Rais CH3.

[0226] In embodiments, each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rbis independently selected from H or CH3. In embodiments, each Rbis H or CH3. In embodiments, each Rbis H.

[0227] In embodiments, each Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rcis independently selected from H or CH3. In embodiments, each Rcis H or CH3. In embodiments, each Rcis H.

[0228] In embodiments, each Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rdis independently selected from H or CH3. In embodiments, each Rdis H or CH3. In embodiments, each Rdis H.

[0229] In embodiments, each Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Reis independently selected from H or CH3. In embodiments, each Reis H or CH3. In embodiments, each Reis H.

[0230] In embodiments, each Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rfis independently selected from H or CH3. In embodiments, each Rfis H or CH3. In embodiments, each Rfis H.

[0231] In embodiments, each instance of Ra, Rb, Rc, Rd, Reand Rfis H or CH3. In embodiments, each instance of Ra, Rb, Rc, Rd, Reand Rfis H.

[0232] In embodiments, L1is a bond. In alternative embodiments, L1is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0233] Where L1 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0234] In embodiments, where present, L2is a bond. In alternative embodiments, L2is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0235] Where L2is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0236] In embodiments, where present, L3 is a bond. In alternative embodiments, L3 is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0237] Where L3 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0238] In embodiments, where present, L4 is a bond. In alternative embodiments, L4 is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0239] Where L4 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechainmay comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0240] In embodiments, if present, each of L2, L3 and L4 is a bond. In alternative embodiments, if present, one, two or three of L2, L3 and L4 is at least one amino acid residue which lacks an amino moiety on its sidechain. The at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids.

[0241] In embodiments, any of said at least one amino acid which lacks an amino moiety on its sidechain is selected from glycine, alanine, protected lysine, protected or unprotected glutamic acid, protected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine. Where the at least one amino acid is protected, the at least one amino acid is protected by a protecting group as defined herein. In embodiments, the at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycine and alanine.

[0242] In embodiments, m is 2. In embodiments, m is 3. In embodiments, m is 4. In embodiments, m is 5.

[0243] In embodiments, m is 2, 3 or 4, and / or each Rb, Rc, Rd, Reand Rfis H or CH3. In embodiments, m is 2, 3 or 4, and / or each Rb, Rc, Rd, Reand Rfis H. In embodiments, m is 4, and / or each Rb, Rc, Rd, Reand Rfis H.

[0244] In embodiments, n1is selected from 5 to 90, from 5 to 80, from 5 to 70, from 5 to 60, from 5 to 50, from 5 to 40, from 5 to 30, from 5 to 20, or from 5 to 10.

[0245] In embodiments, n2is selected from 5 to 90, from 5 to 80, from 5 to 70, from 5 to 60, from 5 to 50, from 5 to 40, from 5 to 30, from 5 to 20, or from 5 to 10.

[0246] In embodiments, n3is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n3is 0.

[0247] In embodiments, n4 is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n4 is 0.

[0248] In embodiments, n5 is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n5 is 0.

[0249] In embodiments, n4 and n5 are 0. In embodiments, n3, n4 and n5 are 0.

[0250] In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 10 to 60. In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 30 to 50. In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 35 to 45.

[0251] Each of A, B, C, D and E are independently selected from a reactive group or a ligand, with the proviso that A and B are different.

[0252] In embodiments, each of A, B, C, D and E are different. In embodiments, at least two of A, C, D and E are the same.

[0253] In embodiments, A, B, C and D are different. In embodiments, A and C are the same, and / or B and D are the same.

[0254] In embodiments, A, B and C are different. In embodiments, A and C are the same.

[0255] In embodiments, each reactive group is independently selected from a nucleophile, an electrophile and a photoactivatable group. For example, each reactive group may be independently selected from a moiety comprising an amine, an azide, a carboxylic acid, an alkyne, an activated alkyne, phosphite, phosphine, thiol, transcyclooctene, and tetrazine.

[0256] In embodiments, each ligand is independently selected from an amino acid, a peptide, a protein, a polysaccharide, a nucleoside, a nucleotide, an oligonucleotide, a nucleic acid, a hapten, a psoralen, a drug, a hormone, a vitamin, a lipid, a lipid assembly (such as a biological membrane or liposome), a synthetic polymer, a polymeric nanoparticle or microparticle, a biological cell, a virus derived component (such as a viral derived protein, nucleic acid, lipid or carbohydrate, or combination thereof), a chromophore, a fluorophore, a dye, a radioisotope and a capping group (e.g. an acetyl group).

[0257] In embodiments, the macromolecule has a polydispersity index (Ð) of less than about 1.4. The macromolecule may have a polydispersity index (Ð) of less than about 1.2. The macromolecule may have a polydispersity index (Ð) of less than about 1.1. METHOD OF PREPARING A BOTTLEBRUSH POLYMER OR MACROMOLECULE

[0258] In another aspect, the invention provides a method of preparing a bottlebrush polymer, comprising: (a) forming a polymer backbone by extending a polypeptide comprising protected amino acid residues, the formed polypeptide backbone comprising at least one block of the protected amino acid residues, wherein in each specific block the protected amino acids: i) comprise an equivalent protecting group; and ii) when at least two blocks of protected amino acid residues are present, the equivalent protecting group is orthogonal to at least the protecting group of any adjacent specific block; (b) forming a functionalised specific block by: i) deprotecting the protected amino acid residues of a first of the specific blocks, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; andiii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; wherein, when at least two blocks of protected amino acid residues are present, the method further comprises (c) forming a subsequent functionalised specific block by: i) deprotecting the protected amino acid residues of a second specific block, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i); ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0259] In embodiments, when at least three blocks of protected amino acid residues are present, the polymer backbone comprises more than two types of orthogonal protecting group, the method further comprising: (d) forming one or more further subsequent functionalised specific block by: i) deprotecting the protected amino acid residues of said further subsequent functionalised specific block, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i), (c) i) (and any previous (d) i)); ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii), (c) iii) (and any previous (d) iii)); and iv) repeating (d) i)-iii) until all protecting groups have been removed and all specific blocks have been functionalised.

[0260] In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4 alkylglycine), poly(glycine), poly(N-C1-4 alkylalanine), poly(alanine), protected poly(lysine), (protected) poly(glutamic acid) or esters or amides thereof, or copolymers thereof. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4 alkylglycine) and poly(glycine). In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide is poly(N-C1-4 alkylglycine).

[0261] In embodiments, the formed poly(N-C1-4 alkylglycine) is selected from poly(N- methylglycine), poly(N-ethylglycine) or poly(N-isopropylglycine). In embodiments, the formedpoly(N-C1-4 alkylglycine) is selected from poly(N-methylglycine) and poly(N-ethylglycine). In embodiments, the formed poly(N-C1-4 alkylglycine) is poly(N-methylglycine).

[0262] In embodiments, the formed poly(N-C1-4 alkylalanine) is selected from poly(N- methylalanine), poly(N-ethylalanine) or poly(N-isopropylalanine). In embodiments, the formed poly(N-C1-4 alkylalanine) is selected from poly(N-methylalanine) and poly(N-ethylalanine). In embodiments, the formed poly(N-C1-4 alkylalanine) is poly(N-methylalanine).

[0263] In embodiments, the polymer backbone comprises three or four equivalent protecting groups that are orthogonal to each other. The orthogonal equivalent protecting groups may be selected from Boc, Alloc, ivDde, and Mmt. For example, the orthogonal equivalent protecting groups may be selected from Boc and Alloc, where only two orthogonal equivalent protecting groups are required

[0264] In embodiments, the polymer backbone substantially comprises (or consists of) protected amino acid residues with a protected active moiety on the sidechain. The polypeptide backbone may be interrupted up to several times by at least one amino acid residue which lacks an active moiety on its sidechain. For the avoidance of doubt, the defined bottlebrush sidechains attach to the polymer backbone at the amine moiety of each of the respective amino acid residues such that an amide bond is formed between the amine moiety and the bottlebrush sidechain.

[0265] The at least one amino acid residue which lacks an active moiety on its sidechain may be selected from glycine, alanine, protected lysine, protected or unprotected glutamic acid, protected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine. Where the at least one amino acid is protected, the at least one amino acid is protected by a protecting group as defined herein. In embodiments, the at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycine, alanine.

[0266] The at least one amino acid residue which lacks an active moiety on its sidechain may comprise from 1 to 10 said amino acids.

[0267] In embodiments, the active moiety on the sidechain of each of the deprotected amino acid residues is an amine, e.g. a primary or secondary amine.

[0268] In embodiments, the amino acid residues with an active moiety on the sidechain are all the same.

[0269] In embodiments, the amino acid residues with an active moiety on the sidechain are selected from lysine, ornithine, diaminobutyric acid, and diaminopropionic acid.

[0270] In embodiments, each of the amino acid residues with an active moiety on the sidechain is lysine.

[0271] In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide of the bottlebrush sidechain comprises a degree of polymerisation (DP) of about 5 to about 100. Inembodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 10 to about 60. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 30 to about 50. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 35 to about 45. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 20 to about 40. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 20 to about 30. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 30. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 20. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 10. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 40. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 25.

[0272] In embodiments, the polymer backbone comprises a polypeptide that is from about 10 to about 300 amino acids in length. In embodiments, the polymer backbone is from about 20 to about 200 amino acids in length.

[0273] In embodiments, the polymer backbone is from about 30 to about 150 amino acids in length.

[0274] In another aspect, the invention provides a method of preparing a macromolecule comprising three or more bottlebrush polymers, comprising: (a) forming a polymer backbone by extending a branched polypeptide comprising three or more branches of protected amino acid residues, the formed branched polypeptide backbone comprising at least one block of the protected amino acid residues in each branch of the branched polypeptide backbone, wherein, in each specific block of each branch of the branched polypeptide backbone, the protected amino acids: i) comprise an equivalent protecting group; and ii) when at least two blocks of protected amino acid residues are present, the equivalent protecting group is orthogonal to at least the protecting group of any adjacent specific block; and (b) forming a functionalised specific block in each branch of the branched polypeptide by: i) deprotecting the protected amino acid residues of a first of the specific blocks in each branch, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues;ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; wherein, when at least two blocks of protected amino acid residues are present in each of the branches of the branched polypeptide, the method further comprises (c) forming a subsequent functionalised specific block in each branch of the branched polypeptide by: i) deprotecting the protected amino acid residues of a second specific block in each branch, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i); ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0275] In embodiments, when at least three blocks of protected amino acid residues are present in each branch, each branch of the branched polypeptide backbone comprises more than two types of orthogonal protecting group, the method further comprising: (d) forming one or more further subsequent functionalised specific block in each branch of the branched polypeptide by: i) deprotecting the protected amino acid residues of said further subsequent functionalised specific block in each branch, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i), (c) i) (and any previous (d) i)); ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii), (c) iii) (and any previous (d) iii)); and iv) repeating (d) i)-iii) until all protecting groups have been removed and all specific blocks in each branch of the branched polypeptide have been functionalised.

[0276] In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide in each specific block of each branch is independently selected from poly(N-C1-4 alkylglycine), poly(glycine), poly(N-C1-4 alkylalanine), poly(alanine), protected poly(lysine), (protected) poly(glutamic acid) oresters or amides thereof, or copolymers thereof. In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide in each specific block of each branch is independently selected from poly(N-C1-4 alkylglycine) and poly(glycine). In embodiments, the formed polypeptide, polypeptoid or polypept(o)ide in each specific block of each branch is poly(N-C1-4 alkylglycine).

