Bone repair composite material with gelatin microspheres capable of releasing drugs and preparation method thereof
By using 3D printing technology and surface-modified microfluidic channels to prepare gelatin microspheres and CPC bone cement composite materials, the problems of gelatin microsphere preparation and drug sustained release were solved, enabling continuous drug release and bone repair during orthopedic surgery, thus improving treatment efficacy and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2023-12-27
- Publication Date
- 2026-06-23
AI Technical Summary
Existing technologies make it difficult to prepare efficient and low-cost gelatin microspheres, and traditional methods are difficult to achieve sustained drug release and long-lasting effects. At the same time, antibiotics in orthopedic surgery are difficult to effectively penetrate ischemic or necrotic tissue to reach the site of infection, resulting in poor treatment outcomes for osteomyelitis.
Microfluidic channels were fabricated using 3D printing technology and modified with tetramethyldisiloxane. These channels were then combined with gelatin and calcium phosphate bone cement to prepare drug-loaded gelatin microspheres and CPC bone cement composite materials, achieving sustained drug release and bone repair.
It achieves sustained drug release, improves treatment efficacy, simplifies administration, reduces toxic side effects, and provides therapeutic effects while repairing bone defects, with drug release lasting for at least 30 days.
Smart Images
Figure CN117771433B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of orthopedic biomedical technology, specifically relating to a bone repair composite material with gelatin microspheres containing sustained-release drugs and its preparation method. Background Technology
[0002] Osteomyelitis is a disease caused by a series of inflammatory reactions triggered by microbial infection of bone tissue, which ultimately destroys the bone tissue itself. Currently, the total number of patients with open fractures due to trauma is showing an increasing trend year by year. Any open wound or orthopedic surgery carries a high risk of infection. Once a patient contracts osteomyelitis, bacteria easily adhere to bone screws, plates, or artificial joints. Because the surgical site cannot completely kill the bacteria, patients often fail to achieve a successful cure, making it a major challenge in orthopedic clinical treatment.
[0003] Treatment of osteomyelitis typically requires long-term antibiotic therapy. When administering the medication by injection or orally, the potential systemic side effects must be considered, and the drug may have difficulty penetrating ischemic or necrotic tissue to reach the site of infection. To prevent osteomyelitis, antibiotics are often added to bone replacement materials during orthopedic surgery. Once implanted, the antibiotics are released slowly and continuously, maintaining a high concentration above the therapeutic limit in the local area, thus effectively preventing or treating osteomyelitis.
[0004] Gelatin is a linear biopolymer composed of amino acids, extracted by boiling animal skin, tendons, ligaments, and bones. When water is added, gelatin powder swells to form a solution, gradually transforming from a sol to a gel (physical gel) during cooling, and reverting upon heating. Due to its good biocompatibility and low cost, gelatin is commonly used as a microparticle carrier for drug delivery. However, based on previous clinical research experience, gelatin is readily soluble in water and has a high degree of swelling; therefore, gelatin-encapsulated drug microparticle carriers are generally only suitable for the release of short-acting drugs. To overcome this problem, chemical cross-linking agents are commonly used clinically to cross-link gelatin microparticle carriers to control their swelling and hydrolysis rate, thereby achieving sustained drug release and long-lasting effects.
[0005] Calcium phosphate has been extensively studied due to its excellent biocompatibility and similar composition to human hard tissue. Calcium phosphate cement (CPC) is made by mixing tetracalcium phosphate and anhydrous dicalcium phosphate powders with water or an acidic solution to form a paste. It is easy to handle and can be tightly filled into bone defect areas. At normal body temperature, it undergoes a hydration reaction similar to Portland cement within 5–60 minutes without exothermic reactions, forming a bone filling material very similar to hydroxyapatite found in human bones. After implantation, it integrates well with bone tissue, exhibiting good biocompatibility and biodegradability.
[0006] Traditional methods for fabricating microchips, such as engraving and photolithography, can only be used to manufacture planar or simple curved structures with limited precision, high material costs, and relatively slow manufacturing processes.
[0007] In addition, the physical gelation process inherent in gelatin itself makes the preparation of gelatin microspheres more difficult. Summary of the Invention
[0008] To overcome the problems in the prior art, the purpose of this invention is to provide a bone repair composite material with gelatin microspheres that can release drugs sustainably and a method for its preparation. This material has a low-cost and high-yield microfluidic channel for producing gelatin microspheres with uniform particle size and drug release function. Furthermore, it aims to develop a novel sustained-release drug that integrates orthopedic repair, treatment, and regeneration functions, namely, a composite material of gelatin microspheres and CPC bone cement scaffold.
