Composite functional microsphere for repairing radiation damage and promoting collagen regeneration as well as preparation method and application of composite functional microsphere

Abstract

The invention discloses a composite functional microsphere for repairing radiation damage and promoting collagen regeneration as well as a preparation method and application of the composite functional microsphere. The microsphere comprises a porous microsphere carrier prepared from a high polymer material with excellent biocompatibility and degradability, and repair polypeptide with functions of cell penetration, free radical removal, DNA protection and apoptosis resistance is loaded in the porous microsphere carrier or covalently bound on the surface of the porous microsphere carrier. The porous microsphere carrier disclosed by the invention is used as a long-term resident sustained-release storage cavern and a physical support bracket, can realize continuous and controllable release of polypeptide through internal pores or a surface modification layer of the microspheres, and can provide free radical scavenging and cell protection effects on an injured part for a long time; meanwhile, the stable three-dimensional space structure of the porous microsphere carrier can provide anchoring points for repairing cells such as fibroblasts and directly guide and support ordered deposition of new collagen fibers, so that substantial regeneration and reconstruction of a tissue structure are mechanically promoted while long-acting molecular protection is achieved.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials and regenerative medicine technology, specifically relating to a composite functional microsphere for radiation damage repair and collagen regeneration, its preparation method, and its application. Background Technology

[0002] Radiation therapy is one of the main treatments for malignant tumors. However, while killing tumor cells, it inevitably causes radiation damage to surrounding normal tissues, such as radiation dermatitis, pneumonia, enteritis, and subsequent fibrosis. These damages can seriously affect the patient's quality of life and even limit the radiation dose, thus affecting the tumor control effect.

[0003] Currently, clinical interventions for radiation-induced tissue damage are very limited. Traditional treatments often focus on symptom management, such as using corticosteroid ointments to suppress inflammation, applying silver ion dressings to prevent infection, or using moisturizers to relieve dryness. These methods only provide superficial, passive relief and cannot fundamentally intervene in the core pathological processes of radiation damage, namely, cellular DNA damage, lipid peroxidation, mitochondrial dysfunction, and the subsequent apoptosis and necrosis triggered by the large number of reactive oxygen species (ROS) directly and indirectly generated by radiation.

[0004] In recent years, some studies have attempted to promote damage repair using antioxidants (such as amifostine), growth factors, or stem cell therapy. However, these strategies often face numerous challenges, such as: short half-lives, lack of targeting, and the need for repeated administration of small molecule drugs; the easy inactivation of protein drugs in the complex damage microenvironment; and safety, cost, and ethical concerns surrounding cell therapy. More importantly, most existing methods focus on "protection" or "stimulation" at the cellular level, neglecting the structural damage and functional loss caused by the degradation and abnormal remodeling of the extracellular matrix (especially collagen) after radiation damage, making it difficult to achieve true "tissue regeneration."

[0005] Therefore, developing an integrated treatment strategy that can target and deliver long-lasting effects while simultaneously achieving "cell protection" and "matrix reconstruction" is an urgent need to solve the problem of radiation damage repair and has significant clinical and market value. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides a composite functional microsphere for radiation damage repair and collagen regeneration, along with its preparation method and applications. The aim is to simultaneously address the molecular damage and structural defects in radiation damage through an integrated microsphere system, with the potential application in the fields of tissue damage repair and regenerative medicine.

[0007] To solve the above-mentioned technical problems and achieve the above-mentioned technical effects, the present invention is implemented through the following technical solution: A composite functional microsphere for radiation damage repair and collagen regeneration, comprising a porous microsphere carrier prepared from a polymer material with excellent biocompatibility and biodegradability, wherein the porous microsphere carrier is internally loaded or covalently bound to a repair polypeptide with functions including cell penetration, free radical scavenging, DNA protection and anti-apoptosis. The polymer material is lactide-glycolic acid copolymer (PLGA), with a LA / GA molar ratio of 50:50 and a molecular weight of 10,000-30,000 Da; The repair peptide is a complex peptide with the amino acid sequence Arg-Gly-Asp-Ser-Lys-Tyr-Glu and a molecular weight of approximately 800 Da.

