hydrogel

Abstract

The invention relates to a device comprising an expandable hollow hydrogel tube encapsulated by an ingestible capsule to enable the targeted delivery of large molecules such as biologics to the gastrointestinal (GI) mucosa. Upon ingestion, the capsule is arranged to release the hydrogel tube in the GI tract, where the hydrogel tube expands from a first configuration to a second configuration upon hydration. In its expanded state, the hydrogel tube exerts an outward radial force on the lining of the GI tract. In some embodiments, the outward-facing surface of the hydrogel tube comprises microneedles. The invention further relates to a hydrogel resin comprising: gelatin or poloxamer 407; a neutralisation agent; acrylic acid or sodium acrylate; a crosslinker; a photoinitiator; and a photoabsorber. The hydrogel tube of the invention may be produced by bioprinting and photo-crosslinking said hydrogel resin.

Description

[0001] Our Reference: P605922PC00

[0002] Hydrogel

[0003] Field of Invention

[0004] The invention relates to devices, expandable hollow hydrogel tubes, hydrogel resins and hydrogels.

[0005] Background to the Invention

[0006] Biologies have transformed modern therapeutics, accounting for 8 out of 10 top selling drugs in 2018 (Pharmalntelligence, Top 10 best-Selling Drugs of 2018 Fund US and EU Pharma R&D). The administration of biologies is currently limited to injection (with a few exceptions). Oral administration is preferred over injections due to patient convenience, acceptability, safety and potential reduction of healthcare costs. However, oral delivery of biologies has been a major challenge due to the acidic and enzymatic degradation in the harsh gastric environment and extremely poor permeability of large molecules (>1 ,000 Da) across the intestinal mucosa. This is further complicated by variable gastric emptying and complex medium composition.

[0007] Various nanomedicine-based methods have been developed to protect therapeutics from degradation in the stomach, such as encapsulation in nanoparticles, liposomes, or polymers, modification of the drug structure, and use of mucoadhesive or transcytotic agents. However, there has been limited success with only a few examples reaching clinical trials, such as those employing silica-based nanoparticles, liver-targeting liposomes, and PEGylated fatty acids nanoparticles (Duran-Lobato et al., Adv. Mater. 2020, 32, 1901935). In addition, these approaches do not address the significant challenge of enhancing the permeation of biologies across the gastrointestinal (Gl) tract mucosa.

[0008] Other strategies have employed permeation enhancers such as acyl carnitine, citric acid, lauryl l-carnitine, bile salts or caprylic acid derivatives, and have focused on the following biologies: calcitonin (MW 3,432Da, Peptilligence® and Eligen® Technologies), semaglutide (4,114Da, Emisphere Technology), octreotide (1 ,019Da, Chiasma Inc.) and insulin (5,808Da, Chiasma Inc.). Notably, such technologies are confined to peptides and proteins <6,000 Da in molecular weight (MW). There is only one clinically approved biologic of MW >1 ,000 Da which utilises absorption enhancers, namely the oral GLP-1 analogue Rybelsus®. The oral bioavailability of this product was reported as 0.4-1%, despite the use of permeation enhancers (FDA. Rybelsus FDA prescribing information. Available at: https: / / www.accessdata.fda.gov / drugsatfda_docs / label / 2019 / 213051s000lbl.pdf). This highlights the scale of the challenge faced to safely facilitate the absorption of intact biologies across the complex and multibarrier nature of the Gl tract.

[0009] Therefore, there is a need for improved methods for delivering biologies to the Gl tract and / or across the Gl tract mucosa.

[0010] Summary of the Invention

[0011] According to a first aspect, there is provided a device comprising an expandable hollow hydrogel tube encapsulated by an ingestible capsule, wherein the ingestible capsule is arranged to release the hydrogel tube in the gastrointestinal (Gl) tract, and wherein the hydrogel tube is arranged to expand outwardly from a first (unexpanded) configuration to a second (expanded) configuration in the Gl tract to exert an outward radial force on the lining of the Gl tract.

[0012] The inventors have developed an expandable hydrogel tube that can be administered orally inside an ingestible capsule. Once administered, the hydrogel tube is released from the capsule into the Gl tract and expands outwardly on hydration to press against the wall of the Gl tract while maintaining a tube structure so that the Gl tract is not obstructed. This is a key advantage over known drug delivery devices which are solid and therefore block the Gl tract. The hydrogel tube may be coated or impregnated with an agent, such as a therapeutic biologic, which, upon hydrogel expansion and contact with the wall of the Gl tract, is driven across the mucosa to provided targeted delivery across the lining of the Gl tract. Advantageously, this device enables the delivery of large molecules (e.g., >1000 Da) that is not possible with prior art devices. In addition, because the agent can be targeted to the Gl tract mucosa, the amount of agent can be reduced, which decreases product costs and potential toxicity effects.

[0013] In some embodiments, the ingestible capsule is arranged to release the hydrogel tube in the small intestine or the large intestine. In some embodiments, the ingestible capsule is arranged to release the hydrogel tube in the small intestine.

[0014] Hydrogel Tube

[0015] The term "hydrogel" is given its ordinary meaning in the art and generally refers to a gel comprising a network of polymer chains that are hydrophilic. Hydrogels are highly absorbent natural or synthetic polymeric networks. The term "polymer" means a synthetic or natural macromolecule comprising many repeated subunits. The term "polymer chain" means a length of polymer comprising multiple subunits linked together in the form of a chain.

[0016] The phrase “expandable hollow hydrogel tube”, as used herein, is intended to mean that (i) the hydrogel is in the form of a conduit with a cavity extending through the hydrogel such that Gl contents of the subject can pass through the hydrogel tube in the second, expanded, configuration, and (ii) that the hydrogel can increase in size in one or more external dimensions).

[0017] The phrase “wherein the hydrogel tube is arranged to expand outwardly from a first configuration to a second configuration in the Gl tract to exert an outward radial force on the lining of the Gl tract”, as used herein, is intended to mean that the hydrogel tube increases in size in the Gl tract to contact and apply pressure against the Gl tract lining. The first and second configuration may alternatively be referred to as a dehydrated and hydrated configuration, respectively, or as an initial and expanded configuration, respectively. The first configuration and the second configuration may alternatively be referred to as the unexpanded hydrogel tube and the expanded hydrogel tube, respectively.

[0018] The outward expansion of the hydrogel tube is not particularly limited provided there is radial expansion of the hydrogel tube such that the outer surface of the tube presses against the wall of the Gl tract (but does not exert such a force that would risk wall degeneration and damage), and that the hydrogel tube remains hollow so that Gl tract contents can pass through the expanded hydrogel tube. In some embodiments, the outward expansion increases the exterior diameter of the hydrogel tube and the interior diameter of the hydrogel tube. In some embodiments, the outward expansion increases the exterior diameter of the hydrogel tube and the length of the hydrogel tube. In some embodiments, the outward expansion increases the exterior diameter of the hydrogel tube, the interior diameter of the hydrogel tube, and the length of the hydrogel tube. In some embodiments, the outward expansion of the exterior diameter of the hydrogel tube is relatively greater than any inward expansion of the interior diameter of the hydrogel tube. In some embodiments, the outward expansion occurs without any inward expansion (i.e., the exterior diameter increases while the interior diameter increases or is unaffected).

[0019] In some embodiments, the exterior diameter of the hydrogel tube is increased by approximately the same amount across the length of the hydrogel tube. In some embodiments, the exterior diameter of the hydrogel tube in the second configuration is at least 2-fold greater than the exterior diameter of the hydrogel tube in the first configuration. In some embodiments, the exterior diameter of the hydrogel tube in the second configuration is at least 3-fold greater than the exterior diameter of the hydrogel tube in the first configuration. In some embodiments, the exterior diameter of the hydrogel tube in the second configuration is at least 3-fold to 5-fold greater than the exterior diameter of the hydrogel tube in the first configuration.

[0020] In some embodiments, the length of the hydrogel tube in the second configuration is at least 2-fold greater than the length of the hydrogel tube in the first configuration.

[0021] In some embodiments, the expanded hydrogel tube exerts an outward radial force of from 0.5 to 10 N on the Gl tract lining. In some embodiments, the expanded hydrogel tube exerts an outward radial force of from 0.8 to 9 N on the Gl tract lining. In some embodiments, the expanded hydrogel tube exerts an outward radial force of from 1 to 8 N on the Gl tract lining. In some embodiments, the expanded hydrogel tube exerts an outward radial force of from 1.5 to 5 N on the Gl tract lining. In some embodiments, the expanded hydrogel tube exerts an outward radial force of from 2 to 3 N on the Gl tract lining. In some embodiments, the expanded hydrogel tube exerts an outward radial force of about 2 N on the Gl tract lining.

[0022] The shape and dimensions of the hydrogel tube are not particularly limited, provided that:

[0023] (1) in the first configuration, the hydrogel tube fits inside the ingestible capsule; and

[0024] (2) in the second configuration, the hydrogel tube remains hollow such that the Gl tract is not blocked, and an exterior surface of the hydrogel tube contacts the lining of the Gl tract and exerts an outward radial force thereon.

[0025] In some embodiments, the hydrogel tube is generally cylindrical. In some embodiments, the hydrogel tube is generally polyhedral (e.g., a square tube, a pentagonal tube, a hexagonal tube, a heptagonal tube, an octagonal tube, etc.). References in this specification to a “exterior diameter” and an “interior diameter” are provided in the context of a cylindrical tube but may also generally refer to other shapes of the hydrogel tube and can be interpreted as a “maximum exterior dimension” and a “maximum interior dimension”, respectively.

[0026] In the first configuration, the maximum exterior diameter of the hydrogel tube may be from 5 mm to 10 mm. In the first configuration, the maximum exterior diameter of the hydrogel tube may be from 5.6 mm to 8.5 mm. In the first configuration, the maximum exterior diameter of the hydrogel tube may be from 6 mm to 8 mm. In the first configuration, the maximum exterior diameter of the hydrogel tube may be about 8 mm.

[0027] In the first configuration, the interior diameter of the hydrogel tube may be from 4 to 8 mm. In the first configuration, the interior diameter of the hydrogel tube may be from 5 to 7 mm. In the first configuration, the interior diameter of the hydrogel tube may be about 6 mm.

[0028] In the first configuration, the maximum length of the hydrogel tube may be from 20 to 25 mm. In the first configuration, the maximum length of the hydrogel tube may be from 21 to 23 mm. In the first configuration, the maximum length of the hydrogel tube may be about 22 mm.

[0029] In the first configuration, a maximum thickness of the wall of the hydrogel tube may be from 0.5 mm to 2 mm. In the first configuration, a maximum thickness of the wall of the hydrogel tube may be from 0.8 mm to 1.2 mm. In the first configuration, a maximum thickness of the wall of the hydrogel tube may be about 1 mm.

[0030] In the second configuration, the maximum exterior diameter of the hydrogel tube may be from 20 to 30 mm. In the second configuration, the maximum exterior diameter of the hydrogel tube may be from 22 to 28 mm. In the second configuration, the maximum exterior diameter of the hydrogel tube may be from 24 to 26 mm. In the second configuration, the maximum exterior diameter of the hydrogel tube may be about 25 mm.

[0031] In the second configuration, the interior diameter of the hydrogel tube may be from 10 mm to 25 mm. In the second configuration, the interior diameter of the hydrogel tube may be from 15 mm to 20 mm. In the second configuration, the interior diameter of the hydrogel tube may be about 18 mm.

[0032] In the second configuration, the maximum length of the hydrogel tube may be from 40 to 70 mm. In the second configuration, the maximum length of the hydrogel tube may be from 50 to 60 mm. In the second configuration, the maximum length of the hydrogel tube may be about 55 mm.

[0033] In the second configuration, a maximum thickness of the wall of the hydrogel tube may be from 2 to 4 mm. In the second configuration, a maximum thickness of the wall of the hydrogel tube may be from 2.5 to 3.5 mm. In the second configuration, a maximum thickness of the wall of the hydrogel tube may be from 2.8 to 3.3 mm. In the second configuration, a maximum thickness of the wall of the hydrogel tube may be about 3 mm. In the second configuration, a maximum thickness of the wall of the hydrogel tube may be about 3.1 mm.

[0034] Typical dimensions of a hydrogel tube may be as follows:

[0035] In some embodiments, an outward-facing surface of the hydrogel tube comprises one or more openings (i.e., through holes in the wall of the hydrogel tube). This provides the advantage that a smaller amount of hydrogel resin can be used per device while maintaining structural integrity and function of the hydrogel tube.

[0036] The hydrogel tube may be constructed in any suitable manner known to the skilled person. In some embodiments, the hydrogel tube is 3D printed (i.e., additive manufacturing using hydrogel resin), injection moulded, or template casted. In some embodiments, the hydrogel tube is 3D printed.

[0037] In some embodiments, the hydrogel tube does not comprise one or more external biodegradable films. In some embodiments, the hydrogel tube does not comprise separate compartments. In some embodiments, the hydrogel tube is formed of continuous hydrogel (i.e., not separated into compartments). In some embodiments, the thickness of the hydrogel tube wall is consistent across a parallel and / or perpendicular cross-section of the tube.

[0038] In some embodiments, the hydrogel tube comprises two or more portions that are arranged to break apart inside the Gl tract. This provides the advantage that the device is self-fragmenting, allowing for easier clearance after drug delivery. In some embodiments, the hydrogel tube comprises two portions (e.g., two halves) that are arranged to break apart inside the Gl tract. In some embodiments, the hydrogel tube comprises three portions (e.g., three thirds) that are arranged to break apart inside the Gl tract. In some embodiments, the hydrogel tube comprises four portions (e.g., four quarters) that are arranged to break apart inside the Gl tract. In some embodiments, the portions are attached together by a soluble binder, such as a biodegradable glue, that is configured to degrade after a certain period of time inside the Gl tract. In some embodiments, the soluble binder is PVP K50.

[0039] Microneedles

[0040] In some embodiments, an outward-facing surface of the hydrogel tube comprises microneedles.

[0041] The term “microneedles”, as used herein, refers to protrusions from the hydrogel tube surface. Microneedles may be any suitable shape, including conical, cylindrical, tubular, pyramid-shaped or hook-shaped. Microneedles may be straight, curved, or semi hook-shaped. A microneedle may protrude at an angle from the hydrogel tube surface, the microneedle having a base integrally connected to the surface, a tip distal to the base, and a body therebetween. A microneedle or a portion of a microneedle may be solid or hollow. A microneedle or a portion of a microneedle can be porous or non-porous. A microneedle or a portion of a microneedle may be degradable or non-degradable. A plurality of microneedles used in accordance with the present disclosure may include a mixture of different microneedles. For instance, a plurality of microneedles may include microneedles having various lengths, base portion materials, base diameters, tip portion shapes, spacing between microneedles, coatings, etc. The length of the microneedles typically is between about 1 pm and 1 mm, preferably between 10 microns and 500 microns, and more preferably between 30 and 200 pm. The base diameter is typically between about 10 nm and 1 mm, preferably between 1 micron and 200 microns, and more preferably between 10 and 100 pm.

