Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L89/00—Compositions of proteins; Compositions of derivatives thereof
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF
  • A23L33/00—Modifying nutritive qualities of foods; Dietetic products; Preparation or treatment thereof
  • A23L33/10—Modifying nutritive qualities of foods; Dietetic products; Preparation or treatment thereof using additives
  • A23L33/17—Amino acids, peptides or proteins
  • A23L33/185—Vegetable proteins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
  • C08J3/03—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
  • C08J3/075—Macromolecular gels
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
  • C08L101/12—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity
  • C08L101/14—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity the macromolecular compounds being water soluble or water swellable, e.g. aqueous gels
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D189/00—Coating compositions based on proteins; Coating compositions based on derivatives thereof
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23V—INDEXING SCHEME RELATING TO FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES AND LACTIC OR PROPIONIC ACID BACTERIA USED IN FOODSTUFFS OR FOOD PREPARATION
  • A23V2002/00—Food compositions, function of food ingredients or processes for food or foodstuffs
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2389/00—Characterised by the use of proteins; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/02—Applications for biomedical use
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/14—Applications used for foams
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/16—Applications used for films

Definitions

• the present invention relates to plant based materials, methods for their manufacture and biomaterials incorporating plant based materials according to the present invention.
• Synthetic polymers such as plastic exhibit excellent mechanical and chemical properties and have been widely used during the last 60 years. However, these polymers are not biodegradable and can accumulate in the environment, causing economic damage, and likely affecting human health through the food chain and air.
• proteins are interesting candidates given their ability to self-assemble into functional structures.
• plant based proteins have not been successfully utilised as a biomaterial and it remains a challenge to generate structured protein materials from renewable and cost-effective sources, and with environmentally sustainable methods.
• a method to produce plant based materials comprising: a) forming a solution comprising one or more plant based protein(s) in a solvent system, wherein the solvent system comprises miscible co-solvents; wherein a first co solvent increases solubility of the plant based protein(s), and a second co-solvent decreases solubility of the plant based protein(s); and b) inducing the protein in the solution to undergo a sol-gel transition to form a plant- based protein hydrogel.
• the method includes the step: c) forming the plant-based protein hydrogel into a structured material.
• Forming the plant-based protein hydrogel into a structured material allows for the formation of structured materials, such as gels, films, microgels, microcapsules and the like.
• the protein hydrogel may be formed into a specified shape by molding.
• the protein hydrogel may be formed into a specified shape using a microfluidic device.
• the present invention has identified a novel method to manufacture functional materials from plant-based proteins.
• By utilising co-solvent mixtures it is possible to exert control over the sol-gel transition allowing for the formation of structurally robust materials from renewable plant protein sources.
• the process allows for the creation of many structured materials, including hydrogels, films, microcapsules, microgels, microscale-sponges and the like. Structured materials can be reliably formed without the need for cross-linkers or any other hazardous materials making them suitable for contact with the human body.
• the materials are also derived from renewable source so reduce the environmental impact over synthetic analogues.
• a solvent system comprises miscible co-solvents, wherein a first co solvent increases solubility of the plant based protein(s), and a second co-solvent decreases solubility of the plant based protein(s), it is possible to control the sol-gel conditions.
• the ratio of first co-solvent to second co-solvent may vary from about 20-80% v/v, about 20-60% v/v, about 25-55% v/v, about 30-50% v/v, about 20%, about 30%, about 40% about 50% or about 60% v/v, most preferably about 30-50% v/v. Such ratios lead to functionally useful materials.
• the solvent system may contain one or more first co-solvent(s) and/or one or more second co-solvent(s).
• plant-based materials can be reliably and reproducibly formed using a scalable process.
• sol-gel conditions it is possible to tune the properties of the resultant material and/or tune the manufacturing process to allow for the production of useful biomaterials.
• the process according to the present invention allows for the formation of plant-based structured materials formed via a thermoreversible cold-set gelation process.
• the plant-based structured materials may be plant-based protein supramolecular structures; or may be a 3- dimensional network of aggregated and entangled plant- based protein supramolecular structures.
• a thermoreversible cold-set gelation process may be considered a process wherein the plant-based protein molecules can be heated to above a temperature to form a liquid solution which can be processed into the desired configuration before cooling the liquid solution to enable a sol-gel transition forming a network of self-assembled protein aggregates held by non-covalent intermolecular interactions.
• the gelation process according to the present invention does not require covalent chemical cross- linking and is therefore reversible.
• a plant-based structured material formed via a thermoreversible cold-set gelation process; wherein the structured material may optionally be a film, a thin film, a micropatterned film (or thin film), a micro or nanostructured thin film, a microgel, a microcapsule, a microbead, a bioscaffold, a bio support, a sponge, a microscale-sponge, a hard capsule, or a functional coating.
• a composite material comprising a plant based material according to the present invention, and one or more further biopolymers, for example proteins, polysaccharides and the like.
• the plant based material of the present invention and the processes for manufacturing them allow for precise control of the sol-gel transition thereby opening the use of plant- based proteins to form biomaterials that, to date, have only successfully been manufactured using animal derived proteins.
• Suitable biomaterials include films, microbeads, microcapsules, scaffolds, gels, sponges and the like.