[0277] In embodiments, in each specific block of each branch, the formed poly(N-C1-4 alkylglycine) is selected from poly(N-methylglycine), poly(N-ethylglycine) or poly(N- isopropylglycine). In embodiments, in each specific block of each branch, the formed poly(N-C1-4 alkylglycine) is selected from poly(N-methylglycine) and poly(N-ethylglycine). In embodiments, in each specific block of each branch, the formed poly(N-C1-4alkylglycine) is poly(N- methylglycine).

[0278] In embodiments, in each specific block of each branch, the formed poly(N-C1-4alkylalanine) is selected from poly(N-methylalanine), poly(N-ethylalanine) or poly(N- isopropylalanine). In embodiments, in each specific block of each branch, the formed poly(N-C1-4 alkylalanine) is selected from poly(N-methylalanine) and poly(N-ethylalanine). In embodiments, in each specific block of each branch, the formed poly(N-C1-4alkylalanine) is poly(N- methylalanine).

[0279] In embodiments, each branch of the branched polypeptide backbone comprises three or four equivalent protecting groups that are orthogonal to each other. The orthogonal equivalent protecting groups may be selected from Boc, Alloc, ivDde, and Mmt. For example, the orthogonal equivalent protecting groups may be selected from Boc and Alloc, where only two orthogonal equivalent protecting groups are required

[0280] In embodiments, each branch of the branched polypeptide backbone substantially comprises (or consists of) protected amino acid residues with a protected active moiety on the sidechain. The branched polypeptide backbone may be interrupted up to several times by at least one amino acid residue which lacks an active moiety on its sidechain. For the avoidance of doubt, the defined bottlebrush sidechains attach to each branch of the branched polypeptide backbone at the amine moiety of each of the respective amino acid residues such that an amide bond is formed between the amine moiety and the bottlebrush sidechain.

[0281] In each branch, the at least one amino acid residue which lacks an active moiety on its sidechain may be selected from glycine, alanine, protected lysine, protected or unprotected glutamic acid, protected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine. Where the at least one amino acid is protected, the at least one amino acid is protected by a protecting group as defined herein. In embodiments, the at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycinea and alanine.

[0282] In each branch, the at least one amino acid residue which lacks an active moiety on its sidechain may comprise from 1 to 10 said amino acids.

[0283] In embodiments, in each branch, the active moiety on the sidechain of each of the deprotected amino acid residues is an amine, e.g. a primary or secondary amine.

[0284] In embodiments, in each branch, the amino acid residues with an active moiety on the sidechain are all the same.

[0285] In embodiments, in each branch, the amino acid residues with an active moiety on the sidechain are selected from lysine, ornithine, diaminobutyric acid, and diaminopropionic acid.

[0286] In embodiments, in each branch, each of the amino acid residues with an active moiety on the sidechain is lysine.

[0287] In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide of the bottlebrush sidechain comprises a degree of polymerisation (DP) of about 5 to about 100. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 10 to about 60. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 30 to about 50. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 35 to about 45. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 20 to about 40. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 20 to about 30. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 30. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 20. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 5 to about 10. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 40. In embodiments, in each specific block of each branch, the formed polypeptide, polypeptoid or polypept(o)ide comprises a degree of polymerisation (DP) of about 25.

[0288] In embodiments, each branch of the branched polypeptide backbone comprises a polypeptide that is from about 10 to about 300 amino acids in length. In embodiments, each branch of the branched polypeptide backbone is from about 20 to about 200 amino acids in length.

[0289] In embodiments, each branch of the branched polypeptide backbone is from about 30 to about 150 amino acids in length.

[0290] In embodiments, the macromolecule comprises three or four bottlebrush polymer units. In embodiments, the macromolecule comprises three bottlebrush polymer units.

[0291] In embodiments, the branched polypeptide backbone comprises three or more polypeptide sequences covalently attached to one another, wherein each polypeptide sequence is independently attached to another at its C-terminus or N-terminus.

[0292] In embodiments, the branched polypeptide backbone comprises three or more polypeptide sequences covalently attached to a core moiety, wherein each polypeptide sequence is independently attached to the core moiety at its C-terminus or N-terminus.

[0293] In embodiments, the core moiety comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue. In embodiments, the core moiety comprises an aryl ring or an amino acid residue. In embodiments, the core moiety comprises an aryl ring, e.g. a phenyl ring. In embodiments, the core moiety comprises an amino acid residue.

[0294] In embodiments, the core moiety comprises an amino acid residue having an amine moiety on its sidechain. For example, the amino acid residue may be selected from: lysine, ornithine, diaminobutyric acid, and diaminopropionic acid. In embodiments, the amino acid residue is lysine.

[0295] In embodiments, the at least three bottlebrush polymer units are attached to the core moiety (e.g. the amino acid residue) via one or more peptide bonds. In embodiments, each of the at least three bottlebrush polymer units is attached to the core moiety (e.g. the amino acid residue) via a peptide bond.

[0296] For the avoidance of doubt, it may be that each peptide bond is formed between a - C(O)- group present on the core moiety and the -NH- group at the N-terminus of the polymer backbone of the bottlebrush polymer unit, or between a -NH- group present on the core moiety and the -C(O)- group at the C-terminus of the polymer backbone of the bottlebrush polymer unit.

[0297] In embodiments, where the core moiety is an amino acid residue, each of the at least three bottlebrush polymer units may be attached to the amino acid residue via (i) a peptide bond between the N-terminus of the amino acid residue and the C-terminus of the polymer backbone of the bottlebrush polymer, (ii) a peptide bond between the C-terminus of the amino acid residue and the N-terminus of the polymer backbone of the bottlebrush polymer, or (iii) a peptide bond between an amino group on the side chain of the amino acid residue and the C-terminus of the polymer backbone of the bottlebrush polymer.

[0298] In embodiments, the method may further comprise ligating the three or more polypeptide sequences together to form the branched polypeptide backbone. In theseembodiments, the three or more polypeptide sequences may be ligated to a core moiety. The core moiety may be as defined herein.

[0299] In embodiments, the ligating comprises click chemistry, Pictet-Spengler ligation, and / or native chemical ligation. Suitable conditions and reagents for performing these ligating reactions are well-established in the art (Meldal et al., Macromolecular Rapid Communications 2008, 29 (12-13), 1016-1051; Pomplun et al., Angew Chem Int Ed Engl, 2019, 58 (11), 3542-3547; and Dawson et al., Science (New York, N.Y.) 1994, 266 (5186), 776-9).

[0300] In another aspect, the invention provides a method of preparing a bottlebrush polymer, comprising: (a) forming a polymer backbone of formula (II) by extending a polypeptide comprising protected amino acid residues: CH3C(O)-[Z’]r-NH-X’’ (III) wherein: r is 1-20 and each instance of Z’ is:wherein R1zis independently for each Z’ selected from H and C1-4 alkyl; R2zis independently for each Z’ selected from H and C1-4 alkyl; Rais independently for each Z’ selected from H and CH3; Rbis independently for each Z’ selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2 andn is independently for each Z’ selected from 5-100; y is 2, 3, 4, or 5; L is independently for each Z’ selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; X’ is independently for each Z’ is a protecting group, with the proviso that the X’ protecting group for each Z’ is an orthogonal protecting group to the X’ of any adjacent Z’ and X’’ is a solid support; or or a salt or solvate thereof; (b) forming a functionalised specific block by:i) removing a first X’, thereby deprotecting the amino acids in at least a first Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block by: i) removing a second X’, that comprises an orthogonal protecting group to the first X’, thereby deprotecting the amino acids in at least a second Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0301] In embodiments, r is at least 3 and the method further comprises: (d) forming a further subsequent functionalised specific block by: i) removing a third X’, that comprises an orthogonal protecting group to each of the first X’ and the second X’, thereby deprotecting the amino acids in at least a third Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of each of (b) iii) and (c) iii).

[0302] In embodiments, r is at least 4 and the method further comprises: (e) forming a further subsequent functionalised specific block by: i) removing a fourth X’, that comprises an orthogonal protecting group to each of the first X’, the second X’ and the third X’, thereby deprotecting the amino acids in at least a fourth Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of each of (b) iii), (c) iii) and (d) iii).

[0303] In embodiments where r is greater than 4, at least one of steps (b), (c), (d) and (e) forms more than one functionalised specific block, with the proviso that said more than one functionalised block does no not comprise adjacent instances of Z’.

[0304] In embodiments, r is 2-20. For example, r may be 2-15, 2-10, 2-8, or 2-6. For example, r may be 3-20, 3-15, 3-10, 3-8, or 3-6. r may be 4-20, 4-15, 4-10, 4-8, or 4-6.

[0305] r may be 2. r may be 3. r may be 4. r may be 5. r may be 6. r may be 7. r may be 8. r may be 9. r may be 10. r may be 11. r may be 12. r may be 13. r may be 14. r may be 15. r may be 16. r may be 17. r may be 18. r may be 19. r may be 20.

[0306] In embodiments, R1zis C1-4alkyl, e.g. methyl. In embodiments, R1zis H.

[0307] In embodiments, R2zis C1-4alkyl, e.g. methyl. In embodiments, R2zis H.

[0308] In embodiments the compound of formula (III) is a compound of formula (III-a) and the invention provides a method of preparing a bottlebrush polymer, comprising: (a) forming a polymer backbone of formula (III-a) by extending a polypeptide comprising protected amino acid residues:wherein: each of R1, R2, R3, R4and R5is independently selected from H and C1-4 alkyl; each of R6, R7, R8, R9and R10is independently selected from H and C1-4 alkyl; each Rais H or CH3;; each Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, and;each Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, ; each of L1, L2, L3 and L4 is independently selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; m is 2, 3, 4, or 5; each of n1 and n2 is independently selected from 5-100; each of n3, n4 and n5 is independently selected from 0-100; each of p1, p2, p3, p4and p5is independently selected from 5 to 100; each of A’, B’, C’, D’ and E’ is a protecting group, with the proviso that: A’ is an orthogonal protecting group to B’, B’ is an orthogonal protecting group to C’ (when C’ is present), C’ is an orthogonal protecting group to D’ (when C’ and D’ are present), D’ is an orthogonal protecting group to E’ (when D’ and E’ are present); and X is a solid support; or a salt or solvate thereof; (b) forming a functionalised specific block by: i) removing A’, thereby deprotecting the amino acids in a second block of length n1by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block by: i) removing B’, thereby deprotecting the amino acids in a first block of length n2by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0309] In embodiments, the compound of formula (III) or (III-a) is a compound of formula (II-wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, L1, L2, L3, L4, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (III-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0310] In embodiments, the compound of formula (III) or (III-a) is a compound of formula (III-wherein each of Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (III-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0311] In embodiments, the compound of formula (III) or (III-a) is a compound of formula (III-wherein each of L1, L2, L3, L4, m, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (III-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0312] In embodiments, the compound of formula (III) or (III-a) is a compound of formula (III- e):wherein each of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, L1, L2, L3, L4, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (III-a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0313] In embodiments, the compound of formula (III) or (III-a) is a compound of formula (III-f):wherein each of L1, L2, L3, L4, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (III- a). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0314] In embodiments, the compound of formula (III) or (III-a) is a compound of formula (III-wherein each of R1, R2, R3, R6, R7, R8, Ra, Rb, Rc, Rd, L1, L2, n1, n2, n3, A’, B’ and C’ are as defined in formula (III-a), wherein A’ and C’ are the same.

[0315] In embodiments, n3 is not 0 and C’ is an orthogonal protecting group to B’ (and optionally also orthogonal to A’), the method further comprising: (d) forming a further subsequent functionalised specific block by: i) removing C’, thereby deprotecting the amino acids in a third block of length n3 by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (c) iii) (and optionally also different to the reactive group or ligand of (b) iii)).

