Diabetes wound repair microneedle dressing and preparation method thereof

Abstract

The invention relates to the technical field of microneedle dressings, in particular to a diabetes wound repairing microneedle dressing and a preparation method thereof.The polyphenol medicine is nanocrystallized and wrapped in a phenylboronic acid modified polymer system, the water solubility of the polyphenol medicine can be improved, the in-vivo metabolism speed of the polyphenol medicine can be slowed down, and the bioavailability of the polyphenol medicine can be improved; the specific binding of phenylboronic acid and the hydrophilic natural high-molecular polymer can be influenced by saccharides or pH environment; in a specific physiological or pathological environment, the polyphenol drug nanoparticles can be released in a more targeted manner, the drug effect is improved, and the side effects of the whole body are reduced. Carboxymethyl chitosan is utilized to endow the microneedle dressing with antibacterial performance and polysaccharide response nanoparticles loaded with polyphenol drugs, the volume of a substrate of the microneedle dressing for repairing the wound of diabetes mellitus is shrunk at the body surface temperature, stress for the wound to shrunk inwards is applied, the area of the wound is reduced, and the wound repairing effect is improved. And polyphenol drugs are released in a diabetes mellitus high-glucose microenvironment so as to clear high-level free radicals in diabetes mellitus wounds.

Description

Technical Field

[0001] The invention relates to the technical field of microneedle dressings, and in particular to a diabetic wound repairing microneedle dressing and a preparation method thereof. Background Art

[0002] Compounds of natural bioactive ingredients have been the subject of extensive research, and their anti-cancer, anti-inflammatory, antioxidant and anti-aging properties have led to their widespread application in many fields; wound dressings of natural bioactive ingredients play various roles in different wound healing stages, such as increasing blood cell adsorption, inhibiting neutrophil infiltration and monocyte migration and adhesion, promoting epithelial regeneration, stimulating angiogenesis, changing collagen synthesis and reducing extracellular matrix (ECM) formation. By loading natural antioxidants into hydrogels, a series of hydrogel dressings with excellent antioxidant activity were developed for the treatment of diabetic wounds.

[0003] However, existing diabetic dressing technology faces some challenges and shortcomings, mainly including the following aspects: diabetic patients' wounds heal slowly and are prone to infection, and existing technologies have limited antibacterial effects, leading to repeated infections; some advanced technologies, such as biomaterials or stem cell therapy, although showing certain prospects in the laboratory, are costly in clinical applications. The drug sustained-release system loaded by the dressing, such as some nanoparticles (PLGA particles) prepared by artificial polymers, not only has certain biological toxicity, but also has slow degradation and low utilization rate, and cannot release drugs on demand.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a diabetic wound repair microneedle dressing and a preparation method thereof, aiming to solve the problems that the existing diabetic dressings have certain biological toxicity, slow degradation rate and low utilization rate.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a diabetic wound repair microneedle dressing, comprising the steps of:

[0008] Pluronic F127 was acrylated to obtain PF127DA;

[0009] Performing methacryloyl treatment on hyaluronic acid to obtain methacryloyl hyaluronic acid;

[0010] Using phenylboronic acid compounds to modify hydrophilic natural high molecular polymers to obtain phenylboronic acid modified polymers;

[0011] Dispersing and recombining the polyphenol drug with the phenylboronic acid modified polymer to obtain polyphenol drug nanoparticles;

[0012] The PF127DA and the methacryloyl hyaluronic acid are mixed with carboxymethyl chitosan, a photoinitiator and the polyphenol drug nanoparticles to obtain a hydrogel solution;

[0013] The hydrogel solution is spread in a microneedle mold and subjected to curing treatment to obtain a diabetic wound repair microneedle dressing.

[0014] The preparation method of the diabetic wound repair microneedle dressing is described, wherein the phenylboronic acid compound includes one or more of 3-aminophenylboronic acid, 3-carboxyphenylboronic acid, 4-carboxyphenylboronic acid, and 4-amino-3-fluorophenylboronic acid; and the hydrophilic natural high molecular polymer includes one or more of sodium alginate, hyaluronic acid, gelatin, and chitosan.

[0015] The method for preparing the diabetic wound repair microneedle dressing, wherein the polyphenol drug includes one or more of quercetin, tannic acid, catechin, and resveratrol.

[0016] The method for preparing the diabetic wound repair microneedle dressing, wherein the step of subjecting Pluronic F127 to acryloylation to obtain PF127DA comprises:

[0017] Pluronic F127 is vacuum dried and then mixed with dichloromethane to obtain a Pluronic F127 solution;

[0018] Triethylamine and a mixed solution of acryloyl chloride and dichloromethane were added to the Pluronic F127 solution for light-protected reaction, and PF127DA was obtained after dialysis treatment and freeze-drying.

