Photodegradable drug-loaded particles as well as preparation method and application thereof

Abstract

The invention relates to the technical field of degradable particles, in particular to photodegradable drug-loaded particles as well as a preparation method and application thereof, and the photodegradable drug-loaded particles comprise a cross-linked polymer M1, a cross-linked polymer M2 and a polyelectrolyte polymer M3; wherein M2 contains a plurality of photocleavable groups; m3 contains a plurality of ionizable groups and is adsorbed with drug molecules through static electricity; m1, M2 and M3 all contain at least two terminal bridging groups, and the terminal bridging groups are mutually subjected to cross-linking reaction to form the photodegradable drug-loaded particles with a gel three-dimensional network structure. When being irradiated by light with specific wavelength, the particles are degraded due to chemical bond breakage; in addition, due to the existence of a gel three-dimensional network and ionizable groups in the particle material structure, various macromolecular or micromolecular drugs can be loaded. When the particles are irradiated by light, light degradation occurs, the medicine loaded in the particles is released, the degradation rate of the particles can be accurately controlled, and programmed release of the medicine can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of degradable microparticles, and in particular to photodegradable drug-loaded microparticles and a preparation method and application thereof. Background Art

[0002] Light is a non-contact stimulus, and photoresponsive materials can achieve remote degradation without the need for additional reagents; in addition, by adjusting relevant parameters such as light intensity and irradiation time, the degradation of the material can be precisely controlled. Light has many unique advantages as a degradation stimulus, so photoresponsive materials have attracted great attention in recent years. The photoresponsive groups currently studied include nitrobenzyl (ONB), coumarin, azobenzene, and spirobenzopyran. Nitrobenzyl-related derivatives are the most widely used photoresponsive molecules that can be triggered by 365nm ultraviolet light, and their photodegradation products have excellent biocompatibility. Photosensitive hydrogels have been shown to be useful in soft actuators, repair materials, adaptive surfaces, dynamic cell microenvironments, and scaffolds for drug release.

[0003] When using microparticles for embolization, if there is a lack of appropriate means of immediate vascular recanalization after non-targeted embolism, most of the embolic agents currently used in clinical practice are non-degradable or biodegradable embolic agents with a long degradation cycle. If non-targeted embolism occurs, there is a lack of effective means of vascular recanalization, leading to serious complications. In addition, drug release lacks controllability. Currently, commonly used drug delivery release systems include microparticles and microspheres, nanoparticles, hydrogels, liposomes, etc., which generally have the problem of uncontrollable release, such as delayed response to environmental stimuli or difficulty in accurately adjusting the release rate, resulting in reduced clinical treatment effects.

[0004] In addition, the biodegradable microparticles commonly used currently generally rely on enzyme degradation in the body, the degradation time point is imprecise and the degradation behavior is uncontrollable; and when using microparticles in vivo, the adaptability of the stimulation to the internal environment and the actual application situation must be considered. For example, chemical reagents such as ethylenediaminetetraacetic acid are highly toxic, which leads to obstacles in clinical use.

[0005] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a photodegradable drug-loaded microparticle and a preparation method and application thereof, aiming to solve the problems of inaccurate degradation time point and uncontrollable degradation behavior of existing degradable drug-loaded microparticles, as well as uncontrollable drug release.

[0007] The technical solution of the present invention is as follows:

[0008] A photodegradable drug-loaded particle, comprising: a cross-linked polymer M1, a cross-linked polymer M2 and a polyelectrolyte polymer M3;

[0009] The cross-linked polymer M2 contains multiple photo-cleavable groups; the polyelectrolyte polymer M3 contains multiple ionizable groups and has drug molecules adsorbed by electrostatics; wherein the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 all contain at least two terminal bridging groups, and the terminal bridging groups of the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 undergo cross-linking reactions to form photodegradable drug-loaded particles with a three-dimensional gel network structure.

[0010] In the photodegradable drug-loaded particles, the cross-linked polymer M1 contains a main chain L1, and the cross-linked polymer M2 contains a main chain L2; both the main chain L1 and the main chain L2 are hydrophilic polymers.

[0011] The photodegradable drug-loaded particles, wherein the hydrophilic polymer includes gelatin, collagen, hyaluronic acid, sodium alginate, agarose, polyamino acid, serum albumin, chitin, chitosan, starch, cellulose, polylactic acid, polylactic acid-glycolic acid copolymer, polyethylene glycol, polyvinyl alcohol, polyacrylic acid or one of the hydrophilic polymer related derivatives.

[0012] The photodegradable drug-loaded particles, wherein the photocleavable group is selected from one of nitrobenzene, coumarin, benzoyl, indole, and quinoline.

[0013] The photodegradable drug-loaded particles, wherein the photocleavable group is selected from one of o-nitrobenzyl, 4-aminobenzoyl, 4-amino-3-nitrobenzoyl, 4-amino-5-nitrobenzoyl, 8-nitroadenine, 8-nitroadenine-5'-diphosphate, 4-nitrobenzoyl, 4-nitro-3-aminobenzoyl, 4,5-dimethoxy-2-nitrobenzyl, 1-(2-nitrophenyl)propyl, 1(-2-nitrophenyl)ethyl, 7-methoxycoumarin-4-methyl, 4-methylcoumarin and its carbonate, and anthraquinone-2-methoxycarbonyl.

[0014] The photodegradable drug-loaded particles, wherein the polyelectrolyte polymer M3 is obtained by modifying the polyelectrolyte with the terminal bridging group; the polyelectrolyte includes at least one of polyacrylic acid, carboxymethyl cellulose, carboxymethyl chitosan, sodium alginate, G4 dendrimer, polyglutamic acid, polyaspartic acid, poly(allylamine), 2-aminoethyl methacrylate hydrochloride, polyethyleneimine, polydiallyldimethylammonium chloride, poly[2-(N,N-dimethylamino)ethyl methacrylate], and chitosan.

[0015] In the photodegradable drug-loaded particles, the ionizable groups include at least one of carboxyl, sulfonic acid, sulfinic acid, phosphate, phosphite, hypophosphite, and amino groups.

[0016] The photodegradable drug-loaded particles, wherein the drug molecules include at least one of doxorubicin hydrochloride, paclitaxel, epirubicin, mitomycin, fluorouracil, cisplatin, oxaliplatin, capecitabine, gemcitabine, irinotecan, topotecan, sorafenib, apatinib, lenvatinib, regorafenib, cabozantinib, ramucirumab, nivolumab, pembrolizumab, vitamin C, copper peptide, glutathione, nicotinamide, dexamethasone, prednisolone, levofloxacin, moxifloxacin, and methylene blue.

[0017] The photodegradable drug-loaded particles, wherein the terminal bridging groups in the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 are independently selected from one of amino, carboxyl, aldehyde, thiol, carbon-carbon double bond, carbon-carbon triple bond, acryloyl, methacryloyl, azido, epoxy, vinyl sulfone, succinimide, dibenzylcyclooctyne, di(p-nitrobenzene) carbonate and norbornene.

[0018] The photodegradable drug-loaded particles, wherein, in terms of mass percentage, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is (0-99):(1-99):(0-99), and the total mass fraction of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is 100.

[0019] The photodegradable drug-loaded particles have a particle size of 20 μm-1000 μm.

[0020] The photodegradable drug-loaded particles can undergo degradation reaction and release drug molecules under light with a wavelength of 200-1200nm.

[0021] A method for preparing photodegradable drug-loaded microparticles comprises the following steps:

[0022] Mixing the cross-linked polymer M1, the cross-linked polymer M2, the polyelectrolyte polymer M3, the initiator and the solvent to obtain an aqueous solution;

[0023] The aqueous solution is subjected to a cross-linking polymerization reaction under external conditions to obtain photodegradable particles;

[0024] The aqueous solution containing the drug is mixed with the photodegradable microparticles to obtain photodegradable drug-loaded microparticles.

[0025] In the method for preparing the photodegradable drug-loaded microparticles, the cross-linking polymerization reaction is initiated by heating, ultraviolet light irradiation or a chemical cross-linking agent.