[0316] In embodiments, n4 is not 0 and D’ is an orthogonal protecting group to C’ (and optionally also orthogonal to A’ and / or B’), the method further comprising: (e) forming a further subsequent functionalised specific block by: i) removing D’, thereby deprotecting the amino acids in a fourth block of length n4by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (d) iii) (and optionally also different to the reactive group or ligand of (b) iii) and / or (c) iii)).

[0317] In embodiments, n5is not 0 and E’ is an orthogonal protecting group to D’ (and optionally A’ and / or B’ and / or C’), the method further comprising: (f) forming a further subsequent functionalised specific block by: i) removing E’, thereby deprotecting the amino acids in a fifth block of length n5 by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (e) iii), (and optionally also different to the reactive group or ligand of (b) iii) and / or (c) iii) and / or (d) iii)).

[0318] In embodiments, each polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4 alkylglycine), poly(glycine), poly(N-C1-4 alkylalanine), poly(alanine), or copolymers thereof. In embodiments, each polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4 alkylglycine) and poly(glycine). In embodiments, each polypeptide, polypeptoid or polypept(o)ide is poly(N-C1-4 alkylglycine).

[0319] In embodiments, the poly(N-C1-4 alkylglycine) is selected from poly(N-methylglycine), poly(N-ethylglycine) or poly(N-isopropylglycine). In embodiments, the poly(N-C1-4 alkylglycine) is selected from poly(N-methylglycine) and poly(N-ethylglycine). In embodiments, the poly(N-C1-4 alkylglycine) is poly(N-methylglycine).

[0320] In embodiments, the poly(N-C1-4alkylalanine) is selected from poly(N-methylalanine), poly(N-ethylalanine) or poly(N-isopropylalanine). In embodiments, the poly(N-C1-4alkylalanine) is selected from poly(N-methylalanine) and poly(N-ethylalanine). In embodiments, the poly(N- C1-4alkylalanine) is poly(N-methylalanine).

[0321] In embodiments, R1is C1-4 alkyl, e.g. methyl. In embodiments, R1is H.

[0322] In embodiments, R2is C1-4alkyl, e.g. methyl. In embodiments, R2is H.

[0323] In embodiments, R3is C1-4alkyl, e.g. methyl. In embodiments, R3is H.

[0324] In embodiments, R4is C1-4alkyl, e.g. methyl. In embodiments, R4is H.

[0325] In embodiments, R5is C1-4alkyl, e.g. methyl. In embodiments, R5is H.

[0326] In embodiments, each of R1, R2, R3, R4and R5is H or methyl. In embodiments, each of R1, R2, R3, R4and R5is H.

[0327] In embodiments, R6is C1-4alkyl, e.g. methyl. In embodiments, R6is H.

[0328] In embodiments, R7is C1-4alkyl, e.g. methyl. In embodiments, R7is H.

[0329] In embodiments, R8is C1-4alkyl, e.g. methyl. In embodiments, R8is H.

[0330] In embodiments, R9is C1-4alkyl, e.g. methyl. In embodiments, R9is H.

[0331] In embodiments, R10is C1-4alkyl, e.g. methyl. In embodiments, R10is H.

[0332] In embodiments, each of R6, R7, R8, R9and R10is H or methyl. In embodiments, each of R6, R7, R8, R9and R10is H.

[0333] In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H.

[0334] In embodiments, each Rais H. In embodiments, each Rais CH3.

[0335] In embodiments, each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rbis independently selected from H or CH3. In embodiments, each Rbis H or CH3. In embodiments, each Rbis H.

[0336] In embodiments, each Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rcis independently selected from H or CH3. In embodiments, each Rcis H or CH3. In embodiments, each Rcis H.

[0337] In embodiments, each Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rdis independently selected from H or CH3. In embodiments, each Rdis H or CH3. In embodiments, each Rdis H.

[0338] In embodiments, each Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Reis independently selected from H or CH3. In embodiments, each Reis H or CH3. In embodiments, each Reis H.

[0339] In embodiments, each Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rfis independently selected from H or CH3. In embodiments, each Rfis H or CH3. In embodiments, each Rfis H.

[0340] In embodiments, each instance of Ra, Rb, Rc, Rd, Reand Rfis H or CH3. In embodiments, each instance of Ra, Rb, Rc, Rd, Reand Rfis H.

[0341] In embodiments, L1is a bond. In alternative embodiments, L1is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0342] Where L1 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0343] In embodiments, where present, L2is a bond. In alternative embodiments, L2is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0344] Where L2is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0345] In embodiments, where present, L3 is a bond. In alternative embodiments, L3 is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0346] Where L3 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0347] In embodiments, where present, L4 is a bond. In alternative embodiments, L4 is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0348] Where L4 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechainmay comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0349] In embodiments, if present, each of L2, L3 and L4 is a bond. In alternative embodiments, if present, one, two or three of L2, L3 and L4 is at least one amino acid residue which lacks an amino moiety on its sidechain. The at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids.

[0350] In embodiments, any of said at least one amino acid which lacks an amino moiety on its sidechain is selected from glycine, alanine, protected lysine, protected or unprotected glutamic acid, protected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine. Where the at least one amino acid is protected, the at least one amino acid is protected by a protecting group as defined herein. In embodiments, the at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycine, alanine.

[0351] In embodiments, m is 2. In embodiments, m is 3. In embodiments, m is 4. In embodiments, m is 5.

[0352] In embodiments, m is 2, 3 or 4, and / or each Rb, Rc, Rd, Reand Rfis H or CH3. In embodiments, m is 2, 3 or 4, and / or each Rb, Rc, Rd, Reand Rfis H. In embodiments, m is 4, and / or each Rb, Rc, Rd, Reand Rfis H.

[0353] In embodiments, n1is selected from 5 to 90, from 5 to 80, from 5 to 70, from 5 to 60, from 5 to 50, from 5 to 40, from 5 to 30, from 5 to 20, or from 5 to 10.

[0354] In embodiments, n2is selected from 5 to 90, from 5 to 80, from 5 to 70, from 5 to 60, from 5 to 50, from 5 to 40, from 5 to 30, from 5 to 20, or from 5 to 10.

[0355] In embodiments, n3is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n3is 0.

[0356] In embodiments, n4 is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n4 is 0.

[0357] In embodiments, n5 is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n5 is 0.

[0358] In embodiments, n4 and n5 are 0. In embodiments, n3, n4 and n5 are 0.

[0359] In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 10 to 60. In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 30 to 50. In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 35 to 45.

[0360] A’, B’, C’, D’ and E’ may be independently selected from the group comprising: N- Fluorenylmethoxycarbonyl (Fmoc), 2-(4-Nitrophenylsulfonyl)ethoxycarbonyl (Nsc), 1-(4,4- Dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde), 1-(4,4-dimethyl-2,6-dioxocyclohex-1-ylidene)isovaleryl (ivDde), allyloxycarbonyl (Alloc), benzyloxycarbonyl (Cbz), phthalimide, sulfonamide, 2,4,6-Triisopropylsulfonamide (Trs), tert-butoxycarbonyl (Boc), 2-(4-biphenylyl)-2- propyloxycarbonyl (Bpoc), trityl, monomethoxytrityl (MMT), 2,4-Dimethoxybenzyl (DMB), N- Diphenylmethyleneamine, 2-(Trimethylsilyl)-ethoxycarbonyl (Teoc), 2-Trimethylsilylethoxymethyl (SEM), 6-nitroveratryloxycarbonyl (NVOC), 2,2’-bis(2-nitrophenyl)ethoxycarbonyl (diNPEOC), benzoyl, and benzyl. A’, B’, C’, D’ and E’ may be independently selected from the group comprising: Boc, Alloc, ivDde, and Mmt.

[0361] In embodiments, each reactive group is independently selected from a nucleophile, an electrophile and a photoactivatable group. For example, each reactive group may be independently selected from a moiety comprising an amine, an azide, a carboxylic acid, an alkyne, an activated alkyne, phosphite, phosphine, thiol, transcyclooctene, and tetrazine.

[0362] In embodiments, each ligand is independently selected from an amino acid, a peptide, a protein, a polysaccharide, a nucleoside, a nucleotide, an oligonucleotide, a nucleic acid, a hapten, a psoralen, a drug, a hormone, a vitamin, a lipid, a lipid assembly (such as a biological membrane or liposome), a synthetic polymer, a polymeric nanoparticle or microparticle, a biological cell, a virus derived component (such as a viral derived protein, nucleic acid, lipid or carbohydrate, or combination thereof), a chromophore, a fluorophore, a dye, a radioisotope and a capping group (e.g. an acetyl group).

[0363] In embodiments, the bottlebrush polymers have a polydispersity index (Ð) of less than about 1.4. The bottlebrush polymers may have a polydispersity index (Ð) of less than about 1.2. The bottlebrush polymers may have a polydispersity index (Ð) of less than about 1.1.

[0364] In another aspect, the invention provides a method of forming a bottlebrush polymer with a longer polymer backbone, comprising: (a) obtaining at least two bottlebrush polymers of the first aspect or second aspect, or performing the method of the third aspect or fourth aspect at least twice to obtain at least two bottlebrush polymers; and (b) ligating the polymer backbones of the at least two bottlebrush polymers.

[0365] In embodiments, the ligating comprises click chemistry, Pictet-Spengler ligation, and / or native chemical ligation. Suitable conditions and reagents for performing these ligating reactions are well-established in the art (Meldal et al., Macromolecular Rapid Communications 2008, 29 (12-13), 1016-1051; Pomplun et al., Angew Chem Int Ed Engl, 2019, 58 (11), 3542-3547; and Dawson et al., Science (New York, N.Y.) 1994, 266 (5186), 776-9).

[0366] In another aspect, the invention provides a method of preparing a macromolecule comprising (a) forming a polymer backbone of formula (IVa) or (IVb) by extending a branched polypeptide comprising protected amino acid residues:wherein G’ comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue, wherein each of Y1’, Y2’, Y3’and Y4’is independently a moiety of formula (Ib’) or (Ic’): -C(O)-[Z’]r-NH2(Ib’) CH3C(O)-[Z‘]r-NH- (Ic’), wherein each of Y1’, Y2’, Y3’and Y4’is independently attached to G’ via the terminal -C(O)- or terminal -NH- group of formula (Ib’) or (Ic’), wherein: each instance of r is independently an integer selected from 1-20 and each instance of Z’ is:wherein R1zis independently for each Z’ selected from H and C1-4 alkyl; R2zis independently for each Z’ selected from H and C1-4 alkyl; Rais independently for each Z’ selected from H and CH3; Rbis independently for each Z’ selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2 andn is independently for each Z’ selected from 5-100; y is 2, 3, 4, or 5; L is independently for each Z’ selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; X’ is independently for each Z’ is a protecting group, with the proviso that the X’ protecting group for each Z’ is an orthogonal protecting group to the X’ of any adjacent Z’; or a salt or solvate thereof wherein the branched polypeptide is attached to a solid support where chemically possible; (b) forming a functionalised specific block in each branch of the branched polypeptide by:i) removing a first X’ in each branch, thereby deprotecting the amino acids in at least a first Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing a second X’ in each branch, that comprises an orthogonal protecting group to the first X’, thereby deprotecting the amino acids in at least a second Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0367] For the avoidance of doubt, the formula: -C(O)-[Z’]r-NH2(Ib’) means that this moiety is attached to G’ via the -C(O)- group.

[0368] Similarly, for the avoidance of doubt, the formula: CH3C(O)-[Z‘]r-NH- (Ic’) means that this moiety is attached to G’ via the -NH- group.

[0369] In embodiments, the polymer backbone has a structure of formula (IVa):

[0370] In embodiments, each of Y1’, Y2’, Y3’and Y4’are different from one another. In embodiments, two or more of Y1’, Y2’, Y3’and Y4’are the same as one another. In embodiments, three of Y1’, Y2’, Y3’and Y4’are the same as one another. In embodiments, each of Y1’, Y2’, Y3’and Y4’are the same as one another.