[0019] The method for preparing the diabetic wound repair microneedle dressing, wherein the step of methacrylating hyaluronic acid to obtain methacrylated hyaluronic acid comprises:

[0020] Dissolving sodium hyaluronate in water and adjusting the pH value to obtain a hyaluronic acid solution;

[0021] The hyaluronic acid solution is mixed with methacrylic anhydride to obtain methacrylylated hyaluronic acid after reaction.

[0022] The preparation method of the diabetic wound repair microneedle dressing, wherein the step of modifying the hydrophilic natural high molecular polymer with a phenylboronic acid compound to obtain a phenylboronic acid modified polymer comprises:

[0023] The hydrophilic natural high molecular polymer is mixed with a water morpholineethanesulfonic acid hydrate solution, and then activated to obtain a polymer solution;

[0024] The polymer solution is subjected to a grafting reaction with a phenylboronic acid compound to obtain a phenylboronic acid-modified polymer.

[0025] The preparation method of the diabetic wound repair microneedle dressing, wherein the mass ratio of the hydrophilic natural high molecular polymer to the phenylboronic acid compound is (0.5-1):2.

[0026] The method for preparing the diabetic wound repair microneedle dressing, wherein the mass ratio of the polyphenol drug to the phenylboronic acid modified polymer is (1-2): (20-120).

[0027] The preparation method of the microneedle dressing for repairing diabetic wounds, wherein the mass ratio of the PF127DA, the methacryloyl hyaluronic acid, the carboxymethyl chitosan, the photoinitiator and the polyphenol drug nanoparticles is (12-15):(1-2):(2-3):(0.5-1):(0.25-0.5).

[0028] A diabetic wound repairing microneedle dressing is prepared by utilizing a preparation method of a diabetic wound repairing microneedle dressing.

[0029] Beneficial effects: The present invention provides a diabetic wound repairing microneedle dressing and a preparation method thereof. The preparation method of the diabetic wound repairing microneedle dressing comprises the following steps: performing acryloylation treatment on Pluronic F127 to obtain PF127DA; performing methacryloylation treatment on hyaluronic acid to obtain methacryloyl hyaluronic acid; performing modification treatment on a hydrophilic natural high molecular polymer using a phenylboronic acid compound to obtain a phenylboronic acid modified polymer; dispersing and recombining a polyphenol drug with the phenylboronic acid modified polymer to obtain polyphenol drug nanoparticles; mixing the PF127DA and the methacryloyl hyaluronic acid with carboxymethyl chitosan, a photoinitiator and the polyphenol drug nanoparticles to obtain a hydrogel solution; spreading the hydrogel solution in a microneedle mold, and performing a curing treatment to obtain a diabetic wound repairing microneedle dressing. The present invention can not only improve the water solubility of polyphenol drugs by nano-forming and encapsulating them in a phenylboronic acid modified polymer system, but also slow down their metabolic rate in the body and improve bioavailability; the specific binding of phenylboronic acid and hydrophilic natural high molecular polymers can be affected by sugars or pH environment, so a responsive release mechanism based on the disease microenvironment can be designed; in a specific physiological or pathological environment, polyphenol drug nanoparticles can be released more targetedly, improve drug efficacy and reduce systemic side effects. Specifically, carboxymethyl chitosan is used to give microneedle dressings antibacterial properties and sugar-responsive nanoparticles loaded with polyphenol drugs. The base of the diabetic wound repair microneedle dressing shrinks in volume at body surface temperature, and exerts stress that the wound shrinks inward, reducing the wound area, and releases polyphenol drugs in the diabetic high-sugar microenvironment to clear the high level of free radicals in the diabetic wound, and when the wound microenvironment is restored to the normal skin microenvironment, the sugar-responsive nanoparticles no longer release polyphenol drugs to maintain the balance of the microenvironment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the process flow of a method for preparing a diabetic wound repair microneedle dressing according to the present invention;

[0031] Figure 2 TEM image of quercetin nanoparticles prepared in Example 1;

[0032] Figure 3 The average particle size and potential diagram of quercetin nanoparticles prepared in Example 1;

[0033] Figure 4 This is a physical picture of the microneedle dressing prepared in Example 1;

[0034] Figure 5 This is a SEM image of the microneedle dressing prepared in Example 1;

[0035] Figure 6The drug release curves of the microneedle dressing prepared in Example 1 under different environments. DETAILED DESCRIPTION

[0036] The present invention provides a diabetic wound repair microneedle dressing and a preparation method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0038] Quercetin (Qu) is a polyphenolic compound belonging to the flavonol family. Quercetin exists in the form of glycosides (with linked sugars) or aglycones (without linked sugars), and the most common form extracted from plants is quercetin-3-O-glucoside, which is usually used as a pigment to give color to a variety of fruits and vegetables. Onions, apples and wine are considered to be rich in quercetin. Quercetin is a ROS (O 2- ) and RNS(NO - 、ONOO - ) is one of the best scavengers of free radicals. When scavenging free radical derivatives, quercetin produces a reaction product called o-quinone / quinone methyl ether by oxidation. o-quinone / quinone methyl ether can be converted back to quercetin form by other antioxidants. It is reported that this antioxidant property of quercetin is due to the catechol group in the β ring and the -OH group in position 3 of the AC ring. Although flavonols such as quercetin have a wide spectrum of biological activities, they are difficult to dissolve in aqueous solutions due to the phenol structure in their structure. Low solubility is the main factor limiting the further commercial application of this type of polyphenol drugs.