[0008] A method for preparing the above-mentioned composite functional microspheres for radiation damage repair and collagen regeneration, the method being based on an emulsification-solvent evaporation method, comprising the following steps: Step 1) Select lactide-glycol copolymer (PLGA), which has excellent biocompatibility and biodegradability, as the polymer carrier material. The LA / GA molar ratio of the lactide-glycol copolymer is 50:50, and the molecular weight is 10000-30000 Da. A complex polypeptide with cell penetration, free radical scavenging, DNA protection and anti-apoptosis functions was selected as the repair polypeptide. The amino acid sequence of the complex polypeptide is Arg-Gly-Asp-Ser-Lys-Tyr-Glu, and the molecular weight is about 800 Da. Dichloromethane was selected as the organic phase solvent; Polyvinyl alcohol (PVA) was selected as the aqueous emulsifier; Phosphate-buffered saline (PBS) with a pH of 7.4 was selected as the system buffer. Step 2) Dissolve a certain mass of lactide-glycolic acid copolymer in a certain volume of dichloromethane, and stir magnetically until completely dissolved. Then add a certain mass of the composite polypeptide and continue stirring for a period of time to form a uniform oil phase suspension. Step 3) Prepare a certain volume of 2% (w / v) polyvinyl alcohol aqueous solution using polyvinyl alcohol to form an aqueous phase containing emulsifier, and preheat it to a certain temperature for later use. Step 4) The uniform oil phase suspension is slowly injected into the aqueous phase containing the emulsifier, and emulsified by high-speed shearing for a period of time to obtain a W / O type primary emulsion; Step 5) Prepare a certain volume of 0.5% (w / v) polyvinyl alcohol aqueous solution using polyvinyl alcohol, and transfer the pre-emulsion into it. Emulsify at room temperature for a period of time under magnetic stirring to achieve slow solvent evaporation. Step 6) After centrifuging the emulsion obtained after emulsification at room temperature, collect the precipitate, wash the precipitate several times with the phosphate buffer solution to remove residual polyvinyl alcohol and unloaded composite polypeptide; Step 7) The purified precipitate is placed in a vacuum freeze dryer for a period of time to obtain a white and loose microsphere powder. Each microsphere in the microsphere powder has a porous microsphere carrier formed by lactide-glycolic acid copolymer, and the repair peptide is loaded inside or covalently bound to the surface of the porous microsphere, thus obtaining a composite functional microsphere for radiation damage repair and collagen regeneration.

[0009] Furthermore, in step 2, the mass ratio of the lactide-glycolic acid copolymer to the composite polypeptide is 5:1.

[0010] Furthermore, in step 2, the stirring time continues for 30 minutes.

[0011] Furthermore, in step 3, the preheating temperature is 37°C.

[0012] Furthermore, in step 4, the volume ratio of the dichloromethane to the 2% (w / v) polyvinyl alcohol aqueous solution is 1:10.

[0013] Furthermore, in step 4, the high-speed shear emulsification speed is 20,000 rpm and the time is 10 min.

[0014] Furthermore, in step 5, the volume ratio of the colostrum to the 0.5% (w / v) polyvinyl alcohol aqueous solution is 11:20.

[0015] Furthermore, in step 5, the magnetic stirring speed is 500 rpm and the time is 2 hours.

[0016] Furthermore, in step 6, the washing is performed 3 times.

[0017] Furthermore, in step 6, the centrifugation speed is 8000 rpm and the time is 15 min.

[0018] Furthermore, in step 7, the vacuum freeze-drying temperature is -50℃ and the time is 24 hours.

[0019] The above-mentioned composite functional microspheres for repairing radiation damage and promoting collagen regeneration are used in the preparation of minimally invasive implantable medical devices that combine the functions of repairing radiation-induced tissue damage and promoting collagen regeneration.

