This application claims the benefit of Taiwan Patent Application No. 110121760, filed Jun. 15, 2021, which is incorporated by reference herein in its entirety.
The present invention relates to a photopolymerized hydrogels blended composition. The hydrogels blended composition of the present invention can be repeatedly mixed with other uncrosslinked materials to adjust the colloidal properties. The polymerized hydrogels blended composition of the present invention can be applied to biomaterials for wound repair, three-dimensional cell culture, personal nursing care, health care, medical and pharmaceutical applications.
Hydrogels are colloidal polymers that swell in water, with characteristics such as high water content and high porosity, and can be applied to simulate natural biological tissues as synthetic biological materials, such as wound dressings, contact lenses, tissue engineering, hygiene products, drug delivery systems, biological drug carriers.
One of the gelation mechanisms of hydrogels is polymerization by crosslinking the functional groups of hydrophilic monomers with each other.
Another gelation mechanism of hydrogels is polymeric crosslinking of colloidal functional groups through the continuous reaction of free radicals, such as photopolymerization.
The crosslinking of hydrogel colloids can be regulated by changing environmental factors, such as changing the temperature, ionic strength, acid-base (pH) value of the colloids, thereby changing the bonding state of the colloids. These environmental factors also further affect the porosity and mechanical properties of the colloids
Clinically, hydrogel colloids can be used in wound dressing for drug delivery or cell therapy.
The clinical application of hydrogels for wound dressing can be covering the wounds with gels fabricated in advance, or by applying a hydrogel prepolymer solution to the wounds, and then polymerizing the gel. The latter is more potential for clinical application, because it provides better matching of the wound shape, and allows on-site customization easily of the dressing content.
However, commercially available photopolymerized hydrogel prepolymers suitable for cell therapy all have the problems of low viscosity and low yield stress at physiological temperature, and are prone to flowing away when applied to intestinal walls, blood vessels, or wounds on the non-horizontal side or uneven surface.
The present invention discloses a hydrogels blended composition comprising: a hydrogel prepolymer comprising a photopolymerizable monomer and a photopolymerizable gel-forming component, wherein the photopolymerizable monomer and the photopolymerizable gel-forming component have not undergone photopolymerization reaction; a crosslinked hydrogel polymer, wherein the crosslinked hydrogel polymer refers to the hydrogel polymer produced by the photopolymerization reaction of the hydrogel prepolymer and a photoinitiator; and the photoinitiator.
The present invention discloses a method of preparing a hydrogels blended composition, comprising: providing a colloidal mixture, wherein the colloidal mixture comprises a hydrogel prepolymer comprising a photopolymerizable monomer and a photopolymerizable gel-forming component, wherein the photopolymerizable monomer and the photopolymerizable gel-forming component have not undergone photopolymerization reaction, and a crosslinked hydrogel polymer, wherein the crosslinked hydrogel polymer refers to the hydrogel polymer produced by the photopolymerization reaction of the hydrogel prepolymer and a photoinitiator; and irradiating the colloidal mixture with the light of a wavelength capable of photopolymerization, so that the colloidal mixture undergoes photocrosslinking polymerization to form a hydrogels blended composition.
The photoinitiator of the present invention refers to the photoinitiator with crosslinking activity that remains in a partially crosslinked hydrogel polymer. Additional photoinitiators can also be added.
Present invention discloses a hydrogels blended composition with high viscosity, high yield stress, good water absorption, and high cytocompatibility, which can significantly increase the viscosity, cohesion, and adhesion of the blended fluids at physiological temperature. Therefore, it can be applied to, including but not limited to, the repair, fixation, support, cell culture, and the carrier for biomaterials delivery, etc, of wounds on inclined and curved surface.
The hydrogels blended composition of the present invention contains functional groups that are still photopolymerizable, such as methacrylic groups and methacrylate groups, and still active photoinitiato. After the freeze-dried powder of the composition is mixed with an aqueous solution containing or not containing a photoinitiator, the mixture is irradiated with the light of the wavelength absorbed by the photoinitiator to solidify the mixture into a gel.