[0009] To achieve the above objectives, the present invention adopts the following technical solution:
[0010] A method for preparing a bone repair composite material containing gelatin microspheres with sustained-release drugs includes the following steps:
[0011] 1) Microfluidic channels were fabricated by 3D printing and their surface was modified with tetramethyldisiloxane;
[0012] Gelatin was added to phosphate buffer and dissolved, then antibiotics were added and stirred until homogeneous to obtain the aqueous phase.
[0013] Mineral oil and dispersant are mixed evenly to obtain the oil phase;
[0014] 2) The aqueous phase and oil phase were simultaneously fed into the modified microfluidic channel to obtain drug-loaded gelatin microspheres;
[0015] 3) Add a cross-linking agent to the drug-loaded gelatin microspheres, freeze-dry, and obtain a gelatin drug encapsulation microparticle carrier that encapsulates the drug.
[0016] 4) Mix the drug-encapsulated gelatin microparticle carrier with calcium phosphate bone cement and cure to obtain a bone repair composite material with gelatin microspheres that can release drugs in a sustained manner.
[0017] Furthermore, the specific process of surface modification of microfluidic channels using tetramethyldisiloxane is as follows: liquid tetramethyldisiloxane is introduced into the reaction chamber by argon gas, and a plasma reaction is carried out under the action of plasma discharge to decompose tetramethyldisiloxane into gaseous monomers. The gaseous monomers form a plasma polymer film on the microfluidic channel through a polymerization reaction.
[0018] Furthermore, the mass ratio of gelatin, phosphate buffer, and antibiotic is 0.5-1.5 g: 25-30 ml: 5-200 mg.
[0019] Furthermore, the gelatin is pigskin gelatin or cowskin gelatin, the antibiotic is vancomycin; dissolution is carried out at 50-60 degrees Celsius; the mineral oil is paraffin oil, and the dispersant is Span 80 or Span 60.
[0020] Furthermore, the ratio of paraffin oil to dispersant is 90-100 ml: 3-10 ml.
[0021] Furthermore, the flow rates of the aqueous phase and the oil phase were set to 40 μl / min and 100 μl / min, respectively.
[0022] Furthermore, the particle size range of the drug-loaded gelatin microspheres is 50-300 μm.
[0023] Furthermore, the cross-linking agent is glutaraldehyde or geniposide.
[0024] Furthermore, the dosage is 6-18 ml, and the concentration is 25%; the mass ratio of gelatin microparticles to CPC bone cement is 1:1.
[0025] A bone repair composite material containing gelatin microspheres with a sustained-release drug, prepared according to the method described above.
[0026] Compared with the prior art, the present invention has the following beneficial technical effects:
[0027] Compared to traditional microfluidic channel fabrication methods for preparing gelatin microspheres, this invention utilizes photopolymerization 3D printing technology to achieve high-resolution microstructure fabrication and precisely control the size, shape, and internal structure of the microfluidic device, ensuring the consistency and accuracy of drug-loaded gelatin microspheres. Its flexible design and rapid device fabrication make it easier to produce microspheres of different sizes. For drug-loaded gelatin microsphere production, it shortens preparation time, improves production efficiency, and reduces the complexity and cost of the preparation process, offering advantages such as greater flexibility, convenience, speed, and low cost. The surface modification of the microfluidic channel using tetramethyldisiloxane (TMDSO) in this invention effectively overcomes the physical gelation process of gelatin, thus facilitating the preparation of drug-loaded gelatin microspheres with uniform particle size.
[0028] The composite material prepared by this invention combines the advantages of carrier microspheres and CPC bone cement, and has excellent drug sustained release capability, with drug release lasting for at least 30 days. This improves the therapeutic effect, simplifies the administration method, and reduces toxic side effects. The material can repair bone defects while also having a drug therapeutic effect. Furthermore, the pore size produced after the degradation of the drug-loaded microspheres provides the space required for cell regeneration. Attached Figure Description
[0029] Figure 1 This is a flowchart of the microfluidic channel fabrication process;
[0030] Figure 2 This is a flowchart of the preparation of gelatin microspheres;
[0031] Figure 3 This is a physical image of a photopolymer 3D printed microfluidic channel;
[0032] Figure 4 The diagram shows the changes in contact angle before and after surface modification, where (a) is before modification and (b) is after modification.