[0042] The microneedles can be constructed from a variety of suitable materials, including metals, ceramics, semiconductors, organics, polymers, and composites. In particular embodiments, the microneedles are composed of a biodegradable material. In particular embodiments, the microneedles are composed of a hydrogel. In particular embodiments, the microneedles are composed of the same material as the hydrogel tube.

[0043] In some embodiments, the microneedles comprise a hardened tip, formed, for example, from cholesterol. This provides the advantage of increasing the micropenetration of the microneedles to improve agent delivery, particularly for larger biologies.

[0044] Advantageously, the microneedles increase the permeability of the Gl tract by micropenetrating into the mucosa and / or submucosa (without perforation), resulting in greater absorption of the delivery agent.

[0045] Typically, the microneedles are arranged to protrude from the outward-facing surface of the hydrogel tube so that, in the second (expanded) configuration, the microneedles interact with the lumen wall of the Gl tract, for example penetrating or abrading the lumen wall.

[0046] The microneedles may be constructed in any suitable manner known to the skilled person. In some embodiments, the microneedles are 3D printed. In some embodiments, the microneedles are integrally formed with the hydrogel tube. As an example, in some embodiments, the hydrogel tube and the microneedles are 3D- printed as a unitary component. As a further example, in some embodiments, the hydrogel tube and the microneedles are mould-casted as a unitary component. In other embodiments, the microneedles are constructed separately from the hydrogel tube and are subsequently adhered to the exterior surface of the hydrogel tube.

[0047] Any suitable number and / or density of microneedles can be used. In some embodiments, the number of microneedles is from about 2 to about 100, 000, about 100 to about 10,000, or about 500 to about 1,000. In some embodiments, the number of microneedles is from about 2-50, 50-500, 500-1 ,000, 1 ,000-5,000, 5,000-10,000, 10,000-50,000, 50,000-100,000. The density of microneedles may be about or greater than about 100,000 / cm2, about 10,000 / cm2, about 5,000 / cm2, about 1,000 / cm2, about 500 / cm2, about 100 / cm2, about 50 / cm2, about 10 / cm2, or about 1 / cm2.

[0048] Agent

[0049] In some embodiments, the hydrogel tube comprises at least one agent for delivery to the Gl tract. In some embodiments, the hydrogel tube comprises one agent for delivery to the Gl tract. In some embodiments, the hydrogel tube comprises two or more agents for delivery to the Gl tract. In some embodiments, the hydrogel tube comprises three or more agents for delivery to the Gl tract.

[0050] The at least one agent may be any agent intended for delivery to the Gl tract. In some embodiments, the at least one agent is a therapeutic agent, a diagnostic agent, and / or a nutraceutical agent, and / or other substance that may be suitable for introduction to biological tissues, including pharmaceutical excipients, surfactants, and the like.

[0051] The phrase “therapeutic agent”, as used herein, refers to any agent that is administered to a subject to treat a disease, disorder, or other clinically recognised condition, or for prophylactic purposes, and has a clinically significant effect on the body of the subject to treat and / or prevent the disease, disorder or condition. Exemplary classes of therapeutic agents include, but are not limited to, analgesics, anti-analgesics, anti-inflammatory drugs, antipyretics, antidepressants, antiepileptics, antipsychotic agents, neuroprotective agents, anti-proliferatives, such as anti-cancer agents (e.g., taxanes, such as paclitaxel and docetaxel; cisplatin, doxorubicin, methotrexate, etc.), antihistamines, antimigraine drugs, hormones, prostaglandins, antimicrobials (including antibiotics, antifungals, antivirals, antiparasitics), antimuscarinics, anxioltyics, bacteriostatics, immunosuppressant agents, sedatives, hypnotics, antipsychotics, bronchodilators, anti-asthma drugs, cardiovascular drugs, anesthetics, anti-coagulants, inhibitors of an enzyme, steroidal agents, steroidal or non-steroidal anti-inflammatory agents, corticosteroids (e.g., budesonide, prednisone, hydrocortisone, triamcinolone, dexamethasone), immunomodulatory drugs (e.g., anti- TNFs, integrin inhibitors, IL-23 inhibitors, GMCSF, IL10), dopaminergics, electrolytes, gastro-intestinal drugs, muscle relaxants, nutritional agents, vitamins, parasympathomimetics, stimulants, anorectics, anti-narcoleptics, and nutraceuticals (such as vitamins, minerals, supplements such as calcium or biotin, or natural ingredients such as plant extracts or phytohormones). Prophylactic agents, such as vaccines (e.g., anti-microbial or anti-cancer vaccines), are also encompassed.

[0052] In some embodiments, the therapeutic agent is a small molecule drug. In some embodiments, the therapeutic agent is a small molecule drug having molecular weight less than about 2000 Daltons, less than about 1000 Daltons, less than about 750 Daltons, less than about 500 Daltons, less or than about 400 Daltons. In some cases, the therapeutic agent is a small molecule drug having molecular weight between 200 Daltons and 400 Daltons, between 400 Daltons and 1000 Daltons, or between 500 Daltons and 2500 Daltons. Small molecules may be organic, inorganic, natural, or synthetic. Small molecules may be hydrophilic, hydrophobic, or amphiphilic compounds.

[0053] In some embodiments, the therapeutic agent is a biological agent. Examples of biological agents including, but are not limited to, monoclonal antibodies, single chain antibodies, aptamers, enzymes, growth factors, hormones, fusion proteins, peptides, cytokines, therapeutic enzymes, recombinant vaccines, blood factors, anticoagulants, polynucleotides (e.g., mRNA, siRNA, antisense oligonucleotides, anti- miRs, locked nucleic acid (LNA)-based oligonucleotides, Dicer substrates, miRNAs, aiRNAs, shRNAs, ribozymes, and nucleic acid aptamers) or analogues thereof. In some embodiments, the therapeutic agent is a component of a gene editing system that disrupts or corrects genes associated with disease. In some embodiments, the components of the gene editing system are polynucleotides (e.g., mRNA) encoding nucleases. Particularly preferred nucleases include zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), CRISPR-associated protein 9 (Cas9), and recombinant meganucleases. In some embodiments, the therapeutic agent comprises cells or cell fragments (e.g., stem cells) that may or may not have been modified (e.g., modified to express a marker or receptor, such as a chimeric antigen receptor). In some embodiments, the therapeutic agent is an antibody, such as a monoclonal antibody.

[0054] In some embodiments, the therapeutic agent is a biological agent having a molecular weight greater than about 1000 Daltons, greater than about 1250 Daltons, greater than about 1500 Daltons, greater than about 1750 Daltons, greater than about 2000 Daltons, greater than about 2500 Daltons, greater than about 3000 Daltons, greater than about 4000 Daltons, or greater than about 5000 Daltons.

[0055] The phrase “diagnostic agent”, as used herein, refers to any agent that is administered to a subject and can be detected in a subject or a test sample from a subject. Exemplary diagnostic agents include radioactive agents, fluorescent agents, contrast agents (e.g., MRI or X-ray contrast agents), and other imaging agents. In some embodiments, the agent is an imaging contrast agent, such as AgNCh. Diagnostic agents also include, for example, immunodiagnostic agents (e.g., antibodies directed to intracellular targets) as well as other specific binding agents. A diagnostic agent may, for example, consist of a diagnostically detectable label conjugated to a lipid nanoparticle, or to other molecules (e.g., specific binding molecules such as peptides, proteins, or polynucleotides). A conjugated diagnostically detectable label may be included. Many different labels exist in the art and methods of labelling are well known to those skilled in the art. General classes of labels that can be used include radioactive isotopes, paramagnetic isotopes, compounds that can be imaged by positron emission tomography (PET), fluorescent or coloured compounds, and labels that can be imaged by magnetic resonance, bioluminescent compounds, chemiluminescent compounds, bioluminescent compounds, and the like. Particularly suitable detectable labels include, without limitation, radioactive, fluorescent, fluorogenic, or chromogenic labels. Useful radiolabels (radionuclides) that are conveniently detected by a gamma counter, scintillation counter or autoradiography include, without limitation, 3H, 1251, 1311, 35S, and 14C.

[0056] In some embodiments, the diagnostic agent is a small molecule. In some embodiments, the diagnostic agent is a small molecule a having molecular weight less than about 2000 Daltons, less than about 1000 Daltons, less than about 750 Daltons, less than about 500 Daltons, less or than about 400 Daltons. In some cases, the diagnostic agent is a small molecule having a molecular weight between 200 Daltons and 400 Daltons, between 400 Daltons and 1000 Daltons, or between 500 Daltons and 2500 Daltons.

[0057] In some embodiments, the diagnostic agent is a biologic. In some embodiments, the diagnostic agent is a biologic having a molecular weight greater than about 1000 Daltons, greater than about 1250 Daltons, greater than about 1500 Daltons, greater than about 1750 Daltons, greater than about 2000 Daltons, greater than about 2500 Daltons, greater than about 3000 Daltons, greater than about 4000 Daltons, or greater than about 5000 Daltons.

[0058] In some embodiments, the hydrogel tube comprises the at least one agent. In some embodiments, the hydrogel tube and / or the microneedles is / are coated with the at least one agent. In some embodiments, an outward-facing surface of the hydrogel tube and / or the microneedles is coated with the agent. The coating may be a full coating (i.e. , covering substantially all of the exterior surface) or a partial coating (i.e. , covering less than 95% of the exterior surface). The coating may be applied in any suitable manner known to the skilled person, for example, by spray-coating the hydrogel tube and / or the microneedles with a composition comprising the at least one agent, by dry-rolling the hydrogel tube and / or the microneedles with a composition comprising the at least one agent, and / or by dipping the hydrogel tube and / or the microneedles into a composition comprising the at least one agent. In some embodiments, the hydrogel tube and / or the microneedles is impregnated with the at least one agent. The hydrogel tube and / or the microneedles may be fully or partially impregnated with the at least one agent. Impregnation may be achieved in any suitable manner known to the skilled person, for example by soaking the hydrogel tube and / or the microneedles in a composition comprising the at least one agent, or by including the at least one agent in the hydrogel resin prior to forming the hydrogel tube.

[0059] In some embodiments, the device is configured to release from about 5 pg to about 1000 mg of the at least one agent to the Gl tract within 24 hours of administration. In some embodiments, the device is configured to release from about 10 pg to about 900 mg of the at least one agent to the Gl tract within 24 hours of administration. In some embodiments, the device is configured to release from about 50 pg to about 800 mg of the at least one agent to the Gl tract within 24 hours of administration. In some embodiments, the device is configured to release from about 100 pg to about 700 mg of the at least one agent to the Gl tract within 24 hours of administration. In some embodiments, the device is configured to release from about 1 mg to about 600 mg of the at least one agent to the Gl tract within 24 hours of administration. In some embodiments, the device is configured to release from about 10 mg to about 500 mg of the at least one agent to the Gl tract within 24 hours of administration. In some embodiments, the device is configured to release from about 50 mg to about 400 mg of the at least one agent to the Gl tract within 24 hours of administration. In some embodiments, the device is configured to release from about 100 mg to about 300 mg of the at least one agent to the Gl tract within 24 hours of administration.

[0060] In some embodiments, the device is configured to release at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 100% of the at least one agent from the device into the Gl tract within the intended duration of treatment. The intended duration of treatment may be at least 4 hours, at least 8 hours, at least 12 hours, at least 1 day, at least 2 days, at least 3 days, at least 4 days, or at least 5 days. In some embodiments, the device is configured to release at least 70% of the at least one agent from the device into the Gl tract within 4 hours.

[0061] In some embodiments, the hydrogel tube further comprises a permeation enhancer for promoting absorption of the at least one agent.

[0062] The phrase “encapsulated by an ingestible capsule”, as used herein, refers to the hydrogel tube in the first configuration being enclosed in a water-tight capsule that can be swallowed whole by a subject. The skilled person is able to select a suitable shape and dimensions for the capsule to allow the capsule to be swallowed whole by a particular subject. Typically, the capsule will have a tubular shape with curved ends. In some embodiments, the capsule has a length from 10 mm to 50 mm with other dimensions contemplated. In some embodiments, the capsule has a diameter from 2 mm to 15 mm with other dimensions contemplated. Typically, the ingestible capsule is sized to be swallowed whole by a human subject.

[0063] The phrase “wherein the ingestible capsule is arranged to release the hydrogel tube in the gastrointestinal (Gl) tract”, as used herein, is intended to mean that the ingestible capsule is degraded in the Gl tract following oral administration causing release of the hydrogel tube into the Gl tract. In some embodiments, the ingestible capsule is degraded in the small intestine such that the hydrogel tube is released in the small intestine. In some embodiments, the ingestible capsule is degraded in the large intestine such that the hydrogel tube is released in the large intestine.

[0064] The capsule may be fabricated from various biodegradable materials known in the pharmaceutical arts, but may also include various enteric coatings, configured to protect the capsule from degradation in the stomach (due to acids etc.), and then subsequently degrade in the in higher pH's found in the small intestine or other area of the intestinal tract. See, for example, Jana et al. (“Biodegradable polymers in drug delivery and oral vaccination.” European Polymer Journal 142 (2021): 110155) and Loh et al. ("Enteric-Coated Polymers Past and Present-A Review." Drug Delivery Letters 12.2 (2022): 85-95). Typically, the ingestible capsule comprises a degradable material configured to degrade at the region to be targeted. In some embodiments, the ingestible capsule comprises a degradable material configured to degrade in the small intestine or in the large intestine. In some embodiments, the ingestible capsule comprises a pH-sensitive degradable material.

[0065] Any suitable hydrogel can be used provided it can expand outwardly from a first configuration to a second (expanded) configuration in the Gl tract to exert an outward radial force on the lining of the Gl tract. Various types of hydrogels are known to the skilled person, see for example, Bashir S, et al. Fundamental Concepts of Hydrogels: Synthesis, Properties, and Their Applications. Polymers (Basel). 2020 Nov 16;12(11):2702. doi: 10.3390 / polym12112702.

[0066] The hydrogel may be fully biodegradable, partially biodegradable or non- biodegradable. The term “biodegradable”, as used herein, refers to substances that are degraded under physiological conditions.

[0067] In some embodiments, the hydrogel is an interpenetrating network (IPN) hydrogel. An IPN is a polymer comprising of two or more networks, which are at least partially interlaced at a molecular scale but not covalently bonded to each other and cannot be separated unless chemical bonds are broken.

[0068] In some embodiments, the hydrogel is a crosslinked co-polymer hydrogel. In some embodiments, the hydrogel comprises at least one soluble polymer or copolymer crosslinked with at least one synthetic polymer or copolymer. In some embodiments, the at least one soluble polymer is selected from gelatin, collagen, chitin, chitosan, soluble semi-synthetised cellulose polymers such as hypromellose, soluble starch, gums, alginate and its salts, carrageenan, and polyphenols (e.g., lignin). In some embodiments, the at least one soluble polymer is gelatin. In some embodiments, the at least one synthetic polymer is poly(acrylic acid) or poloxamer (amphiphilic block copolymer, consisting of poly(ethylene oxide)-poly(propylene oxide)-poly(ethyelene oxide) triblock copolymer (PEO-PPO-PEO); such as poloxamer 407).