[0371] In embodiments, each of Y1’, Y2’and Y3’are different from one another. In embodiments, two of Y1’, Y2’and Y3’are the same as one another (e.g. Y2’and Y3’are the same as one another). In embodiments, each of Y1’, Y2’and Y3’are the same as one another.

[0372] In embodiments, two of Y1’, Y2’and Y3’are attached to G’ via their C-termini and the other one of Y1’, Y2’and Y3’is attached to G’ via their N-terminus.

[0373] In embodiments, Y2’and Y3’are the same as one another. In these embodiments, Y2’is attached to G’ via its N-terminus, and Y1’and Y3’are attached to G’ via their C-termini.

[0374] In embodiments, G’ comprises a C6-10 aryl, a 5- to 10-membered heteroaryl, a C3-8cycloalkyl, a 5- to 10-membered heterocycloalkyl ring, or an amino acid residue. In embodiments, G’ comprises a C6-10aryl, a 5- to 10-membered heteroaryl, or an amino acid residue. In embodiments, G’ comprises a C6-10aryl or an amino acid residue. In embodiments, G’ comprises a phenyl or an amino acid residue. In embodiments, G’ comprises a C6-10aryl (e.g. a phenyl. In embodiments, G’ comprises an amino acid residue (e.g. lysine, ornithine, diaminobutyric acid, or diaminopropionic acid).

[0375] In embodiments, G’ is selected from the group comprising:, wherein Q is independently selected at each occurrence as a functional group capable of forming a bond (e.g. a peptide bond) with the N-terminus or C-terminus of the polymer backbone of a bottlebrush polymer of the invention.

[0376] In embodiments, G’ is selected from the group comprising:wherein Q is independently selected at each occurrence as a functional group capable of forming a bond (e.g. a peptide bond) with the N-terminus or C-terminus of the polymer backbone of a bottlebrush polymer of the invention.

[0377] In embodiments, G’ is:wherein Q is a functional group capable of forming a bond (e.g. a peptide bond) with the N-terminus or C-terminus of the polymer backbone of a bottlebrush polymer of the invention.

[0378] In embodiments, G’ is selected from the group comprising:

[0379] In embodiments, G’ is selected from the group comprising:

[0381] In embodiments, G’ is selected from:

[0383] Thus, it may be that the polymer backbone is of formula (IV-a1):

[0384] In embodiments, in each branch, r is at least 3 and the method further comprises: (d) forming a further subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing a third X’ in each branch, that comprises an orthogonal protecting group to each of the first X’ and the second X’, thereby deprotecting the amino acids in at least a third Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of each of (b) iii) and (c) iii).

[0385] In embodiments, in each branch, r is at least 4 and the method further comprises: (e) forming a further subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing a fourth X’ in each branch, that comprises an orthogonal protecting group to each of the first X’, the second X’ and the third X’, thereby deprotecting the amino acids in at least a fourth Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of each of (b) iii), (c) iii) and (d) iii).

[0386] In embodiments where r is greater than 4, at least one of steps (b), (c), (d) and (e) forms more than one functionalised specific block in each branch, with the proviso that said more than one functionalised block does not comprise adjacent instances of Z’.

[0387] In embodiments, in at least one branch of the branched polypeptide, r is independently selected from 2-20. For example, at least one branch, r may be independently 2-15, 2-10, 2-8,or 2-6. For example, in at least one branch, r may be independently 3-20, 3-15, 3-10, 3-8, or 3- 6. In at least one branch, r may be independently 4-20, 4-15, 4-10, 4-8, or 4-6.

[0388] In at least one branch, r may be 2. In at least one branch, r may be 3. In at least one branch, r may be 4. In at least one branch, r may be 5. In at least one branch, r may be 6. In at least one branch, r may be 7. In at least one branch, r may be 8. In at least one branch, r may be 9. In at least one branch, r may be 10. In at least one branch, r may be 11. In at least one branch, r may be 12. In at least one branch, r may be 13. In at least one branch, r may be 14. In at least one branch, r may be 15. In at least one branch, r may be 16. In at least one branch, r may be 17. In at least one branch, r may be 18. In at least one branch, r may be 19. In at least one branch, r may be 20.

[0389] In each branch, r may be 2. In each branch, r may be 3. In each branch, r may be 4. In each branch, r may be 5. In each branch, r may be 6. In each branch, r may be 7. In each branch, r may be 8. In each branch, r may be 9. In each branch, r may be 10. In each branch, r may be 11. In each branch, r may be 12. In each branch, r may be 13. In each branch, r may be 14. In each branch, r may be 15. In each branch, r may be 16. In each branch, r may be 17. In each branch, r may be 18. In each branch, r may be 19. In each branch, r may be 20.

[0390] In embodiments, each R1zis C1-4alkyl, e.g. methyl. In embodiments, each R1zis H.

[0391] In embodiments, each R2zis C1-4alkyl, e.g. methyl. In embodiments, each R2zis H.

[0392] In embodiments, the moiety of formula (Ib’) or (Ic’) is a moiety of formula (Ib’1) or (Ic’1), and the invention provides a method of preparing a macromolecule, comprising: (a) forming a polymer backbone of formula (IVa) or (IVb) by extending a branched polypeptide comprising protected amino acid residues, wherein each of Y1’, Y2’, Y3’and Y4’is independently a moiety of formula (Ib’1) or (Ic’1):wherein in each of Y1’, Y2’, Y3’and Y4’, each of the following groups are independently defined as follows: each of R1, R2, R3, R4and R5is independently selected from H and C1-4 alkyl; each of R6, R7, R8, R9and R10is independently selected from H and C1-4 alkyl; each Rais H or CH3;; each Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, and; each Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2,; each of L1, L2, L3 and L4 is independently selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; m is 2, 3, 4, or 5; each of n1 and n2 is independently selected from 5-100; each of n3, n4 and n5 is independently selected from 0-100; each of p1, p2, p3, p4 and p5 is independently selected from 5 to 100; each of A’, B’, C’, D’ and E’ is a protecting group, with the proviso that: A’ is an orthogonal protecting group to B’, B’ is an orthogonal protecting group to C’ (when C’ is present), C’ is an orthogonal protecting group to D’ (when C’ and D’ are present), D’ is an orthogonal protecting group to E’ (when D’ and E’ are present); and X is a solid support; or a salt or solvate thereof; (b) forming a functionalised specific block in each branch of the branched polypeptide by: i) removing A’, thereby deprotecting the amino acids in a second block of length n1by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues;ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing B’, thereby deprotecting the amino acids in a first block of length n2 by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

[0393] In embodiments, each moiety of formula (Ib’) or (Ic’) is a moiety of formula (Ib’2) orwherein R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, L1, L2, L3, L4, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (Ib’) or (Ic’). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0394] In embodiments, each moiety of formula (Ib’) or (Ic’) is a moiety of formula (Ib’3) or (Ic’3):wherein each of Ra, Rb, Rc, Rd, Re, Rf, L1, L2, L3, L4, m, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (Ib’) or (Ic’). It may be that n5 is 0. It may be that n4 and n5 are 0.

[0395] In embodiments, the compound of formula (Ib’) or (Ic’) is a compound of formula (Ib’4)wherein each of L1, L2, L3, L4, m, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (Ib’) or (Ic’). It may be that n5is 0. It may be that n4and n5are 0.

[0396] In embodiments, each moiety of formula (Ib’) or (Ic’) is a moiety of formula (Ib’5) orwherein each of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, L1, L2, L3, L4, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (Ib’) or (Ic’). It may be that n5is 0. It may be that n4and n5are 0.

[0397] In embodiments, each moiety of formula (Ib’) or (Ic’) is a moiety of formula (Ib’6) orwherein each of L1, L2, L3, L4, n1, n2, n3, n4, n5, A’, B’, C’, D’ and E’ are as defined in formula (Ib’) or (Ic’). It may be that n5is 0. It may be that n4and n5are 0.

[0398] In embodiments, each moiety of formula (Ib’) or (Ic’) is a moiety of formula (Ib’7) orwherein each of R1, R2, R3, R6, R7, R8, Ra, Rb, Rc, Rd, L1, L2, n1, n2, n3, A’, B’ and C’ are as defined in formula (Ib’) or (Ic’), wherein A’ and C’ are the same.

[0399] In embodiments, n3 is not 0 and C’ is an orthogonal protecting group to B’ (and optionally also orthogonal to A’), the method further comprising: (d) forming a further subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing C’, thereby deprotecting the amino acids in a third block of length n3by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues;ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (c) iii) (and optionally also different to the reactive group or ligand of (b) iii)).

[0400] In embodiments, n4 is not 0 and D’ is an orthogonal protecting group to C’ (and optionally also orthogonal to A’ and / or B’), the method further comprising: (e) forming a further subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing D’, thereby deprotecting the amino acids in a fourth block of length n4by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (d) iii) (and optionally also different to the reactive group or ligand of (b) iii) and / or (c) iii)).

[0401] In embodiments, n5is not 0 and E’ is an orthogonal protecting group to D’ (and optionally A’ and / or B’ and / or C’), the method further comprising: (f) forming a further subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing E’, thereby deprotecting the amino acids in a fifth block of length n5by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (e) iii), (and optionally also different to the reactive group or ligand of (b) iii) and / or (c) iii) and / or (d) iii)).

[0402] In embodiments, in each branch, each polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4 alkylglycine), poly(glycine), poly(N-C1-4 alkylalanine), poly(alanine), or copolymers thereof. In embodiments, in each branch, each polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4 alkylglycine) and poly(glycine). In embodiments, in each branch, each polypeptide, polypeptoid or polypept(o)ide is poly(N-C1-4 alkylglycine).

[0403] In embodiments, in each branch, the poly(N-C1-4 alkylglycine) is selected from poly(N- methylglycine), poly(N-ethylglycine) or poly(N-isopropylglycine). In embodiments, in each branch, the poly(N-C1-4 alkylglycine) is selected from poly(N-methylglycine) and poly(N- ethylglycine). In embodiments, in each branch, the poly(N-C1-4 alkylglycine) is poly(N- methylglycine).

[0404] In embodiments, in each branch, the poly(N-C1-4 alkylalanine) is selected from poly(N- methylalanine), poly(N-ethylalanine) or poly(N-isopropylalanine). In embodiments, in each branch, the poly(N-C1-4 alkylalanine) is selected from poly(N-methylalanine) and poly(N- ethylalanine). In embodiments, in each branch, the poly(N-C1-4alkylalanine) is poly(N- methylalanine).

[0405] The following definitions may apply independently to each of the branches of the branched polypeptide.

[0406] In embodiments, R1is C1-4alkyl, e.g. methyl. In embodiments, R1is H.

[0407] In embodiments, R2is C1-4 alkyl, e.g. methyl. In embodiments, R2is H.

[0408] In embodiments, R3is C1-4alkyl, e.g. methyl. In embodiments, R3is H.

[0409] In embodiments, R4is C1-4alkyl, e.g. methyl. In embodiments, R4is H.

[0410] In embodiments, R5is C1-4alkyl, e.g. methyl. In embodiments, R5is H.

[0411] In embodiments, each of R1, R2, R3, R4and R5is H or methyl. In embodiments, each of R1, R2, R3, R4and R5is H.

[0412] In embodiments, R6is C1-4alkyl, e.g. methyl. In embodiments, R6is H.

[0413] In embodiments, R7is C1-4alkyl, e.g. methyl. In embodiments, R7is H.

[0414] In embodiments, R8is C1-4alkyl, e.g. methyl. In embodiments, R8is H.