[0033] Figure 5 This is a schematic diagram of a monodisperse emulsion droplet;
[0034] Figure 6 The images show the appearance of the orthopedic scaffold material after the gelatin microspheres prepared in this experiment were mixed with CPC bone cement; where (a) is the morphology of the gelatin microspheres and (b) is the morphology of the orthopedic scaffold material after the gelatin microspheres were mixed with CPC bone cement.
[0035] Figure 7 These are absorbance curves of vancomycin at different concentrations at 280 nm.
[0036] Figure 8 The drug release rate curves of the orthopedic composite material of drug-loaded gelatin microspheres and CPC bone cement combined with drug-loaded gelatin microspheres are shown in the figures for 24 hours and 30 days; where (a) is 24 hours and (b) is 30 days. Detailed Implementation
[0037] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.
[0038] This invention relates to a method for preparing a bone repair composite material containing gelatin microspheres with sustained-release drugs, based on LCD photopolymerization 3D printing microfluidic channel technology. Specifically, the preparation process involves the following steps:
[0039] 1) Microfluidic channels were fabricated and their surfaces modified using 3D printing. The 3D printing method used was LCD photopolymerization 3D printing. Tetramethyldisiloxane (TMDSO) was used as the surface modification material.
[0040] Specifically, 1. Fabrication of microfluidic channels:
[0041] First, use CAD2022 software to determine and design the size and shape of the microfluidic fluid according to the requirements.
[0042] Export the designed 3D model as an STL file (assuming the name is stl_1). Open the CHITU BOX software, import the stl_1 file, select the printing angle, set the support, and export it again as an STL file (assuming the name is stl_2).
[0043] Open the HALOT BOX software, import the stl_2 file, set the printing parameters and the number of prints, and slice the file. After confirming that everything is correct, export the sliced file to a USB flash drive, then insert the USB flash drive into the photopolymer 3D printer (HALOT-SKY2022), select the corresponding file, and start printing.
[0044] After printing, remove the microchannel and soak it in alcohol for 3-10 minutes to remove any residual photosensitive resin inside the microchannel. Then, remove it and take out the support. Place it in a curing and cleaning machine (UW-02) for secondary curing (curing each side for 5-10 minutes) to increase its hardness. Remove it after curing.
[0045] 2. Surface modification of microfluidic channels
[0046] Because gelatin undergoes a physical gelation process, it exhibits poor wettability in microfluidics. Once the water column of the dispersed phase (aqueous phase) is formed, it will adhere to the channel wall if it deviates from the channel centerline, preventing the continued formation of W / O type droplets. Therefore, surface modification of the microfluidic channel is necessary, as described below:
[0047] This invention uses argon as the carrier gas and tetramethyldisiloxane (TMDSO) as the material for plasma polymerization. Liquid TMDSO monomer is introduced into the reaction chamber of a PECVD apparatus via argon gas. The current is adjusted to achieve a power of 100W-200W, generating a plasma reaction under high-power plasma discharge, thereby decomposing TMDSO into gaseous monomers (such as methyl and silica). These gaseous monomers are then transported to a substrate placed in a room-temperature vacuum chamber, where a polymerization reaction forms a pinhole-free plasma-polymerized thin film with insulating and hydrophobic properties in microfluidic channels. This process lasts approximately 30-60 minutes.
[0048] 2) Add a certain amount of gelatin to phosphate buffer solution and mix and dissolve at a certain temperature. Then add a certain amount of vancomycin and stir for a period of time so that the vancomycin drug can be evenly dispersed in the gelatin solution. The obtained solution is loaded into syringe 1, which is the aqueous phase.
[0049] The gelatin used is porcine gelatin (or bovine gelatin) with a bloom number of 150-300, and the dosage is 0.5-1.5 grams. The phosphate buffer solution is 25-30 ml. The mixing temperature is 50-60 degrees Celsius. The vancomycin dosage is 5-200 mg.
[0050] 3) A solution obtained by uniformly mixing a certain amount of paraffin oil (or other mineral oil) with a dispersant is loaded into syringe 2, which is the oil phase.