[0069] In some embodiments, the hydrogel comprises 20-60wt% soluble polymer. In some embodiments, the hydrogel comprises at least 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, or 45wt% soluble polymer. In some embodiments, the hydrogel comprises no more than 60wt%, 55wt%, 50wt%, 45wt%, 40wt%, 35wt%, or 30wt% soluble polymer.

[0070] In some embodiments, the hydrogel comprises 20-30wt% gelatine or 40- 60wt% poloxamer.

[0071] Crosslinking of the hydrogel may be achieved by any suitable means, such as photocrosslinking or chemical crosslinking.

[0072] In some embodiments, the hydrogel is a soluble polymer-poly(acrylic acid) hydrogel. In some embodiments, the hydrogel is a gelatin- or poloxamer-based hydrogel. In some embodiments, the hydrogel is a gelatin-poly(acrylic acid) hydrogel or a poloxamer-poly(acrylic acid) hydrogel. In some embodiments, the hydrogel is a gelatin- or poloxamer-based photo-crosslinked hydrogel. In some embodiments, the hydrogel is a gelatin-poly(acrylic acid) photo-crosslinked hydrogel or a poloxamer- poly(acrylic acid) photo-crosslinked hydrogel.

[0073] In some embodiments, the hydrogel comprises 45-75wt% poly (acrylic acid). In some embodiments, the hydrogel comprises at least 45wt%, 50wt%, 55wt%, 60wt%, 65wt% or at least 70wt% poly (acrylic acid). In some embodiments, the hydrogel comprises no more than 75wt%, 70wt%, 65wt%, 60wt%, 55wt%, or 70wt% poly (acrylic acid).

[0074] In some embodiments, the hydrogel comprises a neutralisation agent. In some embodiments, the neutralisation agent is NaOH.

[0075] In some embodiments, the crosslinker is a poly(ethylene glycol) (PEG)-based crosslinker. In some embodiments, the crosslinker is N,N'-methylenebisacrylamide, poly(ethylene glycol) (PEG) diacrylate (PEGDA) or PEG di methacrylate (PEGDMA). In some embodiments, the crosslinker is selected from PEGDA 250, PEGDA 575, PEGDA 700, PEGDMA 550 or PEGDMA 750.

[0076] In some embodiments, the hydrogel comprises 45-75 wt% crosslinker.

[0077] In some embodiments, the hydrogel is not a poly(ethylene glycol) diacrylate (PEGDA) hydrogel, a gelatin methacryloyl (GelMA) hydrogel or a methacrylated hyaluronic acid (MeHA) hydrogel.

[0078] In some embodiments, the hydrogel tube comprises: gelatin-poly(acrylic acid) or poloxamer 407-poly(acrylic acid); and a neutralisation agent. In some embodiments, the hydrogel tube comprises: 80-85% gelatin-poly(acrylic acid) or poloxamer 407-poly(acrylic acid); and 15-20% of a neutralisation agent. In some embodiments, the hydrogel tube comprises: 83% gelatin-poly(acrylic acid) or poloxamer 407- poly(acrylic acid); and 17% of a neutralisation agent.

[0079] Exemplary hydrogel formulations for the hydrogel tube are provided below.

[0080] Formulation A

[0081] 20-30 wt% gelatine

[0082] 65-75% poly (acrylic acid) 0.1-1% MBA up to 100% with solvent (such as water)

[0083] Formulation B

[0084] 40-60 wt% poloxamer 45-55 wt% poly (acrylic acid)

[0085] 0.1-1 wt% MBA up to 100% with solvent (such as water)

[0086] Further exemplary hydrogel formulations for the hydrogel tube are provided below.

[0087] Formulation C

[0088] 26.8 wt% gelatine

[0089] 72.8 wt% poly (acrylic acid)

[0090] 0.5 wt% MBA up to 100% with solvent (such as water)

[0091] Formulation D

[0092] 48.1 wt% poloxamer

[0093] 51.5 wt% poly (acrylic acid)

[0094] 0.4 wt% MBA up to 100% with solvent (such as water)

[0095] In some embodiments, the hydrogel is formed by photocrosslinking a hydrogel resin. The phrase “hydrogel resin”, as used herein, is intended to mean a composition that can be 3D-printed or fabricated into a particular shape or construct using laser or light projection-based light stereolithography, or similar lithographic techniques.

[0096] Exemplary hydrogel resin formulations are provided below.

[0097] Formulation E

[0098] 10-20 wt% gelatin

[0099] 30-50 wt% acrylic acid or sodium acrylate

[0100] 0.05-5 wt% crosslinker

[0101] 9-15 wt% neutralisation agent

[0102] 0.05-3 wt% photoinitiator

[0103] 0.01-1 wt% photoabsorber up to 100% with water Formulation F

[0104] 13-16 wt% gelatin;

[0105] 35-45 wt% acrylic acid or sodium acrylate;

[0106] 0.1-0.3 wt% crosslinker;

[0107] 10-13 wt% neutralisation agent;

[0108] 0.2-1 wt% photoinitiator;

[0109] 0.03-0.07 wt% photoabsorber; up to 100% with water

[0110] Formulation G

[0111] 14.7 wt% gelatin;

[0112] 11.2 wt% neutralisation agent;

[0113] 40 wt% acrylic acid or sodium acrylate;

[0114] 0.2 wt% crosslinker;

[0115] 0.25 wt% photoinitiator;

[0116] 0.05 wt% photoabsorber; up to 100% with water

[0117] Formulation H

[0118] 25-35 wt% poloxamer

[0119] 40-80 wt% acrylic acid

[0120] 0.05-5 wt% crosslinker

[0121] 9-15 wt% neutralisation agent

[0122] 0.05-3 wt% photoinitiator

[0123] 0.01-1 wt% photoabsorber up to 100 wt% with water

[0124] Formulation I

[0125] 10-20 wt% gelatin

[0126] 30-50 wt% acrylic acid or sodium acrylate

[0127] 0.05-5 wt% crosslinker

[0128] 9-15 wt% neutralisation agent up to 100% with water

[0129] Formulation J 13-16 wt% gelatin;

[0130] 35-45 wt% acrylic acid or sodium acrylate;

[0131] 0.1-0.3 wt% crosslinker;

[0132] 10-13 wt% neutralisation agent; up to 100% with water

[0133] Formulation K

[0134] 14.7 wt% gelatin;

[0135] 11.2 wt% neutralisation agent;

[0136] 40 wt% acrylic acid or sodium acrylate;

[0137] 0.2 wt% crosslinker; up to 100% with water

[0138] Formulation L

[0139] 25-35 wt% poloxamer 40-80 wt% acrylic acid 0.05-5 wt% crosslinker 9-15 wt% neutralisation agent up to 100% with water

[0140] The photoinitiator may be any suitable compound or mixture of compounds that produces radical species upon irradiation with visible light to enable crosslinking of polymer chains. The skilled person will appreciate that a photoinitiator is not required if photocrosslinking is not used. In some embodiments, the photoinitiator is a radical photoinitiator (such as a photo-cleavable (type I) or a biomolecular (type II) photoinitiator) or a cationic photoinitiator. In some embodiments, the photoinitiator is selected from lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP), Irgacure 2959 (1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1 -propane-1 -one), 2,2'- azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (VA-086), ruthenium, eosin-Y, riboflavin and camphorquinone. In some embodiments, the photoinitiator is LAP. In some embodiments, the hydrogel resin comprises 0.01-10% of a photoinitiator. In some embodiments, the hydrogel resin comprises 1-5% of a photoinitiator. In some embodiments, the hydrogel resin comprises 2-4% of a photoinitiator. In some embodiments, the hydrogel resin comprises 2-4% LAP. The photoabsorber may be any suitable photoabsorber, for example tartrazine, Sudan I, Sudan II, Orasol Orange G or methyl red. In some embodiments, the photoabsorber is tartrazine. In some embodiments, the hydrogel resin comprises 0-10% of a photoabsorber. In some embodiments, the hydrogel resin comprises 0.05-5% of a photoabsorber. In some embodiments, the hydrogel resin comprises 1- 3% of a photoabsorber. In some embodiments, the hydrogel resin comprises 1-3% tartrazine.

[0141] The skilled person will recognise that in embodiments where photocrosslinking is not used, the above described formulations will not include a photoinitiator and a photoabsorber.

[0142] In embodiments where the hydrogel tube is 3D printed from hydrogel resin, the skilled person can select appropriate parameters for the 3D printing process. For example: the exposure time may be 5 s; the printing slice thickness may be 0.001 mm; the separation and approach velocity may be 1 mm / s; the separation distance may be 2 mm; the wait time after approach may be 1.5 s; the light intensity may be 10 mW / cm2; and / or the lightwavelength may be 385 nm.

[0143] The exposure time may vary depending on the dimensions of the hydrogel tube. In some embodiments, the exposure time is from 2 to 10 s. In some embodiments, the exposure time is from 2 to 5 s. In some embodiments, the exposure time is from 3 to 4 s. In some embodiments, the exposure time is about 3 s. In some embodiments, the device is for use in humans and the exposure time is about 3 s.

[0144] In some embodiments, the light intensity is from 5 mW / cm2to 25 mW / cm2. In some embodiments, the light intensity is from 10 mW / cm2to 20 mW / cm2. In some embodiments, the device is for use in humans and the light intensity is about 20 mW / cm2.

[0145] In some embodiments, the printing slice thickness is from 0.001 mm to 0.1 mm. In some embodiments, the printing slice thickness is from 0.01 mm to 0.05 mm. In some embodiments, the device is for use in humans and the printing slice thickness is about 0.05 mm. In some embodiments, the exposure time is 3 s, the light intensity is 20 mW / cm2, the printing slice thickness is 0.05 mm and the wavelength length is 405 nm.

[0146] Method

[0147] An exemplary method used to prepare the hydrogel tube comprises the steps:

[0148] (i) contacting an aqueous solution of acrylic acid with a crosslinker to provide an acrylic acid-crosslinker solution;

[0149] (ii) contacting the acrylic acid-crosslinker solution with a neutralisation agent;

[0150] (iii) mixing the acrylic acid-crosslinker solution with gelatin or poloaxamer and a photoinitiator and a photoabsorber to provide a hydrogel resin; and

[0151] (iv) irradiating the hydrogel resin with visible light to produce the hydrogel tube.

[0152] The description above in relation to the various components of the hydrogel resin (e.g., acrylic acid, crosslinker, neutralisation agent, gelatin, poloaxamer, photoinitiator, photoabsorber), and the hydrogel tube is equally applicable to the method.

[0153] In some embodiments, the irradiation step is achieved by photo-curing 3D printing.

[0154] The intensity of the light used maybe in the range 5-100 mW / cm2, for example 5, 10, 15, 20, 25, 30, 40 or 50 mW / cm2. In some embodiments, the intensity of the light used is 10 mW / cm2.

[0155] The light irradiation time may be any suitable time for enabling crosslinking of the polymer. In some embodiments of the invention, the irradiation time is 2-10 seconds (for example 2, 3, 4, 5, 6, 7, 8, 9 or 10 seconds).

[0156] The visible light used in the method may have a wavelength in any range suitable for enabling crosslinking of the polymer. In some embodiments, the wavelength is in the range of 350-450 nm. In some embodiments, the wavelength is in the range of 360-400 nm. In some embodiments, the wavele ngth is in the range of 380-390 nm. In some embodiments, the wavelength is 385 nm.

[0157] The foregoing and other objects, features and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures. Brief Description of the Drawings

[0158] Figure 1 : (A) The printable and expandable hydrogel resin was developed and employed to print the tube device using digital light 3D printing. (B) The printed tube devices were packaged in a capsule with enteric coating. (C) The enteric polymer protects the capsule from erosion in acid (stomach) environment and dissolves in small intestine. The devices absorb water and expand after release and exposure to the intestinal fluid. The expanded tubes attach on the wall of small intestine and deploy drugs, while the cavity allows the chyme to pass, reducing the potential risk of intestinal obstruction.

[0159] Figure 2: (A) The structure of interpenetrating polymer network (IPN). The two networks are interpenetrated together. (B) The typical synthesis of the IPN. The second network is polymerized within the first one. Figure adapted from Abdel-Raouf ME. Curr Res Biopolymers 2: 111.

[0160] Figure 3: The water uptake ratios of samples polymerized with different LAP concentrations and crosslinker-acrylic acid ratios. (A) The schematic diagram of the polymerization procedures. (B-C) The water uptake ratios of gelatin samples with 0.25% LAP (B) or 0.10% LAP (C) under various crosslinker ratios. (D-E) The water uptake ratios of Ploronic F127 samples with 0.25% LAP (D) or 0.10% LAP (E) under various crosslinker ratios.

[0161] Figure 4: The water uptake ratios of samples polymerized with different NaOH neutralization. (A) The water uptake ratios of gelatin samples with 0%, 20%, 50% and 70% neutralization degree (0.1% LAP, 0.32 mol% MBA). (B) The water uptake ratios of Ploronic F127 samples with 0% and 20% neutralization degree (0.1% LAP, 0.32 mol% MBA). (C) The disc samples after printing. (D) The disc samples after drying. (E) The disc samples following 2 h hydration. Scale bar: 1 cm. *F127 solutions with high NaOH-AA ratios (70 mol% and 50 mol%) cannot form clear solutions and solid discs samples.

[0162] Figure 5: The water uptake ratios of samples polymerized with different crosslinkers.

[0163] Figure 6: FTIR characterization of samples before and after polymerization. (A) The chemical structure of Gelatin and (B) Pluronic F127. (C) The polymerization reaction of acrylic acid or sodium acrylate (monomer) and N, N'-Methylenebis (acrylamide) (MBA, crosslinker) under the presence of lithium phenyl (2,4,6- Trimethylbenzoyl) phosphinate (LAP, photoinitiator). (D) The FTIR spectra of Gelatin samples before and after polymerization. (E) The enlarged view of peaks between 2000-900 nm in (D). (F) The FTIR spectra of Pluronic F127 samples before and after polymerization. (G) The enlarged view of peaks between 2000-900 nm in (F).

[0164] Figure 7: (A-C) CAD designs used for printability testing of resins with various concentrations of LAP and trartrazine. (A) Front and (B) top view of rendered image of cylindric tubes (Diameter: 2 mm; Height: 5 mm. Thickness: 0.3 mm (2), 0.2 mm (3), 0.1 mm (4). (C) Side view of rendered image of cylindic device with square base (Diameter: 2 mm, Side length of base: 3 mm). (D-F) Modified CAD designs used for printability testing of resins (0.1% LAP, 200 ppm tartrazine) with different exposure times. (D) Tubes witout holes. (E) Tubes with 1.2 mm-diameter holes. (F) Tubes with 1.8 mm-diameter holes. Outer diameter: 2 mm; Thickness: 0.3 mm (3), 0.2 mm (2), 0.1 mm (1). (Diameter: 2 mm, Height: 5 mm).

[0165] Figure 8: Printability test of resins with different amounts of photoinitiator.

[0166] Figure 9: Printability test of resins with different amount of photoabsorber.

[0167] Figure 10: Photographs of tubes printed with exposure time of 5 sec. (A) Tubes without holes. The 0.1 mm thickness (T0.1) tube without holes could be printed hollowly. (B) Tubes with 1.2 mm holes. The T0.1 tube could be printed with holes, while the holes on 0.2 mm thickness tube was blocked. (C) Tubes with 1.8 mm holes. All of the tubes could be printed as designed. Scale bar: 2.5 mm. *T0.1 : 0.1 mm thickness tube; TO.2: 0.2 mm thickness tube; TO.3: 0.3 mm thickness tube; H: hollow.