• microbead comprising a plant-based material according to the present invention.
• a microcapsule comprising a plant based material according to the present invention.
• a hard capsule comprising a plant based material according to the present invention.
• a sponge, or microscale-sponge comprising a plant based material according to the present invention.
• a film preferably a thin film, comprising a plant based material according to the present invention.
• nanopatterned or micropatterned film comprising a plant based material according to the present invention.
• bioscaffold comprising a plant-based hydrogel according to the present invention.
• a functional coating comprising a plant-based hydrogel according to the present invention.
• Figure 1 shows soy protein isolates (SPI) hydrogels formed under varying acetic acid / Dl water co-solvent ratios
• Figure 2 shows a SEM (Scanning electron microscopy) image of a hydrogel produced using a 30%v/v co-solvent ratio
• Figure 3a shows the rheological properties of SPI hydrogels as a function of H20:Acetic acid co-solvent ratios
• Figure 3b shows the shear thinning behaviour of SPI hydrogels prepared at different concentrations
• Figure 4 shows structural changes of SPI hydrogel secondary structure under different H20:Acetic acid co-solvent ratios, calculated from the amide I bands in the FTIR spectra;
• Figure 5 shows an SDS- PAGE electrophoretogram showing increasing degree of protein hydrolysis upon increasing amount of acetic acid
• Figure 6 shows microbeads formed using hydrogels of the present invention.
• 6a shows a schematic representation of microbead formation
• 6c shows Tht stained microbeads suspended in a 50pm Tht aqueous solution
• 6d shows SEM image of microbeads prepared by super-critical point drying
• 6e shows SEM image of the gel network on the surface of a microbead;
• Figure 7a shows a schematic representation of a multi-layer 3D microfluidic droplet generator used to generate core-shell microcapsules with both a lipophilic and a hydrophilic core
• Figure 7b shows core-shell microcapsules containing a lipophilic core suspended in aqueous solution
• Figure 8 shows core-shell microcapsules containing a hydrophilic core containing a suspension of a soluble active ingredient (Riboflavin);
• Figure 9 shows the results of simulated degradation with Figure 9a showing the microcapsules in aqueous solution; Figure 9b showing the microcapsules after 60 minutes in SGF (simulated gastric fluid); and Figure 9c showing the microcapsules after 120 minutes in SIF (simulated intestinal fluid);
• Figure 10a shows core-shell microcapsules containing a core comprised of a riboflavin solution in 1 % (w/w) FIMP pectin
• Figure 10b shows the results of a two-stage in vitro digestibility study following by FIPLC analysis showing cumulative release of riboflavin under simulated conditions
• Figure 1 1 a shows a distribution of fragrance-oil loaded plant-based protein microscale- sponges.
• Figure 1 1 b shows a single fragrance-loaded plant-based protein microscale- sponge at higher magnification (20x), where the protein microgel shell can be easily observed.
• Figure 12 shows a schematic representation of an example generating stable protein films
• Figure 13a shows stress-strain curves for films made according to the present invention
• Figure 13b shows Young’s Modulus
• Figure 13c shows elongation break %
• Figure 14a shows the micropatterning of a uniform array of micropillars on a soy protein film surface, which significantly increases the contact angle of a water droplet (99°) in comparison to a non-micropatterned control sample.
• Figure 14b shows the nanopatterning of a uniform array of nanochannels obtained by casting a soy protein film on a DVD disc. Nanostructured motifs on the soy protein film exhibit photonic properties (Mie scattering).
• Figure 15 shows a schematic process to produce soy protein film coatings on a cardboard substrate.
• the soy protein film coated substrate shows a 50% water-uptake decrease when compared to an uncoated control sample.
• Figure 16a shows the formation of a thin 3-dimensional hydrogel layer around a 2-ml Eppendorf tube substrate.
• Figure 16b shows a soy protein hard capsule obtained after drying the moulded 3-dimensional hydrogel and removing it from the substrate.
• Suitable plant sources include soybean, pea, rice, potato, wheat, corn zein, sorghum, and the like.
• Particular plant proteins include soy proteins and pea proteins.
• a feature of plant derived proteins is their inherent poor solubility in water. To date, this has limited their use in generating biomaterials. However, the present invention has overcome the previous limitations associated with such proteins.
• the material is formed by adding the plant-based protein into a solvent system, wherein the solvent system comprises two or more miscible co-solvents as defined herein.
• the first co-solvent increases solubility of the plant based protein(s).
• the first co solvent may be considered a solubilising co-solvent.
• solubilising co-solvents are organic acids.
• An organic acid is an organic compound with acidic properties. Suitable organic acids include acetic acid or an a- hydroxy acid. Suitable a-hydroxy acids include glycolic acid, lactic acid, malic acid, citric acid and tartaric acid. Preferred organic acids are acetic acid and lactic acid.
• Using an organic acid enables solubilisation of the plant protein and also allows for mild hydrolysis of the protein.
• the solubility of plant-based proteins in organic acid is possible due to: i) the protonation of proteins and ii) the presence of an anion solvation layer which contributes to a reduction of hydrophobic interactions. Once initially dissolved in organic acid, the protonation of plant-based proteins can help to stabilise them in its non-solvent, for example water.
• the first co-solvent is an organic acid.