[0051] The amount of paraffin oil used is 90-100 ml. The dispersant is Span 80 (or other Span series, such as Span 60), and the amount used is 3-10 ml.
[0052] 4) Install syringe 1 (aqueous phase) and syringe 2 (oil phase) on a digital injection pump (micro-injection pump). By controlling the flow rate of the two phases, the solution is delivered into the microfluidic channel through the pipeline under the push of the injection pump, producing drug-loaded gelatin microspheres of a certain size.
[0053] The flow rates of the aqueous and oil phases were set to 40 μl / min and 100 μl / min, respectively. The particle size range of the drug-loaded gelatin microspheres was 50-300 μm.
[0054] 5) The collected droplets were transferred to an ice bath at a certain temperature, and a certain amount of cross-linking agent was added to carry out a cross-linking reaction for 60-70 minutes. After that, they were washed with isopropanol, collected, and freeze-dried at -80 degrees Celsius for 24-36 hours to obtain a gelatin drug encapsulation microparticle carrier containing vancomycin.
[0055] The temperature of the ice bath is 3-5 degrees Celsius. The crosslinking agent is a 25% glutaraldehyde solution (or geniposide solution), and the amount used is 6-18 ml.
[0056] 6) Mix the gelatin drug-encapsulated microparticle carrier containing vancomycin with CPC (calcium phosphate bone cement) in a certain proportion. After the bone cement has solidified, a bone repair composite material with gelatin microspheres containing sustained-release drugs is obtained.
[0057] The mass ratio of gelatin microparticles to CPC bone cement is 1:1.
[0058] This invention enables the production of a bone repair composite material with excellent drug sustained-release capability, which simplifies the administration method, reduces toxic side effects, and has the effect of drug therapy while repairing bone defects.
[0059] Example 1
[0060] The preparation of bone repair composite materials containing gelatin microspheres with sustained-release drugs involves the following processes.
[0061] 1) Fabrication of microfluidic channels:
[0062] See Figure 1 First, the size and shape of the microfluidic fluid are determined and designed according to the requirements using CAD2022 software.
[0063] Export the designed 3D model as an STL file (assuming the name is stl_1). Open the CHITU BOX software, import the stl_1 file, select the printing angle, set the CHITU BOX support, and export it again as an STL file (assuming the name is stl_2).
[0064] Open the HALOT BOX software, import the stl_2 file, set the printing parameters and the number of prints, and slice the file using HALOT BOX. After confirming that everything is correct, export the sliced file to a USB flash drive, then insert the USB flash drive into the photopolymer 3D printer (HALOT-SKY 2022), select the corresponding file, and start printing.
[0065] After printing, remove the microchannel and soak it in alcohol for 5 minutes to remove any residual photosensitive resin inside the microchannel. Then, take it out and remove the support. Place it in a curing and cleaning machine (UW-02) for secondary curing (curing each side for 5 minutes) to increase its hardness. After curing, take it out.
[0066] 2) Surface modification of microfluidic channels
[0067] Because gelatin undergoes a physical gelation process, it exhibits poor wettability in microfluidics. Once the water column of the dispersed phase (aqueous phase) is formed, it will adhere to the channel wall if it deviates from the channel centerline, preventing the continued formation of W / O type droplets. Therefore, surface modification of the microfluidic channel is necessary, as described below:
[0068] Argon was used as the carrier gas, and tetramethyldisiloxane (TMDSO) was used as the material for plasma polymerization. Liquid TMDSO monomer was introduced into the reaction chamber by argon gas. The liquid TMDSO was then evaporated and pyrolyzed into gaseous monomer, which was then deposited in a vacuum chamber at room temperature for 30 minutes with plasma-assisted deposition to form a pinhole-free plasma-polymerized film with insulating and hydrophobic properties.
[0069] 3) Preparation of drug-loaded gelatin
[0070] First, add 1.0 g of 300 Bloom number porcine gelatin to 25 mL of phosphate-buffered saline (PBS) and dissolve it at 50°C to obtain a gelatin solution.
[0071] Then, in a 50-degree Celsius constant temperature water bath, add 0.2 grams of vancomycin (antibiotic) to the gelatin solution and mix and stir for a period of time to allow the vancomycin to be evenly dispersed in the gelatin solution.