[0168] Figure 11 : Photographs of tube devices printed with exposure time of (A) 2.5 or (B) 2.0 Sec. (A) The tubes printed with exposure time of 2.5 sec. The 0.2 mm thickness and 0.3 mm thickness tubes could be printed hollowly with holes, while tubes without holes were still blocked. (B) The tubes printed with exposure time of 2.0 sec. All tubes (0.2 mm thickness and 0.3 mm thickness tubes with or without 1.2 mm holes) could be printed as designed successfully. Scale bar: 0.25 mm. * TO.1 : 0.1 mm thickness tube; TO.2: 0.2 mm thickness tube; TO.3: 0.3 mm thickness tube; H: hollow.

[0169] Figure 12: The optimization of resin with reduction of water in Gelatin solution. (A) The viscosity range of the resin with different amount water in gelatin solution. (F1 : 28 mL water in Gelatin solution; F2: 14 mL water in Gelatin solution; F3: 7 mL water in Gelatin solution; F4: 0 mL water in Gelatin solution). (B) The top and (C) side views of the tube (Diameter: 2 mm, Thickness: 0.1 mm) printed by F4 resin. DLP printing parameters: light intensity: 10 mW / cm2; exposure time: 5 sec. Scale bar:

[0170] 0.25 cm.

[0171] Figure 13: The printed tube devices with different diameter and thickness. Figure 14: The hydrated tube devices printed with different crosslinkers.

[0172] Figure 15: (A) CAD design of microneedle array. (B) The SEM images of microneedles printed by MBA-Gelatin resin.

[0173] Figure 16: Tube device with microneedles (MN-tube) printed with optimized resin and printing parameters. (A-B) The CAD design of tube device with microneedles. (C) The printed MN-tube before and after hydration (scale bar 10 mm). (D) The SEM images of microneedles on the tube device (scale bar 0.5 mm).

[0174] Figure 17: Swelling ability analysis in vitro. (A) The dry tubes. (Diameter: 2 mm; Thickness: 0.1 mm) (B) The tubes after hydration. (C-E) The water uptake ratios (C), diameter change (D), and length change (E) profiles of tubes (Diameter: 2 mm; Thickness: 0.1 mm) at 37°C with different pH (pH 3.2, pH 6.2 and DIW). (F-H) The water uptake ratios (F), diameter change (G), and length change (H) profiles of tubes (Diameter: 2 mm; Thickness: 0.2 and 0.3 mm) at 37°C pH 6.17. (I, J) The diameter (I) and length change ratios (J) of tubes with different thickness (Diameter: 2 mm; Thickness: 0.1 , 0.2 and 0.3 mm) at 5, 30 and 120 min. (K) The printed tubes with different diameter (2, 3, and 4 mm) and thickness (0.1 , 0.2 and 0.3 mm). (L) The diameter change ratios of tubes at 30 min (pH 6.17). D: diameter; T: thickness.

[0175] Figure 18: Swellability test of tube devices (PEG-derivant as crosslinker) in pH 6.2 water solution. (A-C) The water uptake ratios (A), diameter change (B), and length change (C) profiles of tubes with MBA, PEGdMA 750, PEGdMA 550 as crosslinkers, respectively. (The crosslinker concentration was fixed at 0.32%). (D-F) The water uptake ratios (D), diameter change (E), and length change (F) profiles of tubes with different concentration of PEGdMA 550 as crosslinker. (G-l) The water uptake ratios (G), diameter change (H), and length change (I) profiles of tubes with PEGdMA 550, PEGDA 700, PEGDA 575 and PEGDA 250 as crosslinkers. (The crosslinker concentration was fixed at 0.08%).

[0176] Figure 19: The diameter change ratios of tubes at 30 min (pH 6.17). (A) Crosslinkers (MBA, PEGdMA 750, PEGdMA 550) with fixed concentration of 0.32%. (B) Different concentration of PEGdMA 550 as crosslinker. (C) Crosslinkers (PEGdMA 550, PEGDA 700, PEGDA 575 and PEGDA 250) with fixed concentration of 0.08%.

[0177] Figure 20: Swellability test of tube devices (PEG-derived as crosslinker) in different physiological buffer compositions. (A-C) The water uptake ratios (A), diameter change (B), and length change (C) profiles of tubes in PBS, K-H buffer, FeSSIF-V2 and FaSSIF-V2. (D) The diameter change ratios of tubes at 30 min and switching to water solution.

[0178] Figure 21 : The isolation of rats’ small intestine and ex vivo swelling characterization. (A) The small intestine includes duodenum, jejunum (Proximal, Medial and Distal), and ileum. Each section was approximately 9-10 cm. The jejunum (red dot line box) was isolated from rats’ intestine for the ex vivo experiments. (B) The tubes with different diameter before and after 30 min hydration in small intestine. (C) The hydration status of D3T0.2 tube in small intestine at 0, 15, 30, 60, and 90 min. (D) The D3T0.2 tube in small intestine. (E) The cross-section view of D3T0.2 tube in small intestine.

[0179] Figure 22: The pressure testing. (A) The pressure testing setup (dashed circle) connected with operational amplifiers. (B) The enlarged view of the pressure testing part (three sensors). (C) The distance among three sensors (arrow). (D) The hydrated tubes at the centre of the sensors. (E) The pressure generated by hydrated D2 tubes. Sensor distance: 4.5 mm. (F) The pressure generated by hydrated D2 tubes. Sensor’s distance: 7.5 mm.

[0180] Figure 23: The mAb loaded by soaking method. (A) The schematic diagram of soaking method. (B) The drug loading content in hydrogel tube with different concentrations of soaking solution. (C) The release profile of mAb.

[0181] Figure 24: The mAb loaded by dip coating method. (A) The schematic diagram of dip coating method. (B) SEM image of coated hydrogel device. (C) The drug loading content in hydrogel tube with different number of coats. (D) The release profile of mAb.

[0182] Figure 25: Bespoke setup for ex vivo permeation experiments. (A) The slim glass specimen tube with the volume of 10 mL. (B) 3D-printed tissue-holding cap. (C) The setup without tissue. (D) The setup with tissue. (E) The setup in water bath under stirring. (F) HE stained rats’ small intestine tissue before and after incubation in the setup.

[0183] Figure 26: Ex vivo permeation of model drug (BSA-FITC) in intestinal rat model.

[0184] Figure 27: Photos of contrast agent (Ag nanoparticles) loaded hydrogel device. (A) Impact of AgNCh and LAP concentration. (B) Impact of irradiation time.

[0185] Figure 28: (A) Short-term degradation test in PBS, FeSSIF-V2 buffer with active and deactivated pancreatin by wet-weight method. (B,C) Long-term degradation test in PBS, FeSSIF-V2 buffer with active pancreatin by dry-weight method, showing residual dry weight percent of devices in (B) FeSSIF-V2 buffer with 1% pancreatin for 10 days or (C) PBS for 20 days.

[0186] Figure 29: The degradation of tube devices with various polymers and content. (A) Residual wet weight of tube devices in FeSSIF-V2 buffer. (B) Residual wet weight of tube devices in FeSSIF-V2 with 1% active pancreatin.

[0187] Figure 30: Expandability test of tube devices printed by resin with various polymers and content (in FeSSIF-V2 buffer). (A) The length changes of tube devices. (B) The diameter changes of tube devices. (C) The water uptake ratio of tube devices.

[0188] Figure 31 : Self-fragmenting strategy for the in vivo clearance of tube device. (A, B) The CAD design of half-tube. (C) The printed half-tube. (D, E) The bonded tube devices with PVP K90 solution. (F) The self-fragmenting device split to two half parts in PBS.

[0189] Figure 32: (A) The schematic of coating methods. (B) Ex vivo evaluation of coated microneedle-tube devices with two different coating methods and crosslinkers in rat small intestine.

[0190] Figure 33: H&E staining of the microneedle-devices in rat small intestine.

[0191] Figure 34: Swelling test of larger tube devices in FeSSIF. (A) Diameter change, (B) height change, (C) weight change.

[0192] Figure 35: Photographs of the larger tube devices at different timepoints during the swelling test. Also shown is a photograph of the unexpanded tube device encapsulated in an ingestible capsule.

[0193] Figure 36: Ex vivo swelling test in porcine small intestine. Photographs of the tube devices placed in porcine jejunum and immersed in PBS, taken at different time points.

[0194] Figure 37: Ex vivo swelling test in porcine small intestine. Photographs of the tube devices placed in porcine jejunum and immersed in PBS, taken at different time points. Also shown is a graphical representation of the outer diameter of the tube devices after 2 hours.

[0195] Figure 38: Force testing results.

[0196] Figure 39: Photograph of a tube device (D5.8T1H20-MN D0.8H2) with microneedles encapsulated in a size 00 capsule.

[0197] Figure 40: Ex vivo swelling test of microneedle tube device in porcine small intestine. Photographs of the microneedle tube with or without a cholesterol coating placed in porcine jejunum and immersed in PBS, taken at different time points. Figure 41 : Micro-CT signal characterization of sliver loaded tube devices. (A) Dehydrated and hydrated tube devices with / without AgNPs. (B) Projection image of dehydrated tube devices under micro-CT. (C) Maximum HU of dehydrated tube device. (D) Projection image of hydrated tube devices under micro-CT. (E) Maximum HU of hydrated tube device.

[0198] Figure 42: (A) Manufacture processes of size #9h enteric capsules. (B) CAD designs and stainless-steel modules for enteric capsule manufacturing. (C) Silver- loaded hydrogel tube devices encapsulated in size 9h enteric capsules with various pH-thresholds. Enteric capsule fabricated with mixture of Eudragit L100 / L100-55 (weight-ratio 1 :1). Scale bar: 1 mm.

[0199] Figure 43: (A) Images of dissected rat Gl tracts. (A) Intact hybrid enteric capsule in stomach after 4-h. (B) non-expanded tube device in small intestine after 5- h. (C) Expanded tube device in small intestine after 5-h. (B) CT images of hybrid enteric capsule (with sliver-loaded hydrogel tube devices; device diameter 2.0 mm) in gastric intestinal tissues. Capsules kept intact in stomach for 4 hours and transited to small intestine at 5-h. Hydrogel tubes either expanded or non-expanded.

[0200] Figure 44: (A) Expanded D2.7 hydrogel device (original diameter: 2.7 mm) in rats’ small intestine. Compared with D2 device (original diameter: 2.0 mm), D2.7 device can expand to 6 mm in small intestine. (B) CT images of hybrid enteric capsule with sliver-loaded hydrogel tube devices in gastric intestinal tissues after 5-h post-administration. Device diameter 2.7 mm. Capsules kept in stomach or transited to small intestine.

[0201] Detailed Description of the Invention

[0202] The inventors have developed a novel expandable platform for the oral delivery of biologies and other drugs. The disclosure provides novel hydrogel resins based on degradable polymers that can be used to manufacture hydrogel tubes that expand in the Gl tract. Advantageously, the hydrogel tubes can be ingested as they are sized to fit inside an ingestible capsule, and are released in the Gl tract where they expand. The hollow tube structure of the hydrogel tubes means that the hydrogel is not blocking the lumen of the Gl tract, meaning that Gl contents can pass through the hydrogel tube. In addition, an agent can be impregnated in or coated on the hydrogel tube and can be “driven” into the Gl mucosa through the expansion of the tube and outward radial force against the Gl mucosa. This can be further enhanced through the presence of microneedles on the surface of the hydrogel tube. This is particularly beneficial for oral biologies.

[0203] The development of the novel expandable platform is shown in Figure 1. The inventors developed optimised hydrogel resins that could be 3D printed to provide the expandable hydrogel tubes, that showed desired swelling and degradation properties. The skilled person will appreciate, however, that 3D printing is not the only method that can be used to form the hydrogel tubes, and other methods can be used, such as injection moulding (which will not require the presence of photoinitiators or photoabsorbers). The hydrogel tubes provide improvements over existing drug delivery platforms as the tubes expand to exert a radial force against the Gl tract mucosa, and can therefore be used to drive agents across the Gl mucosa. As a result of this expansion, the hydrogel tubes do not require mucosal adhesives to attach to the mucosal wall. Furthermore, the device is of simple construction, requiring the formation of a hollow hydrogel tube, but not requiring complex compartmental structures formed of external films. The device can form a protective layer that maximises the concentration of active agent and / or a permeation enhancer and prevents dilution with lumen contents. In addition, the device can also be used to protect a certain section of the Gl tract.

[0204] In addition, microneedles can be formed on the surface of the hydrogel tube in a uniform body to enhance agent delivery. The inventors have shown that the microneedles do not perforate the gut wall, but have demonstrated micropenetration into the mucosa and / or submucosa to increase the permeability of the mucosa.

[0205] The hydrogel may be an IPN, as shown in Figure 2. Particularly effective hydrogels for use in the invention are crosslinked hydrogels of gelatine and polyacrylic acid and crosslinked hydrogels of poloaxamer and polyacrylic acid.

[0206] The following examples are provided to illustrate certain particular features and / or embodiments. These examples should not be construed to limit the disclosure to the particular features or embodiments described.

[0207] Examples

[0208] Example 1: Hydrogel resin development with various crosslinker-acrylic acid ratios and photoinitiator concentrations based on gelatin and F127 polymers

[0209] A specially made setup was devised with multiple well plate that could be filled with different resin drafts. The resin was tested for its ability to form a hydrogel disc. Solutions preparation:

[0210] (i) LAP stock solution: LAP (150 mg) was dissolved in water (5 mL) to obtain the 3 % LAP stock solution.

[0211] (ii) Pluronic F127 (F127) solution: F127 (9.8 g) was put in cold water in an ice bath under continuous stirring for 30 min, and then the mixture was placed in 4°C fridge overnight to obtain a clear solution.

[0212] (iii) Gelatin solution: Gelatin (1.57 g or 1 g) was added to a 37°C water (10 mL) under stirring until it a clear and yellowish solution was formed. N, N'-Methylenebis (acrylamide) (MBA, cross linker) (0.04 g, 0.26 mmol) was added into acrylic acid (AA) (2.88 mL, 40 mmol), the molar ratio of MBA to AA was 0.65 mol%. Then, the MBA-AA solution was diluted with AA liquid to get a series of MBA-AA solutions with various MBA-AA molar ratio (0.325, 0.1625, 0.08125, 0.040625, and 0 mol%). Then, 0.7 mL of polymer solution (28% F127 or 10% gelatin), MBA-AA solution (various MBA to AA molar ratio) (0.3 mL), and 3 % LAP solution (33 mL) were mixed using vortex to obtain the final solution (Table 1).

[0213] Polymerization:

[0214] The solutions (50 mL) were put into the grooves of 96-well plate lid. The lid was put into the Asiga X27 3D printer and cured for 10 sec at the light intensity of 30 mW / cm2. The obtained disc samples were dehydrated with ethanol (5 min each time, three times) and died overnight under vacuum oven at 60 °C. Each solution was done in triplicates.

