Methods for identifying a labelled species

Abstract

A method of identifying a labelled species, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a unique derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof of the labelled species so as to selectively retain each of the labelled species of the library on a corresponding capture site; and selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species.

Description

METHODS FOR IDENTIFYING A LABELLED SPECIES CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Application No.63 / 548, 695, titled SYSTEMS, APPARATUS AND METHODS FOR MULTIDIMENSIONAL MOVEMENT OF AT LEAST ONE COMPONENT, filed 01 February 2024, which is hereby incorporated by reference in its entirety.FIELD OF THE DISCLOSURE

[0002] This disclosure relates to methods of identifying a labelled species, for example a labelled species provided in a library of unique labelled species.BACKGROUND

[0003] Nucleic acid (NA) encoded libraries, such as DNA-encoded libraries, are collections of large numbers of unique species labelled with unique NAs so that each unique species has its own unique NA identifier. The unique species are typically small molecules covalently bonded to the corresponding unique NA and the libraries can include millions of unique small molecules. These libraries are then used to simultaneously screen the library of unique species against a potential target species of biological or pharmaceutical interest, such as proteins. Those which interact with the target species (herein “target species”) are then identified based on their unique NA label. The use of these libraries can significantly increase the speed of drug discovery, but improvements for these screening methods are required.SUMMARY OF THE DISCLOSURE

[0004] According to a first aspect of the disclosure, there is a method of identifying a labelled species, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a unique derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof of the labelled species so as to selectively retain each of the labelled species of the library on a corresponding capture site; and selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species.

[0005] According to a second aspect of the disclosure, there is a method of identifying a labelled species, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) labelor a derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof so as to selectively retain each of the labelled species of the library on a corresponding capture site; and analyzing the structure of the species portion of at least one of the labelled species bound on at least one of the capture sites.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The present disclosure will now be described in more detail with reference to the accompanying drawings, which are not intended to be limiting:

[0007] FIG. 1 illustrates a flowchart of a method according to the disclosure.

[0008] FIG. 2A depicts a top view of a separation device used in a method according to the disclosure; FIGS. 2B to 2E depict schematic cross-sectional views of the separation device through line A-A of FIG. 2A.

[0009] FIG. 3 illustrates a flowchart of another method according to the disclosure.

[0010] FIG. 4A depicts atop view of a separation device used in a method according to the disclosure; FIGS. 4B to 4D depict schematic cross-sectional views of the separation device through line B-B of FIG. 4A.

[0011] FIG. 5 illustrates a flowchart of another method according to the disclosure.

[0012] FIG. 6 illustrates a flowchart of another method according to the disclosure.

[0013] FIG. 7 illustrates a flowchart of another method according to the disclosure.

[0014] FIG. 8 provides atop view of a separation device which can be used in the method according to the disclosure.

[0015] FIG. 9 provides an expanded view of a part of the separation device of FIG. 10.

[0016] FIG. 10 provides a schematic cross-sectional views of the separation device through line C-C of FIG. 8.DETAILED DESCRIPTION

[0017] According to a first aspect of the present disclosure, a method of identifying a labelled species is provided, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a unique derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof of the labelledspecies so as to (i.e. arranged to) selectively retain each of the labelled species of the library on a corresponding capture site; and selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species.

[0018] According to a second aspect of the present disclosure, a method of identifying a labelled species is provided, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a unique derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA -labels or a derivative thereof so as to (i.e. arranged to) selectively retain each of the labelled species of the library on a corresponding capture site; and analysing the structure of the species portion of at least one of the labelled species bound on at least one of the capture sites.

[0019] As set out above, NA-encoded libraries, such as DNA-encoded libraries (herein “DELs”), are collections of large numbers of unique species labelled with unique NAs so that each unique species has its own unique NA identifier (often referred to as a “barcode”). The unique species are typically small molecules covalently bonded to the corresponding unique NA during a synthesis step where the libraries are formed. These libraries are then used to simultaneously screen the library of unique species against a potential target species of biological or pharmaceutical interest, such as a particular protein. Those which interact with (such as bind to) the target species are then identified based on their unique NA label. That is, the label is identified and this can be related back to the small molecule the label was intended to be attached to during initial synthesis.

[0020] However, these libraries often include errors whereby the species portion labelled by a particular NA label does not have the chemical structure intended. This is because the synthesis of the labelled species may erroneously result in a species portion (e.g. a compound) with a different structure to that intended. This is thought to predominantly occur in the synthesis of the species portion but may occur in the generation and attachment of the NA label. Some estimates are that 70% of the species portion within a library have an error on the species portion itself. As a result, the species portion attached to the unique NA label does not always have the structure it is thought to have. This means that if a species portion successfully binds to a target and is identified using the unique label, as is conventional, in many cases, the wrong species portion is considered to be a positive hit. Any follow up screen retesting the species portion identified by the label may then result in no interaction between the species portion and target. In other words, the species portion to which the label was thought to be attached is not a “hit”; instead, the erroneous species - the structure of which is not known - was a hit. In practice, follow up screening fails in a high number of cases (estimated as the majority of cases), wasting effort andresources and extending projects timelines with false positives. Moreover, the species portion which did successfully bind is unknown, meaning conventional processes may overlook potential species of biological and pharmaceutical interest.

[0021] The methods in the first and second aspects provide improved methods in which the specific structure of the species portion which provided the interaction with the target species can be directly ascertained after the initial screening. The methods can be used to isolate and identify the species portion which bound to the target - whether erroneous or the intended species - rather than assuming that the intended species portion (as identified by the label) was that which created the hit. These methods accordingly avoid the false positives which occur relying solely on identifying the NA-label after the “hit” and cross-referencing with the intended species, speeding up the discovery process and reducing wasted effort and costs. In particular, the methods identify the positive hits for the particular target usings the NA-labels but then use the specific label information to selectively capture and isolate the labelled species which actually bound to the target from the library using the NA-labels so that further analysis of the exact species which interacted with the target species can take place. The species portion can be recovered from the initial, expanded library, from a reduced library of species which provided positive hits for the target or from both. That is, the labelled species can be identified within the usual screening process by the identification of the NA-label but then knowledge of the specific NA-labels of the positive hits can be used to capture the precise labelled species which provided the positive hit and used to separate these out for direct analysis of the species portion. In this way, the structure of the species portion which provided the interaction can be directly ascertained rather than assumed. Subsequent rescreening can focus on the actual structure, rather than the assumed structure.

[0022] The use of the NA-labels still facilitates this process, as these provide an effective means for identifying and separating out the hits. In the first and second aspects, the methods each comprise using a separation device or microarray comprising a sample surface and a plurality of capture sites arranged on the sample surface. Each capture site is configured to selectively bind to one of the NA labels or a derivative thereof - in other words, to one specific and unique NA-label or a unique derivative thereof only so that each capture site captures only one of the species portion types within the library (whether that is the expanded library or the reduced library). The presence of plural such sites enables the capture species to capture all or a sub-set (but still a plurality) of the different labelled species within the library so that, when provided to the sample surface, these can each selectively bind to the respective capture site and be held separately on the sample surface across the different capture sites. In this way, since there are usually multiple hits (e.g. 100-1000 positive hits from a library of 1M-100M+ library members) for any given target species within each screen, each of the positive hits can be captured on the sample surface through their unique NA-label, providing an effective and reliable means of separating out the components of the library.

[0023] Furthermore, the use of the NA-labels or a derivative thereof provides a technique for identification of these hits which can be easily incorporated into existing systems and processes. Themethods to be used with existing DELs and other like systems without a significant redesign of the upstream screening processes and structures of the species portion. Development of these DEL systems and methods requires a vast amount of resources to synthesize millions of species and unique barcodes and, hence, the ability to more accurately use these existing assets is highly beneficial. Moreover, these processes do avoid requiring complex methods of separation (which would otherwise be required to determine which (e.g. unlabeled) species would constitute positive hits, were the NA-labels to not be used).

[0024] The method of the first aspect involves a further separation step (which may optionally also be present in the method of the second aspect) in which the labelled species, where each are held on a different capture species, can be selectively released from their respective capture site(s). In other words, the methods may comprise causing each capture site (whether one or plural) capturing a specific, unique species to release the unique species at a particular time so that each unique species is released at a different point in time, for example sequentially. This allows each species (in its labelled form) to be recovered in isolation to the rest of the species portion of the library. In other words, the separation device may be configured to individually release a species portion retained on each capture site. Where there are plural capture sites capturing the same labelled species, these may be operated together to release the same labelled species together at the same time. The released species can then be recovered separately while the remaining other species remain bound to their respective capture sites on the sample surface. This recovery may be to a separate vessel or on to an analysis platform, for example in a solution.

[0025] The first and second methods each also provide methods of analysing the species portion part of the labelled species. By directly analysing the species portion, for example using an analytical technique which can be used to ascertain or determine the structure of the species portion, the structure of the species portion which bound to the desired target species can be directly identified. In the first method, this is achieved through analysing the recovered labelled species. For example, the recovered labelled species may be transferred to a mass spectrometer or other suitable analysis tool. In the second method, this is achieved by directly analysing the species portion as they are retained on the sample surface. Each capture site isolates the species portion type on a different part of the sample surface, creating distinct regions associated with different species, enabling direct analysis through techniques such as matrix-assisted laser desorption / ionization (MALDI) spectroscopy.Library and Labels

[0026] As set out above, each labelled species comprising a unique species portion (or species) bonded to either a unique NA label or a derivative of a NA label, which derivative will itself be unique. The unique label accordingly acts as a molecular “barcode” or identifier enabling the unambiguous identification of the library component to which it is attached. Each label within the library will have a unique structure. NAs are selected for labels as they are straightforward to synthesize and, inparticular, straightforward to synthesize in a structured and repeatable manner such that each can be given a unique structure. Further, the labels are easily identifiable once attached, for example through decoding (e.g. through sequencing). Even where the labelled species are in a low concentration, the labels can be amplified (e.g. by PCR) to enable detection.

[0027] As used herein, the term “nucleic acid” (or NA) refers to a plurality of nucleotides, for example any oligomeric or polymeric form of nucleotides, including, but not limited to, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in either single -stranded or double -stranded form and synthetic analogues such as locked nucleic acids (LNA), peptide nucleic acids (PNA). An oligonucleotide may have nucleotide generally comprising a sugar moiety (e.g. a ribose or deoxyribose), a phosphate group, and a nucleobase. The nucleobase (or nitrogenous base) may be selected from the group consisting of adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U), but may also include base analogues or chemically modified bases (e.g., 5 -methylcytosine). The phosphate groups link the sugar moieties to form the backbone of the polymer or oligomer. The oligonucleotide may have contiguous bases but alternatively the bases may be interspersed with linker moieties. Each nucleic acid may have a 5'- terminus and a 3'-terminus, with the one or more nucleotides between the 5'- and 3'-termini.

[0028] A typical label used in a library is a DNA label. For example, a DNA barcode may comprise a three-cycle tag. Where the tag is a DNA label, the unique species portion may be provided on one DNA strand (“single -pharmacophore DEL”) or on both DNA strands (“dual-pharmacophore DEL”).

[0029] By derivative thereof, it is meant that the label is a unique derivate of a NA. Derivatives of NAs may be any compound which is derived from a unique NA tag but which still can function as a unique identifier. The derivative may make it easier to separate and recover the labelled species. For example, the library used to screen the target species (also referred to herein as an “expanded library”) may use unique NA labels, but the subsequent steps defined in the methods disclosed herein may rely on a derivative of the unique NA labels for separating the labelled species. Accordingly the labelled species provided to the sample surface may have a label which is a derivative of a NA label but which is still unique. The derivative itself may be a NA which is derived from another NA. For example, a doublestranded NA may be denatured or melted to form a single -stranded NA, for example, by applying heat, changing the pH, or providing a treatment. Derivatives include those in which the sugar moiety, phosphate backbone, or base components differ from the canonical forms. For example, bases may be replaced with analogues possessing altered hydrogen-bonding patterns or enhanced stability.