[0026] The method for preparing the photodegradable drug-loaded microparticles, wherein the method for obtaining the photodegradable microparticles comprises one of a droplet microfluidics method, a mechanical stirring emulsification method, a membrane emulsification method, an electrospray method, a high-pressure homogenization method, and a high-speed shear method;

[0027] And / or, the droplet shear position structure of the microfluidic device in the droplet microfluidic method includes one of a T-type, a Y-type, and a cross-type;

[0028] And / or, the photodegradable particles are spherical, elongated or irregular in shape.

[0029] The invention discloses an application of photodegradable drug-loaded microparticles in the preparation of embolic agents, subcutaneous injection materials and ophthalmic gel materials.

[0030] Application of photodegradable drug-loaded microparticles in the preparation of drugs for treating liver cancer, lung cancer, kidney cancer, uterine fibroids, prostatic hyperplasia, prostatic tumors, breast cancer, skin filling, keratitis and conjunctivitis.

[0031] Beneficial effects: The present invention provides a photodegradable drug-loaded particle and a preparation method and application thereof, wherein the photodegradable drug-loaded particle comprises: a cross-linked polymer M1, a cross-linked polymer M2 and a polyelectrolyte polymer M3; the cross-linked polymer M2 contains a plurality of photo-cleavable groups; the polyelectrolyte polymer M3 contains a plurality of ionizable groups and is electrostatically adsorbed with drug molecules; wherein the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 all contain at least two terminal bridging groups, and the photodegradable drug-loaded particles having a gel three-dimensional network structure are formed by cross-linking reaction between the terminal bridging groups of the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3. The present invention uses cross-linked polymer M1 to provide mechanical strength and biocompatibility for photodegradable microparticles. The cross-linked polymer M2 is formed by incorporating photodegradable groups into the polymer skeleton, which provides photodegradable properties for the microparticles. The polyelectrolyte polymer M3 provides drug-carrying properties for the microparticles. The three polymers are reacted through terminal bridging groups to form gel microparticles. Since the material structure contains photodegradable groups, when irradiated with light of a specific wavelength, chemical bonds break and the microparticles degrade. In addition, due to the presence of the gel three-dimensional network and polyelectrolyte groups in the microparticle material structure, a variety of macromolecular or small molecule drugs can be loaded. When the microparticles are irradiated with light, photodegradation occurs and the loaded drugs are released. By adjusting the wavelength, intensity, irradiation time or intermittent mode of light, the degradation rate of the microparticles can be accurately controlled to achieve programmed release of drugs. The drug is released only when needed by light triggering, avoiding the problem of unstable drug efficacy caused by "early release" or "retention" of drugs in traditional carriers. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the concept of microparticle preparation, drug loading and photodegradation in the present invention;

[0033] Figure 2 A schematic diagram of a process for preparing photodegradable drug-loaded microparticles according to the present invention;

[0034] Figure 3 The schematic diagram of the cleavage mechanism of the photosensitive group o-nitrobenzyl and the photodegradation of the hydrogel;

[0035] Figure 4 The microscopic characterization image shows the capsule-shaped photodegradable PEG-ONB microparticles prepared based on the droplet microfluidics method.

[0036] Figure 5 The microscopic characterization diagram of the in vitro photodegradation process of the photodegradable microparticle PEG-ONB;

[0037] Figure 6Backlight illumination images and thermal imaging images of rabbit ears embolized with PEG-ONB microparticles at different time points (before embolization, after embolization, 6 hours, 2 days, 7 days, and 14 days);

[0038] Figure 7 :(A) Backlight illumination image and thermal imaging image of the rabbit ear before and after 365nm ultraviolet light irradiation 6 hours after rabbit ear embolization; H&E staining images of the rabbit ear after microparticle degradation (B), before embolization (C), and after embolization but without microparticle degradation (D);

[0039] Figure 8 The microscopic characterization of the round photodegradable microparticles prepared by droplet microfluidics method;

[0040] Fig. 9 Schematic diagram of the synthesis principle of PAA-PEGMA;

[0041] Fig.10 Microscopic characterization of (A) PEG-ONB-PAA microparticles and (B) photodegradable drug-loaded microparticles DOX@PEG-ONB-PAA prepared based on droplet microfluidics method;

[0042] Fig.11 The microscopic characterization diagram of the in vitro photodegradation process of the photodegradable microparticle PEG-ONB;

[0043] Fig.12 The drug release curve data of DOX@PEG-ONB-PAA microparticles with and without 365nm ultraviolet light irradiation;

[0044] Fig.13 The figure shows the particle degradation and drug release of DOX@PEG-ONB-PAA particles in the decellularized liver model under 365nm ultraviolet light irradiation;

[0045] Fig.14 Bright field and fluorescence images of the decellularized liver injected with black ink before (A) and after (B) degradation of DOX@PEG-ONB-PAA microparticles;

[0046] Fig.15 :(A) Backlight illumination image and thermal imaging image of rabbit ear (before embolization, after embolization and after UV irradiation); Bright field microscopic image (B) and fluorescence microscopic image (C) of rabbit ear cross section;

[0047] Fig.16 This is a microscopic characterization of the photodegradable drug-loaded microparticles prepared based on the emulsification stirring method;

[0048] Fig.17 The illumination time required for the complete degradation of the photodegradable microparticles prepared in Examples 1-6 in vitro;

[0049] Fig.18 The illumination time required for the complete degradation of the photodegradable microparticles prepared in Examples 7-10 in vitro. DETAILED DESCRIPTION

[0050] The present invention provides a photodegradable drug-loaded microparticle and a preparation method and application 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 used to limit the present invention.

[0051] 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.

[0052] The present invention provides a photodegradable drug-loaded particle, comprising: a cross-linked polymer M1, a cross-linked polymer M2 and a polyelectrolyte polymer M3;

[0053] The cross-linked polymer M2 contains multiple photo-cleavable groups; the polyelectrolyte polymer M3 contains multiple ionizable groups and has drug molecules adsorbed by electrostatics; wherein the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 all contain at least two terminal bridging groups, and the terminal bridging groups of the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 undergo cross-linking reactions to form photodegradable drug-loaded particles with a three-dimensional gel network structure.

[0054] In this embodiment, the schematic diagram of the microparticle preparation, drug loading and photodegradation concept is as follows Figure 1As shown, cross-linked polymer M1 is used to provide mechanical strength and biocompatibility for photodegradable microparticles. Cross-linked polymer M2 is formed by incorporating photodegradable groups into the polymer skeleton, which provides photodegradable properties for the microparticles. Polyelectrolyte polymer M3 provides drug-carrying properties for the microparticles. The three polymers are reacted through terminal bridging groups to form gel microparticles. Since the material structure contains photodegradable groups, when irradiated with light of a specific wavelength, chemical bonds break and the microparticles degrade. In addition, due to the presence of the gel three-dimensional network and polyelectrolyte groups in the microparticle material structure, a variety of macromolecular or small molecule drugs can be loaded. When the microparticles are irradiated with light, they are photodegraded and the loaded drugs are released. By adjusting the wavelength, intensity, irradiation time or intermittent mode of light, the degradation rate of the microparticles can be precisely controlled to achieve programmed release of drugs. The drug is released only when needed by light triggering, avoiding the problem of unstable drug efficacy caused by "early release" or "retention" of drugs in traditional carriers.