[0415] In embodiments, R9is C1-4alkyl, e.g. methyl. In embodiments, R9is H.

[0416] In embodiments, R10is C1-4alkyl, e.g. methyl. In embodiments, R10is H.

[0417] In embodiments, each of R6, R7, R8, R9and R10is H or methyl. In embodiments, each of R6, R7, R8, R9and R10is H.

[0418] In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H or methyl. In embodiments, each of R1, R2, R3, R4, R5, R6, R7, R8, R9and R10is H.

[0419] In embodiments, each Rais H. In embodiments, each Rais CH3.

[0420] In embodiments, each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rbis independently selected from H or CH3. In embodiments, each Rbis H or CH3. In embodiments, each Rbis H.

[0421] In embodiments, each Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rcis independently selected from H or CH3. In embodiments, each Rcis H or CH3. In embodiments, each Rcis H.

[0422] In embodiments, each Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rdis independently selected from H or CH3. In embodiments, each Rdis H or CH3. In embodiments, each Rdis H.

[0423] In embodiments, each Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Reis independently selected from H or CH3. In embodiments, each Reis H or CH3. In embodiments, each Reis H.

[0424] In embodiments, each Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), and N(CH3)2. In embodiments, each Rfis independently selected from H or CH3. In embodiments, each Rfis H or CH3. In embodiments, each Rfis H.

[0425] In embodiments, each instance of Ra, Rb, Rc, Rd, Reand Rfis H or CH3. In embodiments, each instance of Ra, Rb, Rc, Rd, Reand Rfis H.

[0426] In embodiments, L1is a bond. In alternative embodiments, L1is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0427] Where L1 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0428] In embodiments, where present, L2is a bond. In alternative embodiments, L2is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0429] Where L2is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0430] In embodiments, where present, L3 is a bond. In alternative embodiments, L3 is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0431] Where L3 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0432] In embodiments, where present, L4 is a bond. In alternative embodiments, L4 is at least one amino acid residue which lacks an amino moiety on its sidechain.

[0433] Where L4 is at least one amino acid residue which lacks an amino moiety on its sidechain, the at least one amino acid residue which lacks an amino moiety on its sidechainmay comprise from 1 to 10 said amino acids. For example, the at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 2 to 8, 2 to 6, or 2 to 4 said amino acids.

[0434] In embodiments, if present, each of L2, L3 and L4 is a bond. In alternative embodiments, if present, one, two or three of L2, L3 and L4 is at least one amino acid residue which lacks an amino moiety on its sidechain. The at least one amino acid residue which lacks an amino moiety on its sidechain may comprise from 1 to 10 said amino acids.

[0435] In embodiments, any of said at least one amino acid which lacks an amino moiety on its sidechain is selected from glycine, alanine, protected lysine, protected or unprotected glutamic acid, protected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine. Where the at least one amino acid is protected, the at least one amino acid is protected by a protecting group as defined herein. In embodiments, the at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycine, alanine.

[0436] In embodiments, m is 2. In embodiments, m is 3. In embodiments, m is 4. In embodiments, m is 5.

[0437] In embodiments, m is 2, 3 or 4, and / or each Rb, Rc, Rd, Reand Rfis H or CH3. In embodiments, m is 2, 3 or 4, and / or each Rb, Rc, Rd, Reand Rfis H. In embodiments, m is 4, and / or each Rb, Rc, Rd, Reand Rfis H.

[0438] In embodiments, n1is selected from 5 to 90, from 5 to 80, from 5 to 70, from 5 to 60, from 5 to 50, from 5 to 40, from 5 to 30, from 5 to 20, or from 5 to 10.

[0439] In embodiments, n2is selected from 5 to 90, from 5 to 80, from 5 to 70, from 5 to 60, from 5 to 50, from 5 to 40, from 5 to 30, from 5 to 20, or from 5 to 10.

[0440] In embodiments, n3is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n3is 0.

[0441] In embodiments, n4 is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n4 is 0.

[0442] In embodiments, n5 is selected from 0 to 90, from 0 to 80, from 0 to 70, from 0 to 60, from 0 to 50, from 0 to 40, from 0 to 30, from 0 to 20, or from 0 to 10. In embodiments, n5 is 0.

[0443] In embodiments, n4 and n5 are 0. In embodiments, n3, n4 and n5 are 0.

[0444] In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 10 to 60. In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 30 to 50. In embodiments, each of p1, p2, p3, p4 and p5 are independently selected from 35 to 45.

[0445] A’, B’, C’, D’ and E’ may be independently selected from the group comprising: N- Fluorenylmethoxycarbonyl (Fmoc), 2-(4-Nitrophenylsulfonyl)ethoxycarbonyl (Nsc), 1-(4,4- Dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde), 1-(4,4-dimethyl-2,6-dioxocyclohex-1-ylidene)isovaleryl (ivDde), allyloxycarbonyl (Alloc), benzyloxycarbonyl (Cbz), phthalimide, sulfonamide, 2,4,6-Triisopropylsulfonamide (Trs), tert-butoxycarbonyl (Boc), 2-(4-biphenylyl)-2- propyloxycarbonyl (Bpoc), trityl, monomethoxytrityl (MMT), 2,4-Dimethoxybenzyl (DMB), N- Diphenylmethyleneamine, 2-(Trimethylsilyl)-ethoxycarbonyl (Teoc), 2-Trimethylsilylethoxymethyl (SEM), 6-nitroveratryloxycarbonyl (NVOC), 2,2’-bis(2-nitrophenyl)ethoxycarbonyl (diNPEOC), benzoyl, and benzyl. A’, B’, C’, D’ and E’ may be independently selected from the group comprising: Boc, Alloc, ivDde, and Mmt.

[0446] In embodiments, each reactive group is independently selected from a nucleophile, an electrophile and a photoactivatable group. For example, each reactive group may be independently selected from a moiety comprising an amine, an azide, a carboxylic acid, an alkyne, an activated alkyne, phosphite, phosphine, thiol, transcyclooctene, and tetrazine.

[0447] In embodiments, each ligand is independently selected from an amino acid, a peptide, a protein, a polysaccharide, a nucleoside, a nucleotide, an oligonucleotide, a nucleic acid, a hapten, a psoralen, a drug, a hormone, a vitamin, a lipid, a lipid assembly (such as a biological membrane or liposome), a synthetic polymer, a polymeric nanoparticle or microparticle, a biological cell, a virus derived component (such as a viral derived protein, nucleic acid, lipid or carbohydrate, or combination thereof), a chromophore, a fluorophore, a dye, a radioisotope and a capping group (e.g. an acetyl group).

[0448] In embodiments, the macromolecule has a polydispersity index (Ð) of less than about 1.4. The macromolecule may have a polydispersity index (Ð) of less than about 1.2. The macromolecule may have a polydispersity index (Ð) of less than about 1.1.

[0449] In embodiments, the method may further comprise ligating one or more of Y1’, Y2’, Y3’and Y4’to G’.

[0450] In embodiments, the ligating comprises click chemistry, Pictet-Spengler ligation, and / or native chemical ligation. Suitable conditions and reagents for performing these ligating reactions are well-established in the art (Meldal et al., Macromolecular Rapid Communications 2008, 29 (12-13), 1016-1051; Pomplun et al., Angew Chem Int Ed Engl, 2019, 58 (11), 3542-3547; and Dawson et al., Science (New York, N.Y.) 1994, 266 (5186), 776-9).

[0451] In another aspect, the invention provides a bottlebrush polymer or macromolecule obtainable by or obtained by the methods of the invention. USES

[0452] In an aspect of the present invention, the invention provides a bottlebrush polymer or macromolecule of the invention or disclosure for use as a medicament.

[0453] The bottlebrush polymers or macromolecules of the invention or disclosure may be used in biomedical applications. For example, when the bottlebrush polymers comprise a bioactive ligand, the bottlebrush polymers may be used in cell targeting, drug delivery, magneticresonance imaging (MRI), fluorescence imaging and biodetection (Zili Li et al., Progress in Polymer Science, 116, 2021, 101387); Hörtz et al., Macromolecules, 2015, 48, 2074-2086). EXAMPLES Materials and Methods

[0454] All reagents and solvents were purchased from Sigma-Aldrich and were used as received unless specified otherwise. N, N-Dimethylformamide (DMF) was acquired from Fisher Scientific (99.8% purity, further dried over molecular sieves) and subjected to repetitive freeze- pump-thaw cycles for purification (water content, <50 ppm). Milli-Q (MQ) water was generated using a MILLI-Q Reference A+ system, ensuring a resistivity of 18.2 MΩ·cm-1and total organic carbon of < 5 ppm. Hexafluoroisopropanol (HFIP) and potassium trifluoroacetate were sourced from Fluorochem. Deuterated solvents were obtained from Deutero GmbH and utilized without further treatment. Characterisation methods

[0455] Proton nuclear magnetic resonance (1H NMR) spectra were acquired on a Bruker Avance II 400 at room temperature operating at 400 MHz. DOSY NMR spectra were recorded on a Bruker Avance II 400 using a bipolar pulse program (stebpgp1s) with d20 = 0.2 and p30 = 2750 μs for gradient amplitudes from 5 to 95%. Spectral calibration was performed using solvent signals, and the analysis was conducted using MestReNova version 14.0.0 from Mestrelab Research S.L.

[0456] Size-exclusion chromatography (SEC) was conducted using a Jasco SEC setup operating at a flow rate of 1.0 mL·min-1and a temperature of 40 °C. HFIP served as the eluent, containing potassium trifluoroacetate (3 g·L-1). The column material was sourced from PSS Polymer Standards Service GmbH, featuring modified silica gel as the column material (PFG columns, particle size: 7 μm, porosities: 100 and 1000 Å). For polymer detection, a UV detector (Jasco UV-2075+) at a wavelength of λ = 230 nm was utilized with toluene employed as an internal standard. The elution data were evaluated using PSS WinGPC (PSS Polymer Standards Service GmbH).

[0457] Single-angle dynamic light scattering (DLS) measurements were conducted using a ZetaSizer Nano ZS instrument (Malvern Instruments Ltd, Worcestershire, UK) equipped with a He-Ne laser (λ = 632.8 nm) as the incident beam. These measurements were performed at 25 °C and a detection angle of 173°.

[0458] Scanning force microscopy (SFM) measurements were conducted in air using a Dimension ICON (Bruker) in tapping mode (OTESPA (Bruker), back-side coated with a nominalresonance frequency of 300 kHz and a spring constant of 26 N·m-1). We prepared samples by drop-casting a particle solution (20 μL; 1 mg·L-1in MQ water) onto freshly cleaved mica substrates. The prepared samples were allowed to dry overnight at room temperature in vacuum 1 kPa. SFM images were analyzed using Gwyddion software. Exemplary Solid-Phase Peptide Synthesis

[0459] Fmoc-Ala-OH and Fmoc-Lys(Boc)-OH were purchased from Novabiochem. Fmoc-Lys(Fmoc)-OH and Fmoc-Lys(IvDde)-OH were obtained from BLDpharm and Iris Biotech GmbH, respectively.

[0460] The poly-lysine sequences were assembled with a Syro I peptide synthesizer using 9-fluorenylmethoxycarbonyl (Fmoc)-based solid phase peptide chemistry on a 8 µmol scale. The synthesis was initiated on a H-Rinkamide-chemmatrix resin (high loading, 0.41 mmol / g) with an 8-fold excess of the amino acid in each prolongation step. A total of 7.2 equivalents of the activating reagents N,N'-diisopropylcarbodiimide (DIC) and Oxyma Pure were added consecutively. Each coupling reaction was performed at 70 °C for 8-16 min and each cycle was finalized with an Fmoc-deprotection in 20 v / v% piperidine solution in DMF (+2% formic acid) for 4 min at 70 °C.