[0072] Then, the gelatin solution (aqueous phase) containing vancomycin is filled into syringe 1 for later use.
[0073] See Figure 2 Mix 100 ml of paraffin oil with 3 ml of dispersant Span 80 evenly (oil phase), and then load the mixture into syringe 2 for later use.
[0074] 4) Preparation of drug-loaded gelatin microspheres with uniform particle size
[0075] Place syringe 1 (aqueous phase) and syringe 2 (oil phase) onto a microinjection pump. The solution is then delivered into the microfluidic channel through the tubing by the pump.
[0076] The collected droplets were transferred to an ice bath at 4°C, and 10 mL of glutaraldehyde solution, a crosslinking agent, was added for a crosslinking reaction of 65 min. The oil was then removed by isopropanol washing, the powder was collected, and freeze-dried at -80°C for 32 h to obtain the gelatin drug encapsulation microparticle carrier containing vancomycin.
[0077] 5) Preparation of orthopedic scaffold materials using gelatin microspheres and CPC bone cement
[0078] The prepared gelatin microparticles were mixed with medical-grade biocompatible calcium phosphate bone cement (CPC). During mixing, the microspheres and bone cement were mixed in the same proportion, and then the material preparation was completed after the bone cement had cured.
[0079] 6. Drug release experiment
[0080] Analysis was performed using ultraviolet (UV) spectroscopy. The antibiotic used in this experiment was vancomycin, with an optimal detection wavelength of 280 nm. A vancomycin solution with a concentration of 50 mg / ml was used as a stock solution, and this concentration was diluted to 20, 40, 60, 80, 100, 150, 200, 300, and 400 mg / ml (ppm). The absorbance was measured at 280 nm using UV spectroscopy, allowing for the determination of a linear relationship between concentration and absorbance. The concentration of the released antibiotic could then be calculated using the detection line formula.
[0081] See Figure 3 As can be seen from the physical image of the photopolymer 3D printed microfluidic channel, the width and depth of the inner channel are both 1mm.
[0082] See Figure 4As can be seen from (a) and (b), the contact angle before surface modification is 63.43°, and the contact angle after surface modification is 90°.
[0083] See Figure 5 It can be seen that the formation of monodisperse droplets is caused by the shearing action generated by the oil phases at both ends in the cross-junction channel, which rapidly forms gelatin microspheres with uniform particle size.
[0084] See Figure 6 In Figures (a) and (b), it can be seen that the particle size of the gelatin microspheres is 200 μm. The bone repair composite material after the gelatin microspheres are mixed with CPC bone cement is spherical, but it can also be prepared into other shapes. The light yellow dots in the figure are drug-loaded gelatin microparticles, and the white part is CPC bone cement.
[0085] See Figure 7 As can be seen, the detection line formula is y = 0.004x + 0.035. Subsequently, the absorbance value (y value) at 280 nm can be measured based on the ultraviolet absorption spectrum of the released drug and substituted into the detection line formula to calculate the drug release concentration (x value).
[0086] See Figure 8 As shown in (a) and (b), the drug release rate curves of the orthopedic composite material consisting of drug-loaded gelatin microspheres and CPC bone cement combined with drug-loaded gelatin microspheres within 24 hours and 30 days reveal that the drug release rate of the orthopedic composite material is lower than that of drug-loaded gelatin microspheres alone, meaning that the drug release time is longer than that of drug-loaded microspheres alone. This is because the vancomycin released from the composite material can undergo bond decomposition with the hydroxyapatite in the bone cement, thereby delaying the drug release time. Its sustained drug release performance can last for at least 30 days.
[0087] Example 2
[0088] The preparation of bone repair composite materials containing gelatin microspheres with sustained-release drugs involves the following processes.
[0089] 1) Fabrication of microfluidic channels:
[0090] Same as Example 1;
[0091] 2) Surface modification of microfluidic channels
[0092] Same as Example 1;
[0093] 3) Preparation of drug-loaded gelatin
[0094] First, add 0.5 g of 300 Bloom number porcine gelatin to 28 mL of phosphate-buffered saline (PBS) and dissolve it at 50°C to obtain a gelatin solution.
[0095] Then, in a 60-degree Celsius constant temperature water bath, add 0.1 g of vancomycin (antibiotic) to the gelatin solution and mix and stir for a period of time to ensure that the vancomycin is evenly dispersed in the gelatin solution.