[0039] Based on this, Figure 1 As shown, the present invention provides a method for preparing a diabetic wound repair microneedle dressing, comprising the steps of:

[0040] Step S10: performing acrylation treatment on Pluronic F127 to obtain PF127DA;

[0041] Step S20: performing methacrylation on the hyaluronic acid to obtain methacrylated hyaluronic acid;

[0042] Step S30: using phenylboronic acid compounds to modify the hydrophilic natural high molecular polymer to obtain a phenylboronic acid modified polymer;

[0043] Step S40: dispersing and recombining the polyphenol drug and the phenylboronic acid modified polymer to obtain polyphenol drug nanoparticles;

[0044] Step S50: mixing the PF127DA and the methacryloyl hyaluronic acid with carboxymethyl chitosan, a photoinitiator and the polyphenol drug nanoparticles to obtain a hydrogel solution;

[0045] Step S60: spreading the hydrogel solution in a microneedle mold and subjecting it to curing treatment to obtain a microneedle dressing for repairing diabetic wounds.

[0046] In this embodiment, by nano-forming polyphenol drugs and encapsulating them in a phenylboronic acid modified polymer system, not only can the water solubility of polyphenol drugs be improved, but also their metabolic rate in the body can be slowed down and their bioavailability can be improved; and the specific binding of phenylboronic acid to hydrophilic natural polymers can be affected by sugars or pH environment, so a responsive release mechanism based on the disease microenvironment can be designed; in a specific physiological or pathological environment, polyphenol drug nanoparticles can be released more specifically, improving drug efficacy and reducing systemic side effects. Specifically, carboxymethyl chitosan is used to give microneedle dressings antibacterial properties and sugar-responsive nanoparticles loaded with polyphenol drugs. The base of the diabetic wound repair microneedle dressing shrinks in volume at body surface temperature, and exerts stress that shrinks the wound inward, reducing the wound area, and releases polyphenol drugs in the diabetic high-sugar microenvironment to clear the high level of free radicals in the diabetic wound, and when the wound microenvironment is restored to the normal skin microenvironment, the sugar-responsive nanoparticles no longer release polyphenol drugs to maintain the balance of the microenvironment.

[0047] Specifically, phenylboronic acid can form covalent compounds with polyol compounds such as glucose, and by complexing with glucose, the equilibrium can be moved toward increasing the charged phenylborates, because only charged phenylborates can form stable complexes with glucose in aqueous media. In addition, a glucose-responsive phenylboronic acid group is introduced into the main chain of a hydrophilic natural polymer to obtain an amphiphilic polymer phenylboronic acid-modified polymer, and then the catechol on the polyphenol drug reacts with phenylboronic acid in a neutral to alkaline microenvironment to form a tetrahedral borate anion diester bond; at this time, the borate ester combined with the polyphenol drug is a hydrophobic group, that is, the polyphenol drug nanoparticles are also amphiphilic polymers. Through hydrophobic interactions, the polyphenol drug nanoparticles form a phase interface with one side being hydrophilic and the other side being hydrophobic through the bending of the M block and the folding of the G block on the main chain, and combine with most of the free polyphenol drugs dissolved in ethanol, and self-assemble through non-covalent hydrogen bonds to form polyphenol drug nanoparticles with a hydrophobic core and a hydrophilic shell. In addition, the nanoparticles have a cage-like molecular structure similar to that of proteins, which allows small molecules such as glucose to enter the gaps in the macromolecular grid of hydrophilic natural high molecular polymers. When the environmental pH is near the pKa of phenylboronic acid derivatives (generally between 8 and 9, and the pH microenvironment of diabetic wounds is also in this range), the glucose sensitivity of phenylboronic acid is greatly improved, and the original boric acid diester bond is destroyed. Glucose and phenylboronic acid are competitively bound and form a stable complex with glucose through reversible covalent bonds. The amphiphilic polymer macromolecules are converted back into hydrophilic macromolecules. Because the non-covalent hydrogen bonds of the hydrophobic interaction are destroyed, the outer polymer of the self-assembled nanoparticles disintegrates, and the polyphenol drugs free in the hydrophobic core replaced by glucose are released from them.

[0048] In some embodiments, the phenylboronic acid compounds include but are not limited to one or more of 3-aminophenylboronic acid, 3-carboxyphenylboronic acid, 4-carboxyphenylboronic acid, and 4-amino-3-fluorophenylboronic acid; the hydrophilic natural polymers include but are not limited to one or more of sodium alginate, hyaluronic acid, gelatin, and chitosan.