[0030] Accordingly, providing the library may comprise providing a library in which each labelled species comprising a unique species portion bonded to a unique NA label; modifying the unique NA label of each labelled species to form a unique derivative of a NA label. This may be carried out prior to providing the library to the sample surface or after providing the library to the sample surface. Selectively binding to each capture site may accordingly comprise selectively binding one of the unique derivatives of the NA label. The modification may be selected from applying heat, changing the pH (or applying a particular pH) of the solution in which the library is present, or providing a chemicaltreatment. Applying heat or changing the pH may be carried out using the separation device, for example using the modification element(s) disclosed herein. For example, a double -stranded NA may be denatured or melted to form a single-stranded NA, for example, by applying heat, changing the pH, or providing a treatment. Modifying the unique label may comprise applying a stimulus to the unique NA label to form the derivative thereof. This may be carried out using the separation device, for example using the modification element(s) disclosed herein. The stimulus may be application of heat or electrical energy to the NA label or to the solution in which the labelled species is provided.

[0031] The NA label may comprise a double -stranded label and modifying the NA label (e.g. applying a stimulus to the NA label) may comprise denaturing the double -stranded label to form a single strand NA label. For example, the NA label may comprise a DNA label and modifying the NA label (e.g. applying a stimulus to the DNA label) may comprise denaturing the DNA to form a single strand NA label.

[0032] The NA label or the derivative label is linked (e.g. covalently or non-covalently) to the species portion. This may be achieved using e.g. chemical conjugation. This may be a direct link or through a linker species, which may be linked to both the NA or derivative label and the species portion.

[0033] The methods may further comprise synthesising the NA label using the separation device. This may comprise growing the NA label on a respective capture site, for example, using a heater and / or electrode on the capture site to assist in synthesis of NA labels.

[0034] The library provided to the sample surface may be the full library (or “expanded library”) of all of the labelled species which includes those which interacted with the target species (the positive “hits”) and those which did not interact with (e.g. bind to) the target species (the negatives). In such a case, the capture sites may comprise capture species based on the NA sequence or the derivative structure of the labels of the positive hits such that only the positive hits are bound to the capture sites. The other labelled species which are not captured (i.e. the negative species) can be removed from the sample surface, for example by a wash step. Accordingly, it will be appreciated that the step selectively binding “so as to selectively retain each of the labelled species of the library on a corresponding capture site” does not mean that all species within the library need to be bound, only that each of a plurality, which plurality can be a sub-set. Alternatively, the separation device may comprise capture sites with capture species for all of the expanded library, but sequential release, subsequent recovery and / or analysis may be limited to those labelled species deemed to be positive hits.

[0035] Alternatively or additionally, the library provided to the sample surface may be a reduced library comprising only those species which interacted with the target species (the positive “hits”). In such a case, the method may comprise providing an expanded library comprising a plurality of labelled species; and providing the plurality of labelled species of the expanded library to a target so that any of the labelled species that can bind to the target bind to the target. The method may further comprise determining the labels of the labelled species, wherein providing the separation device comprises configuring each capture site based on the determined labels such that each capture site is configuredto selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site. Providing the library to the separation device may then comprise providing at least a portion of the (reduced) library of positive hits to the separation device. This may reduce the risk of further errors interfering with the screen, for example where only some of the species portions labelled with a specific label are erroneous (it will be appreciated that there may be different types of errors within a large library) by directly analysing the portion of the sample in which the hits were present. The screening may therefore comprise providing an expanded library comprising a plurality of labelled species; providing the plurality of labelled species of the expanded library to a target so that any of the labelled species that can bind to the target bind to the target; and separating the labelled species which bind to the target from the other of the plurality of labelled species of the expanded library so as to provide the (reduced) library.

[0036] In some embodiments, the methods may comprise providing both a first expanded library to the sample surface and a second, reduced library to the surface. These may be carried out separately. For example, on a separate separation device or the same separation device, either simultaneously or at the same time. This can be useful where there is a limited sample size in the reduced library. The positive hits for the target can be identified by sequencing the NA label and then used to produce the capture site capture species, which in turn will then capture those hits from the expanded library.

[0037] The library may be in the form of a solid, gas or a solution. For example, it may comprise a carrier (such as a liquid) and the labelled species. It will be appreciated that a sample may not contain the anticipated or target components or analytes.Capture Sites

[0038] The capture sites are each a distinct region of the sample surface and each comprise a portion of the sample surface of the device. Each capture site is adapted so that it captures only one of the species portion type (i.e. one specific compound) based on the unique NA label or a derivate thereof bonded to that specific compound and there are plural different types of capture site so that the separation device overall is capable of capturing or configured to capture multiple different species (identified by their unique, different labels). It will be appreciated that each site may capture a plurality of this one type of species, for example plural species molecules. That is, each site is not limited to a single molecule or compound, but where the library comprises a plurality of species of one structure, the capture site may have a plurality of capture species (of one type) to capture the species portion. The device may further comprise plural capture sites configured to capture the same type of species with the same unique NA label or derivative thereof. It may be advantageous from an incubation time perspective to have plural capture sites across the sample surface configured to capture the same species. Accordingly, in the first aspect (and optionally in the second aspect), selectively releasing may comprise selectively releasing one type of species from plural capture sites simultaneously.

[0039] Each capture site is configured to selectively bind to one of the unique NA-labels or a derivative thereof. The capture site is accordingly configured to interact with the label portion of the labelled species. Each capture site may comprise a capture species (i.e. a molecular species or functional group) (or “capture probe”) adhered to the capture site, each capture species configured to selectively bind to one of the NA labels or a derivative thereof to form a bound pair and retain the corresponding labelled species on the capture site. The capture species may be configured to bind to the species portion to immobilise it on the capture site through covalent-like interactions (e.g., chemisorption of anchor species onto the surface through chemical bond formation) and / or non-covalent-like interactions (e.g., physisorption of capture species onto the surface through weaker, often van der Waals, interactions) depending on the identity of the capture species. The capture species may be selected from or comprise a protein, a peptide (e.g. an enzyme), a carbohydrate, a nucleic acid, an aptamer or a combination thereof. Some examples include a single or double stranded DNA chain. An aptamer may be defined as an oligonucleotide, polynucleotide or peptide configured to selectively bind to the label. In some cases, there may be a plurality of capture species (i.e. plural of the same capture species). Capture species may be plural, such that in some cases, there may be a plurality of capture species (i.e. plural of the same capture species) on each capture site.

[0040] The capture species may be covalently or non-covalently bonded to the capture site. The capture species (for example, a plurality of individual capture species) can be located adjacent to (i.e. next to or abutting) or on the sensing surface. In some examples, the capture species is provided on (e.g. adhered to or bound to) the capture surface (e.g. the surface of an electrode or sensing layer). In some examples, the capture surface is functionalized with the capture species. Such functionalization can be achieved in any suitable manner, such as by covalently or non-covalently immobilizing the capture species to the surface. Each capture site may accordingly be a region of the sample surface with an array or arrangement of one type of capture species

[0041] The capture species may comprise an oligonucleotide adhered to the capture site. Thus, each capture species may be a different (i.e. unique) oligonucleotide with a sequence selected so as to specifically bind to one of the labels of the labelled species.

[0042] The methods can comprise determining the labels of the labelled species which interacted with the target species. The method may then comprise providing the sample surface (and the capture site) with a corresponding capture species based on the determined label. For example, the method may further comprise forming an oligonucleotide capture species on each capture site prior to providing the plurality of labelled species to the sample surface. Accordingly, the methods may further comprise sequencing the NA label of each of the plurality of labelled species and providing an oligonucleotide for each capture site based on the sequenced NA labels. Sequencing may include an amplification step (e.g. PCR). In other words, the method comprises identifying the NA labels of the species portion which resulted in hits for the target by sequencing the labels and subsequently providing oligonucleotidesbased on the sequenced results. In this way, the capture sites can be limited to capturing the specific hits within the library.

[0043] The oligonucleotides can be provided to the sites either by forming the oligonucleotide in situ (i.e. on the sample surface) or these can be produced separately and applied to the capture sites. That is, the oligonucleotides may be synthesised on the corresponding capture site (i.e. in situ). For example, this may be achieved using a solid-phase synthesis based on the phosphoramidite method. This may be achieved by tethering or attaching a base oligonucleotide to the surface and connecting oligonucleotides fragments on site, for example through annealing and ligation or polymerase reactions, for example. In some embodiments, the in situ synthesis of the oligonucleotides(s) on the capture site may be controlled by the thermal control, and this may be carried out by a modification element. For example, WO 2019 / 145713 Al, the content of which is incorporated herein in its entirety, discloses a method of synthesis of oligonucleotides onto the surface of a solid substrate under thermal control. Such a method can be used to form the oligonucleotides(s) on the corresponding capture site.

[0044] As set out below, selective release from the sample surface may also comprise release of a part of the corresponding capture site. For example, a capture species configured to bind to the label of the labelled species may be detachable from the reminder of capture site (and the sample surface) so as to selectively release the labelled species. In such cases, the capture species may be bound to the remainder of the capture site (e.g. the surface) by a cleavable group, such as a linker which can be cleaved. This may be cleavable by the application of a stimulus, such as heat or a change in environment (e.g. pH), which can be applied by the modification element, for example.

[0045] The structure of the separation device lends itself to semiconductor manufacturing processes. As such, the number of capture sites which can be provided on a substrate can be much larger than conventional separation systems. In some embodiments, the number of capture sites is at least 16, such as at least 96 or at least 300.

[0046] The capture site(s) may be defined by the extent of the modification element and / or the sensing element of each capture site site on the sensing surface, where present. Where there are plural of these elements on each site, this may be defined by the outer extent defined by the elements present. This is relative to the extent across the sample surface at the capture site (i.e. perpendicular to the capture site). The capture sites may be spaced apart from one another. This can assist with the local modifications as the local modifications are less likely to impact another site. This may be a spacing of at least 0.01 mm, such as at least 0.05 mm, at least 0.1 mm, at least 1 mm or at least 2mm. For example, from 0.01 mm to 10 cm, 0.01 mm to 5 cm or 0.05mm to 2cm. The substrate or a dielectric may be provided between a part of each of the capture sites.Species portion

[0047] The labelled species include a species portion. This is the component of the labelled species which is part of the library with the intention of determining whether it interacts with the target species(i.e. the biological / pharmaceutical target). Where there is a positive hit for a particular labelled species, it is the determination of the structure or identity of this part of the labelled species portion which is the ultimate aim.

[0048] The species portion may be any species which can interact with a biological / pharmaceutical target and which can be labelled with a nucleic acid. For example, it may be a compound (in other words, a molecular species). A compound may be an such as a small organic molecular compound), a peptide or a protein (such as an antibody or affibody). As used herein, the term "organic molecule" or “small organic molecular compound” refers to small molecules, such as discrete, chemically synthesized compounds which have a weight of less than 1000 Daltons and which do not include a repeating subunit structure. Peptide is a string of amino acids, joined via amide bonds through a condensation reaction. Where present, a peptide portion may comprise a chain of 2-50 amino acids, or 2-40 amino acids, or 2-30 amino acids, or 2-20 amino acids. A peptide portion may be referred to as a targeting vector, as it may function to target a specific receptor or other target in vivo. A peptide portion may be part of a protein, or the compound may be a protein. The protein may be an antibody or an affibody.

[0049] The species portion and the label may be linked directly (e.g. via a covalent bond or bonds) or linked via a linker or linking portion (e.g. to which each is covalently bonded).Selective release

[0050] The method in the first aspect comprises selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species. The method in the second aspect may further comprise selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species. In the second aspect, this is after analysing the structure of the species portion of at least one of the labelled species bound on at least one of the capture sites . The methods may further comprise selectively releasing each of the other labelled species from the sample surface, recovering each of the other labelled species separately and analysing each of the recovered labelled species separately.