• the second co-solvent has decreased solubility of the plant based protein(s), as compared to the first co-solvent.
• the second co-solvent may be considered a de- solubilising co-solvent.
• There may be one or more de-solubilising co-solvent(s).
• de-solubilising second co-solvent(s) are an aqueous buffer solution.
• the second co-solvent may be ethanol, methanol, acetone, acetonitrile, dimethylsulfoxide,dimethylformamide, formamide, 2-propanol, 1 -butanol, 1 - propanol, hexanol, t-butanol, ethyl acetate or hexafluoroisopropanol.
• the second co-solvent is water and ethanol.
• the second co-solvent is water.
• the concentration of plant based protein(s) in the solvent system is 25-200mg/ml, preferably 50-150mg/ml.
• the ratio of organic acid may vary depending on protein concentration, e.g. using a higher organic acid ratio with increasing protein concentration.
• the degree of protein hydrolysis is controlled to modify the properties of the resultant hydrogel. For example, increasing the acid concentration present during formation will increase the degree of protein hydrolysis. Higher degree of protein hydrolysis leads to the formation of less rigid hydrogels.
• Suitable physical stimulus includes ultrasonication, agitation, high-shear mixing or other physical techniques.
• a preferred technique is
• the solution is subjected to ultrasonication for a period of about 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, or greater than 30 minutes.
• a preferred ultrasonication time period is about 30 minutes.
• the protein solution is heated such that the liquid solution is held above the sol-gel transition for the protein(s).
• modifying the solvent system for example through selection of the choice of organic acid, the ratio of organic acid to further solvent or through further means
• the protein solution is heated to about or above 70 e C. In a further embodiment, the protein is heated to about or above 75 e C, about or above 80 e C, about or above 85 e C or about 90 e C. In a preferred embodiment, the protein is heated to 85 e C.
• the protein solution may be held at elevated temperature for a time period of about 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 45 minutes or 1 hour.
• a preferred time period is at least 30 minutes to enable the proteins to fully solubilise. It is possible to hold the protein solution at an elevated temperature for a longer period of time. This may be useful for a commercial batch process or for use in a fluidic processing step where it is necessary to retain the protein solution in liquid form for higher periods of time.
• the temperature of the protein solution can be reduced to a second
• the second temperature may be room temperature.
• the protein solution may be held at the reduced temperature for a time period of about 5 minutes, 10 minutes,
• the method of the present invention allows the protein to remain in solution for long periods of time.
• the protein solution can be kept above the sol-gel transition temperature for as long as required to retain the protein in liquid form. This could be hours, days or more.
• a solution could, for example be kept at a lower temperature (for example room temperature) where a hydrogel will form but thereafter heated to above the sol-gel transition temperature to return the solution to a liquid state for further processing. Protein hydrogels in this way could be stored for hours, days, weeks, months or years as the hydrogel remains stable for a long time.
• the particular temperatures will depend on the properties of the protein source, the solvent conditions used and therefore the sol-gel transition temperature.
• the elevated and reduced temperatures may be relatively fixed (for example about 85 e C then about room temperature) and the co-solvent mixture conditions are adjusted to ensure a suitable sol-gel transition temperature for the selected plant-based protein.
• a method for forming a plant based material comprising: a) forming a protein solution comprising one or more plant based protein(s) and a solvent system, wherein the solvent system comprises miscible co-solvents; wherein a first co-solvent increases solubility of the plant based protein(s), and a second co-solvent decreases solubility of the plant based protein(s);
• Said temperature elevation may be caused by the mechanical agitation in b) or may be from an external heat source;
• hydrogel into a defined shape, for example microgels
• the formation step may be a molding step, namely molding the hydrogel into a defined shape.
• the formation step may use a microfluidic device.
• the protein solution may be held at the elevated temperature in step c) while the solution is conformed to the desired final shape.
• the protein solution may be held at the elevated temperature c) within the device reservoir, but as the solution is expelled from the device its temperature reduces thereby forming a microgel or a microcapsule shell.
• the protein solution may be held at an elevated temperature while it is shaped in a suitable mould where after the temperature is reduced allowing the proteins to form into a hydrogel.
• the process of the present invention enables materials to be formed in which there are high levels of b-sheet intermolecular interactions. This leads to novel materials which have not previously been made.
• the present invention provides a plant-based structured material comprising a film, a thin film, a micropatterned film (or thin film), a micro or nanostructured thin film, a microgel, a microcapsule, a microbead, a bioscaffold, a bio-support, a sponge, a microscale-sponge, a hard capsule, or a functional coating.
• the materials according to the present invention have advantageous mechanical properties. For example, the ability to reversibly change from gel to liquid upon temperature change enables advantageous manufacturing capabilities.
• the hydrogels produced according to the present invention have a storage modulus (G’) at 10rad/s of greater than 500Pa, greater than 1000Pa, greater than 2500Pa, greater than 3000Pa, greater than 4000Pa.
• G storage modulus
• the hydrogels exhibit shear-thinning behaviour, where the viscosity decreases upon increasing shear rates.
• hydrogels formed according to the present invention have unique properties not seen in prior plant based hydrogels. These include the ability of forming hydrogels from plant-based proteins at high concentrations (i.e. 5%- 15% w/w) from commercially available sources, and the ability of keeping such highly concentrated protein solutions in the liquid state upon heat denaturation, which enables their moulding into well- defined objects.