[0049] Specifically, the specific binding of phenylboronic acid compounds can be affected by sugars or pH environment. Therefore, by modifying the hydrophilic natural high molecular polymer with phenylboronic acid compounds and then dispersing and recombining with polyphenol drugs, the polyphenol drug nanoparticles in the microneedle dressing can have a responsive release mechanism based on the disease microenvironment. The phenylboronic acid compound can be selected according to the type of carboxylic acid group, amino group, and hydroxyl group contained in the hydrophilic natural high molecular polymer; further, 4-amino-3-fluorophenylboronic acid is used as a phenylboronic acid compound, because the addition of fluorine atoms will make the pKa of the system lower, increase the affinity of the entire system for polyphenols, and promote the substitution reaction of polyphenols after the glucose concentration increases. The phenylboronic acid modified polymer obtained by modifying the above hydrophilic natural high molecular polymer with phenylboronic acid compounds can make polyphenol drugs be wrapped in the phenylboronic acid modified polymer system, which can not only improve the water solubility of polyphenol drugs, but also slow down their metabolic rate in the body and improve bioavailability.

[0050] In a preferred embodiment, the phenylboronic acid compound is 4-amino-3-fluorophenylboric acid; and the hydrophilic natural high molecular polymer is sodium alginate.

[0051] Alginate is an anionic polymer composed of (1→4)-β-crosslinked D-mannuronic acid (M unit) and (1→4)-α-crosslinked guluronic acid (G unit). Alginate macromolecules are composed of GG, MM, and GM in different proportions. The β(1→4) bond formed by mannuronic acid makes the M block linear and flexible, while guluronic acid increases steric hindrance around the carboxyl group of the G block with α(1→4) bonds, providing the folding and rigid structural conformation of the alginate macromolecule chain.

[0052] At the same time, alginate has -COO- and -COOH groups along the chain that give different charge densities depending on the pH value. In a neutral environment, alginate is a long hydrophilic molecular chain. The hydrophobicity of alginate is increased by modifying the hydrophobic groups on the main chain. Common methods are esterification and amidation. The modified alginate has amphiphilicity and self-assembles into more stable and dense nanoaggregates through intramolecular and intermolecular hydrophobic interactions in aqueous solution.

[0053] In some embodiments, the polyphenol drugs include but are not limited to one or more of quercetin, tannic acid, catechins, and resveratrol. The polyphenol drug nanoparticles obtained by dispersing and recombining the above polyphenol drugs with the phenylboronic acid modified polymer have sugar response characteristics, and can release polyphenol drugs in the diabetic high-sugar microenvironment to achieve the removal of high-level free radicals in diabetic wounds, and when the wound microenvironment is restored to the normal skin microenvironment (pH changes from weak alkaline to weak acid, and the glucose level concentration decreases to below 16.6mmol / ml), the sugar-responsive nanoparticles will no longer release polyphenol drugs to maintain the balance of the microenvironment.

[0054] In a preferred embodiment, the polyphenol drug is quercetin. In a specific physiological or pathological environment, quercetin can be released more specifically, thereby improving efficacy and reducing systemic side effects.

[0055] In some embodiments, in step S10, the step of subjecting Pluronic F127 to acrylation to obtain PF127DA comprises:

[0056] Step S11: vacuum drying Pluronic F127 and mixing it with dichloromethane to obtain a Pluronic F127 solution;

[0057] Step S12: adding triethylamine and a mixture of acryloyl chloride and dichloromethane to the Pluronic F127 solution to react in the dark, and obtaining PF127DA after dialysis treatment and freeze drying.

[0058] In this embodiment, the thermosensitive polymer PF127DA can be obtained by subjecting Pluronic F127 (PF127) to acrylation. The thermosensitive polymer PF127DA is used as a raw material for preparing a microneedle dressing to obtain a thermosensitive hydrogel microneedle dressing.

[0059] Specifically, the step S10 includes the steps of: vacuum drying PF127 at 120° C. for 2 hours and then sealing it, cooling it to room temperature, adding dichloromethane, and dissolving it in an ice bath; after PF127 is completely dissolved, adding triethylamine to absorb the by-product hydrochloric acid after the grafting reaction; then diluting acryloyl chloride in dichloromethane under nitrogen protection, stirring and slowly adding it dropwise into the PF127 solution, and an ice bath is required during the reaction process; after the reaction solution is added dropwise, react at room temperature in the dark, use a rotary evaporator to heat and volatilize the dichloromethane, and dissolve the yellow-white product in xylene, and filter to remove the insoluble by-product triethylammonium salt; add petroleum ether to the solution to precipitate PF127DA, vacuum dry it, dissolve it in water, use a dialysis membrane to perform dialysis treatment, and freeze-dry to obtain a PF127DA finished product.

[0060] In some embodiments, the mass ratio of the Pluronic F127 to the acryloyl chloride is 40:(1-3), and the greater the mass of the acryloyl chloride, the higher the grafting rate.