[0051] By selective release, it is meant that one specific labelled species (whether this is a single molecule or plural) is / are released from the sample surface. This may be that one specific labelled species is / are released from the corresponding capture site(s) to which it is / they are bound, while the other labelled species are retained on their respective capture sites. In this way, the device can separate the components for further use. It will be appreciated that where one labelled species (i.e. one type of molecule and label) is retained across plural capture sites, the labelled species may be selectively released from the plural capture sites on which it is retained, for example simultaneously. It will also be appreciated that release from the sample surface may also comprise release of a part of thecorresponding capture site. For example, where the capture site comprises a capture species configured to bind to the label of the labelled species, it may be that the capture species is detached from the reminder of capture site (and the sample surface) so as to selectively release the labelled species.

[0052] Selective release may be triggered by an external input, such as an external stimulus, or may be caused by the separation device.

[0053] Selectively releasing one of the labelled species from the corresponding capture site, or specifically from the sample surface, may comprise applying a debinding stimulus to the bound pair to debind the NA-label or derivative thereof from the capture species. The debinding stimulus is an input which either directly or indirectly causes the label to debind or disconnect from the capture site, or more specifically the capture species (where present). The debinding stimulus may accordingly be an input which directly acts on the bonds or interaction between the bound pair, such as an electrical input (e.g. current or voltage), light energy, thermal energy. Alternatively or additionally, it may be indirect, for example the stimulus may cause a change in the environmental conditions directly on and adjacent the site (such as a change in temperature or change in pH), which in turn causes the debinding (or “dissociation”).

[0054] The debinding stimulus may be provided by the separation device. For example, this may be provided by a modification element which may be configured to provide an electrical input (e.g. current or voltage), light energy, thermal energy to a specific site. Alternatively or in addition, it may be a force generated by the separation device (such as an electric field) which can cause debinding.

[0055] Selective release on different sites may be achieved using different debinding stimuli. For example, a first type of debinding stimuli may be used for a first set comprising at least one capture site and a second, different type of debinding stimuli may be used for a second set comprising at least one capture site. This may allow for more selective release from capture sites. For example, the first debinding stimulus may be one of an application of heat locally, change in pH using the separation device, using an electric field generated by the separation device and the second debinding stimulus may be one of the other of an application of heat locally, change in pH using the separation device, using an electric field generated by the separation device.

[0056] Prior to applying the debinding stimulus to the bound pair to unbind the NA-label or derivative thereof from the capture species, the method may comprise applying a first stimulus to the capture site, the first stimulus having a lower intensity than the debinding stimulus such that it can cause debinding of any non-selectively bound species present on the capture site. It will be appreciated that there can under certain circumstances be non-specific binding between a capture site and another species, or in some cases imperfect binding between a capture species and another species. This binding will be nonspecific and results in a weaker interaction between the two components in question. For example, it may be that parts of one NA base chain may interact with parts of an oligonucleotide acting as a capture species on the capture site. The first stimulus can be selected to remove non-specifically bound components which are then removed before selective release and / or analysis of the specifically boundlabelled species. Where the type of stimulus used as the first and as the debinding stimulus is the same, the first stimulus may therefore be less than the debinding stimulus. For example, if the stimulus is application of heat, the first stimulus may raise the temperature to a lower temperature than the debinding stimulus. This may take the form of a continuous increase in the stimulus applied to the capture site(s) in question, for example ramping up from or through the first stimulus and to the debinding stimulus but separately (or only) collecting the species portion released at the debinding stimulus. By “lower intensity” it is meant that the force is lower. Variation of the force may be based on the strength or intensity (e.g. as measured by the input voltage (V / m or mV / m)) of the field applied to generate the force, such as the electric field. The strength of the electric field may vary dependent on the species being moved.

[0057] Where an electrical field is used, the species interacting with the field may be a charged species or a species to which a charge can be attached (e.g. temporarily through a change in conditions or with the addition of a tag). Similarly, for the use of a magnetic field, where the species must be moveable in a magnetic field or be provided with a tag or label which can moved within a magnetic field.

[0058] Each capture site may comprise an individually actuatable modification element configured to cause the selectively releasing of the labelled species bound to the capture site. Accordingly, the modification element may be operable to or configured to apply the debinding stimulus and may further be operable or configured to apply the debinding stimulus. The modification element accordingly may be operable (or operated) to cause a debinding of the bound pair. For example, it can be used to apply a stimulus (such as heat or cooling, voltage, current) to the bound pair to cause the debinding.

[0059] Alternatively or additionally, selective release may be selective release of the specific labelled species and the capture species from the sample surface (i.e. the remainder of the capture site). For example, a or each capture species may be detachable from the reminder of capture site (and the sample surface) so as to selectively release the labelled species and at least a part of the capture species bound thereto. In such cases, the capture species may be bound to the remainder of the capture site (e.g. the surface) by a cleavable group, such as a linker which can be cleaved. This may be cleavable by the application of a stimulus, such as heat or a change in environment (e.g. pH). Such a stimulus may be the same as the binding stimulus (i.e. may have any of the features set out for the binding stimulus). For example, this may be provided by a modification element which may be configured to provide an electrical input (e.g. current or voltage), light energy, thermal energy to a specific site.

[0060] The method may further comprise monitoring the binding and / or selective release. For example, fluorescent or other indicators can be included in the system to detect binding and release events.Modification element (or “Unit”)

[0061] As set out above, each capture site may comprise an individually actuatable modification element configured to cause the selectively releasing of the labelled species bound to the capture site.

[0062] The modification element may be used to locally modify a property. That is, it may be configured to modify a property (also referred to herein as “environmental property” or “medium property”) of the medium or environment adjacent (i.e. next to or on) the modification element or only modify the sample within a region local to the modification element. Each capture site may be provided or comprise a separate modification element such that the debinding on each site can occur under the control of a capture site-specific modification element. As such, where the modification element modifies the local environment, this can be local to each capture site.

[0063] By modification of property in this context, it is meant that it to modifies a physical (e.g. material) or chemical property of the bound pair or the environment (e.g. the solution) around the bound pair sample, such as by applying electrical energy or an electric field directly to the sample to change the property or by providing another form of energy (e.g. thermal energy). In some embodiments, this may be a physical or chemical property of the solution. The property can include physical properties, such as thermal properties (e.g. temperature) and / or chemical properties such as the pH of the solution adjacent the modification element. This can create localised regions having a different property. The property may be modified directly, e.g. by direct application of heat to change the temperature, or indirectly for example by causing a chemical change which in turn changes the property, such as hydrolysis or electrolysis due to application of electrical energy which can change the pH. For example, the modification element can be configured to create an electrical field which can cause a localised change in a part of the medium.

[0064] The modification element many be selected from or comprise an electrode or a thermal device, such as a heater or a cooler. A thermal device can be used for the purposes set out above or may be used to generally increase the temperature of the environment and / or bound pair. This can be locally (i.e. configured or operable to modify the temperature of the bound pair and / or the solution adjacent the thermal device). The methods disclosed herein may therefore comprise operating the thermal device to heat the bound pair and / or a portion of the solution adjacent or on the capture site.

[0065] The modification element or modification unit used in the system and methods may comprise an electrode (e.g. a modification electrode) or a plurality of electrodes operable to interact with at least a portion of the library (e.g. the solution on the sample surface). An electrode can be used to provide a chemical, thermal, or mechanical modification, depending on the nature of the sample and the specific requirements of the separation process. For example, it can be used to can alter properties such as pH, electrical conductivity, or temperature of the medium, thereby affecting the behaviour of the components and facilitating their separation and analysis.

[0066] The modification element may be provided on the substrate and form a part of the sample surface. This further allows for integration into a chip or integrated circuit. Further, providing this on or adjacent the sample surface enables the modification locally at each capture site.

[0067] The modification element(s) may be further configured to or operable to cause the transformation of the NA label to a derivative thereof. The methods may accordingly compriseactuating at least one modification element to cause the NA label to undergo a transformation, such as denaturing or melting, to form a derivative thereof. The modification element accordingly may be operable (or operated) to cause a transformation of the bound pair. This can be, for example, a degradation of the structure of the NA label. For example, it can be used to apply a stimulus (such as heat or cooling, voltage, current) to the NA label to cause the transformation.

[0068] The modification element(s) may further be used for other purposes within the methods and systems or additional / separate modification element(s) may be provided. For example, the modification elements can be used to provide a more general temperature increase across the specific capture sites or even the entire sample surface. An increase in temperature can decrease incubation time with the capture site (or a capture species provided thereon) by increasing the rate of binding (Kon). For example, by raising the temperature (e.g. by at least 1 °C, or at least 5 °C), the entire process may be sped up, by increasing mobility, reaction times and / or binding. It has been found that a rate of binding at or close to 37 °C is higher than that at room temperature (e.g. 21 °C), even if limited to the region adjacent the sample surface only (i.e. without increasing the bulk temperature).

[0069] For some labels and capture species, binding may be an annealing process (for example between single-stranded oligonucleotides to form a double -stranded oligonucleotide (e.g. DNA)) such that each thermal device may be heated to an annealing temperature. Due to the individual actuation of the modification element and by providing each thermal device at a capture site, the temperature on each capture site can be locally created and may be different to the other sites. This can be used to heat each capture site to the required annealing temperatures for each pair of labels and capture species.

[0070] Ionic strength and pH (which are linked) also modify the binding parameters. For example, modification of the pH can change the propensity of the capture species and label to bind, which can provide additional information on binding and kinetics of binding. In some cases, this can lead to dissociation. This can speed up measurement time, for example by avoiding separate pre-treatment (e.g. denaturing) and modifying the library and enables debinding.Recovering

[0071] The method in the first aspect comprises recovering the labelled species separately to the other of the plurality of labelled species. The method in the second aspect may further comprise recovering the labelled species separately to the other of the plurality of labelled species.

[0072] Recovering means obtaining the specific labelled species separately to the other labelled species; in other words, in isolation. Isolated means relative to the other labelled species of the library. Recovering may therefore comprise removing a single, isolated labelled species (single molecule or plural) from the sample surface, for example while the other labelled species are either still retained on the sample surface on their respective capture sites or have already been removed from the sample surface. As such, the recovery step may comprise removing the specific labelled species from thesample surface and recovering the labelled species selectively released in a separate solution or vessel, for example.

[0073] Recovering the specific labelled species may comprise releasing the labelled species into a recovery fluid and removing the recovery fluid and isolated labelled species from the sample surface. For example, this may comprise providing (e.g. flowing) a recovery solution over the sample surface as the specific labelled species as it is selectively released or after it is selectively released to remove the specific labelled species from the sample surface. Alternatively or additionally, recovering the labelled species separately to the other of the plurality of labelled species comprises releasing the labelled species and applying a force to remove the labelled species from the sample surface. For example, this may be achieved through the application of an electric field to the surface which can cause the specific labelled species to migrate or move along the sample surface. This is discussed in more detail, below.

[0074] Where the methods involve selectively releasing one of the labelled species from the sample surface, prior to this the method may further comprise removing any unbound species and / or non- selectively bound from the sample surface. Similarly, where the methods comprise analysis of a labelled species bound to the site, prior to this step, the method may further comprise removing any unbound species and / or non-selectively bound from the sample surface. Such a removal step removes any potential contaminants from the surface prior to either selective removal or analysis. The unbound species may be other components within the sample provided to the surface or may be labelled species for which there is not a corresponding capture site. For the latter, it may be that an expanded library is provided to a surface where only the positive hits are provided with capture sites. Accordingly, nonbound labelled species may need to be removed from the surface. It will also be appreciated that, under certain circumstances, non-specific binding between a capture site and another species can occur. Nonspecific binding results in a weaker interaction between the capture agent or species and a species the capture agent or species is not intended to bind to. This could include a different (i.e. wrong) label, another part of a labelled species or another species entirely. Removal may include application of a first stimulus to remove unbound components and non-specifically bound components before selective release and / or analysis of the specifically bound labelled species. Where the type of stimulus used as the first stimulus is the same as that for debinding, the first stimulus may therefore be less than the debinding stimulus. Accordingly, the methods may comprise, prior to applying the debinding stimulus to the bound pair to unbind the NA-label or derivative thereof from the capture species, applying a first stimulus to the capture site, the first stimulus having a lower intensity than the debinding stimulus such that it can cause debinding of any non-selectively bound species present on the capture site. For example, if the stimulus is application of heat, the first stimulus may raise the temperature to a lower temperature than the debinding stimulus. This may take the form of a continuous increase in the stimulus applied to the capture site(s) in question, for example ramping up from or through the first stimulus andto the debinding stimulus but separately (or only) collecting the species portion released at the debinding stimulus. The first stimulus may be an electric field, for example.Analysis

[0075] The methods of the first and second aspects each include analysing the recovered labelled species. In particular, the methods comprise analysis of the structure of the unique species portion. This allows for the determination of the precise structure of the species which bind to the target, rather than simply an assumption based on the structure that had been intended. This in turn can significantly reduce the high error rate of existing library -based screening methods.