[0215] The initial water uptake analysis:

[0216] The dried samples were put into deionized water at room temperature. The samples were weighed at 0, 5, 30 and 120 min. The water uptake ratio (%) = (Wwet-Wdry) / Wdry*100%

[0217] Table 1 : Solutions with different crosslinker-acrylic acid ratios and photoinitiator concentrations

[0218] Results:

[0219] For the Gelatin solution series, the solutions with MBA-AA ratios from 0.65 mol% to 0.32 mol% could form solid discs, but the samples became sticky with the decrease of MBA-AA ratios. However, the solution could not form a solid disc sample when the MBA-AA ratio was decreased to 0.16 mol%. Similar results were obtained with the F127 solution series. To check if the solutions still could be printed with lower LAP (photoinitiator) concentration, the same solutions with 0.1 w / v% LAP (photoinitiator) were tested. The results indicated that solutions (MBA-AA ratio: 0.65 mol% and 0.32 mol%) with 0.1 W / V% LAP could form hydrogel at the light intensity of 30 mW / cm2for 10 s. Similar results were obtained with the F127 solution series.

[0220] The water uptake of obtained solid disc samples from different solutions was analysed (Figure 3A). As the samples with 0.16 mol% and 0.08 mol% MBA could not maintain the disc shape, those samples were not tested. For the gelatin samples with 0.25% LAP (0.65 mol% MBA), the water uptake ratio could achieve 111 ,46±2.74% at 2 h. The 2 hour water uptake ratio increased slightly with the mol ratio of MBA reducing to 0.32 mol% (Figure 3B). Figure 3C showed that photoinitiator concentrations had minor effects on the water uptake ratios of the samples, whilst Figure 3D,E showed there was a major reduction in the water uptake ratios for the disc samples from Pluronic solution.

[0221] Conclusion:

[0222] Swelling ability was limited; a modification of the formulation was needed. Example 2: swellability screening of resins with different amount of NaOH

[0223] Solutions preparation with NaOH:

[0224] To enhance the water uptake ability of the 3D printed hydrogel, NaOH was introduced to neutralise the AA. Specifically, different amounts of NaOH were dissolved into 0.25 mL water in an ice bath. Then, the NaOH solution was added into the 0.3 mL 0.32 mol% MBA-AA (4.2 mmol AA) in ice bath to achieve a 70% neutralization. After that, the high MW Polymer solution (0.7 mL 28% F127 or 15.7% gelatin solution) was added into the previous neutralized solution. Finally, 3% LAP solution (42 mL) was added and mixed using vortex to obtain the final solution. The solutions were showed as Table 2.1.

[0225] Polymerization and swellability analysis were performed as described in Example 1.

[0226] Table 2.1 : Summary of photoresin compositions with different neutralization

[0227] Results:

[0228] To increase the water uptake of the hydrogel further, different amount of NaOH was added to neutralize the solution. The MBA-AA ratio was 0.325 mol%. For F127 solution, the solutions with high NaOH-AA ratios (70 mol% and 50 mol%) could not form clear solutions, only 20 mol% and 0 mol% NaOH-AA solutions formed solid hydrogel after printing. For the Gelatin solution series, all solutions with different amount NaOH could form clear solutions and could be utilized in the next examples for vat 3D printing (Table 2.2).

[0229] Table 2.2: The polymerization of solutions with different NaOH neutralization

[0230] The water uptake of samples formed by solutions containing different amount of NaOH were tested, and the results demonstrated that the addition of NaOH increased the water uptake ratio significantly. Figure 4A displayed the water uptake ratios of disc samples produced by gelatin solutions with different NaOH neutralization ratios. The water uptake ratio raised to 10595.36±133.76% at 2 h with 20% NaOH neutralization, more than 70 times of samples without neutralization (145.56±11.87% at 2 h). Further, the water uptake ratio was doubled (22,238.23±1,794.41% at 2 h) when the NaOH was increased to 50%. Whilst 70% NaOH neutralization weaken the water uptake ability compared with 50% NaOH neutralization, leading to a fall in the water uptake ratio to 15,538.83±536.24% at 2 h. Correspondingly, the water absorption speed was also improved after neutralization. The water uptake ratio of samples with 50% neutralization could reach to 2401.36±379.16% within 5 min, nearly 35 times of those without neutralization (72.47±8.15% within 5 min). The results for Pluronic F127 series samples were showed as Figure 4B. The water uptake ratio was increased significantly with 20% neutralization of NaOH, elevating from 97.73±0.21% to 49097.18±4277.00% at 2 h. The status of the disc samples before and after drying were showed as Figure 4C and D, respectively. Figure 4E displayed the samples after hydration with diameter enlarged dramatically.

[0231] Conclusion:

[0232] Gelatin had less interference compared to Poloxamer, hence selected. Adding sodium in the resin composition significantly boosted swellability and water uptake. Example 3: Biocompatibility improvement of resins by using PEG-derivant as crosslinkers

[0233] Solutions preparation with PEG-derivant crosslinkers:

[0234] To enhance the water uptake ability as well as the biocompatibility of the 3D printed hydrogel, MBA crosslinker was replaced by PEG-derivant crosslinkers (biodegradable). Specifically, six concentrations (1.3%, 0.65%, 0.32%, 0.16%, 0.08%) of the different molecular weights of crosslinker-acrylic acid solutions were prepared by adding 1500 pL of acrylic acid to the stated amount of crosslinker (see Table 3). The solution (750 pL) was then diluted with 750 pL of acrylic acid. Serial dilutions were carried out to produce the rest of the concentrations. The solutions were vortexed for 10 seconds after mixing. Gelatin solutions were prepared by adding 700 pL of gelatin solution (7%) to 300 pL of the corresponding concentration of crosslinker-acrylic acid solution. The solutions were neutralised using 250 pL NaOH solution (50%) and vortexed.

[0235] Table 3 Amounts of crosslinker added for the production of each solution.

[0236] Polymerization and swellability analysis were performed as described in Example 1.

[0237] Results:

[0238] Viscous (semi-solid) hydrogels discs were generated with lower concentrations of crosslinkers (ranging from 0.16%-0.04%) for both gelatin formulations. Figure 5 represented water uptake (%) for gelatin hydrogels with different crosslinkers and concentration respectively. The water uptake demonstrated a negative relationship with crosslinker concentration.

[0239] Conclusion: PEG-derivant as crosslinkers provide an excellent alternative way to produce biocompatible and biodegradable resins.

[0240] Example 4: Fourier-transform infrared spectroscopy (FTIR) for hydrogel characterization

[0241] Samples with MBA as crosslinker were prepared as Example 1. Transmission mode was used to study the polymerization of resin membrane by Perkin Elmer Frontier FTIR spectra were recorded in transmission mode between 650 and 4000 cm-1. The spectra of resin before and after polymerisation were obtained.

[0242] Results:

[0243] Figure 6A and B demonstrated the chemical structure of Gelatin and Pluronic F127 respectively, which do not participate the reaction. Figure 6C illustrated the polymerization of acrylic acid or sodium acrylate (monomer) and N, N'-Methylenebis (acrylamide) (MBA, crosslinker) under the presence of lithium phenyl (2,4,6- Trimethylbenzoyl) phosphinate (LAP, photoinitiator). Acrylic acid or sodium acrylate can form linear poly (acrylic acid) (PAA) or poly (sodium acrylate) (PSA). The linear polymer was crosslinked by MBA to form a three-dimensional network (crosslinked PAA and / or PSA). Figure 6D illustrates the FTIR spectra of gelatin samples before and after polymerization. The absence of the wide and strong peak between 3500- 3000 nm can contribute to the water missing as the samples before polymerization contained a large amount of water and the samples after polymerization were dried. The peaks between 2000-900 nm were enlarged (Figure 6E). The results illustrated that the monosubstituted C=C stretching peak at 1638 nm (the C=C in acrylic acid) and monosubstituted C=C bending peak at 988 nm (the C=C in acrylic acid) weakened or disappeared, suggesting the polymerization of C=C in acrylic acid. Similar results were observed in Pluronic F127 samples. (Figure 6F, G)

[0244] Conclusion:

[0245] The FTIR confirm the polymerization of C=C in acrylic acid.

[0246] Example 5: CAD design of tubes for printability test of different resins

[0247] The prototype of tubes with different thicknesses was designed using 3D MAX 2022 software (Autodesk, UK) based on the capsule #9 size and the rat’s small intestine. The geometric parameters are shown in Table 4. Table 4: The geometric parameters of the designed structures

[0248] Results:

[0249] The CAD-designed tubes and cylindric device with a square base (CS) used for printability testing were demonstrated in Figure 7(A-C). The diameter was 2 mm, and the thicknesses of the tubes were 0.3, 0.2, and 0.1 mm, respectively. The height of the tube was 5 mm. For the cylindrical device with a square base (CS), the diameter of the upper tube was 2 mm with a side length of 3 mm of the base.

[0250] Meanwhile, some holes with different diameters (0.6, 1.2 and 1.8 mm) were made on the wall of the tubes expecting to reduce the obstructed resin in the cavity of the tubes (Figure 7(D-F)).

[0251] Example 6: Printability test of resins with different photoinitiator concentrations

[0252] Firstly, the solutions without LAP were prepared as follows: NaOH (3.36 g) was dissolved in water (10 mL) in an ice bath to obtain 50% neutralization NaOH solution. MBA crosslinker (83.3 mg) was dissolved in acrylic acid (12 mL) to get 0.32 mol% MBA-AA solution. Then, NaOH solution was added into MBA-AA solution gently in an ice bath. When the neutralization reaction finished, the 15.7% gelatin solution (28 mL) was poured into the mixture above under stirring for 2 hours in a dark environment, (i) Resins with 0.05 w / v% LAP: 3% LAP solution (0.835 mL) was added into the 50 mL gelatin solution as above (ii) Resin with 0.1 w / v% LAP: 3% LAP solution (1.67 mL) was added into the 50 mL gelatin solution as above.

[0253] The printability of the resin was tested using Asiga DLP Printer (Asiga MAX-27, Australia) and Asiga Composer software. The key printing parameters are as follows: exposure time: 4.0 sec; separation velocity: 2.475 mm / sec; approach velocity: 4.3 mm / sec; separation distance: 10 mm; wait time after approach: 0 s; slice thickness: 0.01 mm; light intensity: 10 mW / cm2; light wavelength: 385 nm. Results:

[0254] The printing results are summarized as Table 5. The 0.1 mm thickness tube could not be printed with 0.1% w / v LAP, but only the 0.3 mm thickness tube could be printed when the LAP concentration was reduced to 0.05% w / v. In addition, the 3D printing accuracy was quite low as the outside of the structures was surrounded by cured resin and the printed tubes were also blocked with polymerized resin. The hollow structures were failed to be printed (Figure 8).

[0255] Table 5: The printing results for Gelatin resin with different amount of LAP

[0256] *T0.1: 0.1 mm thickness tube; TO.2: 0.2 mm thickness tube; TO.3: 0.3 mm thickness tube

[0257] Conclusion:

[0258] Printability has not improved; a photo absorber will be added.

[0259] Example 7: Printability test of resins with different photo absorber concentrations

[0260] Different amount of tartrazine (food additive, E number E102) was added as a photo absorber to increase the resolution of the 3D printing structures. Specifically, tartrazine (25 mg) was dissolved in water (1 mL) to obtain the tartrazine stock solution (25 mg / mL). Then, the gelatin solution (15.7%) with 0.1% LAP was prepared as the method above. After that, tartrazine stock solution (200 mL for the concentration of 100 ppm or 400 mL for the concentration of 200 ppm) was added into the gelatin solution (50 mL with 0.1% LAP). The printability test of these resins was tested as Example 6.

[0261] Results: The LAP concentration was fixed at 0.1 % w / v. The printing results are summarized as Table 6. With 100 ppm tartrazine, the 3D printing resolution was improved a lot as the side of the CS base became sharper though the 0.1 mm-thickness tube still could not be printed. The printing resolution was improved further when the tartrazine was increased to 200 ppm, but the 0.1 mm-thickness and the 0.2 mm-thickness tube were not able to be obtained. Also, the inner cavity of printed structures was blocked for all hollow structures (Figure 9).

[0262] Table 6: The printing results for Gelatin resin with different amount of LAP and tartrazine

[0263] *T0.1: 0.1 mm thickness tube; TO.2: 0.2 mm thickness tube; TO.3: 0.3 mm thickness tube

[0264] Conclusion:

[0265] The photo absorber improved the shape fidelity of the printed devices.

[0266] Example 8: Printability test of resins with different exposure time

[0267] To obtain the hollow tubes, the exposure times were modified slightly. Gelatin resin (0.32 mol% MBA-AA, 50% NaOH neutralization, 0.1% LAP, 200 ppm tartrazine) was used as the resin for 3D printing. Different printing parameters (exposure time: 5.0, 4.5, 3.5, 2.5, and 2.0 s) were explored also. Printing slice thickness: 0.001 mm; separation and approach velocity: 1 mm / s; separation distance: 2 mm; wait time after approach: 1.5 s; light intensity: 10 mW / cm2; light wavelength: 385 nm. Results:

[0268] To print tubes as designed in Example 5, different exposure times (5.0, 4.5, 3.5, 2.5, and 2.0 s) were explored. Figure 10 demonstrated the printed tubes with an exposure time of 5 s. The 0.1 mm thickness tube without holes could be printed as designed, while the 0.2 mm thickness tube and 0.3 mm thickness tube were blocked (Figure 10A). For the tubes with 1.2 mm holes, 0.2 mm thickness tube and 0.1 mm thickness tube were hollow, but the holes on the 0.2 mm thickness tube wall were blocked (Figure 10B). For the tubes with 1.8 mm holes, all the tubes could be printed with hollow inner cavity and holes on the wall as designed (Figure 10C). The exposure time was reduced further. The 0.2 mm thickness and 0.3 mm thickness tubes 1.2 mm holes could be printed successfully with the exposure time of 2.5 s or 2.0 s, (Figure 11 A) and the 0.2 mm thickness and 0.3 mm thickness tubes without holes were obtained with exposure time of 2.0 s, finally. (Figure 11B). The results were summarized as Table 7. Different structures need different exposure time (Table 8).

[0269] Table 7: A summary of 3D printing outcomes for tube devices with different desgin attributes (wall thickness and built-in side holes) and 3D printing exposure time

[0270] Table 8: The exposure time required for tubes with different structures

[0271] Conclusion: Tubes could be printed as designed successfully with different exposure time.

[0272] Example 9: Resin optimisation with reduced water content

[0273] Resins with reduced water content were explored to obtain the optimised resin that could be utilized for printing after preparing. The solutions were showed as Table 2.1. For each solution, photoinitiator (3% LAP 1.67 mL) and photo absorber (2.5% tartrazine 0.4 mL) were added to get the final resin.

[0274] Before 3D printing, the viscosity range of the resin was tested by Asiga printer following instructions. The Viscosity Range parameter quantifies how viscous a material is, with units in millimetres. In practical terms, it measures the distance at which a surface exerts pressure against a target plate when moved towards it. The platform moves down to a starting position 2 mm above the vat film in the material. It then moves down 0.1 mm and waits until the material settles, recording the distance above the vat film and the time it takes to settle. It repeats this until the settle time is above the settling time threshold and then interpolates the distance above the vat film which corresponds to the settling time threshold. The distance is displayed as the viscosity range. The settling time threshold was set at 3 s.