[0020] Furthermore, the minimally invasive implantable medical device is suitable for the clinical treatment of radiation-induced dermatitis, tissue fibrosis, and other radiation-related injuries, as well as for soft tissue regeneration and repair.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention creatively integrates the functions of "active biorepair" and "passive physical support" into one, with the two working synergistically. The porous microspheres serve as a long-term, sustained-release reservoir and physical support scaffold. Through the continuous and controllable release of repair peptides loaded in the porous microsphere carrier, a long-lasting free radical scavenging and cell protection effect is achieved at the radiation-damaged site. At the same time, the stable three-dimensional spatial structure of the porous microsphere carrier can provide anchoring points for repair cells such as fibroblasts, directly guiding and supporting the orderly deposition of newly formed collagen fibers. Thus, while achieving long-term molecular protection, it mechanically promotes substantial regeneration and reconstruction of tissue structure.

[0022] 2. The microsphere carrier prepared by the present invention using lactide-glycolic acid copolymer polymer material has a porous structure and surface modification strategy that ensures efficient loading and controllable release of high dose repair peptides, overcoming the disadvantages of free peptides being easy to degrade and having a short action time.

[0023] 3. The PLGA polymer material and repair peptides used in this invention have good biocompatibility and degradability, and the final metabolites are safe with no risk of long-term foreign body residue, which meets the safety requirements of implantable medical devices.

[0024] 4. The microsphere carrier of the present invention has a suitable particle size for injection, and can be implanted into the damaged site in a minimally invasive manner, which is convenient to operate and has good patient compliance.

[0025] 5. The platform technology of this invention has scalability. By changing the loaded bioactive molecules, it is expected to be applied to other types of tissue damage repair and regenerative medicine.

[0026] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is an optical microscope image (40×) of the composite functional microspheres prepared in Example 1 of Experiment 1 of the present invention for repairing radiation damage and promoting collagen regeneration.

[0028] Figure 2 The image shows a scanning electron microscope (SEM) image (500×) of the composite functional microspheres prepared in Example 1 of this invention for repairing radiation damage and promoting collagen regeneration.

[0029] Figure 3 This is a diagram showing the HE staining results of a mouse skin tissue pathological section in Experiment Example 2 of this invention.

[0030] Figure 4 This is one of the Masson staining results of mouse skin tissue pathological sections in Experiment Example 2 of the present invention.

[0031] Figure 5 This is the second image showing the Masson staining results of mouse skin tissue pathological sections in Experiment Example 2 of this invention. Detailed Implementation

[0032] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings to provide a clearer understanding of the invention's purpose, features, and advantages. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the invention, but are merely illustrative of the essential spirit of the invention's technical solution.

[0033] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments may be practiced without one or more of these specific details. In other instances, well-known apparatuses, structures, and techniques associated with this application may not have been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0034] Unless the context requires otherwise, throughout the specification and claims, the word “comprising” and its variations, such as “including” and “having”, shall be understood to have an open, inclusive meaning, that is, to be interpreted as “including, but not limited to”.

[0035] Throughout this specification, references to "an embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the appearance of "in an embodiment" or "an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0036] The singular forms “a” and “the” used in this specification and the appended claims include plural references unless otherwise expressly stated herein. It should be noted that the term “or” is generally used to mean “and / or” unless otherwise expressly stated herein.

[0037] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Unless otherwise specified, all reagents and materials used in the present invention are commercially available.

[0038] This invention provides a composite functional microsphere for radiation damage repair and collagen regeneration. The microsphere comprises a porous microsphere carrier prepared from a polymer material with excellent biocompatibility and biodegradability. The porous microsphere carrier is internally loaded or covalently bound to a repair polypeptide with functions including cell penetration, free radical scavenging, DNA protection and anti-apoptosis.

[0039] In this microsphere, the polymer material is lactide-glycolic acid copolymer (PLGA), with an LA / GA molar ratio of 50:50 and a molecular weight of 10,000-30,000 Da.