[0076] In the first aspect, and optionally in the second aspect, the method further comprises selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species. In the second aspect, this may be after individually analysing the structure of the species portion of each labelled species bound on each capture species. This may be specifically the species portion that is separately analysed to determine its structure. Accordingly, analysing the recovered labelled species comprising analysing the recovered labelled species to determine the structure of the species portion.

[0077] This analysis may be a structural analysis for determining the structure of the species portion. The methods may therefore further comprise determining the structure of the species portion. Exemplary techniques for determining the structure of the species portion include nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS) (e.g. electrospray ionization (ESI), matrix- assisted laser desorption / ionization (MALDI), or electron ionization (El)); infrared (IR) spectroscopy (e.g. Fourier transform infrared (FTIR) spectroscopy); chromatography (e.g. high-performance liquid chromatography (HPLC) or gas chromatography (GC), which can be carried out in combination with MS (e.g. HPLC-MS, HPLC-MS-MS or GC-MS); and X-ray crystallography. These methods may be used individually or in combination to establish the structure.

[0078] In the second aspect, and optionally in the first aspect, the methods further comprise analysing the structure of at least one of the labelled species bound on at least one of the capture sites. This may be a species portion of each labelled species bound on each capture site. In other words, the methods can comprise analysing the structure of the species portion while the labelled species is retained on the sample surface. The separation of these onto separate capture sites allows for individual analysis directly on the sample surface. Further, by analysing on the surface without or before release, this reduces the potential losses of sample caused by transfer and, therefore, increases the amount of sample available for analysis. This is important in libraries, since the sample sizes can be particularly small. These analysis techniques may include solid-state or thin film analysis techniques, where any solution may be evaporated leaving behind bound labelled species on the surface. Accordingly, in some embodiments, the method may comprise heating the capture site so as to evaporate any solvents present prior to analysis. This may be using the modification element, for example.

[0079] Exemplary techniques which can be used when the labelled species are bound to a capture site include many of the abovementioned techniques but may specifically be a spectroscopy analysis. For example, MALDI-MS (this may optionally include time-of-flight (TOF) or tandem MS); secondary ion mass spectrometry (SIMS); infrared (IR) or Raman spectroscopy; and X-ray photoelectron spectroscopy (XPS) or energy -dispersive X-ray spectroscopy (EDX).

[0080] The methods may further comprise sensing a property to determine the presence of a labelled species on at least one capture site. This may be sensing a property of the capture site to determine the presence of a labelled species on the capture site. This may be used to monitor the binding and debind of labelled species. For example, this may be used to determine whether a labelled species is bound to a capture site and, further, may be used to determine an amount of a labelled species present on a capture site.

[0081] A sensing element can accordingly be used to monitor the capture site. The sensing element may be provided on or beneath the capture site within the substrate, for example. The sensing element may be an optical sensing element, thermal sensing element, pH sensing element, ion sensing element, conductivity sensing element, fluorescence sensing element or a sensing element configured to detect a chemical property. Electrochemical sensors such as amperometric, potentiometric or conductometric sensors may also be employed. This can then be used to provide information on a state of a capture site. The method may further comprise performing additional steps based on this determination, such as the selective release of the labelled species from the capture site in question.

[0082] The sensing element (or “sensing device”) may provide a measurement signal indicative of the property and therefore may be addressable in some methods to provide the measurement signal. For example, the sensing element may comprise an electrode, which electrode may be addressable to provide the measurement signal. In some embodiments, there may be plural electrodes. Where there are plural electrodes, each may be individually addressable. A sensing layer (e.g. a dielectric layer) may also be provided on or adjacent the electrode to enhance or enable the response of the electrode to a particular component or analyte. In other embodiments, the sensing element may comprise a layer or structure through which current is passed (for example, where the sensing element comprises is a resistive layer or structure located between first and second electrodes). In some embodiments, a portion of the substrate defining the sample surface and / or a portion of the medium may define the sensing layer or structure between electrodes and the sensing element may comprise a pair of electrodes arranged to interrogate the portion of substrate and / or medium such that sample or a component in this particular region can be interrogated.Manipulation and Separation

[0083] The methods may further comprise applying a force to the sample so as to manipulate or move the labelled species on the sample surface. For example, during the step of providing the plurality of labelled species to the sample surface, a force may be applied so as to move the labelled species toand / or across the sample surface. Alternatively or additionally, a force may be applied during the step of recovering the labelled species (where present) so as to move the isolated labelled species away from the capture sites and recover the labelled species separately. Use of such a force can advantageously quickly and efficiently transfer the labelled species without direct handling. Both large-scale and small- scale movements are possible within the system.

[0084] For example, the systems and methods can use these electrodes to generate electric or magnetic fields that guide sample migration along predefined paths or affect a change in the environmental conditions which in turn create a force which causes movement of the along a pathway

[0085] In the methods disclosed herein, applying a force in the method may comprise applying an electric field and / or a magnetic field to the sample or at least one labelled species. The use of an electric field for movement of charged species on the sample surface (and, more generally, in the device) is an efficient and effective means by which to manipulate the labelled species. It will be appreciated that various forces, such as those applies by electric and / or magnetic fields, can be used. With NA labels or derivates thereof, these may be charged. In some cases, the species portion may be charged. This is also advantageous in that it can be combined with the other functionality disclosed herein. For example, using a modification element or a particular medium portion, the charge of a particular component (i.e. a labelled species) can be modified at different points on the sample surface, enabling different responses of the component to an applied electric field.

[0086] The methods may further comprise applying a field (e.g. an electric field) to the labelled species so as to cause movement of the labelled species towards the sample surface, such as towards the capture sites. Such a method can speed up measurement time by causing movement of the species in the sample to migrate to the capture sites at a movement speed which is greater than diffusion. This can reduce the time of or reduce the need for an incubation period.

[0087] Accordingly, the separation device may comprise at least one manipulation assembly operable to cause a labelled species or sample to move on (e.g. along or towards) the sample surface. In other words, this may be operable to apply a force which causes a sample or a component thereof (e.g. a labelled species) to move towards a desired region of the device. Such a manipulation assembly may be operable to generate an electric field and / or a magnetic field to provide the respective force.

[0088] The first manipulation assembly may comprise a first electrode set arranged and operable to provide the respective force. Use of electrodes provides a precise control over the applied forces and allows for integration of the assemblies into a chip or integrated circuit for precise manufacture and miniaturisation. The methods disclosed herein may therefore further comprise operating a manipulation assembly to provide a force. The first electrode set can comprise a pair of electrodes provided as an electrically connectable or connected pair of field-generating electrodes for generating a field for influencing the sample or a part thereof (e.g. an electric field and / or a magnetic field). Each of the pair of electrodes can be provided at an opposing end of the pathway and to define the entire length of the pathway. In other words, these are spaced apart and medium is provided therebetween so that the regiondefined between them is the pathway. The pair of electrodes are electrically connectable or connected so that the field providing the force can be defined therebetween along the length of the pathway. Where a magnetic field is used, this can be applied using an electromagnetic manipulation assembly configured to apply a magnetic field across at least a portion of the respective pathway. The use of an electric field or magnetic field to provide the force is particularly advantageous with the structures and arrangements disclosed herein. For example, the application of an electric field or magnetic field can be achieved using electrodes, further allowing integration of this into a chip or integrated circuit structure and manufacture using traditional semiconductor manufacturing processes (e.g. CMOS manufacturing processes).

[0089] Variation of the force may be based on the strength or intensity (e.g. as measured by the input voltage (V / m or mV / m)) of the field applied, such as the electric field. The strength of the electric field may vary dependent on the species being moved. It will be appreciated that in any of the embodiments mentioned here, although the resultant force of the electric field acting on a particular component will depend on a number of factors, including the charge on the component, the magnitude of the force will be determined by the magnitude of the electric field such that a higher V / m value will lead to a greater force acting on the species in the sample.

[0090] The use of an electric field or magnetic field to provide the force is particularly advantageous with the structures and arrangements disclosed herein. For example, the application of an electric field or magnetic field can be achieved using electrodes, further allowing integration of this into a chip or integrated circuit structure and manufacture using traditional semiconductor manufacturing processes (e.g. CMOS manufacturing processes).

[0091] It will be appreciated that there are also numerous other ways in which forces (beyond those resulting from the direct application of electric or magnetic fields to species affected by these fields) can be applied and separation can be affected, including for example:

[0092] (i) Applying a force may comprise providing a medium in which a property of the medium varies along a pathway so as to provide a force which acts on at least a part of the sample so as to causes the sample or a part thereof to migrate through the medium. This can define the corresponding pathway. In other words, the application of force is through the creation of an environment which leads to osmotic pressure or which causes diffusion across the pathway. This may be a property of the medium or it may be imparted on the medium by a corresponding manipulation assembly (where present in the method). For example, the methods (and systems) may comprise applying a force (which acts on at least one component) by providing a concentration variation or gradient within the medium along the pathway of at least one species. This can be a property of the medium or can provided by creating these regions through manipulations of species in the medium. For example, charged species (e.g. dopants not forming a part of the sample) within a medium could be manipulated by an electric field to create a particular concentration or charge gradient).

[0093] (ii) Applying a force may comprise applying a force to cause sedimentation of a sample (i.e. the separation of at least one non-soluble component from a liquid and / or for separating a plurality of nonsoluble components from one another within a liquid). This may be application of a kinetic force to cause velocity sedimentation (measuring the speed at which a component settles) or isopycnic sedimentation (based on density of the components). The force acting on the particles may be gravity (i.e. the sample is provided at a first height in the medium such that gravity can move the samples to a plurality of different heights, thereby applying the force). The force may alternatively or additionally be a centrifugal or centripetal force device, such as applied by manipulation assembly (e.g. a centrifugal or centripetal force device (such as a zonal rotor)). One implementation of (ii) is separating cells.

[0094] (iii) Causing separation by a difference in at least one of adhesion, cohesion, and surface tension. This may be separating based on the difference in these features and interaction with the medium of the substrate surface or a feature provided on the substrate (such as a coating or functionalization). In some embodiments, these forces may also be used to apply the force so as to cause migration.

[0095] (iv) Applying a force may comprise applying a centrifugal or centripetal force to cause separation through the medium. This may be based on at least one of size of the components of the sample, shape of the components, density of the components, medium viscosity and rotor speed. For example, this can be used in combination with the separation of based on sedimentation (i.e. (ii)). At least one of (or a plurality or each) manipulation assembly may comprise a device configured to apply a centrifugal or centripetal force (such as a zonal rotor).

[0096] (v) applying a force may comprise applying a force using acoustic waves. For example, the respective manipulation assembly or assemblies may be configured to apply a force using sound-waves. These can also advantageously be used to apply a directional force on the sample or a component thereof. In one embodiment, the respective manipulation assembly or assemblies comprise an ultrasonic sound-wave generator, such as an ultrasonic transducer. By ultrasonic it is meant that the device generates high-frequency sound-waves which cause vibrations in a fluid, particularly in a liquid. For example, sound-waves with a frequency of greater than 18kHz, optionally 20-400 kHz and further optionally 40-80 kHz.