• a feature of the materials of the present invention is that it is not necessary to provide cross-linking agents as the plant proteins will self-form hydrogels.
• a plant protein material for example a hydrogel which does not contain or does not substantially contain a cross-linking agent.
• the hydrogels according to the present invention may comprise a cross-linking agent.
• Suitable cross-linking agents include microbial transglutaminase, glutaraldehyde, formaldehyde, glyoxal, phenolic compounds, epoxy compounds, genipin or dialdehyde starch.
• the solvent mixture within the hydrogel can be exchanged for another solvent mixture without compromising the mechanical stability of the hydrogel.
• a solvent-exchange process can be performed to remove the organic acid from the hydrogel porous network.
• the method includes the step of exchanging the solvent system in which the plant-based protein hydrogel has formed for an alternative solvent system. In a further embodiment, this is performed using a solvent- exchange process. This step may be carried out after formation of the hydrogel but may be carried out after the hydrogel has been formed into a structured material (e.g. after step b) or c) of the method of the present invention). In a preferred embodiment, an aqueous buffer is used to replace an organic acid co-solvent mixture within the hydrogel porous network.
• the solvent mixture within the hydrogel is left to evaporate to generate dried materials, such as thin films, microstructured/nanostructured thin films or microbeads.
• one or more co-solvent(s) in the solvent system is a volatile solvent.
• the first co-solvent is a volatile organic acid, such as acetic acid.
• the second or further co- solvent(s) is a volatile alcohol, such as ethanol.
• both the first co-solvent and second or further co-solvent(s) are volatile solvents.
• the materials of the present invention can incorporate one or more plasticizers.
• plasticizers include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, sorbitol, mannitol, xylitol, fatty acids, glucose, mannose, fructose, sucrose, ethanolamine, urea, triethanolamine,; vegetable oils, lecithin, waxes and amino acids.
• the amount of plasticizer to be incorporated will depend on the use of the material, for example a film.
• the composition may comprise about 1 % plasticiser, about 2%, about 5%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60% or more.
• the hydrogel may comprise between about 5-50% plasticiser, about 10-50%, about 20-40% about 15-35% or about 20% plasticizer.
• Adding a plasticizer can influence the mechanical properties of the material. Typically, adding a plasticiser will increase the elasticity of the material but this typically conversely reduces the strength of the resultant material.
• the hydrogels of the present invention allow for the formation of a range of useful plant based biomaterials.
• Using plant based materials has a number of advantages over previously used animal or petrochemical sources. Firstly, plant sources are renewable and can be efficiently obtained in an environmentally efficient manner. Secondly, plant sources are biodegradable and are therefore an environmentally sound alternative to other plastics. Thirdly, in contrast to animal derived proteins, plant based proteins have the significant advantage that they do not introduce animal derived proteins into a human. This has positive impacts both from a pharmacological and pharmaceutical perspective where animal sourced material must undergo stringent checks and processes to ensure no adverse elements are present (for example removing prions and the like); but also because the products are suitable for vegetarian/vegans.
• biomaterials made according to the present invention exhibit a higher degree of digestibility compared to other biopolymers such as polyscahharides (for example, alginates or chitosan). This makes them particularly suitable for pharmaceutical, food and/or cosmetic use.
• the hydrogels of the present invention can be used to form films, for example thin films.
• Plant protein derived films have many applications including forming biodegradable flexible films for food packaging applications or for use with medical devices including implantable devices.
• Films may have a typical thinness of 1 -1000 pm, 1 -100 pm, 10-100 pm, 20-60 pm, 30- 50 pm and the like.
• Films may have a Young’s modulus over 20MPa, over 50MPa, over 80MPa, over 100MPa, over 200MPa, over 300MPa, over 400MPa, over 500MPa, over 600MPa or more.
• Films may have an elongation break percentage of above 10%, above 20%, above 30%, above 40%, above 50%, above 60%, above 70%, above 80%, above 90%, above 100% or more.
• Films can be micropatterned with features ranging from 100nm to 1000pm, enabling novel functional properties such as: superhydrophobicity (lotus-leaf effect) or structural colour (attributed to Mie scattering).
• Functional composite films can be produced by embedding inorganic nanoparticles, such as gold nanoparticles or silver nanoparticles, for the generation of flexible electronics or films with antibacterial properties, respectively.
• the hydrogels of the present invention can be used to form microbeads.
• Forming microbeads from a plant-based source overcomes the environmental issues with current plastic based microbeads.
• Microbeads are typically solid particles with a diameter of less than one millimetre in their largest dimension.
• the microbeads according to the present invention have a size of less than 1 mm in the largest dimension, less than 900 pm, less than 800 pm, less than 700 pm, less than 600 pm, less than 500 pm, less than 400 pm, less than 300 pm, less than 200 pm, or less than 100 pm.
• the hydrogels of the present invention can be used to form microcapsules.
• Microcapsules can be used to encapsulate a variety of substances and find various industrial applications, including in cosmetics, food use, household product use, agrochemical use and pharmaceutical use.
• Microcapsules made according to the present invention provide a completely biodegradable alternative to standard synthetic polymers microencapsulation shell materials.