[0040] In this microsphere, the repair polypeptide is a complex polypeptide with the amino acid sequence Arg-Gly-Asp-Ser-Lys-Tyr-Glu and a molecular weight of approximately 800 Da.

[0041] This invention also provides a method for preparing the above-mentioned composite functional microspheres for radiation damage repair and collagen regeneration. This method is based on an emulsification-solvent evaporation method and includes the following steps: Step 1) Select lactide-glycol copolymer (PLGA), which has excellent biocompatibility and biodegradability, as the polymer carrier material. The LA / GA molar ratio of the lactide-glycol copolymer is 50:50, and the molecular weight is 10000-30000 Da. A complex polypeptide with cell penetration, free radical scavenging, DNA protection and anti-apoptosis functions was selected as the repair polypeptide. The amino acid sequence of the complex polypeptide is Arg-Gly-Asp-Ser-Lys-Tyr-Glu, and the molecular weight is about 800 Da. Dichloromethane was selected as the organic phase solvent; Polyvinyl alcohol (PVA) was selected as the aqueous emulsifier; Phosphate-buffered saline (PBS) with a pH of 7.4 was selected as the system buffer.

[0042] Step 2) Dissolve a certain mass of PLGA in a certain volume of dichloromethane and stir magnetically until completely dissolved. Then add a certain mass of the complex peptide and continue stirring for 30 minutes to form a homogeneous oil phase suspension.

[0043] Preferably, the mass ratio of PLGA to the complex polypeptide is 5:1.

[0044] Step 3) Prepare a certain volume of 2% (w / v) PVA aqueous solution using PVA to form an aqueous phase containing emulsifier, and preheat it to 37°C for later use.

[0045] Step 4) Slowly inject the homogeneous oil phase suspension obtained in Step 2 into the aqueous phase containing emulsifier obtained in Step 3, and emulsify it at high speed of 20,000 rpm for 10 min to obtain the W / O type primary emulsion.

[0046] Preferably, the volume ratio of dichloromethane to 2% (w / v) PVA aqueous solution is 1:10.

[0047] Step 5) Prepare a certain volume of 0.5% (w / v) PVA aqueous solution using PVA, and transfer the pre-emulsion obtained in step 4 into it. Emulsify at room temperature for 2 hours under magnetic stirring at 500 rpm to achieve slow solvent evaporation.

[0048] Preferably, the volume ratio of colostrum to 0.5% (w / v) PVA aqueous solution is 11:20.

[0049] Step 6) After emulsifying at room temperature, centrifuge the emulsion at 8000 rpm for 15 min and collect the precipitate. Wash the precipitate three times with PBS buffer to remove residual PVA and unloaded complex peptides.

[0050] Step 7) The purified precipitate was dried in a vacuum freeze dryer at -50°C for 24 hours to obtain a white, loose microsphere powder. Each microsphere in the obtained microsphere powder has a porous microsphere carrier formed by lactide-glycolic acid copolymer, and the porous microspheres are internally loaded or covalently bound to repair peptides on their surface, thus obtaining composite functional microspheres for radiation damage repair and collagen regeneration.

[0051] The following specific embodiments will be used to illustrate in detail the preparation method and related test results of the composite functional microspheres for radiation damage repair and collagen regeneration according to the present invention.

[0052] Example 1: Preparation of composite functional microspheres for radiation damage repair and collagen regeneration.

[0053] (a) Material preparation: 1. The polymer carrier material is selected from lactide-glycolic acid copolymer (PLGA, LA / GA molar ratio 50:50, molecular weight 10000-30000Da), which has excellent biocompatibility and degradability.

[0054] 2. The repair peptide is a complex peptide with functions of cell penetration, free radical scavenging, DNA protection and anti-apoptosis (amino acid sequence: Arg-Gly-Asp-Ser-Lys-Tyr-Glu, molecular weight approximately 800 Da).

[0055] 3. Auxiliary materials selected: dichloromethane (organic phase solvent), polyvinyl alcohol (PVA, aqueous phase emulsifier), and phosphate buffer (PBS, pH 7.4, used for system buffering).