[0061] In some embodiments, in step S20, the step of performing methacrylation on hyaluronic acid to obtain methacrylated hyaluronic acid comprises:

[0062] Step S21: dissolving sodium hyaluronate in water and adjusting the pH value to obtain a hyaluronic acid solution;

[0063] Step S22: mixing the hyaluronic acid solution with methacrylic anhydride to obtain methacrylated hyaluronic acid after reaction.

[0064] In this embodiment, methacrylylated hyaluronic acid (HAMA) is obtained by methacrylylating hyaluronic acid, and a thermosensitive hydrogel microneedle dressing is prepared based on the thermosensitive polymer PF127DA and the natural active polymer HAMA photo-crosslinked double network hydrogel; finally, carboxymethyl chitosan (CMCS) is added to give the microneedle dressing antibacterial properties and sugar-responsive nanoparticles loaded with polyphenol drugs, so that the base of the hydrogel microneedle dressing shrinks in volume at body surface temperature, and exerts stress that causes the wound to shrink inward, thereby reducing the wound area, and releases quercetin in the diabetic high-sugar microenvironment to clear the high level of free radicals in the diabetic wound, and when the wound microenvironment is restored to the normal skin microenvironment, the sugar-responsive nanoparticles no longer release quercetin to maintain the balance of the microenvironment.

[0065] Specifically, step S20 includes the steps of: dissolving hyaluronic acid in deionized water at room temperature, adjusting the pH value of the hyaluronic acid solution to 8 by dripping sodium hydroxide, slowly dripping methacrylic anhydride for reaction, and continuing to drip sodium hydroxide after the dripping is completed to maintain the pH value of the reaction solution at about 8, and stirring overnight for reaction; after the reaction, using ice ethanol for precipitation, dissolving the precipitated methacryloyl hyaluronic acid (HAMA) in deionized water, continuing to use a 7kDa dialysis bag for dialysis treatment for 7 days, and storing after freeze-drying.

[0066] In some embodiments, the ratio of the mass of the sodium hyaluronate to the volume of the methacrylic anhydride is 1 g:(5-10) mL, and the larger the volume of the methacrylic anhydride, the higher the grafting rate.

[0067] In some embodiments, in step S30, the step of modifying the hydrophilic natural high molecular polymer with a phenylboronic acid compound to obtain a phenylboronic acid modified polymer comprises:

[0068] Step S31: mixing a hydrophilic natural high molecular polymer with a morpholineethanesulfonic acid hydrate solution, and subjecting the mixture to an activation treatment to obtain a polymer solution;

[0069] Step S32: performing a grafting reaction on the polymer solution and a phenylboronic acid compound to obtain a phenylboronic acid-modified polymer.

[0070] In this embodiment, phenylboronic acid can form a covalent complex with polyol compounds such as glucose; by complexing with glucose, the equilibrium can be shifted toward increasing the charged phenylborates, because only charged phenylborates can form a stable complex with glucose in an aqueous medium.

[0071] Specifically, step S30 includes the steps of: dissolving a hydrophilic natural high molecular polymer in a MES hydrate solution, adding EDC for stirring activation, then continuing to add NHS for stirring activation, then adding a phenylboronic acid compound for stirring overnight for grafting reaction, and after the reaction, dialyzing using a 7kDa dialysis bag, and freeze-drying to obtain a phenylboronic acid-modified polymer.

[0072] The invention introduces a phenylboronic acid group with glucose responsiveness into the main chain of a hydrophilic natural high molecular polymer by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC-HCl) and N-hydroxysuccinimide (NHS) coupling agents, thereby obtaining an amphiphilic polymer phenylboronic acid modified polymer.

[0073] In some embodiments, the mass ratio of the hydrophilic natural high molecular polymer to the phenylboric acid compound is (0.5-1):2, and the greater the mass of the phenylboric acid compound, the higher the grafting rate.

[0074] In some embodiments, the mass ratio of the polyphenol drug to the phenylboronic acid modified polymer is (1-2):(20-120).

[0075] In a preferred embodiment, the ratio of the polyphenol drug to the phenylboronic acid modified polymer is 1:20.

[0076] In some embodiments, the mass ratio of the PF127DA, the methacryloyl hyaluronic acid, the carboxymethyl chitosan, the photoinitiator and the polyphenol drug nanoparticles is (12-15):(1-2):(2-3):(0.5-1):(0.25-0.5).

[0077] Specifically, the step S40 includes the steps of: dissolving 1 mg / mL-3 mg / mL of phenylboronic acid modified polymer in deionized water to obtain a phenylboronic acid modified polymer solution (the greater the concentration, the larger the particle size), dissolving the polyphenol drug in anhydrous ethanol to obtain a 1 mg / mL polyphenol drug solution (the larger the volume of anhydrous ethanol, the smaller the encapsulation rate); mixing 2.5 mL-5 mL of the polyphenol drug solution with 100 mL of the phenylboronic acid modified polymer solution, performing ultrasonic treatment for dispersion and reorganization, stirring overnight to volatilize the anhydrous ethanol, and freeze-drying to obtain polyphenol drug nanoparticles.