• Microcapsules made according to the present invention uniquely enable plant-based materials to assemble microfluidically.
• Microcapsules made according to the present invention provide, for example, excellent stability against adverse storage conditions, and become a safer food- or pharmaceutical-grade solution to preserve active ingredients, for example vitamins, essential fatty acids or antioxidants in food use or pharmaceutical active agents including both small and large molecules.
• active ingredients for example vitamins, essential fatty acids or antioxidants in food use or pharmaceutical active agents including both small and large molecules.
• Microcapsules made according to the present invention also may have the advantage that they can be generated using microfluidic technologies, ensuring high reproducibility, the ability to generate complex structures (core-shell) and/or can be made using mild-processing conditions thereby protecting the active agent they encapsulate.
• Robust microcapsules may also be generated from plant-based proteins by controlling the self-assembly of protein aggregates in the absence of cross-linkers or any other hazardous substances.
• microcapsules according to the present invention may encapsulate a hydrophobic inner composition. In a further embodiment, microcapsules according to the present invention may encapsulate a hydrophilic inner composition. In a further embodiment, microcapsules according to the present invention may encapsulate a live organism composition. In a further embodiment, microcapsules according to the present invention may encapsulate a powdered composition. In a yet further embodiment, microcapsules according to the present invention may encapsulate an oil- in-water, water-in-oil, oil-in water-in oil, or water-in-oil-in water emulsion and the like.
• the plant-based hydrogels according to the present invention can form the microcapsule shell.
• the shell may have a thickness of about 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1 pm, 2pm, 3pm, 4pm, 5pm, 6pm, 7pm, 8pm, 9pm, 10 pm, 1 1 pm, 12 pm, 13 pm, 14 pm, 15 pm, 16 pm, 17 pm, 18 pm, 19 pm, 20 pm, 25 pm, 30 pm, 30 pm, 35 pm, 40 pm, or 50 pm and the like.
• Further thicknesses include between 10nm-50000pm, between 10pm-100pm, between 10pm-50pm, between 10pm-10pm and the like.
• Plant based microcapsules according to the present invention may encapsulate any nutraceutical, cosmetic, pharmaceutical or agrochemical suitable active agent including vitamins, essential fatty acids, antioxidants, small molecules, hydrophilic small molecules, hydrophobic small molecules, proteins, antibodies, antibody-drug conjugates, fragrances and other large molecules.
• Suitable encapsulated agents include one or more agents selected from: cross-linkers, hardeners, organic catalysts and metal-based catalysts (for example organo-complexes and inorgano-complexes of platinum, palladium, titanium, molybdenum, copper, or zinc) for polymerization of elastomer formulations, rubber formulations, paint formulations, coating formulations, adhesive formulations, or sealant formulations; dyes, colorants, pigments for inks, personal care products, elastomer formulations, rubber formulations, paint formulations, coating formulations, adhesive formulations, sealant formulations, or paper formulations; fragrances for detergents, housecleaning products, personal care products, textiles (so-called smart textiles), coating formulations.
• cross-linkers for example organo-complexes and inorgano-complexes of platinum, palladium, titanium, molybdenum, copper, or zinc
• metal-based catalysts for example organo-complexes and inorgano-complex
• Fragrances useful to the invention are any of the compounds belonging to the list of standards published and updated by the International Fragrance Association (IFRA); aromas, flavors, vitamins, aminoacids, proteins, essential lipids, probiotics, antioxidants, preservatives for feed and food products; fabric softeners and conditioners for detergents and personal care products;. bioactive compounds such as enzymes, vitamins, proteins, vegetable extracts, moisturizers, sanitizers, antibacterial agents, sunscreen agents, drugs, for personal care products, textiles (so-called smart textiles).
• IFRA International Fragrance Association
• These compounds include but are not limited to vitamin A, vitamin B, vitamin C, vitamin D, vitamin E, para aminobenzoic acid, alpha hydroxyacid, camphor, ceramides, ellagic acid, glycerin, glycin, glycolic acid, hyaluronic acid, hydroquinone, isopropyl, isostearate, isopropyl palmitate, oxybenzone, panthenol, proline, retinol, retinyl palmitate, salicylic acid, sorbic acid, sorbitol, triclosan, tyrosine.; and fertilizers, herbicides, insecticides, pesticides, fungicides, repellents, and disinfectants for agrochemicals.
• Plant based microcapsules according to the present invention may also be useful in diagnostics and high-throughput screening.
• Microgels are micro scale hydrogels.
• Microscale-sponges may be considered to be microgels which are loaded with a substance, for example an active or ingredient.
• Plant based hydrogels according to the present invention may also be useful in manufacturing bio-scaffolds and bio-supports. Such materials may be useful both in- vitro and in-vivo to grow cells and tissue.
• the hydrogels may also be useful in coating medical devices and implants.
• the plant-based proteins according to the present invention may be functionalised and/or derivatised to change the properties of the protein.
• SPI Soy protein isolate
• Glycine max (-)-Riboflavin, glycerol and PFO (1 H,1 H,2H,2H-Perfluoro-1 -octanol) were purchased from Sigma Aldrich. Pectin was kindly provided by Cargill.
• FC-40 Fluorinert
• Self-standing hydrogels were prepared according to the following process.