[0097] Combinations of any of the means for applying a force can be combined, including any of (i) to (v) with the use of an electrical field and / or magnetic field which acts directly on the sample. For example, the combination of (i) and an electric field can be used to move a sample or a part thereof through a gradient (which itself could be generated by a manipulation assembly) under the force of an electric field. Similarly, changing pH across a gradient (e.g. (i)) can be combined with an electric field to separate based on isoelectric point.

[0098] In addition to the force, the system may be provided with a separation component provided on the sample substrate which interacts with at least a part of the sample as it is separated. This may be a component provided within the medium (e.g. particles) or provided on the sample surface (such as acoating or functionalization). Examples include antibodies provided on the sample surface, beads (which can be functionalized) or surface profding on the sample surface.Substrate and Medium

[0099] The methods may comprise providing a substrate defining a sample surface. Accordingly, the separation device may comprise a substrate defining a sample surface. The substrate may be a planar surface or a non -planar surface. For example, the substrate may comprise multiple substrate portions, where the substrate portions are in different planes. For example, these may be angled with respect to each other or in opposing relationship (such that medium is provided therebetween). Each substrate portion may be planar. Where present, the substrate portions may abut one another or may be separated by joined by a liquid or gel medium. The substrate may be formed from or by a layer or, where there are plural substrate portions, may be formed of or by a plurality of layers or sections forming the surface, for example. Medium may be provided onto or over the sample surface but may further extend into the substrate, in some embodiments, and / or beyond the sample surface. The substrate may be formed of or comprise any suitable material. For example, it may be a polymer layer, a glass layer, a glass-ceramic layer, a ceramic layer, a metal oxide layer, a metal nitride layer, a silicon -containing layer (e.g. silicon, silicon dioxide, or silicon nitride), a gallium-containing layer (e.g. gallium nitride or gallium arsenide) or combinations thereof.

[0100] The methods may further comprise a medium provided on the sample surface. The medium may be or comprise a fluid medium, such as a liquid or gel medium. The medium may contain additives in some cases to enhance separation, such as detergents, denaturants, or specific binding molecules. In certain aspects, the medium may have a property gradient, such as a pH or ionic strength gradient, to facilitate separation based on properties such as isoelectric points or charge.Separation device

[0101] The methods comprise providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface. The capture sites and sample surface have been discussed in detail, above. The separation device may further comprise any of the components set out herein. For example, at least one, or each, of the modification element, the manipulation assembly and / or the sensing element. These components may be provided separately or may be provided as a single apparatus. Provision of these components as disclosed herein as an apparatus advantageously lends itself to semiconductor manufacturing techniques and miniaturisation.

[0102] The separation device may comprise a processing unit or control unit configured to carry out the methods steps disclosed herein, such as controlling selective release of the labelled species from the sample surface. Where there is a sensing element, the control unit may receive a measurement signal from the sensing element. The control unit may be further configured to determine a property based on the measurement signal.

[0103] The control unit may be or comprise a processor or controller. The control unit may be implemented in any suitable manner, with software and / or hardware, to perform the various functions required. One or all of the units may, for example, employ one or more microprocessors programmed using software (for example, microcode) to perform the required functions. It will be understood that the control unit may be or run on a single controller or processor or may be distributed over several computers and locations (e.g. connected via internet), such as a cloud-based computing infrastructure. Examples of processor components that may be employed in various embodiments include, but are not limited to, conventional microprocessors (e.g. a central processing unit (CPU), a digital signal processor (DSP)), application specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs). The control unit may include, but is not limited to, PCs, workstations, laptops, PDAs, palm devices, servers, storages, and the like. Generally, in terms of hardware architecture, the control unit may include one or more processors, memory and one or more I / O devices that are communicatively coupled via an interface. In various implementations, the control unit may be associated with one or more non- transitory storage media such as volatile and non-volatile computer memory including any one or combination of volatile memory elements (e.g., random access memory (RAM), such as dynamic random access memory (DRAM), static random access memory (SRAM), etc.) and non-volatile memory elements (e.g., ROM, erasable programmable read only memory (EPROM), electronically erasable programmable read only memory (EEPROM), programmable read only memory (PROM), tape, compact disc read only memory (CD-ROM), disk, diskette, cartridge, cassette or the like, etc.). The memory can have a distributed architecture, where various components are situated remote from one another, but can be accessed by the control unit. The non-transitory storage media may be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform the required functions. Various storage media may be fixed within a processor or controller or may be transportable, such that the one or more programs stored thereon can be loaded into the control unit.

[0104] In some non -limiting examples, the system includes a user interface, such as a display. Alternatively or additionally, the system may include a communications interface device, such as a wireless transmitter, configured to transmit data, such as the property determined by the property determination unit, to an external device, such as a personal computer, tablet, smartphone, remote server, etc.

[0105] In one aspect, there is provided a computer program comprising computer program code which is configured, when said computer program is run on one or more physical computing devices, to cause said one or more physical computing devices to implement the methods disclosed herein.

[0106] In one aspect, there is provided one or more non-transitory computer readable media having a computer program stored thereon, the computer program comprising computer program code which is configured, when said computer program is run on one or more physical computing devices, to cause said one or more physical computing devices to implement the methods disclosed herein.

[0107] In one embodiment, the system may further comprise a signal processing unit configured to process signals received relating to measurements, for example from the sensing elements and electrodes set out herein. A property determination unit may receive processed signals and determined the property based on the processed signals. The property determination unit may, in certain embodiments, be configured to determine the property based on (at least) the absolute change in measurement signal and / or the rate of change of the signals. The control unit may incorporate the property determination unit and / or the signal processing unit or may be in addition to one or both of these. The property unit and / or signal processing unit may each have the form of a processor or controller as set out above for the control unit.Specific Implementations

[0108] Fig. 1 depicts a first method 100 of identifying a labelled species 190. Figs. 2A to 2D provide a schematic depiction of an exemplary separation device 150 for use in the method 100.

[0109] The method 100 is for identifying a structure of a labelled species from a library. A library of labelled species is a collection of a plurality of different members provided in a solution which has been or will be provided to a biological or pharmaceutical target with a view to identifying those members which interact with (e.g. bind to) the biological or pharmaceutical target in question. Each member of the library is a potential species which could bind to the biological or pharmaceutical target in question and which is encoded or labelled with a tag to identify the species in the form a unique nucleic acid (NA) label. However, as set out above, these libraries often include errors whereby the species portion labelled by a particular NA label does not have the chemical structure intended. That is, the synthesis of the species portion may erroneously result in a species with a different structure to that intended.

[0110] The method comprises providing 105 a library comprising a plurality of labelled species. This may be the whole original library as provided to the biological or pharmaceutical target or may be a sub-set thereof, such as a group of positive hits which were identified as interacting with the biological or pharmaceutical target. The labelled species within the library may comprise the unique NA label as in the form of the original library or it may be a derivative thereof, which derivate is a further unique label, such as a further nucleic acid.

[0111] The method 100 further comprises providing 110 a separation device 150. An exemplary separation device 150 is depicted in Figs. 2A (schematic plan view) and 2B to 2E (schematic crosssections through line A-A of Fig. 2A). The separation device 150 depicted therein comprises a substrate 155 and a plurality of heaters 160A-C formed on and in the substrate 155. In this embodiment, the separation device 150 includes eighteen circular heaters 160A-C embedded in the substrate 155 and arranged in a grid. Each of the heaters 160A-C is individually actuatable and is functionalised with a capture species 161A-C specific to one of the labelled species 101A-C of the library and, in particular, one of the positive “hits” from the interaction with the target species. Accordingly, each of the heaters 160A-C and capture species 161A-C defines a capture site 165A-C for a corresponding labelled species101A-C. In particular and as schematically depicted in Fig. 2B, a first capture site 165A comprises a first capture species 161 A functionalised on the surface of a first heater 160A, the first capture species 161A having a sequence which is complimentary to (i.e. will specifically bind to) to the NA label (or a derivative thereof) on a first one of the labelled species 101 A. Similarly, a second capture site 165B comprises a second capture species 16 IB functionalised on a second heater 160B having a sequence which is complimentary to (i.e. will specifically bind to) to the NA label (or a derivative thereof) on a second one of the labelled species 101B. A third capture site 165C comprises a third capture species 161C functionalised on a third heater 160C having a sequence which is complimentary to (i.e. will specifically bind to) to the NA label (or a derivative thereof) on a third labelled species 101C.

[0112] Although not depicted, each of the plurality of heaters 160A-160C are electrically connected to a control unit so that the plurality of heaters 160A- 160C can be actuated under the control of the control unit. The heaters 160A-160C are provided as individual modification elements and can be used to locally heat the region on and above each corresponding capture site 165A-C (e.g. the solution adjacent and on the corresponding capture site 165A-C). This can be used for a number of reasons, including first increasing the temperature of the solution around the capture sites 165A-C to promote binding of the label of the labelled species 101A-C to the corresponding capture species 161A-C. Binding kinetics for NA labels and derivates thereof can be improved when the temperature is raised above standard conditions (e.g. to a temperature of from 25 °C to 37 °C). For some labels and capture species, binding may be an annealing process such that each heater 160A-C may be heated to an annealing temperature. Due to the individual actuation of the heaters 160A-C and the local nature of the heater 160A-C, the temperature on each capture site 165A-C can be different which can be particularly useful for providing appropriate annealing temperatures for each pair of labels and capture species. It can also be further be used for selective release of the bound labelled species 101 A, as set out below.

[0113] The method further comprises providing 115 the plurality of labelled species 101A-C to the sample surface 156 and selectively binding to each capture site 165A-C one of the NA-labels or a derivative thereof of the labelled species 101A-C so as to selectively retain each of the labelled species 101A-C ofthe library on a corresponding capture site 165A-C. This process is depicted in Figs. 2B and 2C, where Fig. 2C shows the labelled species 101A-C and capture species 165A-C bound as a bound pair on each capture site 165A-C. It will be appreciated that this will also have occurred for all of the other capture sites on the separation device 150 (see Fig. 2A), where each of the other captures sites have captures species which correspond to the unique labels on other labelled species within the library. As shown in Fig. 2C, before the subsequent steps, the solution over the sample surface 156 may be free of any labelled species so as to not contaminate any subsequent recovery. This may be achieved by any method, such as flowing a solution over the sample surface 156 to remove any unbound species or applying a force to the unbound species to remove them from the sample surface 156.

[0114] Accordingly, using the separation device 150, the labelled species 101A-C can be separated out from the library and individually bound to different parts of the sample surface 156. This allows foreach positive “hit” for the target species to be separated from the other labelled species, whether these are other positive “hits” or members of the library which were not positive hits, simply by providing the library to the sample surface 156. The method is accordingly efficient and straightforward and can be scaled up by simply adding more capture sites 165A-165C where more labelled species are to be isolated.

[0115] The method further comprises selectively releasing 120 one ofthe labelled species lOlA-C from the corresponding capture site 165A-C and recovering 125 the labelled species 101A-C separately to the other of the plurality of labelled species 101A-C. As depicted in Fig. 2D, this comprises releasing one of the labelled species 101A-C - in Fig. 2D, the third labelled species 101C - from the respective capture site 165A-C - in Fig. 2D, the third capture site 165C - while still retaining the other labelled species 101A-B on their respective capture sites 165A-B. This provides a solution above the sample surface 156 in which only the third labelled species 101C is present and which can then be removed from the sample surface 156 in isolation to the other labelled species 101A-B. In this embodiment, the selective release 120 is achieved using the heater 160A-C forming a part of the corresponding capture site 165A-C. In particular, in the release of the third labelled species 101C, the heater 160C associated with the third capture site 165C can be actuated to provide a debinding stimulus which causes degradation of the bound pair, such as melting or denaturing of the bound pair so that the third labelled species 101C is released from the third capture species 161C. The location of the heaters 160A-C on each capture site 165A-C means that the heating is local only such that this will only release the third labelled species 101C and leave the remaining labelled species 101A-B bound to the sample surface 156.