[0078] In this embodiment, in order to reduce the particle size of the nanoparticles and improve the dispersibility, 0.02%-0.05% W / V Tween 80 surfactant is added to the solution when dissolving the phenylboronic acid modified polymer; the addition of the dispersant can reduce the agglomeration of the nanoparticles and reduce the hydrated particle size of the nanoparticles, and the concentration of the dispersant should not be too high, which will affect the surface energy of the polymer and prevent the nanoparticles from self-assembling.

[0079] In some embodiments, the photoinitiator includes, but is not limited to, 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (I2959).

[0080] In some embodiments, step S60 includes: spreading the hydrogel solution flat in the microneedle mold, and evacuating the vacuum drying oven at room temperature twice to remove bubbles at the needle tip position, and sucking out the hydrogel in the non-needle tip part, drying at 4°C for 12 hours, repeating the operation twice to obtain concentrated needle tip material, and filling the hydrogel into the dressing base layer, curing it in a 365nm UV curing box for 3 minutes, and then taking the microneedle dressing out of the mold with tweezers, placing it with the needle tip facing up and curing it for another 1 minute, and the microneedle dressing is prepared.

[0081] In addition, the present invention also provides a diabetic wound repairing microneedle dressing, which is prepared by using the preparation method of the diabetic wound repairing microneedle dressing.

[0082] In this embodiment, the diabetic wound repair microneedle dressing prepared by the preparation method of the diabetic wound repair microneedle dressing, the introduction of phenylboronic acid (PBA) increases the environmental response of the microneedle dressing, especially PBA can be combined with polyhydroxy compounds such as sugars, so that it can control the release of drugs under different pH values ​​or sugar concentrations. This makes the microneedle dressing have a great application prospect in complex disease microenvironments (such as cancer, diabetes, etc.), and can dynamically release drugs according to changes in the microenvironment.

[0083] In addition, based on the microneedle dressing provided by the present invention, it is also possible to combine targeting molecules (such as antibodies, peptide chains) with nanoparticles through surface modification technology to enhance the targeted therapeutic effect; or, the polyphenol drug nanoparticles are combined with intelligent delivery technology to develop nanoparticles with dual or multiple response characteristics; in addition to pH or sugar concentration response, control mechanisms of external stimuli such as light, heat, and magnetic fields can be introduced, and this intelligent drug delivery system can release drugs at a specific time and specific location, further improving the utilization efficiency of drugs. In addition, the sodium alginate-quercetin system composed of sodium alginate and quercetin using the above-mentioned preparation method has the potential to be applied to skin care, neuroprotection, cardiovascular disease prevention and other fields in addition to anti-cancer and anti-inflammatory effects. The antioxidant capacity of quercetin makes it suitable for use in skin aging protection, after-sun repair, and its protective effect on the nervous system also makes it potentially valuable in the treatment of neurodegenerative diseases.

[0084] The following examples are further given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention.

[0085] Example 1

[0086] The present invention provides a diabetic wound repair microneedle dressing, the preparation steps of which include the following:

[0087] 1) Synthesis of acryloyl Pluronic F127

[0088] 40g (3.2mmol) of PF127 was vacuum dried at 120℃ for 2h and then sealed. After cooling to room temperature, 75mL of dichloromethane was added and dissolved in an ice bath. After PF127 was completely dissolved, 3.62mL (26.3mmol) of triethylamine was added dropwise to absorb the byproduct hydrochloric acid after the grafting reaction. Under nitrogen protection, 2.65g of acryloyl chloride was diluted in dichloromethane, stirred within 2h and slowly added dropwise to the PF127 solution. An ice bath was required during the reaction process. After the reaction solution was added dropwise, it was reacted at room temperature in the dark for 24h. The dichloromethane was heated and volatilized using a rotary evaporator, and the yellow-white product acryloyl Pluronic F127 (PF127DA) was dissolved in 150mL of xylene, and the insoluble byproduct triethylammonium salt was filtered out. Petroleum ether was added to the solution to precipitate PF127DA, and the solution was then vacuum dried for 24 hours and dissolved in water. The solution was dialyzed for 7 days using a 7 kDa dialysis membrane and freeze-dried to obtain the finished PF127DA product.

[0089] 2) Synthesis of methacryloyl hyaluronic acid

[0090] Dissolve 1g of sodium hyaluronate in 100mL of deionized water at room temperature, adjust the pH value of the hyaluronic acid solution to 8 by dropping 1M sodium hydroxide solution, and then slowly drop 7mL of methacrylic anhydride to react. After the dropwise addition is complete, continue to drop 1M sodium hydroxide solution to maintain the pH value of the reaction solution at about 8, and stir overnight to react. After the reaction, precipitate with ice ethanol, dissolve the precipitated methacryloyl hyaluronic acid (HAMA) in deionized water, continue to use a 7kDa dialysis bag for dialysis treatment for 7d, and store after freeze-drying.