• thermoreversible gel A plant-based thermoreversible gel has therefore been prepared for the first time.
• Soy protein hydrogels and microgels were dehydrated in ethanol using 100% dry ethanol at the last step. Samples were transferred to microporous specimen capsules (78 pm pore size, Agar Scientific) soaked and part-filled with 100 % dry ethanol to prevent the sample from drying during transfer. Then, samples were critically point dried using a Quorum E3100 critical point dryer using 4-5 flushes with liquid C0 2 and at least 15 min incubation between each flush. Samples were mounted on aluminium SEM stubs using conductive carbon sticky pads (Agar Scientific) and coated with 15 nm iridium using a Quorum K575X sputter coater.
• Samples were viewed using a FEI Verios 460 scanning electron microscope run at 2 keV and 25-50 pA probe current. Secondary electron images were acquired using either an Everhard- Thornley detector in field-free mode (low resolution) or a Through-Lens detector in full immersion mode (high resolution).
• Example 1 For characterisation of the rheological properties of SPI hydrogels, the samples produced via Example 1 were left to cool down at RT for 1 h, and then kept at 4 e C for 12h.
• Rheological measurements were performed using an ARES controlled strain rheometer. Tests were carried out using 25mm smooth parallel plates at a temperature of 20 e C. The strain and frequency sweeps were carried out on SPI hydrogel samples containing increasing amounts of acetic acid. The strain sweeps were carried out using a frequency of 10 rad/s from 0.01 to 100% strain. The frequency sweeps were carried out using a strain of 1 % (within the linear viscoelastic region) from 0.1 to 100 rad/s. All rheological measurements were performed under temperature control (20 ⁇ 0.25 e C).
• Lactic acid was mixed with deionised water at different ratios (10%v/v, 30 %v/v, 50 %v/v, 70 %v/v and 90%v/v).
• Soy protein isolate was added to the Dl water/lactic acid solution at a final protein concentration of 100 mg/ml. A dispersion of non-soluble protein was obtained.
• Microfluidic devices were fabricated using standard soft lithography techniques with a negative master photoresist (SU8 3050).
• the continuous oil phase (2% 008-FluoroSurfactant in Fluorinert FC-40) was loaded in a 2ml tube, whilst the dispersed liquid SPI phase (85mg/ml SPI in 40% v/v acetic acid, kept at 85 e C) was loaded in a 1.5ml tube and rapidly placed on a heating block at 85 e C.
• a custom-made silicone heater (Holroyd Components), comprising a 1/32” ID stainless steel tubing was used to maintain the temperature of the PTFE tubing connecting the SPI reservoir and the inlet in the microfluidic device.
• the silicon heater temperature was controlled by a custom-built temperature controller. Droplets of -100 pm diameter were generated by pumping both solutions into a standard flow-focusing droplet generator by a pressure-driven system (Elveflow OB1 ). Different pressure rates were tested until achieving a uniform and continuous generation of a monodisperse population of microdroplets.
• Final pressure rates were 175 mbar for the dispersed aqueous phase and 200mbar for the continuous oil phase.
• the generated droplets were collected in a 1 ml pipette tip, and were kept at room temperature for 12h to ensure the gelation process was complete.
• the formed microgels were then washed by a standard de-emulsification procedure: the continuous oil phase containing fluorosurfactant was first removed from the vial. For 500ul of microgels, an equal volume of 10% PFO solution in Fluorinert FC-40 was added and thoroughly mixed for 30 seconds. The 10% PFO solution in Fluorinert FC-40 was then removed and two subsequent oil washes were performed by adding an equal volume of pure Fluorinert FC-40.
• microgels suspended in deionised water were obtained after the final washing step.
• the microgels were washed with 100% ethanol in a 3 step procedure: the microgels were first suspended in a 25% v/v ethanol-aqueous solution and left under constant agitation (100rpm) for 3h. After centrifugation and removal of the supernatant, the microgels were then re-suspended in a 50% v/v ethanol-aqueous solution and left under constant agitation (100rpm) for 3h. Finally, after centrifugation and removal of the supernatant, the microgels were then re-suspended in a 100% v/v ethanol-aqueous solution and left under constant agitation (100rpm) for 12h.
• Figure 6a shows a schematic representation of microbead formation.
• Figure 6d shows SEM image of microbeads prepared by super-critical point drying.
• Figure 6e shows SEM image of the gel network on the surface of a microbead.
• microgels were stable in aqueous solution under acidic conditions, as well as in the presence of 100% ethanol. Once self-assembled, the protein aggregates are completely insoluble in solution, hence the stability of the microgels.
• Two SU8 photoresist masters were required.
• a 25 pm photoresist layer was fabricated for the inner channel, followed by a 50 pm layer for the medium channel and a 75 pm layer for the outer channel.
• the second master contained a 25 pm layer for the medium channel and a 50 pm layer for the outer channel.
• To fabricate the final coaxial flow-focusing device two different PDMS slabs were peeled off from the masters, and were subsequently aligned and bonded by plasma oxidation. A small amount of sprayed water droplets was placed between the two PDMS slabs after plasma oxidation to allow the alignment of the microfluidic channels. The final aligned PDMS device was baked in the oven at 65 e C overnight to complete the bonding between the two layers.