[0116] This process can then be repeated for the other labelled species 101 A-B, such that these labelled species 101A-C are also selectively released 120 from their corresponding capture site 165A-B and recovered 125 separately to the other of the plurality of labelled species. A further selective release 120 and recovery 125 is depicted in Fig. 2D, which comprises releasing one of the labelled species 101A-C - in Fig. 2E, the second labelled species 10 IB - from the respective capture site 165A-C - in Fig. 2E, the second capture site 165B - while still retaining the other labelled species 101A on their respective capture sites 165A. This provides a solution above the sample surface 156 in which only the second labelled species 10 IB is present and which can then be removed from the sample surface 156 in isolation to the other labelled species 101 A.

[0117] The method further comprises analysing 130 the recovered labelled species 101A-C separately and away from the sample surface 156 such that each labelled species 101A-C can be in isolation. Where the release process is repeated for all of the labelled species 101 A-C, this analysis 130 may be concurrently with the subsequent release 120 and recovery 125 of the other labelled species 101A-B (after the third labelled species 101C has been recovered) or it may be after all of the labelled species 101A-C have been selectively released 120 and recovered 125. Accordingly, in this way, the selective release maintains the separation of the labelled species 101 A-C but provides these in a form in whichthey can individually be analysed and further processed, if required, separately to the remainder of the library.

[0118] The analysis 130 step in this embodiment comprises carrying out a structural analysis to determine the structure of the species portion of each labelled species 101A-C. This ultimately enables each individual labelled species to be analysed independently so that the species portion of the labelled species can be identified and the true identity - rather than the assumed identity - of the species portion can be determined.

[0119] Accordingly, this method 100 provides a means for determining the specific structure of the species portion which provided the interaction with the target species. The methods identify the species portion which bound to the target species - whether erroneous or the intended species - rather than assuming that the intended species was that which created the hit. Accordingly, the method avoids the false positives which occur relying solely on identifying the NA-label after the “hit” and crossreferencing with the intended species, speeding up the discovery process and reducing wasted effort and costs.

[0120] Fig. 3 depicts another method 200 of identifying a labelled species within a library of labelled species. The method comprises the step of providing 105 a library comprising a plurality of labelled species. This may be the whole original library as provided to the biological or pharmaceutical target or may be a sub-set thereof, such as a group of positive hits which were identified as interacting with the biological or pharmaceutical target. The labelled species within the library may comprise the unique NA label as in the form of the original library or it may be a derivative thereof, which derivate is a further unique label, such as a further nucleic acid.

[0121] As with the first method, the method 200 comprises providing 205 a library comprising a plurality of labelled species. This may be the whole original library as provided to the biological or pharmaceutical target or may be a sub-set thereof, such as a group of positive hits which were identified as interacting with the biological or pharmaceutical target. The labelled species within the library may comprise the unique NA label as in the form of the original library or it may be a derivative thereof, which derivate is a further unique label, such as a further nucleic acid.

[0122] The method 200 further comprises providing 210 a separation device 250. An exemplary separation device 250 is depicted in Fig. 4A (schematic plan view) and Figs. 4B-4D (schematic crosssections through line B-B of Fig. 4A).

[0123] The separation device 250 depicted therein comprises a substrate 255 and a plurality of electrodes 260A-C formed on and in the substrate 255. In this embodiment, the separation device 250 includes 18 circular electrodes 260A-C embedded in the substrate 255 and arranged in a grid. Each of the electrodes 260A-C is individually actuatable and is functionalised with a capture species 261A-C specific to one of the labelled species 201A-C of the library members and, in particular, one of the positive “hits” from the interaction with the target species. Accordingly, each of the electrodes 260A- C and capture species 261A-C defines a capture site 265 A-C for a corresponding labelled species 201 A-C. In particular and as schematically depicted in Fig. 4B, a first capture site 265A comprises a first capture species 261 A functionalised on the surface of a first electrode 260A, the first capture species 261 A having a sequence which is complimentary to (i.e. will specifically bind to) to the NA label (or a derivative thereof) on a first one of the labelled species 201 A. Similarly, a second capture site 265B comprises a second capture species 26 IB functionalised on a second electrode 260B having a sequence which is complimentary to (i.e. will specifically bind to) to the NA label (or a derivative thereof) on a second one of the labelled species 20 IB. A third capture site 265C comprises a third capture species 261C functionalised on a third electrode 260C having a sequence which is complimentary to (i.e. will specifically bind to) to the NA label (or a derivative thereof) on a third one of the labelled species 201C. Although not depicted, each of the plurality of electrodes 260A-C are electrically connected to a control unit (optionally via a signal processing unit) so that the plurality of electrodes 260A-C can be individually actuated and addressed by the control unit. This can be used to provide stimuli, such as a debinding stimulus, and also to address the electrodes 260A-C to obtain measurement signals which can indicate whether the labelled species are bound to the sample surface 256. Accordingly, the electrodes 260A-C can act as both a modification element and a sensing element.

[0124] The method further comprises providing 215 the plurality of labelled species 201A-C to the sample surface 256 and selectively binding to each capture site 265A-C one of the NA-labels or a derivative thereof of the labelled species 201A-C so as to selectively retain each of the labelled species 201 A-C of the library on a corresponding capture site 265A-C. This process is depicted in Figs. 4B and 4C, where Fig. 4C shows the labelled species 101A-C and capture species 165A-C bound as a bound pair on each capture site 165 A-C. It will be appreciated that this will also have occurred for all of the other capture sites on the separation device 150 (see Fig. 4A), where each of the other captures sites have captures species which correspond to the unique labels on other labelled species within the library. As shown in Fig. 4C, before the subsequent steps, the solution over the sample surface may be free of any labelled species so as to not contaminate any subsequent recovery. This may be achieved by any method, such as flowing a solution over the sample solution to remove any unbound species or applying a force to the species to remove them from the sample surface. Accordingly, using the separation device 250, the labelled species 201 A-C can be separated out from the library and individually bound to different parts of the sample surface 256.

[0125] If desired, the method can further comprise addressing the electrodes 260A-C of each capture site 265A-C so as to monitor the capture of the labelled species 201 A-C on each capture site 265A-C. This may be used to determine when to proceed with the subsequent steps.

[0126] The method further comprises analyzing 218 the structure of the species portion of at least one of the labelled species 201 A-C while the labelled species 201 A-C remains bound on the corresponding capture site 265A-C. Fig. 4D depicts the analysis of the species portion of the first labelled species 201 A while it is retained on the first capture site 265A. In this example, an arrow 270 depicts an incident beam used in the analysis step. This may be a laser beam as part of MALDI-MS analysis, for example,or could be an X-ray beam as part of an XPS analysis process. This analysis allows the structure of the species portion (i.e. the part which interacted with the target) to be identified independently of the other labelled species 201B-C within the sample. The separation device 250 lends itself to this analysis because each of the labelled species 201A-C is adhered to separated and distinct capture sites and are provided as a layer on top of the surface 256 (caused by the location of the capture species 261A-C on the substrate 255). This process can then be repeated for the other labelled species 201B-C, such that the structures of the other labelled species 201B-C are analysed.

[0127] Accordingly, this method 200 provides a means for directly determining the specific structure of the species portion which provided the interaction with the target species.

[0128] Although the methods 100, 200 of Fig. 1 and Fig. 3 are described as two separate methods, it will be appreciated that the steps disclosed therein may be combined. Fig. 5 depicts an exemplary method 300 in which these are combined. The method 300 comprises providing 305 a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a derivative of a NA label; providing 310 a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing 315 the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof so as to selectively retain each of the labelled species of the library on a corresponding capture site; analysing 318 the structure of the species portion of at least one of the labelled species bound on at least one of the capture sites; and, after the step of analysing 318, selectively releasing 320 one of the labelled species from the sample surface, recovering 325 the labelled species separately to the other of the plurality of labelled species and (further) analysing 330 the recovered labelled species. In this method 300, selective release 320 of any particular labelled species occurs after analysis of that particular labelled species on the corresponding capture site(s), but it will be appreciated that the order of these steps for one labelled species may not be sequential or in series with another. For example, it is not necessary that all labelled species be analysed on the sample surface before sequential release 320 - and further optionally analysis 325 - of some of the labelled species (which have already been analysed 318 on the sample surface) occurs.

[0129] The methods 100, 200, 300 set out above use capture sites 165A-C, 265 A-C provided with captures species 161A-C, 261A-C to capture the corresponding labels ofthe labelled species. Although a separation device may be provided with capture sites for all members of the library (whether the full, original library used for screening, or a reduced library of positive hits for a target), it may be more efficient to provide only capture species forthose which are positive hits.

[0130] The methods accordingly can comprise determining the labels of the labelled species which interacted with the target species. The method may then comprise providing the sample surface (and the capture site) with a corresponding capture species based on the determined label.

[0131] Fig. 6 depicts a method which includes a pre-processing step which includes these steps.

[0132] The method 400 comprises providing a library which has or can be used in a screening process for a target species, the library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a unique derivative of a NA label. The method 400 further comprises determining 408 the structure of the labels of the labelled species which interacted with a target species in a screening step (“positive hits”). This may comprise separating the library of hits into two groups and determining the label using one of the groups. This may comprise sequencing the labels. The method further comprises providing 410 a separation device, wherein providing the separation device comprises providing a plurality of capture species to a sample surface of the separation device, wherein the capture species are selected based on the determined labels of the positive hits. This may be through spotting an appropriate capture species (e.g. oligomers) or may be by growing the capture species in situ on each of the capture sites. The separation device according comprises a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site. The method then comprises providing 415 the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof of the labelled species so as to selectively retain each of the labelled species of the library on a corresponding capture site.

[0133] The method 400 may then proceed as per any of the previous disclosed methods 100-300. For example, this may comprise analysing 418 the structure of the species portion of at least one of the labelled species bound on at least one of the capture sites; and, after the step of analysing 418, selectively releasing 420 one of the labelled species from the sample surface, recovering 425 the labelled species separately to the other of the plurality of labelled species and (further) analysing 430 the recovered labelled species. In this method 400, selective release 420 of any particular labelled species occurs after analysis of that particular labelled species on the corresponding capture site(s).

[0134] As set out herein, the methods disclosed herein can be used as a post -processing method for a screening process in which a library of species are provided to a target species to determine which of the labelled species provided a positive hit. Thus, the “library” provided to the separation device may be the original library prior to screening or a library of positive hits or combinations thereof.

[0135] Providing the original library prior to screening can be advantageous as the amount of each labelled species remaining in the isolated library of positive hits may be low (after screening and isolation). In such methods, the labels can be identified and then the larger library can be exposed to the separation device to isolate the positive hits from the original library, where the positive hits are more abundant. This may be providing the original library hits only, or providing both the original library and the positive hits library. Given that the sample used in the screening is based on the original library, any errors present in the isolated hits will also be present in the positive hits, such that there will still be accurate identification of any positive hits.

[0136] One such method may comprise determining the structure of each of the labels of a labelled species from an expanded or original library which has been determined to interact with a target species of interest and using that to provide the capture species corresponding to the hits. The library then “provided” to the separation device may be the original library comprising all of the labelled species.

[0137] In a further method depicted in Fig. 7, the method 500 may further comprise the screening process. Accordingly, the method may comprise providing 505 an expanded library comprising a plurality of labelled species and splitting 506 the expanded library into two sub-groups: a first subgroup which will be exposed to the target and a second sub-group which will not. The method comprises providing 507 one of the sub-groups comprising the plurality of labelled species of the expanded library to a target so that any of the labelled species that can bind to the target bind to the target. The method may then further comprise determining 508 the labels of the labelled species to identify the labels associated with the labelled species which bound to the target.

[0138] Once the labels have been determined, the method may comprise providing 510 a separation device, wherein providing the separation device comprises providing a plurality of capture species to a sample surface of the separation device, wherein the capture species are selected based on the determined labels of the labelled species which bound to the target. This may be through spotting an appropriate capture species (e.g. oligomers) or may be by growing the capture species in situ on each of the capture sites. The separation device according comprises a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site.