[0091] 3) Preparation of phenylboronic acid modified sodium alginate

[0092] 2 g of sodium alginate (Alg) was dissolved in 200 mL of 0.1 M aqueous morpholineethanesulfonic acid (MES) hydrate solution, and 1.4 g of EDC was added for stirring and activation for 15 min, and then NHS was added for stirring and activation for 15 min. Then, 0.5 g of 3-aminophenylboronic acid was added and stirred overnight for grafting reaction. After the reaction, it was dialyzed using a 7 kDa dialysis bag and freeze-dried to obtain phenylboronic acid-modified sodium alginate (Alg-PBA) for storage.

[0093] 4) Preparation of quercetin nanoparticles

[0094] 1 mg / mL Alg-PBA was dissolved in deionized water, 1 mg / mL quercetin (Qu) was dissolved in anhydrous ethanol, and 5 mL of Qu solution was added dropwise to the Alg-PBA solution, ultrasonically treated for 10 min for dispersion and reorganization, stirred overnight to evaporate the anhydrous ethanol, and freeze-dried to obtain quercetin nanoparticles (QuNPs). In order to reduce the particle size of the nanoparticles and improve the dispersibility, 0.02% W / V Tween 80 surfactant was added to the solution when dissolving Alg-PBA.

[0095] The prepared quercetin nanoparticles were characterized, and the TEM images are shown in Figure 2 As shown, Figure 2 The right picture is an enlarged view of the box on the left (scale: left 200 μm; right 100 μm). From the picture, we can see the core-shell structured nanoparticles with quercetin as the core and phenylboronic acid-modified sodium alginate as the shell.

[0096] Figure 3 The average particle size and potential diagram of quercetin nanoparticles. The addition of Tween 80 increases the dispersibility of nanoparticles and reduces the particle size of nanoparticles. The surface of nanoparticles is negatively charged. The lower the potential, the more stable the particle structure.

[0097] 5) Preparation of hydrogel microneedle dressing

[0098] PF127DA, 1% W / V HAMA, and 2% W / V CMCS were dissolved in deionized water at a volume concentration of 15% W / V, and 0.5% W / V of the photoinitiator 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (I2959) was added to the solution. The dissolved hydrogel solution was stored at 4° C. When the material was dissolved, 500 μg / mL of QuNPs freeze-dried powder was added and stirred together, and the hydrogel solution was stored at 4° C.

[0099] Spread 50 μL of hydrogel in the microneedle mold, and evacuate the mold twice at room temperature in a vacuum drying oven to remove bubbles at the needle tip, and suck out the hydrogel in the non-needle tip part and dry it at 4°C for 12 h. Repeat the operation twice to obtain concentrated needle tip material, and fill the hydrogel into the base layer of the dressing. After curing in a 365nm UV curing box for 3 min, use tweezers to take the microneedle dressing out of the mold, place it with the needle tip facing up, and cure it for another 1 min. The microneedle dressing is ready.

[0100] The actual picture of the prepared microneedle dressing is shown in Figure 4, and the SEM picture of the microneedle dressing is shown in Figure 5 As shown (scale: 100 μm), it can be seen from the figure that the microneedle structure is regular and clear, and the molding rate is good, indicating that the hydrogel microneedle has a good photocuring effect and is conducive to the puncture and drug delivery of skin necrotic tissue and bacterial biofilm.

[0101] Figure 6 The following is a graph showing the drug release curve of microneedle dressings under different environments. Because the shell of the nanoparticles is composed of sodium alginate, sodium alginate exists in the form of alginate in an acidic environment, and the hydrophilicity becomes hydrophobicity, the affinity for glucose decreases, and the structure is stable, and quercetin is not released. In both neutral and alkaline environments, the nanoparticles are glucose-responsive, and more quercetin drugs are released in a high-sugar environment. Since boric acid esters are more active in alkaline environments, more drugs are released in alkaline environments.