• microfluidic process to generate core-shell microcapsules was equivalent to the one employed in Example 3 to generate microbeads. However, an additional inlet for the inner phase (core) was added to the system.
• core an additional inlet for the inner phase
• 450 pi of soybean oil were pre-emulsified in 550 pi SPI protein solution (20mg/ml, 30% v/v acetic acid).
• the soybean oil-in-water emulsion (inner phase), SPI solution (85mg/ml, 40% v/v acetic acid, middle phase) and FC-40 (2% v/v 008-Fluorosurfactant, outer phase) were pumped to a coaxial flow focusing microfluidic device by a pressure-driven system (Elveflow OB1 ).
• Elveflow OB1 a pressure-driven system
• Different pressure rates were tested until achieving a uniform and continuous generation of a monodisperse population of core-shell microcapsules with -120 pm diameter (Pressure Inner phase (100 mbar), Pressure Middle Phase (150mbar) and Pressure Outer Phase (l OOmbar).
• the core-shell ratio could be adjusted by simply controlling the relative pressure between the inner and the middle phase.
• the microcapsules were collected and subsequently washed as described in the previous section.
• the inner core materials are kept separate in this example to the shell materials, which is different to a standard microencapsulation matrix approach where the active ingredients are previously mixed with the matrix materials.
• the reason for this approach was the pH of the starting protein solution being very low due to the high amount of acetic acid initially present, and also the high temperatures required to keep the protein solution in a liquid state.
• a 3-D coaxial microfluidic device was used that allowed for easy production of the core-shell structures without compromising the stability of the encapsulated ingredients.
• FIG. 7a A schematic representation of the microfluidic droplet generator is shown in Figure 7a, showing a 3D flow-focusing microfluidic device.
• Core-shell microcapsules produced according to the present invention containing a lipophiliccore suspended in an aqueous solution are shown in Figure 7b.
• the microcapsule shell solely comprises self- assembled SPI proteins and the core is an oil-in water microemulsion (lipophilic).
• Example 5 core-shell microcapsule fabrication encapsulating an active agent
• Example 4 The microfluidic process described in Example 4 was repeated to generate a microcapsule comprising a hydrophilic core.
• the core comprised a 1 % (w/w) HMP pectin solution containing a suspension of a soluble active ingredient (Riboflavin).
• Core-shell microcapsules made according to the present invention containing a hydrophilic core suspended in an aqueous solution are shown in Figure 8.
• the microcapsule shell solely comprises self-assembled SPI proteins and the core is a hydrophilic suspension of an active agent, in this case riboflavin.
• the protein shells are solely comprised of protein aggregates, an experiment was carried out to confirm that the release of the cargo can be triggered by the degradation of the protein shell in the presence of digestive enzymes, via a two-stage in vitro digestibility test.
• a 1 L stock solution of SGF (simulated gastric fluid) electrolyte solution was prepared by dissolving 0.257g KCI, 0.061 g KH2P04, 1 .05g NaHC03, 1 .38g NaCI, 0.122g MgCI2(H20)6, and 0.024g (NH4)2C03 in 11 of deionised water.
• a 11 stock solution of SIF (simulated intestinal fluid) electrolyte solution was prepared by dissolving 0.253g KCI, 0.054g KH2P04, 3.57g NaHC03, 1 .12g NaCI, 0.335g MgCI2(H20)6, 0.44g CaCI2-2FI20 and 0.23g of bile extract in 1 I of deionised water.
• pancreatin For the simulated intestinal phase, 3mg of pancreatin were dissolved in 1 ml of SIF electrolyte solution. 400 mI of SIF were added to the previous microcapsule in SGF solution. The pH was adjusted to 7 by adding a small amount of 1 M NaOFI.
• Microcapsules were then incubated at 37 e C for 120min.
• microcapsules remained intact under simulated gastric conditions but rapidly disintegrated under simulated intestinal conditions demonstrating that the microcapsules according to the present invention can be used for controlled delivery of nutraceutical or pharmaceutical active ingredients.
• Example 7 controlled release microcapsules including an active agent
• Example 6 The experiment of Example 6 was repeated but using microcapsules containing a hydrophilic core containing the active agent riboflavin made according to Example 5.
• Riboflavin microcapsules are shown in Figure 10a (i.e. microcapsules with a hydrophilic core (1 % FIMP pectin + Riboflavin).
• Figure 10b shows the results of a two-stage in vitro digestibility study following by HPLC analysis showing cumulative release of riboflavin under simulated conditions. It can be seen that there is a controlled release of riboflavin under simulated gastric and small intestine conditions, enabled by the encapsulation of the hydrophilic active ingredient within a plant-based protein microcapsule shell.
• Encapsulation is shown to prevent the rapid diffusion of riboflavin and promotes controlled release.
• Soy protein microscale-sponges were prepared according to the present invention.
• the microfluidic process described in Example 2 was repeated to generate soy protein microgels (100miti in diameter).
• the microgels were washed with 100% ethanol in a 3 step procedure: the microgels were first suspended in a 25% v/v ethanol-aqueous solution and left under constant agitation (100rpm) for 1 h. After centrifugation and removal of the supernatant, the microgels were then re-suspended in a 50% v/v ethanol-aqueous solution and left under constant agitation (100rpm) for 1 h.