[0139] In this method 500, rather than or in addition to providing the labelled species which bound to the target (the smaller, positive hits of the first sub-group of the expanded library), the method 500 comprises providing 515 the plurality of labelled species of the second sub-group library to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof of the labelled species so as to selectively retain each of the labelled species of the library on a corresponding capture site.

[0140] The method 500 may then proceed with any of the analysis and separation steps disclosed herein. For example, in this embodiment, the method 500 further comprises selectively releasing 520 one of the labelled species from the corresponding capture site and recovering 525 the labelled species separately to the other of the plurality of labelled species. This process can then be repeated for the other labelled species such that all of the labelled species which were positive hits are also selectively released 520 from their corresponding capture site and recovered 525 separately to the other of the plurality of labelled species.

[0141] The method further comprises analysing 530 the recovered labelled species separately.

[0142] Although specific separation devices 150, 250 have been depicted in respect of the methods 100, 200 of Figs. 1 and 3, it will be appreciated that these are interchangeable and that other separation devices may be used.

[0143] Figs. 8 to 10 schematically depict a further separation device 650, which can be used in the methods disclosed herein. Fig. 8 provides a schematic plan view of the separation device 650, Fig. 9 shows an expanded view of a part of the separation device 650 and Fig. 10 provides a cross-section along line C-C in Fig. 8. Although not shown, the separation device 650 comprises a control unit (not shown) which can be used in embodiments to perform the device -related steps of the methods.

[0144] The separation device 650 comprises a substrate 655 in part defining an upper sample surface 656. The separation device 650 also comprises a plurality of capture sites 665 (only the outer electrode arrays 690 are labelled in Fig. 8 for the sake of clarity) arranged in a 4 x 4 grid in part also defining the upper sample surface 656 of the substrate 655 (although it will be appreciated that any number of the capture sites 665 may be provided in any configuration). The capture sites 665 have a similar form to the capture sites 165A-C of the separation device of Figs. 2A-2E. That is, each capture site 665 comprises a heater 660 embedded in the substrate 655. Each of the heaters 660 is individually actuatable and is functionalised with a capture species 661 specific to one of a labelled species of a library members and, in particular, one of the positive “hits” from the interaction with the target species. Accordingly, each of the heaters 660 and capture species 661 defines a capture site 665 for a corresponding labelled species.

[0145] Although not depicted, each of the plurality of heaters 660 are electrically connected to a control unit so that the plurality of heaters 660 can be actuated under the control of the control unit. The heaters 660 can act as individual modification elements and can be used to locally heat the region on and above each corresponding capture site 665 (e.g. the solution adjacent and on the corresponding capture site 665). As set out above, this can be used to aid incubation (i.e. to promote binding of the label of a labelled species to the corresponding capture species 661) and, in some cases, may cause annealing. Due to the individual actuation of the heaters 660 and the local nature of the heater 660 (i.e. that each provides and is limited to a single capture site 665), the temperature on each capture site 665 can be different which can be particularly useful for providing appropriate annealing temperatures for each pair of labels and capture species. It can also be further be used for selective release of the bound labelled species, as set out above.

[0146] The functionality and use of the capture sites 665 is accordingly the same as for the other separation devices 150, 250 disclosed herein, and particularly the separation device 150 of Figs. 2A to 2E. It will, therefore, be appreciated how such a device can be used with the methods disclosed herein.

[0147] However, the separation device 650 of Figs. 8 to 10 includes additional functionality to aid this process. In particular, the separation device 650 is provided with a plurality of electrode arrays 690 arranged around each of the capture sites 665, where each electrode array 690 comprises four individual electrodes 691A-D (see Fig. 9) arranged so that each of the four electrodes 691A-D defines the edge ofa square surrounding the capture site 665. Fig. 9 shows an expanded view of a part of the separation device 650 in which the upper left electrode array 690 (as it is shown in Fig. 8 - i.e. the first electrode array 690 in the 4 x 4 grid) is more clearly visible. Here it can be seen that this (and each) electrode array 690 comprises four elongated electrodes 691A-D defining the edges of a square shape. This provides two sets of opposing pairs of electrodes. Specifically, there is a first pair comprising a first electrode 691 A arranged spaced apart and opposing from a third electrode 691C (i.e. defining the opposite side of the square). The first electrode 691A and third electrode 691C of the first electrode array 691 A are electrically connected or connectable to one another so that an electric field can be formed therebetween. There is also a second pair comprising a second electrode 69 IB (in this arrangement, this extends between the top ends of the first electrode 691 A and third electrode 691C). This opposes and is spaced apart from a fourth electrode 691D (i.e. defining the opposite side of the square), which is also arranged to extend across the bottom edge of the square between the bottom ends of the first electrode 691A and third electrode 691C. The second electrode 691B and fourth electrode 69 ID of this electrode array 690 are electrically connected or connectable to one another so that an electric field can be formed therebetween. Each of the electrode arrays 690 of the separation device 650 has a corresponding structure. Although we have noted that the opposing pairs of electrodes can be electrically connected, it should be noted that, in some configurations, all of the electrodes of the electrode arrays 690 may be connectable to or connected to all of the other electrodes of the electrode arrays 690 in a particular row or column of the grid to provide the ability to generate an electric field therebetween. This allows movement therebetween and sensing. In some configurations, all of the electrodes of the electrode arrays 690 may be connectable to or connected to all of the other electrodes of the electrode arrays 690.

[0148] These electrode arrays 690 of the separation device 650 can serve multiple purposes and, accordingly, the control unit may be configured to operate these for a number of different reasons and operations during implementation of the methods disclosed herein.

[0149] First, these may be used to manipulate the labelled species (or, indeed, any other species) provided to the sample surface 656. That is, the electrodes 691A-D of each electrode array 690 may act as manipulation assemblies which can be used to apply a force to the labelled species (which, by virtue of their label at least, may be charged). In particular, any combination of two electrodes 691A-D on the separation device 650 can act as a manipulation assembly by providing an electric field therebetween. For example, a first manipulation assembly 693 could be considered to be formed across the top row defined by the first and third electrodes 691 A, 691C of each electrode array 690 extending across the width of the substrate 655. An electric field formed between the first and third electrodes 691 A, 691C of each electrode array 690 will cause charged species within the library to move along the sample surface 656 between the corresponding first and third electrodes 691A, 691C (i.e. from right to left or left to right, as depicted in Fig. 8). Because of the provision of electrodes 691A-D between eachof the capture sites 665, this provides granular control of the movement of the labelled species such that fine manipulation is possible across small regions of the sample surface 656.

[0150] These electrodes 691A-D (and the manipulation assemblies they form) can be used to aid the specific steps of the methods disclosed herein. For example, these can be used to remove any unbound species prior to selective release and / or analysis. This can also be used to strip off non-specifically bound species from the capture species 661 prior to selective release and / or analysis. The provision of the electrode arrays 690 surrounding each capture site 665 - and, accordingly, providing each capture site 665 with its own electrode array 690 - allows for different electric field strengths to be provided to different capture sites 665. This allows for greater control and for the electric field strength to be tailored to the capture species / labelled species relationship (i.e. the strength of the bound pair). This allows for more accurate removal of non-specifically bound species, for example. Alternatively or additionally, this can be used as part of the selective release, where present. For example, by applying an electric field of an appropriate strength, this can be used to pull the bound labelled species off the capture site 665. As noted above, the provision of the electrode arrays 690 surrounding each capture site 665 - and, accordingly, providing each capture site 665 with its own electrode array 690 - allows for different electric field strengths to be provided to different capture sites 665. This allows for greater control of the selective release stage. With respect to removal of a released labelled species, the electrodes 691 A-C can be used to apply a force and remove the labelled species from the sample surface where it can be recovered. Because of the provision of electrodes 691A-D between each of the capture sites 665, this provides granular control of the movement of the released labelled species such that fine manipulation is possible across small regions of the sample surface 656. Further, it is possible that movement of the labelled species will lead to diffusion of the labelled species with the medium / solution; the electrodes 691 A-C can be used (e.g. during the recovery step) to concentrate the labelled species on a particular part of the sample surface 656, from which they can be recovered.

[0151] More generally, the electrodes 691A-D can be used to move species around the sample surface 656. For example, the library may be provided to one part of the sample surface 656 and the electrodes 691A-D can be actuated to cause the library members to migrate across the sample surface 656 and ensure all capture sites 665 are exposed to the library. For example, a first electrode 691A (e.g. the upper left most electrode) and a third electrode 691C (e.g. the upper right most electrode) along the same row of the grid could be used to generate an electric field therebetween causing sample to migrate from one side of the separation device 650 to the other side. It will be further be appreciated that the grid structure of the electrode arrays 690 is such that a species could be manipulated in more than one dimension - i.e. in two or more dimensions. For example, it is possible for a species to be migrated along a first dimension, followed by migration along a second dimension. At this point, the control unit may be further configured to cause another electrode pair to cause the species to be moved along another (third) dimension. Accordingly, the separation device 650 provides a multi-dimensional manipulation system with a vast degree of flexibility to perform complex separations and manipulations.

[0152] Each electrode array 690 could also be used to influence a part of the library with respect to the capture site 665. For example, at least two opposing electrodes 691 A-D of an electrode array 690 could be used to direct the part of the library to the capture site 665. This can be useful to overcome diffusion which may cause labelled species not yet attached to the capture site 665 to drift away from a capture site 665.

[0153] Second, the electrodes 691A-D can be used for sensing - i.e. as sensing elements - or modifications - i.e. as modification elements. For example, the configuration and location of the electrodes arrays 690 is such that these can be operated to (e.g. by the control unit) to serve as sensing elements or modification elements. For instance, the electrodes 691 A-D can be used to interrogate species located between any of the two electrodes 691 A-D. For example, it may be that the labelled species bound to the capture site 665 will change the permittivity of the medium located therebetween and the electrodes 691 A-D are calibrated or arranged so that the change in permittivity can be determined. Individual electrodes 691 A-D could also be used to determine the location of species. Each electrode 691 A is individually addressable so that it can provide its own measurement signal. These could further be operated to act as a modification element, for example for applying a stimulus.

[0154] Although not depicted, it will be appreciated that the separation device of Figs. 8 to 10 may further include other components. For example, each of the capture sites 665 may comprise a corresponding electrode provided in the substrate 655, in a similar manner to the separation device 250 of FIGS . 4A to 4E. Each of the electrodes can be individually actuatable and can be functionalised with the capture species 661 specific to a labelled species of a library members. Each of the plurality of electrodes can be electrically connected to a control unit (optionally via a signal processing unit) so that the plurality of electrodes can be individually actuated and addressed by the control unit. This can be used to provide stimuli, such as a debinding stimulus, and also to address the electrodes to obtain measurement signals which can indicate whether the labelled species are bound to the sample surface 656. Accordingly, the electrodes can act as both a modification element and a sensing element. These can be used in conjunction with the heaters 660 such that both are present on the device. For example, the electrodes can be provided at the sample surface and be functionalized, with the heaters located beneath the electrodes within or beneath the substrate. Each capture site 665 in this arrangement will accordingly have a corresponding heater 660 and electrode.

[0155] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the disclosed systems and methods, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfil the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. If a computer program is discussed above, it may be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with oras part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to". Any reference signs in the claims should not be construed as limiting the scope.

[0156] The flow diagrams and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the disclosed systems and methods. In this regard, each block in the flow diagrams orblock diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flow diagrams and combinations of blocks in the block diagrams and / or flow diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.

[0157] Further examples of the methods and systems disclosed herein are provided as clauses:

[0158] Clause 1. A method of identifying a labelled species, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a unique derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof of the labelled species so as to selectively retain each of the labelled species of the library on a corresponding capture site; and selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species.

[0159] Clause 2. The method of clause 1, wherein each capture site comprises a capture species adhered to the capture site, each capture species configured to selectively bind to one of the NA labels or a derivative thereof to form a bound pair and retain the corresponding labelled species on the capture site.

[0160] Clause 3. The method of clause 2, wherein the capture species comprises an oligonucleotide adhered to the capture site.