[0096] Then, the gelatin solution (aqueous phase) containing vancomycin is filled into syringe 1 for later use.
[0097] See Figure 2 Mix 97 ml of paraffin oil with 8 ml of dispersant Span 80 evenly (oil phase), and then load the mixture into syringe 2 for later use.
[0098] 4) Preparation of drug-loaded gelatin microspheres with uniform particle size
[0099] Syringe 1 (aqueous phase) and syringe 2 (oil phase) are placed on a microinjection pump. The pump then delivers the solution through the tubing into the microfluidic channel. The flow rates of the aqueous phase and oil phase are set to 40 μl / min and 100 μl / min, respectively.
[0100] The collected droplets were transferred to an ice bath at 5°C, and 18 mL of the cross-linking agent geniposide solution was added for a cross-linking reaction for 60 min. The oil was then removed by isopropanol washing, the powder was collected, and freeze-dried at -80°C for 28 h to obtain the gelatin drug encapsulation microparticle carrier containing vancomycin.
[0101] 5) Preparation of orthopedic scaffold materials using gelatin microspheres and CPC bone cement
[0102] The prepared gelatin microparticles were mixed with medical-grade biocompatible calcium phosphate bone cement (CPC). During mixing, the microspheres and bone cement were mixed in the same proportion, and then the material preparation was completed after the bone cement had cured.
[0103] Example 3
[0104] The preparation of bone repair composite materials containing gelatin microspheres with sustained-release drugs involves the following processes.
[0105] 1) Fabrication of microfluidic channels:
[0106] Same as Example 1;
[0107] 2) Surface modification of microfluidic channels
[0108] Same as Example 1;
[0109] 3) Preparation of drug-loaded gelatin
[0110] First, add 1.2 grams of bovine gelatin to 27 ml of phosphate-buffered saline (PBS) and dissolve it at 50 degrees Celsius to obtain a gelatin solution.
[0111] Then, in a 55-degree Celsius constant temperature water bath, add 0.005 grams of vancomycin (antibiotic) to the gelatin solution and mix and stir for a period of time to allow the vancomycin to be evenly dispersed in the gelatin solution.
[0112] Then, the gelatin solution (aqueous phase) containing vancomycin is filled into syringe 1 for later use.
[0113] See Figure 2 Mix 95 ml of paraffin oil with 10 ml of dispersant Span 80 evenly (oil phase), and then load the mixture into syringe 2 for later use.
[0114] 4) Preparation of drug-loaded gelatin microspheres with uniform particle size
[0115] Syringe 1 (aqueous phase) and syringe 2 (oil phase) are placed on a microinjection pump. The pump then delivers the solution through the tubing into the microfluidic channel. The flow rates of the aqueous phase and oil phase are set to 40 μl / min and 100 μl / min, respectively.
[0116] The collected droplets were transferred to an ice bath at 4°C, and 6 mL of glutaraldehyde solution, a crosslinking agent, was added for a crosslinking reaction of 70 min. The oil was then removed by isopropanol washing, the powder was collected, and freeze-dried at -80°C for 36 h to obtain the gelatin drug encapsulation microparticle carrier containing vancomycin.
[0117] 5) Preparation of orthopedic scaffold materials using gelatin microspheres and CPC bone cement
[0118] The prepared gelatin microparticles were mixed with medical-grade biocompatible calcium phosphate bone cement (CPC). During mixing, the microspheres and bone cement were mixed in the same proportion, and then the material preparation was completed after the bone cement had cured.
[0119] Example 4
[0120] The preparation of bone repair composite materials containing gelatin microspheres with sustained-release drugs involves the following processes.
[0121] 1) Fabrication of microfluidic channels:
[0122] Same as Example 1;
[0123] 2) Surface modification of microfluidic channels
[0124] Same as Example 1;
[0125] 3) Preparation of drug-loaded gelatin
[0126] First, add 1.5 g of 300 Bloom number porcine gelatin to 30 mL of phosphate-buffered saline (PBS) and dissolve it at 50°C to obtain a gelatin solution.
[0127] Then, in a 53°C constant temperature water bath, add 0.05 g of vancomycin (antibiotic) to the gelatin solution and mix and stir for a period of time to allow the vancomycin to be evenly dispersed in the gelatin solution.
[0128] Then, the gelatin solution (aqueous phase) containing vancomycin is filled into syringe 1 for later use.