The partially crosslinked hydrogels blend composition is formed by mixing the hydrogels blend composition with a photoinitiator and irradiating with the light of a specific wavelength to initiate crosslinking polymerization.
The specific wavelength of the light for irradiation is determined by the characteristics of the photoinitiator, and the irradiation time can also be adjusted.
The partially crosslinked hydrogels blended composition after photocrosslinking photopolymerization can be further freeze-dried into colloidal granular powder, which has commercial value, expanded usage, and extended shelf life.
The granular powder can be prepared by photomask or microfluidic molding during photopolymerization, or by electrospinning into nanoparticles before photopolymerization, followed by freeze drying; or grinding the whole block freeze-dried hydrogels blended composition into powder.
The freeze-dried colloidal powder is easy to store. Since the active photoinitiators still remains in the colloidal powder, and it already contains functional groups that can undergo photopolymerization, a hydrogel can be formed again by dissolving the colloidal powder in an aqueous solution and irradiation with the light of specific wavelength corresponding to a specific photoinitiator.
The present invention discloses a recrosslinkable hydrogels blended composition comprising: a crosslinked hydrogel polymer, wherein the crosslinked hydrogel polymer refers to the hydrogel polymer produced by photopolymerization of a hydrogel prepolymer and a photoinitiator; and a buffer, wherein the crosslinked hydrogel polymer comprises a photoinitiator.
The present invention discloses a method of preparing a recrosslinkable hydrogels blended composition comprising: providing a crosslinked hydrogel polymer and a buffer, wherein the crosslinked hydrogel polymer refers to the hydrogel polymer produced by photopolymerization of a hydrogel prepolymer and a photoinitiator; and a buffer; dissolving the crosslinked hydrogel polymer in the buffer, followed by irradiating with light at a wavelength capable of photopolymerization to induce the photopolymerization crosslinking reaction of the crosslinked hydrogel polymer dissolved in the buffer to form a re-crosslinked hydrogel blended composition.
The partially-crosslinked hydrogels blended compositions of the present invention can be applied to wound repair, including but not limited to wounds on body surface, deep wounds such as those on intestinal walls, blood vessels, and the non-horizontal or curved wounds.
The wound dressing solution of the present invention obtained by mixing with the freeze-dried hydrogel powder can solve the above-mentioned problem of easy loss of the solution when coated on the wound due to its increased viscosity and yield stress.
In addition to being photocrosslinking with a hydrogel prepolymer by mixing with the prepolymer and another irradiation of the mixture, the freeze-dried hydrogel powder of the present invention can also be directly added to an aqueous solution of specific biological products. After mixing thoroughly, the mixture can be directly injected into the treatment target, which can be used as a therapeutic agent for repairing wounds or diseased tissue, cultivating three-dimensional cells, and improving the viscosity of biological products.
Aqueous solutions of biological products comprise pharmaceuticals, physiological saline, dextrose water injection, cell suspensions, exosomes, platelet-rich plasma, or mixtures of the above and a photopolymerizable hydrogel prepolymers solution, etc.
In detail, the aqueous solution of biological product and the freeze-dried hydrogel powder of appropriate percentage by weight are placed into an empty syringe. After thoroughly mixing, the mixture is pushed to the treatment target such as wound or diseased tissue by a plunger.
The term “appropriate percentage by weight” refers to a weight percentage that can increase the viscosity and yield stress of the mixture while maintaining considerable fluidity, in order to facilitate the smearing and retention of the mixture at the treatment target.
Through the above mixing steps, the viscosity, fluidity, and yield stress of the mixture can be adjusted to facilitate smearing, retention, or injection at the target, and the above-mentioned mechanical properties can be adjusted according to the condition of the treatment target.
Because the dried granular powder of the present invention has colloidal properties and also contains a photoinitiator, it can be re-gelled by photocuring.
In addition, the freeze-dried powder is easy to store, and already contains functional groups that can undergo photopolymerization, as well as photoinitiators that can still be activated, which can be used for making gels.