[0275] The resins were utilized to print tubes (diameter: 2 mm; thickness: 0.1 mm) under the exposure time of 5 s. Printing slice thickness: 0.001 mm; separation and approach velocity: 1 mm / s; separation distance: 2 mm; wait time after approach: 1.5 s; light intensity: 10 mW / cm2; light wavelength:385 nm.

[0276] Table 9: Photo resins with different water content

[0277] Results:

[0278] The viscosity range parameter can reflect the viscosity of the resin with different water content. Figure 12A indicated that the viscosity range increased along the reduction of water in the resin. For the printing results, only F4 solution with viscosity range of 0.37±0.053 mm (the Gelatin powder was put into the neutralized acrylic acid solution) could be utilized for printing tubes instantly (Figure 12B,C).

[0279] Conclusion: Resin with increased concentration was optimised.

[0280] Example 10: Tubes with various diameter and thickness printed by MBA-crosslinker resin

[0281] F4 resin in Example 9 was prepared using the previous method. Tube with different diameters and thickness were designed and printed with Asiga printer. 3D printing slice thickness: 0.001 mm; separation and approach velocity: 1 mm / s; separation distance: 2 mm; wait time after approach: 1.5 s; light intensity: 10 mW / cm2; light wavelength: 385 nm. The exposure time for different designs is shown as below (Table 10).

[0282] Table 10: 3D Printing parameters for tubes with different dimension

[0283] Results:

[0284] The tube devices with different diameters and thicknesses were printed successfully under various exposure time (Figure 13).

[0285] Example 11: Tubes printed by resins with PEG-derivant crosslinkers

[0286] Aim: to optimise the concentration and cross-linker length for a maximum expansion upon hydration. Resin preparation:

[0287] Gelatin resins were prepared by adding 12 mL of acrylic acid to the stated amount of PEGDA / PEGdMA (refer to Table 11). 50% NaOH solution (10 mL) was added for neutralisation. Gelatin powder (4.4 g) was added gradually to resins, whilst stirring at 37°C. 1.667 mL LAP (3%) and 400 pL tartrazine (25 mg / mL) were added to each gelatin resin and left to stir on heat for 1-2 hours (refer to Example 6). Resins were left to stir overnight. Samples were placed in sonicator for 30 seconds before printing.

[0288] Table 11 : Amount of crosslinker added for production of resins.

[0289] 3D Printing and post-curing:

[0290] The resins were utilized to print tubes (diameter: 3 mm; thickness: 0.2 mm) under the exposure time of 3.5 sec. Printing slice thickness: 0.001 mm; separation and approach velocity: 1 mm / s; separation distance: 2 mm; wait time after approach: 1.5 s; light intensity: 10 mW / cm2; light wavelength: 385 nm.

[0291] After printing was done, the structures were carefully washed with water, including the centre of the tube structures. Paper towels were used to blot off excess water from the surface of the structures. They were then left to dry in fume cupboard overnight. All samples were cured for 5 minutes.

[0292] Results:

[0293] Figure 14 demonstrated the hydrated tube devices with different crosslinkers. For details of the water uptake, see Example 16.

[0294] Example 12: Microneedles printed by optimized resins

[0295] CAD design of microneedle array: The prototype of microneedles with different diameter and height were designed using 3D MAX 2022 software (Autodesk, UK). The height of the microneedles were 1, 0.8, 0.6, 0.4, 0.2 mm, respectively; the bottom diameters were 0.5, 0.4, 0.3, 0.2, 0.1 mm, respectively.

[0296] Resins preparation and 3D printing:

[0297] Gelatin resin (0.32 mol% MBA-AA, 50% NaOH neutralization, 0.1% LAP, 200 ppm tartrazine) was used as the resin for microneedle array printing. The exposure time was 5 s. Printing slice thickness: 0.001 mm; separation and approach velocity: 1 mm / s; separation distance: 2 mm; wait time after approach: 1.5 s; light intensity: 10 mW / cm2; light wavelength: 385 nm.

[0298] SEM characterization:

[0299] SEM imaging was used to analyse the quality of the microneedle structures. Samples were placed on adhesive pads stuck on stubs and coated with gold under a vacuum. Imaging was optimised by adjusting the brightness and focus. SEM imaging was carried out for microneedles produced by all gelatin formulations.

[0300] Results:

[0301] Figure 15A displayed the CAD design of microneedles with different dimension, and the SEM characterization indicated that MN with height of 1.0 and 0.8 mm and diameter of 1.0, 0.8, 0.6 mm could be printed well (Figure 15B).

[0302] Example 13: Tube device with microneedles (MN-tube) printed with optimized resin CAD design of MN-tube:

[0303] The prototype of tube device with microneedles was designed using 3D MAX 2022 software (Autodesk, UK). Height of the microneedles: 1.0 mm; bottom diameter: 0.4 mm; diameter of the tube: 2 mm; thickness: 0.3 mm.

[0304] Optimized resins and 3D printing:

[0305] Gelatin resin with 0.08 mol% PEGdMA 550-AA and 50% NaOH neutralization was prepared as Example 11. Then, 400 mg LAP (potentiator) and 800 pL (25 mg / mL) tartrazine were added. Asiga printer with light wavelength of 405 nm was utilized for printing, and the exposure time was 1 sec. Other printing parameters were as described in Example 12. SEM characterization was as described in Example 12.

[0306] Results:

[0307] Figure 16A-B displayed the CAD design of microneedles-tube device. The image (Figure 16C) and SEM characterization (Figure 16D) indicated that MNs were printed successfully on the tube device.

[0308] Example 14: Swellability level of tube devices (MBA as crosslinker) in different pH water solution

[0309] Resins preparation and 3D printing methods were as described in Example 10.

[0310] Swell ability test of tube devices:

[0311] Firstly, the effect of pH on the swelling ability of tubes were tested. Briefly, the tube was placed into vial with 2 mL water with different pH (pH 3.17 and pH 6.17) at 37°C. The weight, diameter and length of the tubes were measured at 0 (before putting into water), 5, 30, 120 min after being put into water. Then, the swelling ability of tubes with different diameter (2, 3 or 4 mm) and thickness (0.3, 0.2 or 0.1 mm) were also tested as above in pH 6.17 water at 37°C. Three tubes were tested for each group.

[0312] Water uptake (%)=(W hydrated sample" W dry sample) / W dry sample* 100,

[0313] Diameter change ratio— D hydrated sample / D dry sample 100, Length change ratio= L hydrated sample / L dry sample *100.

[0314] Results:

[0315] The dry tubes (Figure 17A) demonstrated the ability to absorb water and expand (Figure 17B). The water uptake ratio, diameter, and length change of tubes after hydration were determined at different conditions. Firstly, the swelling abilities of 0.1 mm thickness tubes (diameter: 2 mm) at different pH (pH 3.2, pH 6.12 and deionised water (DIW)) was tested. Figure 17C-E indicated that the pH of the aqueous medium did not influence the water uptake ratio, and device expansion in diameter and length. The 0.2 and 0.3 mm thickness tubes demonstrated similar swelling profile with slightly higher water uptake ratio (Figure 17F-H). According to the diameter and length change ratios at different time points (Figure 171, J), tubes with different thickness almost reached their fully hydration status at 5 min for diameter and 30 min for length. Then, tubes with various diameter and thickness (Figure 17K) were printed to check if the geometric parameters can affect the diameter change ratios of the tubes. The result reflected that all of the tubes had similar diameter change ratios at 30 min (approximately 2.5), which meant the diameter and thickness of tubes did not affect the diameter change ratios.

[0316] Conclusion:

[0317] Swelling takes place in wide range of pH. Most of the swelling takes place within 30 min.

[0318] Example 15: Swellability level of tube devices (PEG-derivant as crosslinker) in pH 6.2 water solution

[0319] Resins preparation and 3D printing methods were as described in Example 11. Swellability was measured as described in Example 14.

[0320] Swellability is shown in Figure 18. The diameter change ratios of tubes at 30 min is shown in Figure 19.

[0321] Conclusion: Compared with resin with MBA as crosslinker, the PEG-derivant resins showed a higher water uptake ratio.

[0322] Resins preparation and 3D printing methods were as described in Example 11.

[0323] Swellability test:

[0324] The swelling ability of tubes in different buffers were tested. Briefly, the tube was placed into vial with 2 mL buffer (Krebs-Henseleit buffer with D-glucose, PBS, FeSSIF-V2, FeSSIF-V2) at 37°C. The weight, diameter and length of the tubes were measured at 0 (before putting into water), 5, 30, 120 min after being put into buffer. The buffer was switched to pH 6.2 water solution at 2 h. The calculation refers to Example 14.

[0325] Results:

[0326] The swellability, including water uptake, hydrated diameter and length, was reduced in Krebs-Henseleit buffer with D-glucose, PBS, FeSSIF-V2, FeSSIF-V2 buffers. But the Swellability was recovered when tubes were put into pH 6.2 water solution (Figure 20).

[0327] Conclusion:

[0328] Swellability decreased in different physiological buffer compositions, but it was reversable after switching the buffer after 2 hours.

[0329] Example 17: Isolation of rats’ small intestine and swelling characterization ex vivo Aim: to test the interaction between the device and intestinal mucosa.

[0330] Isolation and collection of rats’ small intestine:

[0331] Rats were euthanised using CO2 before dissection. The small intestine was cut at 10 cm to 37 cm sites from stomach to separate the jejunum. Then, the jejunum was washed with ice Krebs-Henseleit buffer with D-glucose. The buffer was oxygenated using Oxygen Concentrator (Visionaire, USA), and the jejunum was stocked with oxygenated buffer in the fridge (4°C) before using.

[0332] Swelling characterization ex vivo:

[0333] The jejunum was cut into 5 cm sections, and one side of section was tightened with string. One tube was put into the jejunum section with 0.2 mL Krebs-Henseleit buffer with D-glucose solution. Then, another side of the jejunum section was tightened with string, and the jejunum section was put into the oxygenated buffer at 37°C for 30 min. The jejunum sections with tube before and after 30 min hydration were recorded. Devices with different diameter (2, 3 or 4 mm) and thickness (0.2 mm) were tested, and three tubes were tested for each group.

[0334] Results:

[0335] Figure 21A-B displayed the small intestine and the tubes before and after 30 min hydration. For the 0.2 mm thickness tubes with 2 mm and 3 mm diameter (D2T0.2 and D3T0.2), the hydrated tubes can shore up the small intestine wall and remain circular. Whilst 0.2 mm thickness tubes with 4 mm diameter (D4T0.2) could not support the intestinal wall and was squashed to oblate (Figure 21 B). When the D4T0.2 tube was taken out from the small intestine, it restored its circular shape. The hydration process of D3T0.2 tube in small intestine was recorded, and the status at 0, 15, 30, 60, and 90 min was demonstrated (Figure 21 C). It took longer time to achieve fully expanded status for tubes in small intestine compared with those in vitro, and the final diameter of the tube after 24 h hydration in small intestine was 6.60±0.18 mm, which was relatively smaller than that of the hydrated tubes in vitro (7.73±0.15 mm). Figure 21 D represented the tube in the small intestine, and the cross-section view was shown as Figure 21 E. The tube attached on and supported the intestinal wall without blocking the intestine.

[0336] Conclusion:

[0337] Compared with the prior arts, the inventors’ tube device avoids the potential risk of obstructing the small intestine. The 3D printing techniques with novel hydrogel resins ensure the rapid and affordable production of hydrogel devices.

[0338] Example 18: Radial force testing of tube devices in vitro

[0339] Pressure setup establishment and pressure testing in vitro:

[0340] To investigate the force that produced by the hydrated tubes on the inner surface of the rat’s small intestine, an in vitro setup with three force sensors was established. Three FSG020WNPB force sensors (Honeywell, USA) were assembled on the 3D printed scaffold to mimic the small intestine. The sensors were connected with TL082BCP (Texas Instruments, USA) operational amplifiers to record the voltage change.

[0341] Force (N) produced by the hydrated tubes on the surface of the sensor was calculated as:

[0342] F=(Vatter - Vbefore) / (Sensitivity*Vinput) where Vatter (mV) and Vbetore (mV) were the voltage values before and after the hydrated tubes being put into the centre of the sensors; Sensitivity was the ratio of output signal change to the corresponding input force change of the FSG020WNPB force sensor which is equal to 1.8 mV / V / N; Vjnput (V) is the voltage applied to power the sensor, which was 10 V.

[0343] Results:

[0344] The pressure generation by 3D printed device upon hydration was assessed using a specially design axial pressure measurement (Figure 22A-D). Initial pressure testing in vitro setup indicated that the pressure generated by the tube-shaped devices on the small intestinal wall was positively associated with the thickness of the tubes, with the highest pressure of 232.9±39.3 mN (Figure 22E,F).

[0345] Example 19: BSA-FITC loading and release profile by soaking method

[0346] Resin formulation and preparation:

[0347] Gelatin resin with 0.16% PEGdMA 550-acrylic acid and 50% NaOH neutralization was utilized. 1.667 mL of LAP (3%) and 400 mL of tartrazine (25 mg / mL) were added as Photo initiator and absorber, respectively. For the detailed processes, refer to Example 11.

[0348] For the 3D printing processes and printing parameters, refer to Example 11.

[0349] BSA-FITC loading by soaking method:

[0350] BSA-FITC and Trehalose were mixed in a 1 :1 ratio to obtain three different concentrations: 5 mg / mL, 1 mg / mL, and 500 pg / mL. Blank hydrogel tube devices were placed in 1 mL of each BSA-FITC-Trehalose concentration, ensuring additional repetitions for repeatability. The tubes were stored overnight at 4°C to facilitate proper diffusion and absorption. Using tweezers, the tubes were removed from the solutions and transferred onto a clear 12-well plate for drying. Any excess surrounding solution was carefully el iminated using a 200 pL Gilson pipette. The loaded tubes were left to dry overnight in a dark environment, followed by further drying in a dark fume cupboard.

[0351] In vitro release experiments for BSA-FITC loaded tube devices:

[0352] For in vitro release experiments, coated hydrogels were placed in tubes containing 5.2 mL pure water (pH 6.2) as the release medium. During the experiment, the tubes were incubated in a shake water bath at 55 rpm and 37°C. At predetermined time points (5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 40 min, 50 min, 60 min, 90 min, 120 min, 4 hrs, 6 hrs, 8 hrs, 12 hrs, and 24 hrs), an aliquot of 200 pL solution was taken and replaced with an equal volume of fresh medium to maintain the original volume. The concentration of BSA-FITC in the aliquoted solutions was determined using the values from fluorescence spectroscopy at an excitation wavelength of 485 and emission wavelength of 535 nm and a calibration curve ranging from 500 pg / mL to 0.5 pg / mL. Results:

[0353] The mAb was loaded as Figure 23A. Around 800 g mAb could be loaded in per hydrogel tube with 5 mg / mL soaking solution (Figure 23B), and more than 70% of drug released over 4 hours (Figure 23C).