[0161] Clause 4. The method of clause 3, wherein the method further comprises forming an oligonucleotide capture species on each capture site prior to providing the plurality of labelled species to the sample surface.

[0162] Clause 5. The method of clause 3 or clause 4, wherein the method further comprises sequencing the NA label of each of the plurality of labelled species and providing an oligonucleotide for each capture site based on the sequenced NA labels.

[0163] Clause 6. The method of any of clauses 2 to 5, wherein selectively releasing one of the labelled species from the sample surface comprises applying a debinding stimulus to the bound pair to debind the NA-label or derivative thereof from the capture species.

[0164] Clause 7. The method of clause 6, further comprising, prior to applying the debinding stimulus to the bound pair to unbind the NA-label or derivative thereof from the capture species, applying a first stimulus to the capture site, the first stimulus having a lower intensity than the debinding stimulus such that it can cause debinding of any non-selectively bound species present on the capture site.

[0165] Clause 8. The method of any preceding clause, wherein providing the library comprising a plurality of labelled species comprises providing a library in which each labelled species comprising a unique species bonded to a unique NA label; wherein the method further comprises applying a stimulus to the unique NA label to form a unique derivative of a NA label; and wherein selectively binding to each capture site comprises selectively binding one of the unique derivatives of the NA label to each capture site.

[0166] Clause 9. The method of clause 8, wherein the NA label comprises a DNA label and wherein applying a stimulus to the DNA label comprises denaturing the DNA to form a single strand NA label.

[0167] Clause 10. The method of any preceding clause, wherein each capture site comprises an individually actuatable modification element configured to cause the selectively releasing of the labelled species bound to the capture site.

[0168] Clause 11. The method of clause 10, wherein the modification element is selected from an electrode or a thermal device.

[0169] Clause 12. The method of any preceding clause, wherein recovering the labelled species separately to the other of the plurality of labelled species comprises releasing the labelled species and applying a force to remove the labelled species from the sample surface.

[0170] Clause 13. The method of any preceding clause, wherein selectively releasing one of the labelled species from the sample surface is selectively releasing one of the labelled species from the corresponding capture site.

[0171] Clause 14. The method of any preceding clause, wherein, prior to selectively releasing one of the labelled species from the sample surface, the method further comprises removing any unbound labelled species from the sample surface.

[0172] Clause 15. The method of any preceding clause, further comprising selectively releasing each of the other labelled species from the sample surface, recovering each of the other labelled species separately and analysing each of the recovered labelled species separately.

[0173] Clause 16. The method of any preceding clause, wherein analysing the recovered labelled species comprising analysing the recovered labelled species to determine the structure of the species portion.

[0174] Clause 17. The method of any preceding clause, wherein selectively releasing one of the labelled species from the sample surface is selectively releasing one of the labelled species from the corresponding capture site.

[0175] Clause 18. The method any preceding clause, further comprising: providing an expanded library comprising a plurality of labelled species; and providing the plurality of labelled species of the expanded library to a target so that any of the labelled species that can bind to the target bind to the target.

[0176] Clause 19. The method of clause 18, further comprising separating the labelled species which bind to the target from the other of the plurality of labelled species of the expanded library to provide the library, optionally further comprising: determining the labels of the labelled species; and wherein providing the separation device comprises configuring each capture site based on the determined labels such that each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site.

[0177] Clause 20. The method of any preceding clause, further comprising sensing a property to determine the presence of a labelled species on at least one capture site.

[0178] Clause 21. A method of identifying a labelled species, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof so as to selectively retain each of the labelled species of the library on a corresponding capture site; and analysing the structure of the species portion of at least one of the labelled species bound on at least one of the capture sites.

[0179] Clause 22. The method of clause 21, wherein each capture site comprises a capture species adhered to the capture site, each capture species configured to selectively bind to one of the NA labelsor a derivative thereof to form a bound pair and retain the corresponding labelled species on the capture site.

[0180] Clause 23. The method of clause 22, wherein the capture species comprises an oligonucleotide adhered to the capture site.

[0181] Clause 24. The method of clause 23, wherein the method further comprises forming an oligonucleotide capture species on each capture site prior to providing the plurality of labelled species to the sample surface.

[0182] Clause 25. The method of clause 23 or clause 24, wherein the method further comprises sequencing the NA label of each of the plurality of labelled species and providing an oligonucleotide for each capture site based on the sequenced NA labels.

[0183] Clause 26. The method of any of clauses 22 to 25, wherein the method further comprises, after analysing the structure of the species portion of each labelled species bound on each capture species, selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species.

[0184] Clause 27. The method of clause 26, wherein selectively releasing one of the labelled species from the sample surface comprises applying a debinding stimulus to the bound pair to debind the NA- label or derivative thereof from the capture species.

[0185] Clause 28. The method of clause 27, further comprising, prior to applying the debinding stimulus to the bound pair to unbind the NA-label or derivative thereof from the capture species, applying a first stimulus to the capture site, the first stimulus having a lower intensity than the debinding stimulus such that it can cause debinding of any non-selectively bound species present on the capture site.

[0186] Clause 29. The method of any of clauses 26 to 28, wherein selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species.

[0187] Clause 30. The method of any of clauses 26 to 29, wherein recovering the labelled species separately to the other of the plurality of labelled species comprises releasing the labelled species and applying a force to remove the labelled species from the sample surface.

[0188] Clause 31. The method of any preceding clause, wherein, prior to analysing the structure of the species portion of each labelled species bound on each capture site, the method further comprises removing any unbound labelled species.

[0189] Clause 32. The method of any of clauses 21 to 31, wherein providing the library comprising a plurality of labelled species comprises providing a library in which each labelled species comprising a unique species portion bonded to a unique NA label;wherein the method further comprises applying a stimulus to the unique NA label to form a unique derivative of a NA label; and wherein selectively binding to each capture site comprises selectively binding one of the unique derivatives of the NA label to each capture site.

[0190] Clause 33. The method of clause 32, wherein the NA label comprises a DNA label and wherein applying a stimulus to the DNA label comprises denaturing the DNA to form a single strand NA label.

[0191] Clause 34. The method of any of clauses 21 to 33, wherein each capture site comprises an individually actuatable modification element configured to cause the selectively releasing of the labelled species bound to the capture site.

[0192] Clause 35. The method of clause 34, wherein the modification element is selected from an electrode or a thermal device.

[0193] Clause 36. The method of any of clauses 21 to 35, further comprising selectively releasing each of the other labelled species from the sample surface, recovering each of the other labelled species separately and analysing each of the recovered labelled species separately.

[0194] Clause 37. The method of clause 36, wherein analysing the recovered labelled species comprising analysing the recovered labelled species to determine the structure of the species portion.

[0195] Clause 38. The method any of clauses 21 to 37, further comprising providing an expanded library comprising a plurality of labelled species; and providing the plurality of labelled species of the expanded library to a target so that any of the labelled species that can bind to the target bind to the target.

[0196] Clause 39. The method of clause 38, further comprising separating the labelled species which bind to the target from the other of the plurality of labelled species of the expanded library to provide the library.

[0197] Clause 40. The method of clause 38, further comprising determining the labels of the labelled species; and wherein providing the separation device comprises configuring each capture site based on the determined labels such that each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site.

[0198] Clause 41. The method of clause 40, wherein providing the library to the separation device comprises providing the expanded library to the separation device.

[0199] Clause 42. The method any of clauses 21 to 41, further comprising sensing a property to determine the presence of a labelled species on at least one capture site.

Claims

CLAIMS:

1. A method of identifying a labelled species, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a unique derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site; providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof of the labelled species so as to selectively retain each of the labelled species of the library on a corresponding capture site; and selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species.

2. The method of claim 1, wherein each capture site comprises a capture species adhered to the capture site, each capture species configured to selectively bind to one of the NA labels or a derivative thereof to form a bound pair and retain the corresponding labelled species on the capture site.

3. The method of claim 2, wherein selectively releasing one of the labelled species from the sample surface comprises applying a debinding stimulus to the bound pair to debind the NA-label or derivative thereof from the capture species.

4. The method of any preceding claim, wherein providing the library comprising a plurality of labelled species comprises providing a library in which each labelled species comprising a unique species bonded to a unique NA label; wherein the method further comprises applying a stimulus to the unique NA label to form a unique derivative of a NA label; and wherein selectively binding to each capture site comprises selectively binding one of the unique derivatives of the NA label to each capture site.

5. The method of any preceding claim, wherein each capture site comprises an individually actuatable modification element configured to cause the selectively releasing of the labelled species bound to the capture site.

6. The method of any preceding claim, wherein recovering the labelled species separately to the other of the plurality of labelled species comprises releasing the labelled species and applying a force to remove the labelled species from the sample surface.

7. The method of any preceding claim, wherein, prior to selectively releasing one of the labelled species from the sample surface, the method further comprises removing any unbound labelled species from the sample surface.

8. The method of any preceding claim, wherein analysing the recovered labelled species comprising analysing the recovered labelled species to determine the structure of the species portion.

9. The method of any preceding claim, further comprising: providing an expanded library comprising a plurality of labelled species; and providing the plurality of labelled species of the expanded library to a target so that any of the labelled species that can bind to the target bind to the target; and separating the labelled species which bind to the target from the other of the plurality of labelled species of the expanded library to provide the library, optionally further comprising: determining the labels of the labelled species; and wherein providing the separation device comprises configuring each capture site based on the determined labels such that each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site.

10. A method of identifying a labelled species, the method comprising: providing a library comprising a plurality of labelled species, each labelled species comprising a unique species portion bonded to either a unique nucleic acid (NA) label or a derivative of a NA label; providing a separation device comprising a sample surface and a plurality of capture sites arranged on the sample surface, wherein each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site;providing the plurality of labelled species to the sample surface and selectively binding to each capture site one of the NA-labels or a derivative thereof so as to selectively retain each of the labelled species of the library on a corresponding capture site; and analysing the structure of the species portion of at least one of the labelled species bound on at least one of the capture sites.

11. The method of claim 10, wherein each capture site comprises a capture species adhered to the capture site, each capture species configured to selectively bind to one of the NA labels or a derivative thereof to form a bound pair and retain the corresponding labelled species on the capture site.

12. The method of claim 10 or claim 11, wherein the method further comprises, after analysing the structure of the species portion of each labelled species bound on each capture species, selectively releasing one of the labelled species from the sample surface, recovering the labelled species separately to the other of the plurality of labelled species and analysing the recovered labelled species.

13. The method of claim 12, wherein selectively releasing one of the labelled species from the sample surface comprises applying a debinding stimulus to the labelled species and capture species to debind the NA-label or derivative thereof from the capture species.

14. The method of any of claims 10 to 13, wherein, prior to analysing the structure of the species portion of each labelled species bound on each capture site, the method further comprises removing any unbound labelled species.

15. The method of any of claims 10 to 14, wherein providing the library comprising a plurality of labelled species comprises providing a library in which each labelled species comprising a unique species portion bonded to a unique NA label; wherein the method further comprises applying a stimulus to the unique NA label to form a unique derivative of a NA label; and wherein selectively binding to each capture site comprises selectively binding one of the unique derivatives of the NA label to each capture site.

16. The method any of claims 10 to 15, wherein each capture site comprises an individually actuatable modification element configured to cause the selectively releasing of the labelled species bound to the capture site.

17. The method any of claims 10 to 16, further comprising: providing an expanded library comprising a plurality of labelled species; providing the plurality of labelled species of the expanded library to a target so that any of the labelled species that can bind to the target bind to the target; and separating the labelled species which bind to the target from the other of the plurality of labelled species of the expanded library to provide the library.

18. The method of claim 17, further comprising determining the labels of the labelled species; and wherein providing the separation device comprises configuring each capture site based on the determined labels such that each capture site is configured to selectively bind to one of the NA labels or a derivative thereof to retain the corresponding labelled species on the capture site.

19. The method of claim 18, wherein providing the library to the separation device comprises providing the expanded library to the separation device.

20. The method any of claims 10 to 19, further comprising sensing a property to determine the presence of a labelled species on at least one capture site.

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