[0056] (II) Preparation steps (emulsification-solvent evaporation method): 1. Weigh 100mg PLGA and dissolve it in 5mL dichloromethane. Stir magnetically until completely dissolved. Add 20mg of repair peptide and continue stirring for 30min to form a homogeneous oil suspension. 2. Prepare 50 mL of 2% (w / v) PVA aqueous solution to form an aqueous phase containing emulsifier, and preheat to 37°C for later use; 3. Slowly inject the oil phase suspension into the aqueous phase and emulsify at a high speed of 20,000 rpm for 10 minutes to form a W / O type primary emulsion; 4. Transfer the colostrum to 100 mL of 0.5% (w / v) PVA aqueous solution and emulsify at room temperature for 2 h with magnetic stirring at 500 rpm to achieve slow solvent evaporation.

[0057] 5. Centrifuge the emulsion obtained after emulsification at room temperature (8000 rpm, 15 minutes) to collect the precipitate, and wash it three times with PBS buffer to remove residual PVA and unloaded repair peptides.

[0058] 6. The purified precipitate was placed in a vacuum freeze dryer and dried at -50℃ for 24 hours to obtain a white, loose composite functional microsphere powder. Each microsphere in this composite functional microsphere powder has a porous microsphere carrier formed by lactide-glycolic acid copolymer, and the porous microspheres are internally loaded or covalently bound to repair peptides with functions of cell penetration, free radical scavenging, DNA protection and anti-apoptosis. Thus, composite functional microspheres for radiation damage repair and collagen regeneration are obtained.

[0059] Experimental Example 1: Characterization of microsphere performance.

[0060] 1. Morphological observation: (1) See Figure 1 As shown, under an optical microscope (40×), the composite functional microspheres prepared in Example 1 are regular spherical in shape, have good dispersibility, and show no obvious aggregation.

[0061] (2) See Figure 2 As shown, scanning electron microscopy (500×) observation shows that the microspheres prepared in Example 1 have a porous structure on the surface and inside, with uniform pore distribution, which meets the requirements for peptide loading and cell anchoring.

[0062] 2. The average particle size of the composite functional microspheres prepared in Example 1 was measured by a laser particle size analyzer to be 10-50 μm, which meets the requirements for minimally invasive injection.

[0063] 3. High-performance liquid chromatography (HPLC) analysis showed that the polypeptide loading of the composite functional microspheres prepared in Example 1 was 15-20% (w / w); in vitro release experiments showed that the composite functional microspheres prepared in Example 1 achieved sustained release for 28 days in PBS buffer at 37℃, with a cumulative release rate of over 85%.

[0064] 4. After co-culturing the composite functional microspheres prepared in Example 1 with fibroblasts for 72 hours, the cell survival rate was ≥90%, with no obvious cytotoxicity, meeting the safety requirements for biomedical materials.

[0065] Experimental Example 2: Application of radiation damage repair.

[0066] (a) In vitro cell experiments: 1. A radiation-damaged cell model was constructed by irradiating mouse fibroblasts (L929 cells) with 8 Gy 60Co γ rays.

[0067] 2. A blank control group (unirradiated cells), a damage control group (irradiated cells without the addition of the composite functional microspheres prepared in Example 1), and a microsphere experimental group (irradiated cells with 50 μg / mL of the composite functional microspheres prepared in Example 1) were set up.

[0068] 3. Key test results: (1) Free radical scavenging: After 24 hours of culture, the ROS level in the experimental group cells was reduced by more than 60% compared with the damaged control group, effectively reducing oxidative stress damage.

[0069] (2) DNA damage repair: After 48 hours of culture, the comet experiment showed that the comet tail length of the experimental group cells was shortened by 50% compared with the damaged control group, and the DNA damage repair effect was significant.

[0070] (3) Cell proliferation and anti-apoptosis: After 72 hours of culture, the CCK-8 assay showed that the cell survival rate of the experimental group was 45% higher than that of the damaged control group, and the cell apoptosis rate decreased from 35% to below 10%.