[0461] The resin was subjected to a cleavage cocktail of TFA:TIS:H2O (v:v:v, 95:2.5:2.5, 4 ml) for 2 hours, after which the filtrate was concentrated under a flow of nitrogen gas. The resulting residue was precipitated in ice-cold Et2O (50 ml) and pelleted (10.000 RCF, 5 min). The solvent was carefully decanted and the crude residue was purified by reversed-phase column chromatography (Sfär Bio C18, 300 A) using an 15-45% gradient of MeCN in milliQ grade water containing 0.1% TFA as additive.

[0462] The fractions were analyzed on a SCIEX X500B QTOF equipped with a Synergi Fusion-RP column (4 µm, 80 Å, 50x2 mm) and a Shimadzu LCMS-2020 equipped with a Kinetex XB-C18 column (2.6 µm, 100 Å, 50x3 mm), both using Buffer A (0.1% formic acid in water) and buffer B (0.1% formic acid in MeCN). Product fractions were combined and lyophilized to yield a fluffy white solid. The molecular weight of the product was reconstructed based on the observed charge states using the SCIEX Bio Tool Kit software. Example 1: Synthesis of bottlebrush polymer (Alloc)]10[Lys(Boc)40][Lys(Alloc)]10

[0463] A polylysine-based brush backbone may assembled via solid phase synthesis. Different patches of lysines are blocked with different orthogonal protecting groups (e.g., Boc and Alloc). The stepwise deprotection of specific lysines segments within the backbone polymeris leveraged to initiate the controlled living ring opening polymerization of sarcosine N- carboxyanhydride (Birke et al., Progress in Polymer Science, 2019; Fetsch et al., Macromolecules 2013). Even in a grafting-from synthesis, polysarcosine chain length can be easily adjusted by controlling the ratio of initiator to monomer ratio (Hörtz et al, Macormolecules 2016; Kappel et al. ACS Nano 2021), while quantitative end group integrity can be achieved (Birke et al., Progress in Polymer Science 2019). Without wishing to be bound by theory, it is thought that the high grafting density in bottlebrush polymers leads to stretched polymer side chains, which transfers the structural information encrypted in the polymer backbone to the nanoparticle surface, thereby providing full control of size, shape and surface functionality in synthetic nanoparticles

[0464] A solid support was treated with trifluoroacetic acid to release a sequence defined polymer backbone, and concomitantly remove all Boc protecting groups. As determined by LC- MS, the resulting 60-mer [Lys(Alloc)]10Lys40[Lys(Alloc)] was obtained high purity. The synthesis took less than one day. The stepwise sarcosine-NCA polymerization was then initiated by the free lysine side chains. The backbone with the free lysine block is dissolved in DMF. After 1 h stirring with DIPEA, sarcosine NCA (40 eq. with respect to the free amine) in DMF was added. The solution was stirred at room temperature and kept at a constant pressure of 1.25 bar of dry nitrogen (Schlenk techniques) to prevent impurities from entering the reaction vessel while allowing CO2to escape.

[0465] When the reaction was finished (completion of the reaction was confirmed by IR spectroscopy), the sarcosine polymers were end-capped with azidobutyric acid pentafluorphenylester. NMR results confirmed the number of repeat units. The Alloc protective group was then removed from the remaining lysines and sarcosine polymerization was then performed on the remaining backbone to form a bottlebrush polymer with patterned surface functionality.

[0466] Step 1: N-ε-Benzyloxycarbonyl-l-lysine-N-carboxyanhydride (Lys(Z)NCA) synthesis.

[0467] In a three-neckedflask equipped with a reflux condenser, dropping funnel, and septum, 14.00 g (50 mmol, 1.0 eq) of Z-protected lysine was suspended in 100 mL of THF, and the suspension was heated to 70 °C.6.6 mL (55 mmol, 1.1 eq) of diphosgene was added over 30 min. The solution was heated until all solid disappeared (30-60 min). Dry nitrogen was then bubbled through the solution for 2-3 h to remove excess HCl and phosgene. The solution was concentrated in vacuo, and dry cyclohexane was added to precipitate the NCA. The suspension was stored in the fridge for 1 h. The solid was collected byfiltration in an inert atmosphere and washed with cyclohexane. It was then dissolved in the smallest possible volume of THF, and again cyclohexane was added to precipitate the product. The suspension was left in the fridge overnight. The solid was then collected byfiltration in an inert atmosphere and dried in a stream of dry nitrogen. The recrystallization was repeated and AgNO3(0.1 M in water) was added to the filtrate, to confirm the absence of chloride ions (AgCl would immediately precipitate as a colorless solid). The Lys(Z)NCA, a colorless solid (Yield: 86%), was transferred to a Schlenk tube and stored at −80 °C; mp = 99 °C.1H NMR (400 MHz, DMSO-d6) δ [ppm] = 9.09 (s, 1H, CONH−Cα), 7.40−7.25 (m, 6H, Ar H, NH(Z)), 5.01 (s, 2H, NHCH2Ph), 4.43 (t, 1H, CαH), 2.99 (q, 2H, CH2NH), 1.74−1.63 (m, 2H, CH−CH2), 1.44−1.31 (m, 4H, CH2−CH2).

[0468] Step 2: Sarcosine NCA (Sar-NCA) synthesis

[0470] Sarcosine (15.16 g, 170.2 mmol, 1 eq) was weighed into a pre-dried three neck round bottomed flask and dried in vacuo overnight.300 mL THF were added under a steady flow of nitrogen and diphosgene (16.26 ml, 136.2 mmol, 0.8 eq) was added slowly via a syringe. The colorless suspension was heated to 70 °C yielding a clear solution after 3 h of stirring. A steady flow of dry nitrogen was lead through the solution into two gas washing bottles filled withaqueous sodium hydroxide solution to remove excess HCl and phosgene. The solvent was evaporated under reduced pressure yielding a brown oil as crude reaction product. The oil was heated to 50 °C and dried under reduced pressure (20 mbar, then < 10-1mbar for 2 h) to obtain an amorphous solid. The crude reaction product was redissolved in 60 mL THF and precipitated with 300 mL dry n-hexane. The solution was cooled to −18 °C to complete precipitation and was filtered off under dry nitrogen atmosphere. Afterwards, a stream of dry nitrogen was used to dry the product for 60-90 min to remove residual traces of THF. The next day the product was dried in high vacuum for 2 h in the sublimation apparatus. Then, the crude product was sublimated at 80-85 °C and < 1 × 10-2mbar. The product was collected from the sublimation apparatus in a glove box on the same day and aliquoted subsequently afterwards when the melting point was above 100 °C. Colorless crystals were obtained (60 %). mp = 103 °C,1H NMR (400 MHz, CDCl3) δ [ppm] = 4.22 (s, 2H, NH-CH2-CO), 2.86 (s, 3H, NH-CH3).

[0471] Step 3: Peptobody (Y-shape) polymerisation

[0472] In general, the monodisperse macroinitiator (10.00 mg, 0.79 µmol, 1.0 eq) was weighed into a predried Schlenk tube and dried by azeotropic distillation with toluene in vacuo overnight. Next, the macroinitiator was dissolved in freshly degassed dry DMF (1.0 mL) and cooled to 10 °C. Then 1.2-fold excess DIPEA based on amine groups was added (11.56 μL, 66.36 µmol) to neutralize TFA salts. After stirring for 30 min, Sar-NCA (127.76 mg, 1.11 mmol, 1400 eq) was dissolved in dry DMF, cooled to 10 °C and added to the Schlenk tube via syringe. The polymerization was performed at an overall mass concentration of β = 100 g·L−1and monitored by IR spectroscopy. After 5 d, full conversion was observed and 1.2-fold excess acetic anhydride or azido-butyric acid pentafluorophenyl ester on amine groups was added and stirred for 2 d at room temperature. The peptobody crude product was dispersed in MQ water and centrifuged with Amicon Ultra Centrifugal Filters (50 kDa, 4000 rpm, 10 x 10 min). After lyophilization, a colourless product was obtained (Yield: 85%). The size of the peptobody was confirmed by atomic force microscopy.

[0473] 1H NMR (400 MHz, D2O): δ [ppm] = 4.6-4.0 (br, -CO-CH-NH- and –NCH3-CH2-CO), 3.2-2.6 (br, -CH2-NH-CO-, –NCH3-CH2-CO-).

[0474] Example 3: Stability testing of Y-shaped peptobody

[0475] The influence of elevated solution temperatures and freeze-drying-solubilization cycles on the size distribution of peptobody was investigated. After being heated for 24 h at 60°C, the hydrodynamic diameter (Dh) of peptobody remained stable. Following two freeze cycles, the Dh was also stable, indicating the robust (thermal) stability of peptobody in aqueous solution.

Claims

CLAIMS 1. Bottlebrush polymers, comprising: a monodisperse polymer backbone; and defined bottlebrush side chains; wherein the polymer backbone is a polypeptide comprising amino acid residues with an amine moiety on the sidechain of each amino acid residue; wherein each of the defined bottlebrush sidechains is attached to the polymer backbone at the amine moiety of each of the respective amino acid residues; and wherein the defined bottlebrush sidechains comprise at least one block (optionally at least two blocks) of polypeptide, polypeptoid or polypept(o)ide, wherein, in each block of polypeptide, polypeptoid or polypept(o)ide, the polypeptide, polypeptoid or polypept(o)ide) is functionalised proximate to the end of its chain with a reactive group or ligand, wherein when there are at least two blocks the adjacent blocks of the at least two blocks do not comprise the same reactive group or ligand.

2. The bottlebrush polymers of claim 1, comprising at least two blocks of polypeptide, polypeptoid or polypept(o)ide.

3. The bottlebrush polymers of claim 1 or claim 2, wherein each block of polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4alkylglycine), poly(glycine), poly(N-C1-4alkylalanine), poly(alanine), (protected) poly(lysine), (protected) poly(glutamic acid), esters or amides thereof, or copolymers thereof.

4. The bottlebrush polymers of any preceding claim, wherein each of the at least two blocks of polypeptide, polypeptoid or polypept(o)ide is poly(N-C1-4alkylglycine).

5. The bottlebrush polymers of any preceding claim, wherein the polymer backbone substantially comprises (or consists of) amino acid residues with an amine moiety on the sidechain of each of the respective amino acid residues, optionally interrupted up to several times by at least one amino acid residue which lacks an amino moiety on its sidechain.

6. The bottlebrush polymers of any preceding claim, wherein the amine moiety on the sidechain is a primary or secondary amine.

7. The bottlebrush polymers of any preceding claim, wherein the amino acid residues with an amine moiety on the sidechain are all the same.

8. The bottlebrush polymers of any preceding claim, wherein the amino acid residues with an amine moiety on the sidechain are selected from lysine, ornithine, diaminobutyric acid, and diaminopropionic acid.

9. The bottlebrush polymers of any preceding claim, wherein each of the amino acid residues with an amine moiety on the sidechain is lysine.

10. The bottlebrush polymers of any preceding claim, wherein at least one amino acid residue which lacks an amino moiety on its sidechain is selected from glycine and alanine; optionally wherein the at least one amino acid residue which lacks an amino moiety on its sidechain comprises from 1 to 10 said amino acids.

11. The bottlebrush polymers of any preceding claim, wherein the polypeptide, polypeptoid or polypept(o)ide of the bottlebrush sidechain comprises a degree of polymerisation (DP) of from about 5 to about 100, optionally of from about 10 to about 60.

12. The bottlebrush polymers of any preceding claim, wherein the polymer backbone comprises a polypeptide that is from about 10 to about 300 amino acids in length; optionally wherein the polymer backbone is from about 20 to about 200 amino acids in length further optionally wherein the polymer backbone is from about 30 to about 150 amino acids in length.