[0055] Specifically, the microparticles can be loaded with a variety of macromolecular or small molecule drugs (such as anticancer drugs, anti-inflammatory drugs or antibacterial drugs) and degrade under specific wavelength light to release the loaded drugs; traditional embolization therapy easily leads to permanent vascular obstruction, and the present invention can achieve on-demand reopening of embolized blood vessels through the photodegradation function of the microparticles, which is convenient for dynamic adjustment of treatment plans and handling of possible accidental embolism; by adjusting the wavelength, intensity, irradiation time or intermittent mode of light, the degradation rate of the microparticles can be precisely controlled to achieve programmed release of drugs. In addition, in addition to being used for vascular embolization, the photodegradable drug-loaded particles also show great potential in the filling, repair and treatment of injectable superficial tissues. Therefore, the photodegradable drug-loaded particles can also be used in non-surgical beauty. By filling subcutaneous tissue, light-triggered drug release (collagen production factors, whitening factors or antioxidants, etc.) and shape adjustment are used to repair facial wrinkles; they can also be used in the field of ophthalmology, such as by directly injecting particles loaded with anti-inflammatory or antibacterial drugs into the corneal stroma or conjunctiva to treat keratitis or conjunctivitis-like diseases, providing continuous drug release and significantly improving local treatment effects.

[0056] In some embodiments, the cross-linked polymer M1 contains a main chain L1, and the cross-linked polymer M2 contains a main chain L2; both the main chain L1 and the main chain L2 are hydrophilic polymers.

[0057] In some embodiments, the hydrophilic polymer comprises C 2 -C nNatural or synthetic polymer compounds with alkyl chains, or their derivatives after substitution, position substitution, or functional modification, specifically including but not limited to linear or branched structures with hydroxyl, carboxyl, amide, ether or ester groups, and modified forms containing aromatic or cyclic groups. Because the macromolecules used are macromolecules, the number of carbon atoms in the main chain alkyl chain is relatively large. Here, C is used for synthetic macromolecules. 2 -C n To summarize, natural polymers have no repeating units.

[0058] In some embodiments, the hydrophilic polymer includes gelatin, collagen, hyaluronic acid, sodium alginate, agarose, polyamino acid, serum albumin, chitin, chitosan, starch, cellulose, polylactic acid, polylactic acid-co-glycolic acid, polyethylene glycol, polyvinyl alcohol, polyacrylic acid or one of the derivatives related to the hydrophilic polymer. That is, the main chain L1 and the main chain L2 are independently selected from but not limited to gelatin, collagen, hyaluronic acid, sodium alginate, agarose, polyamino acid, serum albumin, chitin, chitosan, starch, cellulose, polylactic acid, polylactic acid-co-glycolic acid, polyethylene glycol, polyvinyl alcohol, polyacrylic acid or one of the derivatives related to the hydrophilic polymer of various molecular weights. The main chain L1 and the main chain L2 are used to provide the microparticles with the strength and morphology of the hydrogel and biocompatibility. The above materials are commonly used medical polymer materials with excellent biocompatibility.

[0059] In some embodiments, the photocleavable group is selected from but not limited to one of nitrobenzenes, coumarins, benzoyls, indoles, and quinolines.

[0060] In some embodiments, the photocleavable group is selected from but not limited to o-nitrobenzyl, 4-aminobenzoyl, 4-amino-3-nitrobenzoyl, 4-amino-5-nitrobenzoyl, 8-nitroadenine, 8-nitroadenine-5'-diphosphate, 4-nitrobenzoyl, 4-nitro-3-aminobenzoyl, 4,5-dimethoxy-2-nitrobenzyl, 1-(2-nitrophenyl)propyl, 1(-2-nitrophenyl)ethyl, 7-methoxycoumarin-4-methyl, 4-methylcoumarin and its carbonate, anthraquinone-2-methoxycarbonyl. The photocleavable group provides the microparticle with photodegradable properties. The above photosensitive groups and their related derivative groups can be photodegraded under light of different wavelengths, so that when the microparticles are irradiated with light of a specific wavelength, the chemical bonds of the microparticles are broken to achieve microparticle degradation.

[0061] In some embodiments, the polyelectrolyte polymer M3 is obtained by modifying the polyelectrolyte with the terminal bridging group; the polyelectrolyte includes but is not limited to at least one of polyacrylic acid, carboxymethyl cellulose, carboxymethyl chitosan, sodium alginate, G4 dendrimer, polyglutamic acid, polyaspartic acid, poly(allylamine), 2-aminoethyl methacrylate hydrochloride, polyethyleneimine, polydiallyldimethylammonium chloride, poly[2-(N,N-dimethylamino)ethyl methacrylate], and chitosan; and / or, the ionizable group includes but is not limited to at least one of carboxyl, sulfonic acid, sulfinic acid, phosphate, phosphite, hypophosphite, and amino. The polyelectrolyte is used to provide the microparticle with drug-carrying properties. The multiple ionizable groups on the polyelectrolyte form a local potential after ionization, inducing the aggregation of drugs with opposite charges to achieve drug loading. When the microparticle is irradiated with light, it undergoes photodegradation and releases the loaded drug therein, and by adjusting the wavelength, intensity, irradiation time, or intermittent mode of light, the degradation rate of the microparticle can be precisely controlled to achieve programmed release of the drug.

[0062] In some embodiments, the drug molecule includes but is not limited to at least one of doxorubicin hydrochloride, paclitaxel, epirubicin, mitomycin, fluorouracil, cisplatin, oxaliplatin, capecitabine, gemcitabine, irinotecan, topotecan, sorafenib, apatinib, lenvatinib, regorafenib, cabozantinib, ramucirumab, nivolumab, pembrolizumab, vitamin C, copper peptide, glutathione, nicotinamide, dexamethasone, prednisolone, levofloxacin, moxifloxacin, and methylene blue.

[0063] In some embodiments, the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 all include at least two terminal bridging functional groups, and the polymers can be connected to form a gel through the terminal bridging functional group reaction. The terminal bridging groups in the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 are independently selected from one of amino, carboxyl, aldehyde, thiol, carbon-carbon double bond, carbon-carbon triple bond, acryloyl, methacryloyl, azido, epoxy, vinyl sulfone, succinimide, dibenzylcyclooctyne, di(p-nitrobenzene) carbonate and norbornene.

[0064] Specifically, carbon-carbon double bonds, acryloyl groups, and methacryloyl groups can initiate free radical polymerization reactions through light or heat; groups containing active olefinic bonds or carbonyl groups, such as carbon-carbon double bonds, carbon-carbon triple bonds, acryloyl groups, and methacryloyl groups, can undergo Michael addition reactions with sulfhydryl groups and amine groups; aldehyde groups can undergo nucleophilic addition reactions with amine groups, sulfhydryl groups, and hydroxyl groups; azido groups, alkynyl groups, or dibenzylcyclooctyne groups can undergo azide-alkyne cycloaddition reactions; epoxy groups can undergo epoxy ring-opening reactions with amine groups, sulfhydryl groups, and hydroxyl groups; amino groups can undergo electrophilic addition reactions with carboxyl groups or The hydroxyl group undergoes a condensation reaction to form an amide bond or an ester bond; the succinimide group as an activated carboxyl group can react with the amine group to form an amide bond; the double bond of the norbornene group can undergo an addition reaction with nucleophilic reagents such as amine groups and hydroxyl groups under catalytic conditions; the di(p-nitrobenzene) carbonate group undergoes a nucleophilic substitution reaction with the amine group or the thiol group, so through different bridging groups at the ends of the polymer, the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 can react to form gel particles.

[0065] In some embodiments, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is (0-99): (1-99): (0-99), and the total mass fraction of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is 100. The cross-linked polymer M1 provides mechanical strength and biocompatibility for the microparticles, the cross-linked polymer M2 provides photodegradability, and the polyelectrolyte polymer M3 enhances drug loading performance. When the microparticles are composed of cross-linked polymer M1 (dosage range (w / v): 1-99%) and cross-linked polymer M2 (dosage range (w / v): 1-99%), they are photodegradable microparticles, and the drug loading performance only depends on a small amount of ionizable groups on the main chains L1 and L2, and the drug loading effect is poor; when the microparticles are composed of cross-linked polymer M1 (dosage range (w / v): 0-98%), cross-linked polymer M2 (dosage range (w / v): 1-99%) and polyelectrolyte polymer M3 (dosage range (w / v): 1-99%), they are photodegradable drug-loaded microparticles. The weight percentage of each component in the microparticles can be adjusted according to actual conditions. When the weight of the cross-linked polymer remains unchanged, the more weight percentage of the cross-linked polymer M2 that provides photodegradability, the stronger the photodegradability of the obtained microparticles; the more weight percentage of the polyelectrolyte polymer M3 that provides drug loading performance, the stronger the drug loading of the obtained microparticles.