[0071] (II) In vivo animal experiments: 1. After hair removal on the back of SPF-grade Balb / c mice, a radiation dermatitis model was established by local irradiation with 30 Gy 60Co γ rays (symptoms of erythema, dryness, and desquamation appeared 3 days after irradiation).

[0072] 2. Seven days after irradiation, the experimental group was subcutaneously injected with the composite functional microsphere suspension prepared in Example 1 (100 mg / mL, 0.2 mL / animal); the control group was injected with an equal amount of blank PLGA microspheres.

[0073] 3. Observation of repair effect: (1) 28 days after administration, the erythema on the back of the mice in the experimental group completely disappeared, the wound healing rate reached more than 80%, and the skin smoothness was close to the normal level; the control group still had obvious pigmentation and scar-like changes.

[0074] (2) See Figure 3 As shown, HE staining of skin tissue sections 28 days after drug administration revealed that the dermal thickness in the experimental group recovered to 90% of the normal level, the tissue structure was intact, and the infiltration of inflammatory cells was significantly reduced; while the dermal layer in the control group became thinner and the tissue arrangement was disordered.

[0075] (3) See Figure 4 and Figure 5 As shown, Masson staining results indicate that the experimental group has abundant and orderly arranged new collagen fibers, while the control group has sparse and randomly distributed collagen fibers, confirming that the composite functional microspheres prepared in Example 1 can effectively promote orderly collagen regeneration and tissue repair.

[0076] This invention creatively integrates the functions of "active biorepair" and "passive physical support" into one, with the two working synergistically. The porous microspheres serve as a long-term, sustained-release reservoir and physical support scaffold. By continuously and controllably releasing repair peptides loaded in the porous microsphere carrier, it provides sustained free radical scavenging and cell protection at the radiation-damaged site. At the same time, the stable three-dimensional structure of the porous microsphere carrier can provide anchoring points for repair cells such as fibroblasts, directly guiding and supporting the orderly deposition of newly formed collagen fibers. Thus, while achieving long-term molecular protection, it mechanically promotes substantial regeneration and reconstruction of tissue structure.

[0077] Based on the above test results, it can be shown that the composite functional microspheres of this invention for repairing radiation damage and promoting collagen regeneration, with their porous structure and surface modification strategy, ensure efficient loading and controllable release of high-dose repair peptides, overcoming the disadvantages of free peptides being easily degraded and having a short duration of action. The PLGA polymer material and repair peptides used have good biocompatibility and degradability, and the final metabolites are safe with no risk of long-term foreign body residue, meeting the safety requirements of implantable medical devices. The microsphere carrier has a suitable particle size for injection, can be implanted into the damaged site in a minimally invasive manner, is convenient to operate, and has good patient compliance.

[0078] Therefore, the composite functional microspheres of this invention for repairing radiation damage and promoting collagen regeneration are expected to be applied in the preparation of minimally invasive implantable medical devices that combine the functions of repairing radiation-induced tissue damage and promoting collagen regeneration, especially suitable for the clinical treatment of radiation-induced dermatitis, tissue fibrosis, and other radiation-induced injuries, as well as soft tissue regeneration and repair scenarios. In addition, the platform technology of this invention is scalable, and by changing the loaded bioactive molecules, it is expected to be applied to other types of tissue damage repair and regenerative medicine.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite functional microsphere for repairing radiation damage and promoting collagen regeneration, characterized in that: This includes porous microsphere carriers prepared using polymeric materials with excellent biocompatibility and biodegradability, wherein the porous microsphere carriers are internally loaded or covalently bound to a repair polypeptide with functions including cell penetration, free radical scavenging, DNA protection and anti-apoptosis. The polymer material is a lactide-glycolic acid copolymer with a LA / GA molar ratio of 50:50 and a molecular weight of 10,000-30,000 Da. The repair peptide is a complex peptide with the amino acid sequence Arg-Gly-Asp-Ser-Lys-Tyr-Glu and a molecular weight of 800 Da.