13. A macromolecule comprising three or more bottlebrush polymers as defined in any of claims 1 to 12, wherein at least three of the three or more bottlebrush polymers are covalently linked to one another via the C-terminus or N-terminus of each bottlebrush polymer.

14. The macromolecule of claim 13, wherein the covalently linked to one another comprises covalent attachment to a core moiety, wherein each of the at least three of the three or more bottlebrush polymers is independently linked to the core moiety at the (optionally modified) C- terminus or N-terminus of the polymer backbone of the bottlebrush polymer.

15. The macromolecule of claim 14, wherein the core moiety comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue; optionally wherein the core moiety is an amino acid residue having an amine moiety on its sidechain; further optionally wherein the amino acid residue is lysine.

16. The macromolecule of claim 15, wherein each of the at least three bottlebrush polymer units is attached to the amino acid residue via a peptide bond.

17. The macromolecule of any of claims 13 to 16, wherein the macromolecule is formed from three bottlebrush polymer units.

18. The macromolecule of any claim 17, wherein two of the three bottlebrush polymer units are the same as one another.

19. Bottlebrush polymers of formula (I): CH3C(O)-[Z]r-NH2 (I) wherein: r is 1-20; and each instance of Z is:wherein: R1zis independently for each Z selected from H and C1-4alkyl; R2zis independently for each Z selected from H and C1-4alkyl; R3zis independently for each Z selected from H and C1-4alkyl; Rais independently for each Z selected from H and CH3; Rbis independently for each Z selected from H, CH3, CH2CH3, NH2, NH(CH3),L is independently for each Z selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; n is independently for each Z selected from 5-100; p is independently at each occurrence selected from 0-100; y is 2, 3, 4, or 5; and X is independently at each occurrence selected from a reactive group or a ligand, with the proviso that the X moieties on adjacent Z groups are different; or a salt or solvate thereof.

20. The bottlebrush polymers of claim 19, wherein the bottlebrush polymers are of formula (I-a):wherein: each of R1, R2, R3, R4and R5is independently selected from H and C1-4alkyl; each of R6, R7, R8, R9and R10is independently selected from H and C1-4alkyl; each of R11, R12, R13, R14and R15are independently selected from H and C1-4alkyl; each Rais H or CH3; each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach of L1, L2, L3 and L4 is independently selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; m is 2, 3, 4, or 5; each of n1 and n2 is independently selected from 5-100; each of n3, n4and n5are independently selected from 0-100; each of p1, p2, p3, p4and p5are independently selected from 5 to 100; each of A, B, C, D and E are independently selected from a reactive group or a ligand, with the proviso that A and B are different; or a salt or solvate thereof.

21. The bottlebrush polymers of claim 20, wherein each of R1, R2, R3, R4and R5is H.

22. The bottlebrush polymers of claim 20 or claim 21, wherein each of R6, R7, R8, R9and R10is H or methyl.

23. The bottlebrush polymers of any of claims 20-22, wherein each of R11, R12, R13, R14and R15is methyl.

24. The bottlebrush polymers of any of claims 20-23, wherein m is 4 and / or each Rb, Rc, Rd, Reand Rfis H or methyl.

25. The bottlebrush polymers of any of claims 20-24, wherein L1is a bond.

26. The bottlebrush polymers of any of claims 20-25, wherein L1is at least one amino acid residue which lacks an amino moiety on its sidechain; optionally wherein the at least one amino acid residue which lacks an amino moiety on its sidechain comprises from 1 to 10 said amino acids.

27. The bottlebrush polymers of any of claims 20-26, wherein, if present, each of L2, L3 and L4 is a bond.

28. The bottlebrush polymers of any of claims 20-27, wherein, if present, one, two or three of L2, L3 and L4 is at least one amino acid residue which lacks an amino moiety on its sidechain; optionally wherein the at least one amino acid residue which lacks an amino moiety on its sidechain comprises from 1 to 10 said amino acids.

29. The bottlebrush polymers of any of claims 20-28, wherein said at least one amino acid which lacks an amino moiety on its sidechain is selected from glycine, alanine, protected lysine, protected or unprotected glutamic acid, protected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine.

30. The bottlebrush polymers of any of claims 20-29, wherein each of p1, p2, p3, p4 and p5 are independently selected from 30 to 50.

31. The bottlebrush polymers of any preceding claim, wherein each reactive group is independently selected from a nucleophile, an electrophile and a photoactivatable group.

32. The bottlebrush polymers of any preceding claim, wherein each reactive group is independently selected from a moiety comprising an amine, an azide, a carboxylic acid, an alkyne, an activated alkyne, phosphite, phosphine, thiol, transcyclooctene, and tetrazine.

33. The bottlebrush polymers of any preceding claim, wherein each ligand is independently selected from an amino acid, a peptide, a protein, a polysaccharide, a nucleoside, a nucleotide, an oligonucleotide, a nucleic acid, a hapten, a psoralen, a drug, a hormone, a vitamin, a lipid, a lipid assembly (such as a biological membrane or liposome), a synthetic polymer, a polymeric nanoparticle or microparticle, a biological cell, a virus derived component (such as a viral- derived protein, nucleic acid, lipid or carbohydrate, or combination thereof), a chromophore, a fluorophore, a dye, a radioisotope, and a capping group (e.g. an acetyl group).

34. The bottlebrush polymers of any preceding claim, having a polydispersity index (Ð) of less than about 1.4, optionally wherein the Ð is less than about 1.2, further optionally wherein the Ð is less than about 1.

1.

35. A macromolecule having a structure of formula (II-a) or (II-b):wherein G comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue, wherein each of Y1, Y2, Y3and Y4is independently a bottlebrush polymer moiety of formula (Ib) or (Ic): -C(O)-[Z]r-NH2 (Ib) CH3C(O)-[Z]r-NH- (Ic), wherein each of Y1, Y2, Y3and Y4is independently attached to G via the terminal - C(O)- or terminal -NH- group of formula (Ib) or (Ic), wherein: each r is independently an integer selected from 1-20; and each instance of Z is:wherein: R1zis independently for each Z selected from H and C1-4alkyl; R2zis independently for each Z selected from H and C1-4alkyl; R3zis independently for each Z selected from H and C1-4alkyl; Rais independently for each Z selected from H and CH3; Rbis independently for each Z selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andL is independently for each Z selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; n is independently for each Z selected from 5-100; p is independently at each occurrence selected from 0-100; y is 2, 3, 4 or 5; and X is independently at each occurrence selected from a reactive group or a ligand, with the proviso that the X moieties on adjacent Z groups are different; or a salt or solvate thereof.

36. The macromolecule of claim 35, wherein the macromolecule has a structure of formula37. The macromolecule of claim 35 or claim 36, wherein Y2and Y3are the same as one another.

38. The macromolecule of any of claims 35 to 37, wherein two of Y1, Y2and Y3are attached to G via their C-termini and the other one of Y1, Y2and Y3is attached to G via its N-terminus.

39. The macromolecule of claim 38, wherein G is selected from the group comprising:

40. The polymer of claim 39, wherein G is:.

41. The polymer of any of claims 35 to 40, wherein each of the bottlebrush polymer moieties are of formula (I-d) or (I-e):wherein each bottlebrush polymer moiety is independently further defined as follows: each of R1, R2, R3, R4and R5is independently selected from H and C1-4alkyl; each of R6, R7, R8, R9and R10is independently selected from H and C1-4alkyl;each of R11, R12, R13, R14and R15are independently selected from H and C1-4 alkyl; each Rais H or CH3; each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2, andeach of L1, L2, L3and L4is independently selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; m is 2, 3, 4, or 5; each of n1 and n2 is independently selected from 5-100; each of n3 , n4 and n5 are independently selected from 0-100; each of p1, p2, p3, p4 and p5 are independently selected from 5 to 100; each of A, B, C, D and E are independently selected from a reactive group or a ligand, with the proviso that A and B are different; or a salt or solvate thereof.

42. The polymer of claim 41, wherein the three or more bottlebrush polymer moieties are further independently defined according to any of claims 21 to 34.

43. A method of preparing a bottlebrush polymer, comprising:(a) forming a polymer backbone by extending a polypeptide comprising protected amino acid residues, the formed polypeptide backbone comprising at least one block of the protected amino acid residues, wherein in each specific block the protected amino acids: i) comprise an equivalent protecting group; and ii) when at least two blocks of protected amino acid residues are present, the equivalent protecting group is orthogonal to at least the protecting group of any adjacent specific block; (b) forming a functionalised specific block by: i) deprotecting the protected amino acid residues of a first of the specific blocks, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; wherein, when at least two blocks of protected amino acid residues are present, the method further comprises: (c) forming a subsequent functionalised specific block by: i) deprotecting the protected amino acid residues of a second specific block, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i); ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

44. The method of claim 43, wherein when at least three blocks of protected amino acid residues are present, the method further comprises, the polymer backbone comprises more than two types of orthogonal protecting group, the method further comprising: (d) forming one or more further subsequent functionalised specific block by: i) deprotecting the protected amino acid residues of said further subsequent functionalised specific block, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i), (c) i) (and any previous (d) i));ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii), (c) iii) (and any previous (d) iii)); and iv) repeating (d) i)-iii) until all protecting groups have been removed and all specific blocks have been functionalised.

45. The method of claim 43 or claim 44, wherein each polypeptide, polypeptoid or polypept(o)ide is selected from poly(N-C1-4alkylglycine), poly(glycine), poly(N-C1-4alkylalanine), poly(alanine), or copolymers thereof.

46. The method of any of claims 43 to 45, wherein each polypeptide, polypeptoid or polypept(o)ide is poly(N-C1-4alkylglycine).

47. The method of any of claims 43 to 46, wherein the polymer backbone comprises three or four equivalent protecting groups that are orthogonal to each other, optionally wherein the orthogonal equivalent protecting groups are selected from Boc, Alloc, ivDde, and Mmt.

48. The method of any of claims 43 to claim 47, wherein the equivalent protecting groups of each specific block comprise are selected from Boc, Alloc, ivDde, and Mmt.

49. The method of any of claims 43 to 48, wherein the polymer backbone substantially comprises (or consists of) protected amino acid residues with a protected active moiety on the sidechain, optionally interrupted up to several times by at least one amino acid residue which lacks an active moiety on its sidechain.

50. The method of claim 49, wherein the at least one amino acid residue which lacks an active moiety on its sidechain is selected from glycine, alanine, protected or unprotected lysine, protected or unprotected glutamic acid, protected or unprotected ornithine, protected or unprotected serine, protected or unprotected threonine, leucine and isoleucine; optionally wherein the at least one amino acid residue which lacks an active moiety on its sidechain comprises from 1 to 10 of said amino acids 51. The method of any of claims 43 to 50, wherein the active moiety on the sidechain of each of the deprotected amino acid residues is an amine, optionally a primary or secondary amine.

52. The method of any of claims 43 to 51, wherein the amino acid residues with an active moiety on the sidechain are all the same.

53. The method of any of claims 43 to 52, wherein the amino acid residues with an active moiety on the sidechain are selected from lysine, ornithine, diaminobutyric acid, and diaminopropionic acid.

54. The method of any of claims 43 to 53, wherein each of the amino acid residues with an active moiety on the sidechain is lysine.

55. The method of any of claims 43 to 54, wherein the formed polypeptide, polypeptoid or polypept(o)ide of the bottlerush sidechain comprises a degree of polymerisation (DP) of about 5 to about 100.