[0066] In some embodiments, the particle size of the photodegradable drug-loaded microparticles is 20 μm-1000 μm.

[0067] In some embodiments, the photodegradable drug-loaded microparticles can undergo degradation reaction and release drug molecules under light with a wavelength of 200-1200 nm.

[0068] Photodegradable drug-carrying microparticles are prepared based on droplet microfluidics equipment. Cross-linked polymers M1, M2 and polyelectrolyte polymers M3 can react through terminal bridging groups to form photodegradable drug-carrying microparticles through microfluidics. The microparticles are rich in ionizable groups, which form local potentials after ionization, inducing the aggregation of particles with opposite charges to achieve drug loading.

[0069] Based on this, Figure 2 As shown, the present invention also provides a method for preparing photodegradable drug-loaded microparticles, comprising the steps of:

[0070] Step S10: mixing the cross-linked polymer M1, the cross-linked polymer M2, the polyelectrolyte polymer M3, the initiator and the solvent to obtain an aqueous solution;

[0071] Step S20: subjecting the aqueous solution to a cross-linking polymerization reaction under external conditions to obtain photodegradable particles;

[0072] Step S30: mixing the aqueous solution containing the drug with the photodegradable microparticles to obtain photodegradable drug-loaded microparticles.

[0073] In this embodiment, the cross-linked polymer M1 is used to provide mechanical strength and biocompatibility for the photodegradable microparticles. The cross-linked polymer M2 is formed by incorporating photodegradable groups into the polymer skeleton, which provides the microparticles with photodegradable properties. The polyelectrolyte polymer M3 provides the microparticles with drug-carrying properties. The three polymers are used to react through the terminal bridging groups to form gel microparticles. Since the material structure contains photodegradable groups, when irradiated with light of a specific wavelength, chemical bonds break and the microparticles degrade. In addition, due to the presence of the gel three-dimensional network and polyelectrolyte groups in the microparticle material structure, a variety of macromolecular or small molecule drugs can be loaded. When the microparticles are irradiated with light, photodegradation occurs and the loaded drugs are released. By adjusting the wavelength, intensity, irradiation time or intermittent mode of light, the degradation rate of the microparticles can be accurately controlled to achieve programmed release of drugs. In addition, the preparation method is simple, has a high yield rate, and is easy to achieve large-scale production.

[0074] In some embodiments, the cross-linking polymerization reaction is initiated by heating, ultraviolet light irradiation, or a chemical cross-linking agent.

[0075] In some embodiments, the method for obtaining the photodegradable microparticles comprises one of a droplet microfluidics method, a mechanical stirring emulsification method, a membrane emulsification method, an electrospray method, a high-pressure homogenization method, and a high-speed shear method; and / or, the droplet shear position structure of the microfluidic device in the droplet microfluidics method comprises one of a T-type, a Y-type, and a cross-type; and / or, the shape of the photodegradable microparticles is spherical, elongated, or irregular.

[0076] This embodiment adopts a microfluidic method to prepare microparticles, and the size and shape of the microparticles can be controlled by regulating the flow rates of the oil phase and the water phase, and selecting microfluidic chips with different flow channels.

[0077] In some embodiments, the preparation of microparticles with regular shape and uniform size can also be prepared by other methods without special restrictions; such as mechanical stirring emulsification, membrane emulsification, electrospraying, high-pressure homogenization and high-speed shearing, etc. After the microparticles are prepared, they can be sieved to obtain microparticles with a narrower particle size range.

[0078] In some embodiments, in step S20, the external conditions include ultraviolet light crosslinking, glutaraldehyde thermal crosslinking, ionic crosslinking, etc., which mainly depends on the bridging group at the end of the polymer, the selection of a suitable initiator and reaction conditions to achieve reaction crosslinking between the crosslinked polymer M1, the crosslinked polymer M2 and the polyelectrolyte polymer M3.

[0079] In some embodiments, the initiator includes a photoinitiator, a thermal initiator, etc.; the photoinitiator includes but is not limited to at least one of LAP, ammonium persulfate, benzoyl peroxide, azobisisobutyronitrile, and diphenylmethane.

[0080] In some embodiments, in the step S20, the preparation of photodegradable particles by a droplet microfluidic method specifically includes building an experimental system; for example, the oil phase solution and the aqueous phase solution are respectively sucked into a syringe, the needle of the syringe is connected to a silicone hose, a small steel tube is put on the other end of the silicone hose, and the small steel tube is inserted into a cross-shaped liquid inlet to achieve liquid injection, and the syringe is installed on a microinjector, and the flow rate of the two solutions is controlled by the microinjector; the aqueous phase solution and the oil phase solution entering the microfluidic chip meet at the intersection of the "T"-shaped structure, because the oil phase and water are incompatible with each other and the flow rate of the oil phase is set to be relatively large, the photo-crosslinkable aqueous phase solution is cut into droplets of a certain length; after the droplets are generated, they are solidified in the pipeline (ultraviolet light irradiates the droplets in the flow channel) and are discharged at the end of the straight tube, the end of the microfluidic chip is immersed in a beaker containing a collection liquid, and then the microparticle-shaped photodegradable material is collected: the collection liquid is centrifuged to separate the photodegradable particles at the bottom, washed and stored.

[0081] In some embodiments, the oil phase solution includes but is not limited to pure soybean oil, paraffin oil lamp vegetable oil or mineral oil. The collection solution includes but is not limited to 1*PBS-10*PBS or pure soybean oil, paraffin oil and other vegetable oils or mineral oils.

[0082] In addition, the present invention also provides an application of photodegradable drug-loaded microparticles in the preparation of embolic agents, subcutaneous injection solutions, and ophthalmic gel materials; or, an application of photodegradable drug-loaded microparticles in the preparation of treatments for diseases such as liver cancer, lung cancer, kidney cancer, uterine fibroids, prostate hyperplasia, prostate tumors, breast cancer, skin fillings, keratitis, conjunctivitis, etc.

[0083] In this embodiment, the microparticles can achieve controllable and programmed release of the loaded drugs by regulating the light irradiation process, which can be used to enhance the drug treatment effect during embolization therapy, and can also be used for filling, repairing and treating injectable superficial tissues, such as corneal, conjunctival or skin filling.

[0084] In some embodiments, blank photodegradable microparticles without drug loading can be used for transcatheter interventional embolization therapy, and drug-loaded photodegradable microparticles can be loaded with a variety of chemotherapy drugs for transcatheter interventional embolization chemotherapy, and the loaded drugs include but are not limited to doxorubicin, paclitaxel, cisplatin, etc. The treatment range includes interventional treatment of liver cancer, lung cancer, kidney cancer, uterine fibroids, prostatic hyperplasia, prostate tumors, breast cancer and other diseases, which has important medical value and broad application prospects.

[0085] Specifically, the microparticles have the function of photodegradation on demand and can be used in the field of interventional embolization. When blank photodegradable microparticles are used for embolization, the microparticles can achieve on-demand recanalization of blood vessels through the photodegradation function; when drug-loaded photodegradable microparticles are used for embolization, the microparticles can effectively deal with possible non-targeted embolism and enhance the killing effect of drugs through the functions of on-demand photodegradation and controllable drug release.

[0086] In addition, the drug-loaded photodegradable microparticles can also be used in non-surgical cosmetic surgery to repair facial wrinkles. The microparticles can effectively improve dynamic and static wrinkles by filling subcutaneous tissue and restoring the elasticity and luster of the skin. In addition, light-triggered microparticles can be used to release drugs or adjust their shapes to provide patients with personalized treatment plans. For example, microparticle materials with adjustable degradation rates can continuously release collagen production factors (vitamin C, copper peptides, etc.) or whitening factors (glutathione, niacinamide, etc.), significantly prolonging the duration of wrinkle removal effects or achieving targeted whitening treatments.