[0354] Conclusion:

[0355] The method achieved a loading of up to 800 pg per device with >70% drug release over 4 hours.

[0356] Example 20: BSA-FITC loading and release profile by dip coating BSA-FITC loading by dip coating method:

[0357] A 5 mL coating solution was prepared using the formulation consisting of 12.5% BSA- FITC, 67.5% methylcellulose, and 20% trehalose. To prevent internal coating, rolled tissue paper was slid through each hydrogel. Each hydrogel was then dipped into the coating solution using tweezers and held for 10 seconds. The coated hydrogels were left in a dark environment to dry in a 12-well plate for 50 minutes. This dipping and drying process was repeated three times to obtain hydrogels coated 1x, 2x, and 3x. The coated hyd r ogels were left to dry overnight and subsequently transferred to a fume cupboard to complete the drying process.

[0358] In vitro release experiments for BSA-FITC loaded tube devices refer to Example 19.

[0359] Results:

[0360] The mAb was loaded as Figure 24A. The SEM image showed the coating layer of mAb (Figure 24B). The method achieved a loading of 731.47±93.53 ug per device with 3 times of coats, and 69.25±6.30% drug release over 4 hours (Figure 24C,D).

[0361] Conclusion:

[0362] The method achieved a loading of up to 700 pg per device with >70% drug release over 4 hours. Example 21: ex vivo setup design and development

[0363] To check the permeability of biologicals loaded on the tube device, a tailored ex vivo setup, mainly including a medical gas cylinder (95% O2 and 5% CO2), water bath with string apparatus, Slim Glass Specimen Tube (10 mL) with bespoke and 3D-printed tissue-holding cap, was established. The diameter of glass bottle was 16 mm, and the height was 75 mm (Figure 25A). The CAD design of the tissue-holding cap is shown in Figure 25B. The whole setup is demonstrated as Figure 25C-E. HE staining results revealed that the small intestine kept integrity for over 1 hour (Figure 25F).

[0364] Conclusion:

[0365] The tailored ex vivo setup was established successfully and could be utilized to investigate the ex vivo permeation of biologicals within 1 hour.

[0366] Example 22: BSA-FITC permeation with or without expandable tube devices ex vivo For ex vivo release experiments, oxygenated Krebs-Henseleit buffer with D-glucose was prepared as the medium for the experiment. 5 cm of intestine was secured to a 3D-printed set-up and placed in 10 mL medium as shown in Example 21. The sample was then placed in a 37°C stirring water bath at 200-300 rpm. A release experiment was performed with three groups of samples (n=3 for each group).

[0367] Group 1 : non-expandable tube devices (printed with clear resin) loaded with BSA- FITC by dip coating.

[0368] Group 2: expandable hydrogel tube devices loaded with BSA-FITC by dip coating (3X).

[0369] Group 3: expandable hydrogel tube devices loaded with BSA-FITC by soaking method.

[0370] Each group had blank small intestine as background control to remove the interference caused by tissue. The diameter of dry tube device was 2 mm, the thickness was 0.3 mm. Samples of 0.6 mL were taken at the following time points (10, 20, 30, 40, 50, and 60 mins) and placed in a centrifugation tube. An equal volume of the medium was replaced to maintain the original volume. All samples were centrifuged and plated on a black 96-well plate with a 100 pg / mL - 0.005 pg / mL calibration curve. Fluorescence readings were taken on all samples. Result:

[0371] Figure 26 shows the cumulative permeation percentage for the three groups of samples over a 60 min timescale.

[0372] Conclusion:

[0373] Dip coating method potentially enhanced drug permeation, this could be a result of maximizing drug concentration on the intestinal mucosa.

[0374] Example 23: In-situ AgNP deposition in tube devices

[0375] Aim: to produce a contrast-agent-loaded device for micro-CT imaging of the device.

[0376] Preparation of Ag@tube devices:

[0377] The hydrogel tube devices were prepared as previous method. Then, 5 mL 0.01% silver nitrate (AgNCh) with 0.05% LAP and 0.05% AgNCh with 0.1% LAP solutions were prepared, respectively. The solution was purged with N2 for 1 min. The tube devices were immersed and incubated in AgNCh solution with LAP overnight at fridge. Hydrated tubes in AgNCh solution were taken out and put in UV irritation chamber (UV wavelength: 405 nm) for 30 min or 60 min. After irritation, Ag@tube devices were washed with 10 mL water for 30 min to remove the unreacted AgNCh (3 times). Finally, the Ag@tube devices were dried (Figure 27}. Example 24: Degradation test of tube device in different conditions

[0378] Aim: To assess the degradation of hydrogel following the full expansion and confirm the impact of pancreatin on the digestion of the gelatine.

[0379] For the resin preparation, 3D Printing, and post-curing methods, refer to Examples 10 and 11.

[0380] Buffer preparation:

[0381] Degradation was assessed by measuring the residual weight of tube devices in PBS buffer, FeSSIF-V2 buffer with active and deactivated enzyme at different time points. PBS buffer was prepared by adding one PBS tablet in 100 mL pure water. FeSSIF- V2 buffer was prepared as instruction. Briefly, for 100 mL FeSSIF-V2 buffer, 5.061 g of FeSSIF-V2 buffer concentrate was diluted with 95.89 g purified water, followed by adding 0.976 g FeSSIF-V2 powder under stirring. The medium was used within 48 h.

[0382] Pancreatin (8X USP) was utilized as enzyme source to mimic the small intestinal environment. Active or deactivated pancreatin powder (50 mg) was added to 5 ml FeSSIF-V2 buffer to achieve an enzyme concentration of 10 mg / mL (1% w / v). (The enzyme was deactivated by putting the pancreatin powder into oven at 60 °C for 48 h.)

[0383] Short-term degradation test in PBS, FeSSIF-V2 buffer with active and deactivated enzyme by wet-weight method:

[0384] Firstly, the test tubes were dried in the oven at 60 °C for overnight. Then, the tube device was immersed in 5 mL of buffer at 37°C with shaking (100 rpm). For wet weight assessments, tubes were taken out, blotted and weighed the wet residual weight. After weighting, tubes were put back to the buffer for next time point weighting. Four samples were tested for each buffer. The percentage of wet residual weight (WR%) was calculated using the formula:

[0385] WR% = (Wt / W2h) x 100% where Wt is the weight of the hydrogel at different time points, and W2h is the weight of the hydrogel at 2 hours (previous studies have shown that the device reaches full water absorption and expansion within 2 hours).

[0386] Long-term degradation test in PBS, FeSSIF-V2 buffer with active by dry-weight method:

[0387] PBS and FeSSIF-V2 buffer were prepared as above. Firstly, the test tubes were dried in the oven at 60 °C for overnight. For dry weight assessments, the weight of the dry tube devices was weighed as Wj before putting it into the buffer (37°C with shaking). At each time point, tubes were taken out, dried at 60 °C for overnight, and weighed the dry residual weight (Wt). Four replicates were tested at each time point. The percentage of dry residual weight (WR%) was calculated using the formula: WR% = (Wt / Wi) x 100% where Wi is the initial weight of the hydrogel, while Wt is the weight of the hydrogel at different time points.

[0388] Result: For the short-term testing by wet-weight method, approximately 10% weight loss was observed in PBS and FeSSIF-V2 buffer with deactivated pancreatin within 96 h. The mass percentage dropped to 83.6% in the FeSSIF-V2 buffer with deactivated pancreatin at 96 h, indicating -20% weight loss achieved (Figure 28A). For long-term testing over 20 days, the residual weight percent decreased to 75.7±0.68% within 10 days in FeSSIF-V2 buffer with pancreatin. However, the residual weight of tubes in PBS remained at 90% after 20 days incubation (Figure 28B,C).

[0389] Conclusion:

[0390] The tube device can degrade naturally in PBS and FeSSIF-V2 buffer, and the presence of pancreatin can promote the degradation processes. The maximum weight loss was -25%, which is achieved in FeSSIF-V2 buffer with active pancreatin.

[0391] Example 25: Degradation test of tube devices printed by resin with different gelatine concentrations and other water soluble polymers

[0392] Aim: To demonstrate the suitability of using other water soluble polymers in this expanding system. To assess the impact of gelatine concentration on hydrogel degradation rate.

[0393] Resin preparation:

[0394] Gelatine resin with 0.16 mol% PEGdMA as a crosslinker were prepared as per Example 11. While different amount of Gelatine (Table 12) was added to generate a series of resins. The polymer percent was calculated by the formula:

[0395] Polymer percent (w / w%) = polymer amount / amount of (Soluble Polymer + acrylic acid + NaOH) *100

[0396] Table 12: Resins with different amount of polymers

[0397] 3D Printing and post-curing method:

[0398] To achieve the best printing quality, the printing parameters are adjusted for high viscosity resin. The summary of the printing parameters is shown as Table 13. Other printing parameters, like light intensity, and post-curing method refer to Examples 10 and 11.

[0399] Table 13: The summary of the printing parameters for each resin For the short-term degradation test in FeSSIF-V2 buffer with or without active enzyme by wet-weight method, refer to Example 24.

[0400] Result:

[0401] The degradation of tube devices with various polymers and content was tested in FeSSIF-V2 buffer with active and deactivated pancreatin. There is almost no degradation for tubes printed by resin without polymers both in FeSSIF-V2 buffer with or without pancreatin. For other tube devices produced with different polymers and content, the maximum loss weight percentage tends to the content percent of polymers in buffer with active enzyme (Figure 29).

[0402] Conclusion:

[0403] The poly acrylic acid / poly sodium acrylate tube devices nearly undegraded both in FeSSIF-V2 buffer with or without pancreatin, while the degradability can be enhanced by increasing the soluble / degradable polymer content in tube devices. The pancreatin in the buffer can relatively accelerate the degradation processes of polymers.

[0404] Example 26: Expandability test of tube devices printed by resin with various polymers and content (in FeSSIF-V2 buffer)

[0405] For resin preparation, 3D Printing, and post-curing methods, refer to Example 25.

[0406] For swellability test method in FeSSIF-V2 buffer, refer to Example 16.

[0407] Result:

[0408] The Swellability test of tube devices with various polymers and content was tested in FeSSIF-V2 buffer. The length, diameter and weight percentage of hydrated tube devices at different time points were measured (Figure 30). The pure poly acrylic acid tube has the fastest swelling rate, reaching its fully hydrated status in 5 mins. However, the final water uptake ratio, length and diameter are positive related to the polymer content. The maximum diameter was achieved by the tube device printed with gelatine-11 g resin in FeSSIF-V2 for 2 h.

[0409] Conclusion: The pure poly acrylic acid tube has the fastest swelling rate. The inclusion of soluble polymers in tube devices did not significantly affect the polymethacrylate swelling ability while contributed to degradation.

[0410] Example 27 Self-fragmenting strategy for the in vivo clearance of tube device

[0411] Aim: To develop an architectural solution for device fragmentation based on two or more components and a soluble binder.

[0412] CAD design of half-tube:

[0413] The tube (D2 TO.3) as in Example 5 was split to two parts lengthwise, and the crosssection was transformed from a circle to a semi-circle.

[0414] For 3D Printing and post-curing methods, refer to Examples 10 and 11.

[0415] The bonding of two half-tubes:

[0416] PVP K50 was utilized as the glue to bind two half-tubes together. Briefly, PVP K50 was dissolved in water (50% w / v) to obtain a viscous solution. Then, the glue was brushed on the fracture surface of one half-tube, and the other half-tube was attached to the previous half-tube. The bonded tube was dried overnight at room temperature.

[0417] Disintegration of the self-fragmenting device:

[0418] The bonded tubes were soaked in 5 mL of PBS at 37 °C with shaking (100 rpm). The PVP, a water-soluble polymer, will dissolve overtime, and the tube will split to two parts again. The disintegration time was recorded.

[0419] Result:

[0420] The CAD design of half-tube is shown as Figure 31 (A, B). The printed half-tube is displayed as Figure 31 (C), and the bonded tube devices are demonstrated in Figure 31 (D, E). The results of disintegration test indicated that the self-fragmenting device split to two half parts at 1.5 mins at 37°C in PBS under stirring Figure 31 (F).

[0421] Conclusion: Self-fragmenting provides another strategy for the in vivo clearance of tube device. The fragmentation rate can be controlled by changing the nature and the concentration of the binder e.g. PVP, methyl cellulose, HPMC, HPC, etc.

[0422] Example 28: The penetration of MN-tube

[0423] MN-tubes design, printing and post-curing:

[0424] D2 T0.3-MN DO.4 H1.0 (No.4 design in Example 13) MN-tube devices were printed with optimized resins with different PEGdMA 550 crosslinker ratio (0.08 mol% and 0.16 mol%). For the design, resin formulation and specific printing parameters refer to Example 13. For the post-curing method, refer to Example 10.

[0425] Methylcellulose (MC) coating:

[0426] The MC coating solution was prepared by adding 337.5 mg of MC in 1 mL of hot water (above 90°C) with stirring. Then, 2 mL of cold water was added to obtain a transparent solution. The solution was placed at 4°C for overnight. Methylene blue was added to the MC solution before coating to help the observation of coating processes.

[0427] Two coating methods, namely dry-tube rolling coating and wet-tube dip coating were explored. For dry-tube rolling coating method, the dry MN-tube was rolled in a thin groove as shown in Method 1 of Figure 32(A). For the wet-tube dip coating method, the MN-tube was fully hydrated firstly. After that, each row of microneedles was dipped into the coating solution. After coating, the MN-tubes were dried at room temperature.

[0428] Table 14: The summary of MN-tube printing and coating

[0429] Ex vivo penetration test:

[0430] Fresh rat small intestine was isolated for penetration test. For the isolation method, refer to Example 17. The jejunum was cut into 5-cm sections, and one side of section was tightened with string. One tube was put into the jejunum section with 0.2 mL Krebs-Henseleit buffer with D-glucose solution. Then, another side of the jejunum section was tightened with string, and the jejunum section was put into the oxygenated- Krebs-Henseleit D-glucose solution at 37°C for 30 min. The jejunum sections with MN-tube after 30-min hydration were recorded. After that the tissue was taken out and fixed with 4% PFA at 4°C for at least 12 h. H&E staining and slicing were performed to visualize the penetration of microneedles to gut wall.

[0431] Result:

[0432] The coated microneedles-tube devices with different methods and expandable tube devices in rat small intestine are shown as Figure 32B. Many bumps are observed on the surface of small intestine tissue, representing the microneedles on the tube devices. The enlarged view illustrated that the microneedles did not punch through the gut wall. The wet rolling method did not affect the ability of the device to expand. The further H&E staining results (Figure 33) indicated that the tube printed with PEGdMA 550 (0.16 mol%) resin and coated with dry rolling method has the potential to penetrate the submucosal layer of the small intestine.

[0433] Conclusion:

[0434] Tubes printed with PEGdMA 550 (0.16 mol%) resin and coated with dry rolling method have the potential to penetrate the submucosal layer of the small intestine.

[0435] Example 29: larger devices

[0436] Optimised printing parameters for larger devices are shown in the table below. The maximum light intensity cannot be stable above 25 mW / cm2, so it should be declined to 20 mW / cm2. Layer thickness of all printing attempts was 0.05 mm.