[0129] See Figure 2 Mix 90 ml of paraffin oil with 3 ml of dispersant Span 60 evenly (oil phase), and then load the mixture into syringe 2 for later use.
[0130] 4) Preparation of drug-loaded gelatin microspheres with uniform particle size
[0131] Syringe 1 (aqueous phase) and syringe 2 (oil phase) are placed on a microinjection pump. The pump then delivers the solution through the tubing into the microfluidic channel. The flow rates of the aqueous phase and oil phase are set to 40 μl / min and 100 μl / min, respectively.
[0132] The collected droplets were transferred to an ice bath at 3°C, and 12 mL of glutaraldehyde solution, a crosslinking agent, was added for a crosslinking reaction of 62 min. The oil was then removed by isopropanol washing, the powder was collected, and freeze-dried at -80°C for 24 h to obtain the gelatin drug encapsulation microparticle carrier containing vancomycin.
[0133] 5) Preparation of orthopedic scaffold materials using gelatin microspheres and CPC bone cement
[0134] The prepared gelatin microparticles were mixed with medical-grade biocompatible calcium phosphate bone cement (CPC). During mixing, the microspheres and bone cement were mixed in the same proportion, and then the material preparation was completed after the bone cement had cured.
[0135] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.
[0136] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
Claims
1. A method for preparing a bone repair composite material containing gelatin microspheres with sustained-release drugs, characterized in that, Includes the following steps: 1) Microfluidic channels were fabricated by 3D printing and their surface modified with tetramethyldisiloxane; Gelatin was added to phosphate buffer and dissolved, then antibiotics were added and stirred until homogeneous to obtain the aqueous phase. Mineral oil and dispersant are mixed evenly to obtain the oil phase; 2) The aqueous phase and oil phase were simultaneously fed into the modified microfluidic channel to obtain drug-loaded gelatin microspheres; 3) Add a cross-linking agent to the drug-loaded gelatin microspheres, freeze-dry, and obtain a gelatin drug encapsulation microparticle carrier that encapsulates the drug; 4) Mix the drug-encapsulated gelatin microparticle carrier with calcium phosphate bone cement and cure to obtain a bone repair composite material with gelatin microspheres that can release drugs in a sustained manner. The specific process of surface modification of microfluidic channels using tetramethyldisiloxane is as follows: liquid tetramethyldisiloxane is introduced into the reaction chamber by argon gas, and plasma reaction is carried out under the action of plasma discharge to decompose tetramethyldisiloxane into gaseous monomers. The gaseous monomers form a plasma polymer film on the microfluidic channel through polymerization reaction. The ratio of gelatin, phosphate buffer, and antibiotics is 0.5-1.5 g: 25-30 ml: 5-200 mg.
2. The method for preparing the bone repair composite material with gelatin microspheres containing a sustained-release drug according to claim 1, characterized in that, The gelatin used is pigskin gelatin or cowskin gelatin, and the antibiotic is vancomycin; dissolution is carried out at 50-60 degrees Celsius; the mineral oil is paraffin oil, and the dispersant is Span 80 or Span 60.
3. The method for preparing the bone repair composite material with gelatin microspheres containing a sustained-release drug according to claim 1, characterized in that, The ratio of paraffin oil to dispersant is 90-100 ml: 3-10 ml.
4. The method for preparing the bone repair composite material with gelatin microspheres containing a sustained-release drug according to claim 1, characterized in that, The flow rates of the aqueous phase and the oil phase were set to 40 μl / min and 100 μl / min, respectively.
5. The method for preparing the bone repair composite material with gelatin microspheres containing a sustained-release drug according to claim 1, characterized in that, The particle size range of the drug-loaded gelatin microspheres is 50-300 μm.
6. The method for preparing the bone repair composite material with gelatin microspheres containing a sustained-release drug according to claim 1, characterized in that, The cross-linking agent is glutaraldehyde or geniposide.
7. The method for preparing the bone repair composite material with gelatin microspheres containing a sustained-release drug according to claim 1, characterized in that, The amount of crosslinking agent used is 6-18 ml, and the concentration is 25%; the mass ratio of gelatin microparticles to CPC bone cement is 1:
1.
8. A bone repair composite material containing gelatin microspheres with a sustained-release drug, prepared by the method according to any one of claims 1-7.