[0087] Moreover, the drug-carrying photodegradable microparticles can also be applied in the field of ophthalmology, such as injecting the corneal stroma layer to treat keratitis or injecting into the conjunctival sac to treat conjunctivitis-like diseases. The cornea, as the transparent protective layer of the eyeball, is prone to inflammation or ulcers when infected or damaged, affecting vision and even causing blindness. By directly injecting microparticles carrying anti-inflammatory (dexamethasone, prednisolone, etc.) or antibacterial drugs (levofloxacin, moxifloxacin, etc.) into the corneal stroma layer, with the help of the characteristics of photosensitive materials, the on-demand release of drugs can be achieved under the stimulation of external light sources, avoiding the problem of reduced efficacy of traditional eye drops due to tear dilution or frequent dripping. Similarly, for conjunctival diseases, the use of drug-carrying hydrogel microparticles can provide continuous drug release, significantly improving the local treatment effect.

[0088] 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.

[0089] Example 1

[0090] In this example, a droplet microfluidic method is used to prepare photodegradable microparticles, wherein the cross-linked polymer M1 is polyethylene glycol dimethacrylate (PEGDA, molecular weight: 400), and the terminal bridging groups R1 and R2 are acryloyl groups; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated o-nitrobenzyl (ONB) into the polyethylene glycol polymer main chain, the photosensitive groups A1 and A2 are o-nitrobenzyl groups, and the terminal bridging groups R3 and R4 are acryloyl groups; the cross-linked polymers M1 and M2 can be prepared into uniform-sized photodegradable PEG-ONB microparticles through a microfluidic system by photoinitiated free radical cross-linking in the presence of a photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP). The photosensitive group o-nitrobenzyl in the cross-linked polymer M2 can undergo chemical bond cleavage under the irradiation of 365nm ultraviolet light to generate carboxylic acid and o-nitrobenzylidene acetaldehyde to achieve degradation of the microparticles, such as Figure 3 In this embodiment, the mass ratio of the cross-linked polymer M1 to the cross-linked polymer M2 is 50:50. The preparation process is as follows:

[0091] (1) Weigh 40 mg of cross-linked polymer M2 and 40 μL of cross-linked polymer M1 into a centrifuge tube, add 1 mL of 1*PBS buffer to fully dissolve them, and then add 100 μL of photoinitiator LAP with a concentration of 2.5 wt% to prepare a dispersed phase solution.

[0092] (2) Analytically pure soybean oil was used as the continuous phase solution.

[0093] (3) Analytically pure soybean oil was placed in a 50 mL beaker and a magnetic bar was added as the collection liquid.

[0094] (4) Use 5 mL and 20 mL disposable plastic syringes to extract a certain volume of dispersed phase solution and continuous phase solution, respectively. Connect the syringe needle to the injection hole of the microfluidic chip (channel diameter 700 μm) through a silicone hose and a small steel tube, so that the dispersed phase solution and the continuous phase solution are injected from the two branches of the T-shaped structure respectively. The disposable plastic syringe is loaded on a microinjection pump to achieve flow rate control of the injection liquid. The flow rate of the continuous phase solution is controlled to be 20 μL / min, and the flow rate of the dispersed phase solution is controlled to be 10 μL / min.

[0095] (5) The injected dispersed phase solution is dispersed into long strip-shaped droplets at the T-junction. When the droplet shape is stable, 405 nm ultraviolet light is irradiated on the droplets in the channel of the microfluidic chip to solidify the droplets. The end of the microfluidic chip is immersed in the collecting liquid (the collecting liquid just covers the particle discharge port), and the collecting liquid is stirred at 200 rpm. After solidification, the ultraviolet lamp is removed.

[0096] (6) After continuously injecting the dispersed phase solution and the continuous phase solution for one hour, the microfluidic chip was evacuated, and the collected liquid and the particles were transferred to a 15 mL centrifuge tube. After the particles settled, the upper oil was removed. The obtained particles were washed with acetone, added with acetone, shaken, and after the particles settled, the acetone was removed. Repeat the acetone wash twice, and then wash with pure water three times. The final particles were long strips of hydrogel, which were stored in 1*PBS.

[0097] (7) Capsule-shaped photodegradable microparticles of PEG-ONB were obtained and observed under a microscope. Figure 4 As shown (scale bar: 1 mm).

[0098] The photodegradation effect of the prepared photodegradable PEG-ONB microparticles in vitro was studied as follows: an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The image of the particle degradation process is shown in Figure 5 As shown (scale bar: 1 mm), the complete degradation time is Fig.17 shown.

[0099] The in vivo embolization effect of the prepared photodegradable microparticles PEG-ONB was studied as follows: After the photodegradable microparticles were disinfected with 75% alcohol, the microparticles were injected into the central auricular artery of the rabbit using a syringe. Figure 6 As shown (scale: 1 cm, the dotted circle indicates the injection site, and the dotted line indicates the embolized blood vessel), the blood flow in the rabbit ear was significantly blocked after embolization with PEG-ONB microparticles, and the embolism stability was maintained within two weeks.

[0100] The photodegradation effect of the prepared photodegradable PEG-ONB microparticles in vivo was studied as follows: After the photodegradable PEG-ONB microparticles were injected into the blood vessels of the rabbit ears, the embolization area of ​​the rabbit ears was irradiated with 365nm ultraviolet light to verify its photodegradation effect in vivo. The macroscopic appearance and thermal imaging images of the embolized rabbit ears before and after the photodegradation of the PEG-ONB microparticles were recorded with a camera and a thermal imager. Figure 7 As shown in (A) in the figure. After the intravascular PEG-ONB microparticles were exposed to ultraviolet light, both backlight illumination and thermal imaging images confirmed the restoration of blood flow, indicating that the microparticles were photodegraded to achieve vascular restoration. The H&E stained tissue sections of the rabbit ears after microparticle degradation are shown in Figure 7 As shown in (B), compared with the rabbit ears without embolization and the rabbit ears without degradation of microparticles after embolization ( Figure 7 Compared with (C) and (D) in the figure, the thickness of the blood vessel wall was restored after the restoration, and the blood vessel maintained a smooth lumen. This further proves that the photodegradable function of PEG-ONB particles can achieve blood vessel restoration, providing a potential possibility for solving non-targeted embolism. Figure 7 Scale bars: 1 mm (B1, C1, D1); 250 μm (B2, C2, D2)

[0101] Example 2

[0102] In this embodiment, photodegradable microparticles are prepared by a droplet microfluidic method, wherein the cross-linked polymer M1 is double-bond modified starch, the main chain L1 is starch, and the terminal bridging groups R1 and R2 are double bonds; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated 7-methoxycoumarin-4-methyl into the main chain of a hyaluronic acid polymer, the main chain L2 is hyaluronic acid, the photosensitive groups A1 and A2 are 7-methoxycoumarin-4-methyl, and the terminal bridging groups R3 and R4 are acryloyl groups. In this embodiment, the mass ratio of the cross-linked polymer M1 and the cross-linked polymer M2 is 30:70. The microparticle preparation steps refer to Example 1, wherein in this embodiment, the weighed masses of the cross-linked polymer M1 and the cross-linked polymer M2 are 15 mg and 35 mg, respectively, in 1 mL 1*PBS buffer, the channel diameter of the microfluidic chip in this embodiment is 300 μm, the flow rate of the continuous phase solution is 40 μL / min, and the flow rate of the dispersed phase solution is 10 μL / min. Round photodegradable microparticles are obtained, and observation under a microscope is as follows Figure 8 As shown (scale bar: 500 μm).

[0103] The photodegradation effect of the prepared photodegradable particles in vitro was studied as follows: the particles were illuminated with an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The time for complete degradation of the particles is as follows Fig.17 shown.