56. The method of any of claims 43 to 55, wherein the polymer backbone comprises a polypeptide that is from about 10 to about 300 amino acids in length; optionally wherein the polymer backbone is from about 20 to about 200 amino acids in length, further optionally wherein the polymer backbone is from about 30 to about 150 amino acids in length.

57. A method of preparing a macromolecule comprising three or more bottlebrush polymers, comprising: (a) forming a polymer backbone by extending a branched polypeptide comprising three or more branches of protected amino acid residues, the formed branched polypeptide backbone comprising at least one block of the protected amino acid residues in each branch of the branched polypeptide backbone, wherein in each specific block of each branch of branched polypeptide backbone, the protected amino acids: i) comprise an equivalent protecting group; and ii) when at least two blocks of protected amino acid residues are present, the equivalent protecting group is orthogonal to at least the protecting group of any adjacent specific block; and (b) forming a functionalised specific block in each branch of the branched polypeptide by: i) deprotecting the protected amino acid residues of a first of the specific blocks in each branch, thereby exposing an active moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; wherein, when at least two blocks of protected amino acid residues are present in each of the branches of the branched polypeptide, the method further comprises (c) forming a subsequent functionalised specific block in each branch of the branched polypeptide by: i) deprotecting the protected amino acid residues of a second specific block in each branch, thereby exposing an active moiety on the sidechain of each of the deprotectedamino acid residues, wherein said deprotecting comprises an orthogonal deprotecting to the deprotecting of (b) i); ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii)method of preparing a polymer comprising three or more bottlebrush polymer moieties, comprising: (a) performing the method of any of claims 43 to 56 three or more times to produce three or more bottlebrush polymers; and (b) ligating the three or more bottlebrush polymers to one another, optionally via a core moiety.

58. A method of preparing a bottlebrush polymer, comprising: (a) forming a polymer backbone of formula (III) by extending a polypeptide comprising protected amino acid residues: CH3C(O)-[Z’]r-NH-X’’ (III) wherein: r is 1-20 and each instance of Z’ is:wherein R1zis independently for each Z’ selected from H and C1-4 alkyl; R2zis independently for each Z’ selected from H and C1-4alkyl; Rais independently for each Z’ selected from H and CH3; Rbis independently for each Z’ selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2andn is independently for each Z’ selected from 5-100; y is 2, 3, 4 or 5; L is independently for each Z’ selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; X’ is independently for each Z’ is a protecting group, with the proviso that the X’ protecting group for each Z’ is an orthogonal protecting group to the X’ of any adjacent Z’and X’’ is a solid support; or a salt or solvate thereof; (b) forming a functionalised specific block by: i) removing a first X’, thereby deprotecting the amino acids in at least a first Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block by: i) removing a second X’, that comprises an orthogonal protecting group to the first X’, thereby deprotecting the amino acids in at least a second Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

59. The method of claim 58,wherein r is at least 3 and the method further comprises: (d) forming a further subsequent functionalised specific block by: i) removing a third X’, that comprises an orthogonal protecting group to each of the first X’ and the second X’, thereby deprotecting the amino acids in at least a third Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of each of (b) iii) and (c) iii).

60. The method of claim 58 or 59,wherein r is at least 4 and the method further comprises: (e) forming a further subsequent functionalised specific block by: i) removing a fourth X’, that comprises an orthogonal protecting group to each of the first X’, the second X’ and the third X’, thereby deprotecting the amino acids in at least a fourth Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; andiii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of each of (b) iii), (c) iii) and (d) iii).

61. The method of any of claims 58 to 60, where the compound of formula (III) is a compound of formula (III-a) and the method comprises: (a) forming a polymer backbone of formula (II-a) by extending a polypeptide comprising protected amino acid residues:wherein: each of R1, R2, R3, R4and R5is independently selected from H and C1-4 alkyl; each of R6, R7, R8, R9and R10is independently selected from H and C1-4 alkyl; each Rais H or CH3; each Rbis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2each Rcis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2,each Rdis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2,each Reis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2,each Rfis independently selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2,each of L1, L2, L3 and L4 is independently selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain;m is 2, 3, 4, or 5; each of n1 and n2 is independently selected from 5-100; each of n3, n4 and n5 is independently selected from 0-100; each of p1, p2, p3, p4 and p5 is independently selected from 5 to 100; each of A’, B’, C’, D’ and E’ is a protecting group, with the proviso that: A’ is an orthogonal protecting group to B’, B’ is an orthogonal protecting group to C’ (when C’ is present), C’ is an orthogonal protecting group to D’ (when C’ and D’ are present), D’ is an orthogonal protecting group to E’ (when D’ and E’ are present); and X is a solid support; or a salt or solvate thereof; (b) forming a functionalised specific block by: i) removing A’, thereby deprotecting the amino acids in a second block of length n1by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block by: i) removing B’, thereby deprotecting the amino acids in a first block of length n2by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

62. The method of claim 61, wherein n3 is not 0 and C’ is an orthogonal protecting group to B’ (and optionally also orthogonal to A’), the method further comprising: (d) forming a further subsequent functionalised specific block by: i) removing C’, thereby deprotecting the amino acids in a third block of length n3 by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is differentto the reactive group or ligand of (c) iii) (and optionally also different to the reactive group or ligand of (b) iii)).

63. The method of claim 61 or claim 62, wherein n4 is not 0 and D’ is an orthogonal protecting group to C’ (and optionally also orthogonal to A’ and / or B’), the method further comprising: (e) forming a further subsequent functionalised specific block by: i) removing D’, thereby deprotecting the amino acids in a fourth block of length n4 by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (d) iii) (and optionally also different to the reactive group or ligand of (b) iii) and / or (c) iii)).

64. The method of any of claims 61 to 63, wherein n5is not 0 and E’ is an orthogonal protecting group to D’ (and optionally A’ and / or B’ and / or C’), the method further comprising: (f) forming a further subsequent functionalised specific block by: i) removing E’, thereby deprotecting the amino acids in a fifth block of length n5by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (e) iii), (and optionally also different to the reactive group or ligand of (b) iii) and / or (c) iii) and / or (d) iii)).

65. The method of any of claims 61 to 64, wherein each polypeptide, polypeptoid or polypept(o)ide is independently selected from poly(N-C1-4 alkylglycine), poly(glycine), poly(N-C1-4 alkylalanine), poly(alanine), or copolymers thereof.

66. The method of any of claims 61 to 65, wherein each polypeptide, polypeptoid or polypept(o)ide is poly(N-C1-4 alkylglycine).

67. The method of any of claims 61 to 66, wherein each of R1, R2, R3, R4and R5is H or methyl.

68. The method of any of claims 61 to 67, wherein each of R6, R7, R8, R9and R10is H or methyl.

69. The method of any of claims 61 to 68, wherein m is 4 and / or each Rb, Rc, Rd, Reand Rfis H.

70. The method of any of claims 61 to 69, wherein L1 is a bond.

71. The method of any of claims 61 to 69, wherein L1 is at least one amino acid residue which lacks an amino moiety on its sidechain; optionally wherein the at least one amino acid residue which lacks an amino moiety on its sidechain comprises from 1 to 10 said amino acids.

72. The method of any of claims 58 to 71, wherein, if present, each of L, L2, L3 and L4 is a bond.

73. The method of any of claims 58 to 72, wherein, if present, one, two or three of L, L2, L3 and L4is at least one amino acid residue which lacks an amino moiety on its sidechain; optionally wherein the at least one amino acid residue which lacks an amino moiety on its sidechain comprises from 1 to 10 said amino acids.

74. The method of any of claims 58 to 73, wherein said at least one amino acid which lacks an amino moiety on its sidechain is selected from glycine, alanine, lysine, unprotected glutamic acid, protected glutamic acid, leucine, ornithine and isoleucine.

75. The method of any of claims 43 to 74, wherein each reactive group is independently selected from a nucleophile, an electrophile and a photoactivatable group.

76. The method of any of claims 43 to 75, wherein each reactive group is independently selected from a moiety comprising an amine, an azide, a carboxylic acid, an alkyne, an activated alkyne, phosphite, phosphine, thiol, transcyclooctene, tetrazine.

77. The method of any of claims 43 to 76, wherein each ligand is independently selected from an amino acid, a peptide, a protein, a polysaccharide, a nucleoside, a nucleotide, an oligonucleotide, a nucleic acid, a hapten, a psoralen, a drug, a hormone, a vitamin, a lipid, a lipid assembly (such as a biological membrane or liposome), a synthetic polymer, a polymeric nanoparticle or microparticle, a biological cell, a virus derived component (such as a viral derived protein, nucleic acid, lipid or carbohydrate, or combination thereof), a chromophore, a fluorophore, a dye, a radioisotope, and a capping group (e.g. an acetyl group).

78. The method of any of claims 43 to 77, wherein the prepared bottlebrush comprises a polydispersity index (Ð) of less than about 1.4, optionally wherein the Ð is less than about 1.2, further optionally wherein the Ð is less than about 1.

1.

79. A method of forming a bottlebrush polymer with a longer polymer backbone, comprising: (a) obtaining at least two bottlebrush polymers of any of claims 1 to 34, or performing the method of any of claims 43 to 78 at least twice to obtain at least two bottlebrush polymers; and (b) ligating the polymer backbones of the at least two bottlebrush polymers.

80. The method of claim 79, wherein the ligating comprises click chemistry, Pictet-Spengler ligation, and / or native chemical ligation.

81. A method of preparing a macromolecule comprising(a) forming a polymer backbone of formula (IVa) or (IVb) by extending a branched polypeptide comprising protected amino acid residues:wherein G’ comprises an aryl ring, a heteroaryl ring, a cycloalkyl ring, a heterocycloalkyl ring, or an amino acid residue, wherein each of Y1’, Y2’, Y3’and Y4’is independently a moiety of formula (Ib’) or (Ic’): -C(O)-[Z’]r-NH2 (Ib’) CH3C(O)-[Z‘]r-NH- (Ic’), wherein each of Y1’, Y2’, Y3’and Y4’is independently attached to G’ via the terminal -C(O)- or terminal -NH- group of formula (Ib’) or (Ic’), wherein: each instance of r is independently an integer selected from 1-20 and each instance of Z’ is:wherein R1zis independently for each Z’ selected from H and C1-4 alkyl; R2zis independently for each Z’ selected from H and C1-4 alkyl; Rais independently for each Z’ selected from H and CH3; Rbis independently for each Z’ selected from H, CH3, CH2CH3, NH2, NH(CH3), N(CH3)2 andn is independently for each Z’ selected from 5-100; y is 2, 3, 4 or 5; L is independently for each Z’ selected from a bond and at least one amino acid residue which lacks an amino moiety on its sidechain; X’ is independently for each Z’ is a protecting group, with the proviso that the X’ protecting group for each Z’ is an orthogonal protecting group to the X’ of any adjacent Z’;or a salt or solvate thereof wherein the branched polypeptide is attached to a solid support where chemically possible; (b) forming a functionalised specific block in each branch of the branched polypeptide by: i) removing a first X’ in each branch, thereby deprotecting the amino acids in at least a first Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand; (c) forming a subsequent functionalised specific block in each branch of the branched polypeptide by: i) removing a second X’ in each branch, that comprises an orthogonal protecting group to the first X’, thereby deprotecting the amino acids in at least a second Z’ by exposing an amine moiety on the sidechain of each of the deprotected amino acid residues; ii) forming a polypeptide, polypeptoid or polypept(o)ide on each of the exposed active moiety on said sidechain; and iii) functionalising the polypeptide, polypeptoid or polypept(o)ide proximate to the end of its chain with a reactive group or ligand, wherein said reactive group or ligand is different to the reactive group or ligand of (b) iii).

82. A bottlebrush polymer obtainable by or obtained by the method of any of claims 43 to 81.

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