[0102] In summary, the present invention provides a diabetic wound repair microneedle dressing and a preparation method thereof. The preparation method of the diabetic wound repair microneedle dressing comprises the steps of: performing acrylation treatment on Pluronic F127 to obtain PF127DA; performing methacrylation treatment on hyaluronic acid to obtain methacrylated hyaluronic acid; modifying a hydrophilic natural high molecular polymer with a phenylboronic acid compound to obtain a phenylboronic acid modified polymer; dispersing and recombining a polyphenol drug with the phenylboronic acid modified polymer to obtain polyphenol drug nanoparticles; mixing the PF127DA and the methacrylated hyaluronic acid with carboxymethyl chitosan, a photoinitiator and the polyphenol drug nanoparticles to obtain a hydrogel solution; spreading the hydrogel solution in a microneedle mold, and performing a curing treatment to obtain a diabetic wound repair microneedle dressing. The present invention can not only improve the water solubility of polyphenol drugs by nano-forming and encapsulating them in a phenylboronic acid modified polymer system, but also slow down their metabolic rate in the body and improve bioavailability; the specific binding of phenylboronic acid and hydrophilic natural high molecular polymers can be affected by sugars or pH environment, so a responsive release mechanism based on the disease microenvironment can be designed; in a specific physiological or pathological environment, polyphenol drug nanoparticles can be released more targetedly, improve drug efficacy and reduce systemic side effects. Specifically, carboxymethyl chitosan is used to give microneedle dressings antibacterial properties and sugar-responsive nanoparticles loaded with polyphenol drugs. The base of the diabetic wound repair microneedle dressing shrinks in volume at body surface temperature, and exerts stress that the wound shrinks inward, reducing the wound area, and releases polyphenol drugs in the diabetic high-sugar microenvironment to clear the high level of free radicals in the diabetic wound, and when the wound microenvironment is restored to the normal skin microenvironment, the sugar-responsive nanoparticles no longer release polyphenol drugs to maintain the balance of the microenvironment.

[0103] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a microneedle dressing for repairing diabetic wounds, characterized in that: Includes steps: Pluronic F127 was acrylated to obtain PF127DA; Performing methacryloyl treatment on hyaluronic acid to obtain methacryloyl hyaluronic acid; Using phenylboronic acid compounds to modify hydrophilic natural high molecular polymers to obtain phenylboronic acid modified polymers; Dispersing and recombining the polyphenol drug with the phenylboronic acid modified polymer to obtain polyphenol drug nanoparticles; The PF127DA and the methacryloyl hyaluronic acid are mixed with carboxymethyl chitosan, a photoinitiator and the polyphenol drug nanoparticles to obtain a hydrogel solution; The hydrogel solution is spread in a microneedle mold and subjected to curing treatment to obtain a diabetic wound repair microneedle dressing.

2. The method for preparing the diabetic wound repair microneedle dressing according to claim 1, characterized in that: The phenylboronic acid compounds include one or more of 3-aminophenylboronic acid, 3-carboxylphenylboronic acid, 4-carboxylphenylboronic acid, and 4-amino-3-fluorophenylboronic acid; the hydrophilic natural high molecular polymer includes one or more of sodium alginate, hyaluronic acid, gelatin, and chitosan.

3. The method for preparing the diabetic wound repair microneedle dressing according to claim 1, characterized in that: The polyphenol drugs include one or more of quercetin, tannic acid, catechins and resveratrol.

4. The method for preparing the diabetic wound repair microneedle dressing according to claim 1, characterized in that: The step of subjecting Pluronic F127 to acrylation to obtain PF127DA comprises: Pluronic F127 is vacuum dried and then mixed with dichloromethane to obtain a Pluronic F127 solution; Triethylamine and a mixed solution of acryloyl chloride and dichloromethane were added to the Pluronic F127 solution for light-protected reaction, and PF127DA was obtained after dialysis treatment and freeze-drying.

5. The method for preparing the diabetic wound repair microneedle dressing according to claim 1, characterized in that: The step of subjecting hyaluronic acid to methacryloylation to obtain methacryloyl hyaluronic acid comprises: Dissolving sodium hyaluronate in water and adjusting the pH value to obtain a hyaluronic acid solution; The hyaluronic acid solution is mixed with methacrylic anhydride to obtain methacrylylated hyaluronic acid after reaction.

6. The method for preparing the diabetic wound repair microneedle dressing according to claim 1, characterized in that: The step of modifying the hydrophilic natural high molecular polymer by using phenylboronic acid compounds to obtain the phenylboronic acid modified polymer comprises: The hydrophilic natural high molecular polymer is mixed with a water morpholineethanesulfonic acid hydrate solution, and then activated to obtain a polymer solution; The polymer solution is subjected to a grafting reaction with a phenylboronic acid compound to obtain a phenylboronic acid-modified polymer.

7. The method for preparing the diabetic wound repair microneedle dressing according to claim 1, characterized in that: The mass ratio of the hydrophilic natural high molecular polymer to the phenylboric acid compound is (0.5-1):

2.

8. The method for preparing the diabetic wound repair microneedle dressing according to claim 1, characterized in that: The mass ratio of the polyphenol drug to the phenylboronic acid modified polymer is (1-2):(20-120).

9. The method for preparing the diabetic wound repair microneedle dressing according to claim 1, characterized in that: The mass ratio of the PF127DA, the methacryloyl hyaluronic acid, the carboxymethyl chitosan, the photoinitiator and the polyphenol drug nanoparticles is (12-15):(1-2):(2-3):(0.5-1):(0.25-0.5).

10. A microneedle dressing for repairing diabetic wounds, characterized in that: The microneedle dressing for repairing diabetic wounds is prepared by the preparation method of the microneedle dressing for repairing diabetic wounds as described in any one of claims 1 to 9.

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