[0104] Example 3

[0105] In this embodiment, a droplet microfluidic method is used to prepare photodegradable microparticles, wherein the cross-linked polymer M1 is double-bond modified alginic acid, the main chain L1 is alginic acid, and the terminal bridging groups R1 and R2 are double bonds; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated 4-aminobenzoyl into the main chain of the polylactic acid polymer, the main chain L2 is polylactic acid, the photosensitive groups A1 and A2 are 4-aminobenzoyl, and the terminal bridging groups R3 and R4 are acryloyl. In this embodiment, the mass ratio of the cross-linked polymer M1 and the cross-linked polymer M2 is 60:40. The microparticle preparation steps refer to Example 1, wherein the weighed masses of the cross-linked polymer M1 and the cross-linked polymer M2 in this embodiment are 120 mg and 80 mg respectively in 1 mL 1*PBS buffer, the channel diameter of the microfluidic chip in this embodiment is 500 μm, the flow rate of the continuous phase solution is 30 μL / min, and the flow rate of the dispersed phase solution is 10 μL / min.

[0106] The photodegradation effect of the prepared photodegradable particles in vitro was studied as follows: the particles were illuminated with an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The time for complete degradation of the particles is as follows Fig.17 shown.

[0107] Example 4

[0108] In this embodiment, a droplet microfluidic method is used to prepare photodegradable microparticles, wherein the cross-linked polymer M1 is a double-bond modified polylactic acid-glycolic acid copolymer, the main chain L1 is a polylactic acid-glycolic acid copolymer, and the terminal bridging groups R1 and R2 are double bonds; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated anthraquinone-2-methoxycarbonyl into the main chain of polyvinyl alcohol, the main chain L2 is polyvinyl alcohol, the photosensitive groups A1 and A2 are anthraquinone-2-methoxycarbonyl, and the terminal bridging groups R3 and R4 are acryloyl groups. In this embodiment, the mass ratio of the cross-linked polymer M1 and the cross-linked polymer M2 is 80:20. The microparticle preparation steps refer to Example 1, wherein the weighed masses of the cross-linked polymer M1 and the cross-linked polymer M2 in this embodiment are 120 mg and 30 mg respectively in 1 mL 1*PBS buffer, the channel diameter of the microfluidic chip in this embodiment is 700 μm, the flow rate of the continuous phase solution is 30 μL / min, and the flow rate of the dispersed phase solution is 10 μL / min.

[0109] The photodegradation effect of the prepared photodegradable particles in vitro was studied as follows: the particles were illuminated with an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The time for complete degradation of the particles is as follows Fig.17 shown.

[0110] Example 5

[0111] In this example, a droplet microfluidics method was used to prepare photodegradable drug-loaded microparticles, wherein the cross-linked polymer M1 was polyethylene glycol dimethacrylate (PEGDA, molecular weight: 400), and the terminal bridging groups R1 and R2 were acryloyl groups. The cross-linked polymer M2 was obtained by incorporating the photocleavable group acrylated o-nitrobenzyl (ONB) into the polyethylene glycol polymer backbone, the photosensitive groups A1 and A2 were o-nitrobenzyl groups, and the terminal bridging groups R3 and R4 were acryloyl groups. The polyelectrolyte polymer M3 was composed of a polyelectrolyte polyacrylic acid (PAA, average molecular weight: 2000) and acrylate-polyethylene glycol-amino (Acrylate-PEG-NH 2 , average molecular weight: 2000) is modified by amidation reaction. The schematic diagram of the synthesis principle is shown in Fig. 9 As shown in Figure 2, under the catalysis of EDC / NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide / N-hydroxysuccinimide), the carboxyl group of PAA was activated and could react with Acrylate-PEG-NH 2 The amino group of the polyelectrolyte polymer M3 undergoes an amidation reaction to synthesize PAA-PEGMA. The ionizable group in the polyelectrolyte polymer M3 is a carboxyl group, which is negatively charged after ionization and can load the positively charged drug doxorubicin (DOX). The terminal bridging groups R5 and R6 are acryloyl groups. The cross-linked polymers M1, M2 and M3 can be prepared into uniform-sized photodegradable drug-loaded particles through a microfluidic system by light-initiated free radical cross-linking in the presence of LAP. In this embodiment, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 is 40:40:20. The preparation process is as follows:

[0112] (1) Carboxyl macromolecules were modified (polyacrylic acid, PAA). 80 mg PAA, 258 mg 1-ethyl-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) were weighed into a centrifuge tube, and 15 mL 1*PBS buffer was added. After ultrasonication for 15 seconds, the tube was wrapped with tin foil and shaken on a shaker for 15 minutes. Then 160 mg Acrylate-PEG-NH 2 ), the pH of the solution was adjusted to 7.20-7.40, and the reaction was continued on a shaker for 12 hours to obtain acrylate-modified carboxyl macromolecule PAA-PEGMA.

[0113] (2) 20 mg of the acrylate-modified carboxyl macromolecule PAA-PEGMA prepared in step (1) of Example 5 was added to the dispersed phase solution prepared in step (1) of Example 1, and the rest remained unchanged. The following can be prepared by droplet microfluidics (the channel diameter of the microfluidic chip is 500 μm): Fig.10PEG-ONB-PAA microparticles shown in (A) (scale bar: 1 mm).

[0114] (3) 5 mg of doxorubicin hydrochloride was added to 1 ml of ultrapure water and ultrasonicated for 10 minutes to completely dissolve the doxorubicin hydrochloride in the ultrapure water. The PEG-ONB-PAA microparticles obtained in (2) were immersed in the doxorubicin (DOX) solution and shaken on a shaker for 24 hours. The doxorubicin hydrochloride drug was adsorbed on the microparticles to obtain the following: Fig.10 (B) shows the photodegradable drug-loaded microparticles DOX@PEG-ONB-PAA (scale bar: 1 mm).

[0115] The in vitro photodegradation performance and drug release performance of the prepared photodegradable drug-loaded microparticles DOX@PEG-ONB-PAA were studied as follows: The photodegradable drug-loaded microparticles DOX@PEG-ONB-PAA were irradiated under 365nm ultraviolet light to observe their degradation and drug release effects. Fig.11 As shown (scale bar: 1 mm).

[0116] The time for complete degradation of microparticles is Fig.17 As shown in the figure, DOX@PEG-ONB-PAA microparticles were completely degraded within 7 minutes. As the microparticles gradually degraded, the loaded drug DOX was gradually released into the solution, and finally 100% of the drug was released, while the control group without UV irradiation only released 2.7% of the drug, as shown in the figure. Fig.12 shown.

[0117] The photodegradation and drug release properties of the prepared photodegradable drug-loaded microparticles DOX@PEG-ONB-PAA in a decellularized liver model were studied as follows: the drug-loaded microparticles DOX@PEG-ONB-PAA were injected into the decellularized liver of rats and irradiated with a 365nm ultraviolet flashlight to observe their embolization and photodegradation drug release effects. The bright field and fluorescence images are shown in Figure 2. Fig.13 To further verify the degradation of the photodegradable drug-loaded microparticles DOX@PEG-ONB-PAA in the decellularized liver after irradiation with 365nm ultraviolet light, black ink was injected into the decellularized liver. Fig.14 As shown (scale bar: 2 mm).

[0118] During 365 nm UV irradiation, the drug diffusion area gradually increased over time, indicating that the microparticles degraded and released the drug into the surrounding decellularized liver matrix. After 9 minutes of UV irradiation, the embolized blood vessels could be refilled with black ink solution, further confirming that the DOX@PEG-ONB-PAA microparticles were completely photodegraded. Therefore, using UV light to photodegrade the drug-loaded microparticles, DOX can be effectively released and diffused into the surrounding tissues, showing the precise spatiotemporal controllability of local chemotherapy.