2. A method for preparing composite functional microspheres for radiation damage repair and collagen regeneration, characterized in that, Based on the emulsification-solvent evaporation method, the following steps are included: Step 1) Select lactide-glycol copolymer with excellent biocompatibility and biodegradability as polymer carrier material. The LA / GA molar ratio of the lactide-glycol copolymer is 50:50 and the molecular weight is 10000-30000 Da. A complex polypeptide with cell penetration, free radical scavenging, DNA protection and anti-apoptosis functions was selected as the repair polypeptide. The amino acid sequence of the complex polypeptide is Arg-Gly-Asp-Ser-Lys-Tyr-Glu, and the molecular weight is 800 Da. Dichloromethane was selected as the organic phase solvent; Polyvinyl alcohol was selected as the aqueous emulsifier; A phosphate buffer solution with a pH of 7.4 was selected as the system buffer. Step 2) Dissolve a certain mass of lactide-glycolic acid copolymer in a certain volume of dichloromethane, and stir magnetically until completely dissolved. Then add a certain mass of the composite polypeptide and continue stirring for a period of time to form a uniform oil phase suspension. Step 3) Prepare a certain volume of 2% (w / v) polyvinyl alcohol aqueous solution using polyvinyl alcohol to form an aqueous phase containing emulsifier, and preheat it to a certain temperature for later use. Step 4) The uniform oil phase suspension is slowly injected into the aqueous phase containing the emulsifier, and emulsified by high-speed shearing for a period of time to obtain a W / O type primary emulsion; Step 5) Prepare a certain volume of 0.5% (w / v) polyvinyl alcohol aqueous solution using polyvinyl alcohol, and transfer the pre-emulsion into it. Emulsify at room temperature for a period of time under magnetic stirring to achieve slow solvent evaporation. Step 6) After centrifuging the emulsion obtained after emulsification at room temperature, collect the precipitate, wash the precipitate several times with the phosphate buffer solution to remove residual polyvinyl alcohol and unloaded composite polypeptide; Step 7) The purified precipitate is placed in a vacuum freeze dryer for a period of time to obtain a white and loose microsphere powder. Each microsphere in the microsphere powder has a porous microsphere carrier formed by lactide-glycolic acid copolymer, and the repair peptide is loaded inside or covalently bound to the surface of the porous microsphere, thus obtaining a composite functional microsphere for radiation damage repair and collagen regeneration.

3. The preparation method according to claim 2, characterized in that, In step 2, the mass ratio of the lactide-glycolic acid copolymer (PLGA) to the composite polypeptide is 5:1, and the stirring time is continued for 30 minutes.

4. The preparation method according to claim 2, characterized in that, In step 3, the preheating temperature is 37℃.

5. The preparation method according to claim 2, characterized in that, In step 4, the volume ratio of dichloromethane to the 2% (w / v) polyvinyl alcohol aqueous solution is 1:10, the high-speed shear emulsification speed is 20000 rpm, and the time is 10 min.

6. The preparation method according to claim 2, characterized in that, In step 5, the volume ratio of the colostrum to the 0.5% (w / v) polyvinyl alcohol aqueous solution is 11:20, the magnetic stirring speed is 500 rpm, and the time is 2 hours.

7. The preparation method according to claim 2, characterized in that, In step 6, the washing is performed 3 times, the centrifugation speed is 8000 rpm, and the time is 15 minutes.

8. The preparation method according to claim 2, characterized in that, In step 7, the vacuum freeze-drying temperature is -50℃ and the time is 24 hours.

9. The application of the composite functional microspheres for radiation damage repair and collagen regeneration as described in claim 1 and / or the composite functional microspheres for radiation damage repair and collagen regeneration prepared by any one of the preparation methods described in claims 2-8 in the preparation of minimally invasive implantable medical devices that combine the functions of radiation tissue damage repair and collagen regeneration promotion.

10. The application according to claim 9, characterized in that, The radiation-induced tissue damage includes radiation dermatitis and tissue fibrosis.

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