[0437] Table 15: Optimised printing parameters for larger devices

[0438] Swelling Test in FeSSIF: 0.08% PEGdMA:

[0439] ❖ Samples: T0.5-3s, T1-3s, T2-3s, T1-5s

[0440] ❖ The samples were placed in 200 mL of freshly prepared FeSSIF and the changes in length, height and weight were measured at different time points (0, 15 min, 2h, 3h) at 37°C and 100 rpm. See Figure 34.

[0441] ❖ The differences between 3s and 5s were not significant in changes in diameter and height. Increasing the exposure had less effect on the expanding behaviour of the devices.

[0442] ❖ T0.5-3s swelled faster and stabilised after 15 min.

[0443] ❖ The expansion rate of T2-3s was slow, and the diameter increase over 3h was not as great as in T1.

[0444] Hydration studies:

[0445] ❖ Samples: T0.5-3s, T1-3s, T2-3s, T1-5s

[0446] ❖ Hydration results are shown in Figure 35.

[0447] ❖ TO.5 expanded quickly but was too soft and easily deformed, which may result in its inability to generate sufficient force in the small intestine to hold up and exert pressure on the intestinal wall.

[0448] ❖ Slow expansion of T2 may result in its inability to expand and function normally in the small intestine.

[0449] Ex vivo test in porcine small intestine:

[0450] ❖ Samples: T0.5-3s-0.08%, T1-3s-0.08%, T1-3s-0.04%, T1-3s-0.02%, T2-3s- 0.08%. ❖ The test tubes were placed in approximately 7 cm of porcine jejunum and then immersed in approximately 200 mL of PBS (37°C, 100rpm), and the intestines were removed for photographs at the time points (30 min, 1 h, and 2 h).

[0451] ❖ T0.5-3s-0.08% could not maintain the shape of the tube in the small intestine. T2-3s-0.08% absorbed water too slowly to swell properly. See Figure 36. Because the tubes could not expand quickly, or they deformed easily, they would fall out of the gut and were therefore secured with the aid of thread at the early stage.

[0452] ❖ Expansion of the hydrogel tube was shown for T1-3s-0.08%, T1-3s-0.04%, T1-3s-0.02%. Greatest expansion of outer diameter was shown for higher PEGdMA concentration (0.08%). See Figure 37.

[0453] Force Testing:

[0454] % Strain = (Diameter of the tube before compression-Diameter after compression) / (Diameter before compression)

[0455] The diameter of the tubes was measured before compression (after soaking in PBS for 2 h). The diameter of the tubes was measured after compression (the diameter of the porcine small intestine).

[0456] Force = (Voltage after placing of the tube - Voltage before placing of the tube) / (Sensitivity x Voltage of power supply)

[0457] The force sensors have a sensitivity of 1.8 mV / V / N with a 10.0 V power supply, giving a SensitivityxVoltage value of 18. The total force on the test tube’s surface was determined by summing the forces from all four sensors. The height of the pillars were set to 8 cm for all samples and the diameters were set to 2 cm / 2.5 cm / 3 cm for different samples.

[0458] The results of the force testing are shown in Figure 38. The total force for the 0.08% and 0.04% tubes was about 1.5 N.

[0459] Example 30: larger microneedle tube Adjusted dimensions and printing parameters for a larger microneedle tube are shown in the table below.

[0460] Table 16: Printing parameters for a larger microneedle tube

[0461] Tube (D5.8T1H20-MN D0.8H2) was appropriately sized for a size 00 capsule, as shown in Figure 39.

[0462] An ex vivo test in porcine small intestine was carried out as in Example 29. Expansion of the tube is shown in Figure 40.

[0463] Example 31: Swellability of AqNP labelled hydrogel tube devices

[0464] Aim: to test the effect of in-situ AgNP labelling on hydrogel swellability using microCT imaging

[0465] In-situ sliver nanoparticle deposition in hydrogel tube devices

[0466] The hydrogel tube devices (Diameter 2 mm; Thickness 0.3 mm) were obtained via the method of Example 11. AgNCh-LAP solutions (0.05 w / v% AgNOs-0.1, 0.2, or 0.3 w / v% LAP were prepared via the methods of Example 23. Each dehydrated hydrogel tube was immersed and incubated in AgNCh-LAP solution (1 mL) overnight at around 4°C. After incubating, tubes were taken out and put into a UV irritation chamber for 60 min (wavelength: 405 nm). Silver-loaded hydrogel tube (Ag@tube) devices were transferred to 10 mL water for 30 min to remove the unreacted AgNCh. Ag@tube devices were then dried overnight for further characterizations. Expandability of sliver-loaded hydrogel tube (Ag@tube) devices

[0467] The Ag@tube devices were put into PBS for different time lengths to check if the expandability would be affected by the Ag particles loading.

[0468] In vitro micro-CT imaging signal intensity of sliver-loaded hydrogel tube (Ag@tube) Dry Ag@tubes were placed on the bottom of a petri dish. Then, the petri dish was put into the micro-CT chamber for imaging. (X-ray energy 40 kV, Current 8 mA) The images were reconstructed by embedded software. Reconstructed images were analysed by 3D Slicer software (Version 5.8.1 , USA). Hydrated Ag@tube devices in pure water were put into the wells of a 96-well plate for micro-CT imaging.

[0469] To calculate the Hounsfield Units (HU), Segment Editor module was utilized to select the cross-section of the tube area. Segment Statistics module was applied to calculate the maximum HU values for each segment.

[0470] Results:

[0471] The colour of hydrogel tubes immersed in 0.05 w / v% AgNO3 solution with various concentrations of LAP shifted from transparent to bright blue (0.1 w / v% LAP), dark blue (0.3 w / v% LAP) or yellow (2.0 w / v% LAP). This might be caused by the concentration differences of in-suit deposited AgNPs in hydrogel matrix. After drying, the colour variations were not obvious. Ag@tube prepared with 0.05 w / v% AgNOs-O.3 w / v% LAP demonstrated highest signal before and after dehydration. See Figure 41.

[0472] Conclusions:

[0473] In situ labelling with sliver nanoparticles did not affect the device hydration.

[0474] Example 32: Manufacture of size #9 enteric capsules

[0475] Aim: To manufacture specially made enteric capsule size#9 to include the device for animal testing.

[0476] Methods:

[0477] Size #9h capsules with a diameter of around 2.7 mm and length 5.1 mm, are the smallest capsule for rat’s oral gavage. In this project, hydrogel devices are designed to be activated and expand in the small intestine, thus, an enteric capsule should be manufactured specially for rat’s small intestine-targeted delivery. Here, a casting strategy producing size #9h enteric capsule directly with enteric polymer was explored. In addition, due to the interspecies differences in gastrointestinal anatomy and physiology between human and rodents, enteric capsules were engineered with various pH-threshold using different enteric polymers by established manufacturing processes.

[0478] CAD design and computer numerical control (CNC) machining of capsule moulds

[0479] For making capsules, two sets of rods as casting moulds were designed via Fusion 360 (version 2024, Autodesk, USA) and fabricated via CNC machining with different dimensions: one for capsule body and the other one for the cap. The specific dimensions of rods are shown as Table 17 according to the reported dimensions for size 9h capsule for rodents. All rods were made from Stainless Steel (SS304) and coated with PTFE for non-sticking purpose.

[0480] Table 17: Dimensions of capsule moulds

[0481] To manufacture size #9h enteric capsule shell, capsule rods were held with tweezers and dipped into the coating solution. The rods were withdrawn from the enteric solution slowly, ensuring that the end of the capsule rod just touched the surface of the solution and allowing the excess solution to drip off for about five seconds. Then, rods were lifted and turned over so that the coated side of the rod faced up. The capsule rods were placed on a shelf for 30 to 40 minutes to allow solvent evaporation and polymer forming the shell. This process was repeated 3 times to generate capsules with different wall thicknesses. After the final coating, capsule bars were placed on the shelf overnight. The dried capsule shell was cut along the groove of the mould using a scalpel and removed with a tweezer. See Figure 42A. The outer diameter and thickness of capsule shells (both capsule cap and body) were measured.

[0482] Casting #9h capsules with different enteric polymers coating solutions

[0483] Capsules were fabricated using a 1 :1 (w / w) blend of EUDRAGIT® L100 and L100-55. Enteric polymer formulations were shown as Table 18. The integrity of the capsule was analysed in vivo, as the in vitro medium condition can not reflect the real gastrointestinal environment for rats’ purpose.

[0484] Table 18: Formulation of EUDRAGIT® L100 / L100-55 enteric polymer coating solution

[0485] Results:

[0486] The designs of rods for capsule cap and body are shown as Figure 42 B. specially, a locker was designed on the capsule cap for sealing. The stainless-steel casting moulds were shown as Figure 42 B. Capsules with mixture of EUD L100 / L100-55 were fabricated successfully. See Figure 42 C. The dimensions of different capsules were displayed as Table 19.

[0487] Table 19: Dimension of Eudragit L100 / L100-55 hybrid capsules Conclusion:

[0488] Capsules with a mixture of EUD L100 / L100-55 (target pH threshold of pH 5.75) were fabricated successfully

[0489] Example 33: In-vivo application of hydrogel device in rodent animal model Aim: to provide a preliminary in vivo proof of concept of activation mechanism of the device in rodent animal model.

[0490] Methods:

[0491] Male Sprague-Dawley rats with weight of 450-500 g were utilized for the experiments. Gel food was provided during the experimental period. Animals had free access to water overnight. During experiments, rats were subcutaneously injected with 5 mg / kg metoclopramide hydrochloride to induce gastric emptying, followed by immediate oral administration of Ag@tube capsules. Extra water (3.5 mL per time) was given at 2 and 4 h, rats were culled at 4 and 5 h, and small intestinal tissues were collected and stored at -80 0C before CT scanning.

[0492] Image processes

[0493] 3D rendering was completed using 3D Slicer software (version 5.8.1, USA). Reconstructed data were imported into Slicer software as DICOM data and visualized with volume rendering module. The present module was CT-Cardiac. The tissue and sliver-loaded device were separated based on their signals.

[0494] Results:

[0495] Hybrid capsules fabricated from mixture of EUD L100 and L100-55 (1 :1) were utilized for hydrogel delivery. Results showed that L100 / L100-55 capsule kept intact for 4 hours in stomach and transited or released hydrogel device in small intestine at 5-h. The expanded diameter of tube delivered by L100 / L100-55 capsule was approximately 4 mm. See Figure 43. Then, larger device with diameter of 2.7 mm was given to rats, and results demonstrated that larger devices could expand to 6 mm in small intestine. See Figure 44. Overall, L100 / L100-55 capsule can protect hydrogel device from activating in stomach for 4-5 hours. 50% (3 out of 6) of capsules can reach to small intestine. Hydrogel devices can expand >2 times of its original diameter in small intestine.

[0496] Conclusions:

[0497] L100 / L100-55 hybrid capsule can achieve a small intestine-target delivery. Despite variability in transit time, initial in vivo investigation showed the dissolution of the shell and the expansion of the device following gastric emptying. The device was well- tolerated and voided from the rats Gl tract within 24 h. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety.

[0498] In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognised that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.

Claims

Claims1. A device comprising an expandable hollow hydrogel tube encapsulated by an ingestible capsule, wherein the ingestible capsule is arranged to release the hydrogel tube in the gastrointestinal (Gl) tract, and wherein the hydrogel tube is arranged to expand outwardly from a first configuration to a second configuration in the Gl tract to exert an outward radial force on the lining of the Gl tract.

2. A device according to claim 1, wherein an exterior diameter of the hydrogel tube in the second configuration is at least 2-fold greater than the exterior diameter of the hydrogel tube in the first configuration.

3. A device according to claim 1 or claim 2, wherein a length of the hydrogel tube in the second configuration is at least 2-fold greater than the length of the hydrogel tube in the first configuration.

4. A device according to any preceding claim, wherein an outward-facing surface of the hydrogel tube comprises microneedles.

5. A device according to claim 4, wherein the microneedles are composed of the same material as the hydrogel tube.

6. A device according to any preceding claim, wherein the hydrogel tube comprises at least one agent for delivery to the Gl tract.

7. A device according to claim 6, wherein an outward-facing surface of the hydrogel tube and / or the microneedles is coated with the at least one agent.

8. A device according to claim 6 or claim 7, wherein the hydrogel tube and / or silvere microneedles is impregnated with the at least one ent.

9. A device according to any one of claims 6-8, wherein the at least one agent is a therapeutic agent, a diagnostic agent and / or a nutraceutical agent.

10. A device according to claim 9, wherein the at least one agent is a biological agent, optionally wherein the biological agent is an antibody, further optionally wherein the biological agent is a monoclonal antibody.

11. A device according to claim 9, wherein the at least one agent is an imaging contrast agent, optionally wherein the imaging contrast agent is AgNCh.

12. A device according to any one of claims 6-11 , wherein the device is configured to release at least 70% of the at least one agent from the device into the Gl tract within 4 hours.

13. A device according to any preceding claim, wherein an outward-facing surface of the hydrogel tube comprises one or more openings.

14. A device according to any preceding claim, wherein the hydrogel tube is 3D printed, injection moulded, or template casted.

15. A device according to any preceding claim, wherein the hydrogel tube is composed of a gelatin- or poloxamer-based crosslinked hydrogel.

16. A device according to claim 15, wherein the crosslinked hydrogel is a gelatin- poly(acrylic acid) hydrogel or a poloxamer-poly(acrylic acid) hydrogel.

17. A device according to claim 16, wherein the hydrogel tube comprises: gelatin-poly(acrylic acid) or poloxamer 407-poly(acrylic acid); and a neutralisation agent.

18. A device according to claim 17, wherein the hydrogel tube comprises: 80-85% gelatin-poly(acrylic acid) or poloxamer 407-poly(acrylic acid); and 15-20% of a neutralisation agent.

19. An expandable hollow hydrogel tube arranged to fit inside an ingestible capsule,wherein the hydrogel tube is arranged to expand outwardly from a first configuration to a second configuration in the Gl tract to exert an outward radial force on the lining of the Gl tract.

20. A hydrogel resin comprising: gelatin or poloxamer 407; a neutralisation agent; acrylic acid or sodium acrylate; a crosslinker; a photoinitiator; and a photoabsorber.

21. A hydrogel resin according to claim 20, comprising:14.7 wt% gelatin;11.2 wt% neutralisation agent;40 wt% acrylic acid or sodium acrylate;0.2 wt% crosslinker;0.25 wt% photoinitiator;0.05 wt% photoabsorber; up to 100% with water.

22. A hydrogel resin according to claim 20 or claim 21 , wherein the neutralisation agent is NaOH.

23. A hydrogel resin according to any one of claims 20-22, wherein:(i) the crosslinker is selected from N,N'-Methylenebis(acrylamide), PEGDA 250, PEGDA 575, PEGDA 700, PEGdMA 550 or PEGdMA 750;(ii) the photoinitiator is lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP); and / or(iii) the photoabsorber is tartrazine.

24. A hydrogel produced by photo-crosslinking the hydrogel resin according to any one of claims 20-23.

25. An expandable hollow hydrogel tube produced by bioprinting and photocrosslinking the hydrogel resin according to any one of claims 20-23.

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