[0119] The in vivo photodegradation and drug release effects of the prepared photodegradable drug-loaded microparticles DOX@PEG-ONB-PAA were studied as follows:

[0120] The prepared photodegradable drug-loaded microparticles DOX@PEG-ONB-PAA were injected into the blood vessels of rabbit ears, and then irradiated with 365nm ultraviolet light to observe their in vivo photodegradation performance and drug release effect. The macroscopic appearance and thermal imaging images of the rabbit ears before and after embolization and after microparticle photodegradation, such as Fig.15 The corresponding bright field and fluorescence images of the rabbit ear cross section are shown in (A) (scale bar: 1 cm). Fig.15 (B) and (C) (Scale bar: 500 μm; triangles indicate the location of blood vessels). After the blood vessels were embolized by DOX@PEG-ONB-PAA microparticles, blood flow was blocked. After irradiation with 365 nm ultraviolet light, blood flow was restored, indicating that DOX@PEG-ONB-PAA microparticles were photodegraded. As the microparticles degraded, the drug was released into the surrounding tissues, and the fluorescence signal corresponding to the drug in the tissues was enhanced.

[0121] Example 6

[0122] In this embodiment, the stirring emulsification method is used to prepare photodegradable drug-loaded microparticles, wherein the cross-linked polymer M1 is methacrylated gelatin (GelMA), the main chain L1 is gelatin, and the terminal bridging groups R1 and R2 are acryloyl groups; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated o-nitrobenzyl (ONB) into the main chain of polyethylene glycol polymer, the main chain L2 is PEG, the photosensitive groups A1 and A2 are o-nitrobenzyl, and the terminal bridging groups R3 and R4 are acryloyl groups; the polyelectrolyte polymer M3 is a modified polyaspartic acid, and the polyelectrolyte group is a carboxyl group, which can load positively charged drugs such as epirubicin after ionization. In this embodiment, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is 30:60:10. The steps of microparticle preparation and drug loading are as follows;

[0123] (1) Weigh 30 mg of cross-linked polymer M1, 60 mg of cross-linked polymer M2 and 10 mg of polyelectrolyte polymer M3 into a centrifuge tube, add 1 mL of 1*PBS buffer, dissolve in a 40-65°C water bath until fully dissolved, and then add 100 μL of 2.5 wt% photoinitiator LAP to prepare an aqueous solution;

[0124] (2) Weigh 200 g soybean oil in a beaker as the oil phase solution;

[0125] (3) Add the aqueous phase solution and the oil phase solution into a three-necked flask at the same time, stir at 200-5000 rpm for 20 min, and irradiate with ultraviolet light for curing and crosslinking;

[0126] (4) Remove the UV lamp, collect the particles and wash them thoroughly to obtain spherical photodegradable particles such as Fig.16 As shown (scale bar: 250 μm).

[0127] The in vitro photodegradation effect of the prepared photodegradable drug-loaded microparticles was studied as follows: an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The time for complete degradation of the particles is as follows Fig.17 shown.

[0128] Example 7

[0129] In this embodiment, the stirring emulsification method is used to prepare photodegradable drug-loaded microparticles, wherein the cross-linked polymer M1 is double-bond modified polyvinyl alcohol, the main chain L1 is polyvinyl alcohol, and the terminal bridging groups R1 and R2 are double bonds; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated o-nitrobenzyl (ONB) into the main chain of polyethylene glycol polymer, the main chain L2 is PEG, the photosensitive groups A1 and A2 are o-nitrobenzyl, and the terminal bridging groups R3 and R4 are acryloyl; the polyelectrolyte polymer M3 is a modified polyacrylic acid, and the polyelectrolyte group is a carboxyl group, which can load positively charged drugs such as mitomycin after ionization. In this embodiment, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is 20:70:10. The microparticle preparation steps refer to Example 6, wherein the weighed masses of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 in this embodiment are 20 mg, 70 mg, and 10 mg respectively in 1 mL 1*PBS buffer

[0130] The in vitro photodegradation effect of the prepared photodegradable drug-loaded microparticles was studied as follows: an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The time for complete degradation of the particles is as follows Fig.18 shown.

[0131] Example 8

[0132] In this embodiment, the stirring emulsification method is used to prepare photodegradable drug-loaded microparticles, wherein the cross-linked polymer M1 is double-bond modified polyvinyl alcohol, the main chain L1 is polyvinyl alcohol, and the terminal bridging groups R1 and R2 are double bonds; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated o-nitrobenzyl (ONB) into the main chain of polyethylene glycol polymer, the main chain L2 is PEG, the photosensitive groups A1 and A2 are o-nitrobenzyl, and the terminal bridging groups R3 and R4 are acryloyl; the polyelectrolyte polymer M3 is a modified polyacrylic acid, and the polyelectrolyte group is a carboxyl group, which can load positively charged drugs such as mitomycin after ionization. In this embodiment, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is 40:50:10. The microparticle preparation steps refer to Example 6, wherein the weighed masses of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 in this embodiment are 40 mg, 50 mg, and 10 mg respectively in 1 mL 1*PBS buffer

[0133] The in vitro photodegradation effect of the prepared photodegradable drug-loaded microparticles was studied as follows: an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The time for complete degradation of the particles is as follows Fig.18 shown.

[0134] Example 9

[0135] In this embodiment, the stirring emulsification method is used to prepare photodegradable drug-loaded microparticles, wherein the cross-linked polymer M1 is double-bond modified polyvinyl alcohol, the main chain L1 is polyvinyl alcohol, and the terminal bridging groups R1 and R2 are double bonds; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated o-nitrobenzyl (ONB) into the main chain of polyethylene glycol polymer, the main chain L2 is PEG, the photosensitive groups A1 and A2 are o-nitrobenzyl, and the terminal bridging groups R3 and R4 are acryloyl; the polyelectrolyte polymer M3 is a modified polyacrylic acid, and the polyelectrolyte group is a carboxyl group, which can load positively charged drugs such as mitomycin after ionization. In this embodiment, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is 60:30:10. The microparticle preparation steps refer to Example 6, wherein the weighed masses of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 in this embodiment are 60 mg, 30 mg, and 10 mg respectively in 1 mL 1*PBS buffer

[0136] The in vitro photodegradation effect of the prepared photodegradable drug-loaded microparticles was studied as follows: an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The time for complete degradation of the particles is as follows Fig.18 shown.

[0137] Example 10

[0138] In this embodiment, the stirring emulsification method is used to prepare photodegradable drug-loaded microparticles, wherein the cross-linked polymer M1 is double-bond modified polyvinyl alcohol, the main chain L1 is polyvinyl alcohol, and the terminal bridging groups R1 and R2 are double bonds; the cross-linked polymer M2 is obtained by incorporating the photocleavable group acrylated o-nitrobenzyl (ONB) into the main chain of polyethylene glycol polymer, the main chain L2 is PEG, the photosensitive groups A1 and A2 are o-nitrobenzyl, and the terminal bridging groups R3 and R4 are acryloyl; the polyelectrolyte polymer M3 is a modified polyacrylic acid, and the polyelectrolyte group is a carboxyl group, which can load positively charged drugs such as mitomycin after ionization. In this embodiment, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 is 80:10:10. The microparticle preparation steps refer to Example 6, wherein the weighed masses of the cross-linked polymer M1, the cross-linked polymer M2, and the polyelectrolyte polymer M3 in this embodiment are 80 mg, 10 mg, and 10 mg respectively in 1 mL 1*PBS buffer

[0139] The in vitro photodegradation effect of the prepared photodegradable drug-loaded microparticles was studied as follows: an ultraviolet flashlight (365 nm, 130 mW / cm 2 ) until the particles are completely degraded. The time for complete degradation of the particles is as follows Fig.18 shown.

[0140] The types of microparticle cross-linked polymers M1, M2, and M3 prepared in Examples 7-10 remain unchanged. When the weight of the cross-linked polymer remains unchanged (10wt%), the greater the weight portion of the cross-linked polymer M2 with photodegradable properties, the stronger the photodegradability of the obtained microparticles, and the shorter the illumination time required for complete degradation of the microparticles.