Therefore, the mixture after smearing can be photocured by irradiating with light of a wavelength absorbed by the photoinitiator in the powder.
The above photopolymerizable hydrogel prepolymer can be the same hydrogel component as the freeze-dried hydrogel powder, or a combination with other hydrogel prepolymers.
Through the above re-polymerization, the mechanical properties of the hydrogel such as the hardness can be adjusted, thus facilitating the colloid to engage with the target surface and conform to its geometry.
The freeze-dried hydrogel powder can also be mixed with a cell suspension and placed into a cell culture equipment, followed by being irradiated with the light of a wavelength absorbed by the photoinitiator in the powder to solidify for three-dimensional cell culture.
Due to the biocompatibility of the hydrogel colloidal polymers, the colloidal components that can undergo colloidal polymerization include but not limited to the following components: gelatin methacryloyl (GelMA), methacrylated hyaluronic acid, dextran-methacrylate, carboxymethylcellulose-methacrylate, 2-hydroxyethyl methacrylate, chitosan-gelatin methacrylate, methacrylated hydroxylbutyl chitosan, poly(ethylene glycol)methacrylate, poly(ethylene glycol)dimethacrylate, poly(ethylene glycol)diacrylate, carboxybetaine methacrylate, pullulan methacrylate, hyaluronic acid glycidyl methacrylate, 2-hydroxyethly methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, sulfobetaine methacrylate.
In a preferred embodiment, the partially crosslinked colloidal polymer in the hydrogel of the present invention is composed of a photopolymerized gelatin methacryloyl (GelMA) polymer composed of gelatin and methacrylic anhydride.
In an embodiment of the present invention, the photopolymerizable monomer may be: gelatin, dextrin, carboxymethyl cellulose, hydroxyethyl methacrylate, hyaluronic acid, amylopectin, ethylene glycol, carboxybetaine, 2-hydroxyethyl ester, 2-hydroxypropyl ester, glycidyl ester, sulfobetaine, or a combination thereof.
In an embodiment of the present invention, the photopolymerizable gel-forming component may be: methacrylic anhydride, methyl acrylate, methacrylic acid, methacrylic ester, hyaluronic acid sodium salt, dextrin, carboxymethyl cellulose, hydroxyethyl methacrylate, 3-[[2-(methacryloyloxy)ethyl]dimethylamine]propionate, diacrylate, or a combination thereof.
In an embodiment of the present invention, the photoinitiator may be: lithium phenyl-2,4,6-trimethylbenzoylphosphinate and its salts, 2-Hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, eosin-Y, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, or a combination thereof.
In a preferred embodiment, the photoinitiator used in the hydrogel of the present invention is lithium phenyl-2,4,6-trimethylbenzoylphosphinate.
In a preferred embodiment, the irradiation time to activate the photoinitiator of the hydrogel of the present invention to form a gel is 60 seconds.
In an embodiment of the present invention, the buffer may be HEPES buffer, MES buffer, Bis-Tris buffer, citrate, ADA buffer, ACES buffer, PIPES buffer, imidazole/imidazole buffer, Bis-Tris propane buffer, maleic acid buffer, phosphate buffer, MOPSO buffer, BES buffer, MOPS buffer, TES buffer, DIPSO buffer, MOBS buffer, TAPSO buffer, HEPPSO buffer, POPSO buffer, EPPS (HEPPS) buffer, Tricine buffer, Gly-Gly buffer, Bicine buffer, HEPBS buffer, TAPS buffer, AMPD buffer, TABS buffer, AMPSO buffer, PIPPS buffer, methyl malonate, diethyl malonate, glycinamide hydrochloride buffer, or a combination thereof, or a buffer formulated according to any of the above buffers.
In a preferred embodiment, the buffer solution in which the hydrogel of the present invention dissolves is Dulbecco's Phosphate Buffered Saline (DPBS).
The hydrogels blended composition of the present invention may further comprise one or more drugs, active ingredients, bioactive materials, absorbent materials, or a combination thereof.