• the microgels were then re suspended in a 100% v/v ethanol-aqueous solution and left under constant agitation (1 OOrpm) for 1 h. At this point, ethanol should have completely replaced water within the microgel porous network.
• the microgel suspension was centrifuged (l OOOrpm, 1 min) and the ethanol supernatant was removed. Then, 250mI of geranium oil (Natural) were added to the microgels.
• the microgels were suspended in the oil solution by gently shaking the Eppendorf vial. At this stage, the ethanol-miscible oil phase permeated the microgel porous network. After addition of 500mI of deionised water to the oil-microgel suspension, oil-loaded SPI microscale-sponges were then transferred into the aqueous phase. The remaining oil phase was removed from the Eppendorf tube.
• Figure 1 1 a shows a distribution of fragrance-oil loaded plant-based protein microscale- sponges.
• Figure 1 1 b shows a single fragrance-loaded plant-based protein microscale- sponge at higher magnification (20x), where the protein microgel shell can be easily observed.
• water immiscible solvents can be loaded into plant-based protein microscale-sponges, such as fragrance oils.
• This method enables high-loading efficiencies without the need of using complex microcapsule generation approaches, such as core-shell architectures.
• the solution was cast into a glass petri dish to form a hydrogel (2mm thickness).
• the glass petri dish was heated around 100 C to avoid any gelling during the casting process.
• the glass dish was then removed from the heating plate and air-dried overnight. After drying, the thin film was removed from the glass petri dish and stored in a 50% humidity chamber until further use.
• the bottom surface of the glass petri dish was coated with Teflon sheet so that the films could be peeled off easily.
• the tensile properties of the thin films generated in Example 9 were tested as a function of the amount of plasticizer added. Films were manufactured using 10%, 20%, 30%, 40% and 50% (w/w) glycerol.
• Tensile properties of the film were tested using a Tinius Olson 5 kN with 10 N load cell.
• the film was cut into slips with 5 mm width and both ends of the films were glued with a paper holder which has a gap length of 1 mm.
• the holder and film were mounted to the mechanical testing machine and then the paper folder was cut prior to the
• Example 10 microstructure and nanostructure patterning
• Films made according to Example 9 were micro patterned according to the process below.
• a negative pattern of a 20pmx20pm array of micropillars was fabricated on a silicon wafer through standard photolithographic techniques using SU-8 3025 as a photoresist.
• a mixture of Polydimethylsiloxane elastomer and curing agent (Sylgard 184, Dow Corning) in a 10:1 ratio was poured onto the wafer and cured at 65 °C for 1 hour.
• the cured PDMS was peeled off from the wafer and used as a negative pattern for the soy protein film.
• the SPI thin film was peeled off the PDMS master and the resulting micropatterned structures were observed using scanning electron microscopy (SEM) with a 10 nm coating of platinum (MIRA 3 FEG-SEM, TESCAN).
• SEM scanning electron microscopy
• MIRA 3 FEG-SEM platinum
• TESCAN TESCAN
• the contact angle of the film was measured using a FTA1000B, First Ten Angstroms.
• the patterned PDMS was peeled off from the DVD substrate, and a film-forming soy protein solution as prepared in Example 9 was cast on the PDMS substrate and dried at room temperature overnight.
• the SPI thin film was peeled off the PDMS master and the resulting nanopatterned structures were observed using scanning electron microscopy (SEM) with a 10 nm coating of platinum (MIRA 3 FEG-SEM, TESCAN).
• SEM scanning electron microscopy
• MIRA 3 FEG-SEM, TESCAN platinum
• Example 9 in the absence of plasticisers. After dipping the cardboard in the film forming solution for approximately 5 seconds, the cardboard was removed from the solution and air-dried at room temperature overnight. After complete drying, the protein-coated cardboard was immersed in 10 mL of deionsed water to measure the cardboard’s water uptake. The water uptake was calculated by measuring the weight increase of the cardboard when immersed in deionised water at different time intervals.
• the non-coated cardboard control sample exhibits a very high-water uptake after immersion for 10 seconds in water.
• the amount of water uptake in the SPI-coated carboard was reduced by almost 50% compared to the uncoated control sample or the cardboard sample coated with a Soy protein solution prepared under alkaline conditions, which also exhibited a very low water resistance.
• Sey pretein hard capsules were manufactured acccrding tc the present inventicn.
• a 100mg/ml SPI scluticn was first prepared by dissclving 5g cf SPI intc 50ml cf an aquecus scluticn ccntaining acetic acid (40%v/v).
• the pretein dispersicn was heated at 95 °C fer 30 min, fcllcwed by expesure tc ultrascnicaticn fer 5 min (High-Frequency
• the scluticn was kept at 85 °C to prevent gelation.
• a 2 ml Eppendorf tube was dipped into the heated solution, then kept into the liquid solution for 5 seconds and subsequently removed.
• a thin layer of SPI hydrogel formed around the outer surface of the 2ml Eppendorf tube within seconds after removing it from the liquid SPI solution ( Figure 16a).
• the vial was then placed in an oven at 45 °C for one hour to ensure the evaporation of the water/acetic acid solvent fraction within the hydrogel layer to generate a 3-dimensional thin film.

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