[0141] Therefore, the photodegradable drug-loaded microparticles of the present invention can achieve effective recanalization of blood vessels and controlled release of drugs through photoresponsive degradation in rabbit ear blood vessels. This application shows that the microparticles have good biocompatibility and photoresponsive characteristics, and can achieve directional degradation in vivo. Based on its photodegradation mechanism and material properties, its microparticles are also suitable for a variety of scenarios in injectable superficial tissues, such as cosmetic uses of tissue filling by subcutaneous injection or the treatment of diseases such as keratitis. Specifically, by regulating the degradation rate and drug release process of the microparticles through local illumination, it is expected to achieve dynamic adjustment of the filling function, and promote further enhancement of the cosmetic effect by loading specific drugs (such as collagen production factors or whitening factors). In addition, the potential application of the microparticles in the corneal stroma is also feasible, such as injection into the corneal stroma or conjunctival sac, and light-triggered release of anti-inflammatory or antibacterial drugs for the treatment of diseases such as keratitis or conjunctivitis.

[0142] In summary, the present invention provides a photodegradable drug-loaded particle and a preparation method and application thereof. The photodegradable drug-loaded particle comprises: a cross-linked polymer M1, a cross-linked polymer M2 and a polyelectrolyte polymer M3; the cross-linked polymer M2 contains multiple photocleavable groups; the polyelectrolyte polymer M3 contains multiple ionizable groups and is electrostatically adsorbed with drug molecules; wherein the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 all contain at least two terminal bridging groups, and the terminal bridging groups of the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 undergo cross-linking reaction with each other to form a photodegradable drug-loaded particle with a gel three-dimensional network structure. The present invention uses cross-linked polymer M1 to provide mechanical strength and biocompatibility for photodegradable microparticles. The cross-linked polymer M2 is formed by incorporating photodegradable groups into the polymer skeleton, which provides photodegradable properties for the microparticles. The polyelectrolyte polymer M3 provides drug-carrying properties for the microparticles. The three polymers are reacted through terminal bridging groups to form gel microparticles. Since the material structure contains photodegradable groups, when irradiated with light of a specific wavelength, chemical bonds break and the microparticles degrade. In addition, due to the presence of the gel three-dimensional network and polyelectrolyte groups in the microparticle material structure, a variety of macromolecular or small molecule drugs can be loaded. When the microparticles are irradiated with light, photodegradation occurs and the loaded drugs are released. By adjusting the wavelength, intensity, irradiation time or intermittent mode of light, the degradation rate of the microparticles can be accurately controlled to achieve programmed release of drugs. The drug is released only when needed by light triggering, avoiding the problem of unstable drug efficacy caused by "early release" or "retention" of drugs in traditional carriers.

[0143] 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 photodegradable drug-loaded microparticle, characterized in that: Comprising: cross-linked polymer M1, cross-linked polymer M2 and polyelectrolyte polymer M3; The cross-linked polymer M2 contains multiple photo-cleavable groups; the polyelectrolyte polymer M3 contains multiple ionizable groups and has drug molecules adsorbed by electrostatics; wherein the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 all contain at least two terminal bridging groups, and the terminal bridging groups of the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 undergo cross-linking reactions to form photodegradable drug-loaded particles with a three-dimensional gel network structure.

2. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The cross-linked polymer M1 contains a main chain L1, and the cross-linked polymer M2 contains a main chain L2; both the main chain L1 and the main chain L2 are hydrophilic polymers.

3. The photodegradable drug-loaded microparticles according to claim 2, characterized in that: The hydrophilic polymer includes gelatin, collagen, hyaluronic acid, sodium alginate, agarose, polyamino acid, serum albumin, chitin, chitosan, starch, cellulose, polylactic acid, polylactic acid-glycolic acid copolymer, polyethylene glycol, polyvinyl alcohol, polyacrylic acid or one of the hydrophilic polymer related derivatives.

4. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The photocleavable group is selected from nitrobenzene, coumarin, benzoyl, indole and quinoline.

5. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The photocleavable group is selected from one of o-nitrobenzyl, 4-aminobenzoyl, 4-amino-3-nitrobenzoyl, 4-amino-5-nitrobenzoyl, 8-nitroadenine, 8-nitroadenine-5'-diphosphate, 4-nitrobenzoyl, 4-nitro-3-aminobenzoyl, 4,5-dimethoxy-2-nitrobenzyl, 1-(2-nitrophenyl)propyl, 1(-2-nitrophenyl)ethyl, 7-methoxycoumarin-4-methyl, 4-methylcoumarin and its carbonate, and anthraquinone-2-methoxycarbonyl.

6. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The polyelectrolyte polymer M3 is obtained by modifying the polyelectrolyte with the terminal bridging group; the polyelectrolyte includes at least one of polyacrylic acid, carboxymethyl cellulose, carboxymethyl chitosan, sodium alginate, G4 dendrimer, polyglutamic acid, polyaspartic acid, poly(allylamine), 2-aminoethyl methacrylate hydrochloride, polyethyleneimine, polydiallyldimethylammonium chloride, poly[2-(N,N-dimethylamino)ethyl methacrylate], and chitosan.

7. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The ionizable group includes at least one of a carboxyl group, a sulfonic acid group, a sulfinic acid group, a phosphoric acid group, a phosphite group, a hypophosphite group, and an amino group.

8. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The drug molecules include at least one of doxorubicin hydrochloride, paclitaxel, epirubicin, mitomycin, fluorouracil, cisplatin, oxaliplatin, capecitabine, gemcitabine, irinotecan, topotecan, sorafenib, apatinib, lenvatinib, regorafenib, cabozantinib, ramucirumab, nivolumab, pembrolizumab, vitamin C, copper peptide, glutathione, nicotinamide, dexamethasone, prednisolone, levofloxacin, moxifloxacin, and methylene blue.

9. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The terminal bridging groups in the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 are independently selected from one of amino, carboxyl, aldehyde, thiol, carbon-carbon double bond, carbon-carbon triple bond, acryloyl, methacryloyl, azide, epoxy, vinyl sulfone, succinimide, dibenzylcyclooctyne, di(p-nitrobenzene) carbonate and norbornene.

10. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: In terms of mass percentage, the mass ratio of the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 is (0-99):(1-99):(0-99), and the total mass fraction of the cross-linked polymer M1, the cross-linked polymer M2 and the polyelectrolyte polymer M3 is 100.

11. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The particle size of the photodegradable drug-loaded microparticles is 20 μm-1000 μm.

12. The photodegradable drug-loaded microparticles according to claim 1, characterized in that: The photodegradable drug-loaded microparticles can undergo degradation reaction under light with a wavelength of 200-1200 nm and release drug molecules.

13. A method for preparing photodegradable drug-loaded microparticles according to any one of claims 1 to 12, characterized in that: Includes steps: Mixing the cross-linked polymer M1, the cross-linked polymer M2, the polyelectrolyte polymer M3, the initiator and the solvent to obtain an aqueous solution; The aqueous solution is subjected to a cross-linking polymerization reaction under external conditions to obtain photodegradable particles; The aqueous solution containing the drug is mixed with the photodegradable microparticles to obtain photodegradable drug-loaded microparticles.

14. The method for preparing photodegradable drug-loaded microparticles according to claim 13, characterized in that: The cross-linking polymerization reaction is initiated by heating, ultraviolet light irradiation or a chemical cross-linking agent.

15. The method for preparing photodegradable drug-loaded microparticles according to claim 13, characterized in that: The method for obtaining the photodegradable microparticles includes one of a droplet microfluidics method, a mechanical stirring emulsification method, a membrane emulsification method, an electrospray method, a high-pressure homogenization method, and a high-speed shear method; And / or, the droplet shear position structure of the microfluidic device in the droplet microfluidic method includes one of a T-type, a Y-type, and a cross-type; And / or, the photodegradable particles are spherical, elongated or irregular in shape.

16. Use of the photodegradable drug-loaded microparticles according to any one of claims 1 to 12 in the preparation of embolic agents, subcutaneous injection materials, and ophthalmic gel materials.

17. Use of the photodegradable drug-loaded microparticles according to any one of claims 1 to 12 in the preparation of a preparation for treating liver cancer, lung cancer, kidney cancer, uterine fibroids, prostatic hyperplasia, prostate tumors, breast cancer, skin filling, keratitis, and conjunctivitis.

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