Gelatin and methacrylic anhydride were mixed in a 0.1M carbonate-bicarbonate buffer at a ratio of 10 g to 1 mL. The pH value of the mixture was adjusted to 7.4. After fully dialysis and purification with double distilled water, it was freeze-dried to form a white solid.
The freeze-dried GelMA solids were dissolved in phosphate buffer at 10% by weight, and 0.25% photoinitiator (lithium phenyl-2,4,6-trimethylbenzoylphosphinate) was added. After being heated to 60° C. in oven followed by sterile filtration, the mixture was irradiated with the ultraviolet light at the absorption wavelength of lithium phenyl-2,4,6-trimethylbenzoylphosphinate for 60 seconds to form a gel.
The 10% GelMA hydrogel was placed in a −20° C. refrigerator until freeze, followed by being freeze-dried with a freeze dryer. The resulting freeze-dried product was ground into powder and sieved to obtain the desired freeze-dried hydrogel powder.
Measurement of Viscosity Coefficient
The 10% freeze-dried hydrogel powder was mixed with phosphate buffer at 16.66% by weight and the viscosity of the mixture was measured by a rheometer. The result showed that the viscosity coefficient of the mixture was about 1 to 10 (Pa·s) in the shear rate ranging from 10 to 100 s-1. In contrast, within the same shear rate range, the viscosity coefficient of water was about 10-3 (Pa·s), and the viscosity coefficient of 20 wt % gelatin methacryloyl (GelMA) prepolymer solution was about 10-1 (Pa·s).
The percent number in front of the group of freeze-dried gel powder dissolved in DPBS represented the concentration of the hydrogel before polymerization. All hydrogels were polymerized by irradiation for 60 seconds, and after lyophilization and grinding, the lyophilized hydrogel powder was mixed with DPBS (Dulbecco's phosphate-buffered saline) at a ratio of 1 g to 6000 μl. The group of 10% freeze-dried gel powder plus 20% gelatin methacryloyl (GelMA) hydrogel prepolymer solution was prepared by mixing freeze-dried hydrogel powder with 20% gelatin methacryloyl (GelMA) hydrogel prepolymer solution at a ratio of 1 g to 6000 μl. The number of samples in each group was 3.
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Cytotoxicity Assay
Cytotoxicity of the freeze-dried hydrogel powder was examined using a Cell Counting Kit-8 (CCK8) kit. The test groups were as follows: a blank group using only cells and culture medium, three experimental groups in which the culture medium was mixed with the extract of the gelatin methacryloyl freeze-dried hydrogel powder dissolved in buffer with three weight volume ratios respectively, and a positive control group using bleach.
The method for obtaining the freeze-dried hydrogel powder extract was as follows: 10% gelatin methacryloyl freeze-dried hydrogel powder and culture medium were mixed in a weight-to-volume ratio of 1 gram to 6000 microliters, 2 grams to 6000 microliters, 0.5 grams to 6000 microliters and placed in a 37° C. incubator, followed by continuous extraction for 24 hours at a stirring speed of 100 rpm.
The cells used were NIH 3T3 fibroblasts cultured in a 96-well plate, and the cell amount was about 104 per well.
After incubation, the Cell Counting Kit-8 (CCK8) reagent was used to detect cell viability. The absorbance wavelength of the reagent was 450 nm. The number of samples in each group was 5.
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According to the models, the yield stress of the 10% powder dissolved in DPBS, the 10% powder plus 20% gelatin methacryloyl prepolymer solution, and the 20% gelatin methacryloyl prepolymer solution were 41.5 Pa, 64.8 Pa, 0.14 Pa, respectively, indicating that the cohesive force of the freeze-dried hydrogel powder mixture was much greater than that of the prepolymer solution, which made it easier to stay on the inclined surface without running off.
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Although the present invention has been described and illustrated in sufficient detail to enable those skilled in the art to make and use it, various alternatives, modifications and improvements should be apparent without departing from the spirit and scope of the present invention.
Number | Date | Country | Kind |
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110121760 | Jun 2021 | TW | national |