外科植入引导牙周组织再生载药PLGA/CS/nHA复合膜的制备及表征

Preparation and characteristics of drug loaded PLGA/chitosan/nano-hydroxyapatite membrane for guided periodontal tissue regeneration in surgical implanting

目的制备聚乳酸-羟基乙酸共聚物(PLGA)/壳聚糖(CS)/纳米羟基磷灰石(nHA)多孔性载药膜,用于外科植入牙周引导组织再生,并评价其体外性能。方法按照PLGA/CS的质量比将实验设为4组:分别为100/0、90/10、80/20、70/30,采用冷冻干燥法制备PLGA/CS/nHA复合膜,并用聚乙烯吡咯烷酮(PVP)作为致孔剂。依据孔隙率、吸水率、力学性能、体外降解率筛选出最优质量比的PLGA/CS/nHA复合膜作为药物载体,制备克林霉素缓释膜。采用扫描电子显微镜观察PLGA/CS/nHA复合膜的表面形貌,无水乙醇液体置换法检测复合膜的孔隙率,质量干湿率比考察复合膜的吸水率,电子万能材料实验机测试复合膜的湿态力学性能,质量损失考察膜的降解率,紫外分光光度法考察载药膜的体外药物释放特性。体外实验:在载药膜上接种牙周膜成纤维细胞(PLFs),培养1~7d,采用CCK-8法测定细胞活性和增殖情况。结果 PLGA/CS质量比为90∶10时制备的PLGA/CS/nHA复合膜最为理想,孔隙率为(28.66±1.35)%,吸水率为(108.65±2.27)%,拉伸强度为(2.36±0.04)MPa,断裂伸长率为(203.64±3.89)%,断裂力为(45.98±2.46)N,30d时降解率为(17.60±0.86)%,最大每日释放量为150μg/mL,平稳释放药物并维持有效药物浓度时间>15d,载药膜能促进牙周膜成纤维细胞的增殖。结论本研究制备的载药PLGA/CS/nHA复合膜孔隙率适中,体外降解与组织生长相适应,力学测试结果能够创造和维持牙周引导组织生长特定的空间,在一定时间内能持续稳定释放药物。

Objective To prepare the porous drug-containing membrane by poly （lactic-co-glycolic acid） （PLGA）/ chitosan （CS）/nano-hydroxyapatite for guided periodontal tissue regeneration in surgery, and to evaluate its performance in vitro. Methods The samples were divided into four groups by different mass ratios of the PLGA to CS （100 ： 0, 90 ： 10, 80 ：20 and 70 ： 30）. The PLGA/CS/nano-hydroxyapatiteporous films were prepared by freeze-drying process, with polyvinylpyrrolidone （PVP） used as porogen. The best ratio was chosen by detecting the porosity, water absorption, mechanical properties and degradation of the films; and then it was used as drug carrier to prepare membrane material for clindamycin controlled release. The morphology of membrane was observed by scan electronmicroscope, the porosity was detected by anhydrous ethanol liquid displacement method, water absorption was determined by ratio of wet to dry weight of the film, the wet mechanical performance was tested by electronic universal material testing, the degradation was determined by weight loss and swelling degree, and the release character was investigated by ultraviolet spectrophotometric method. In the in vitro experiments, periodontal ligament fibroblast cells （PLFs） were cultured in the membrane for 1-7 days, and cell proliferation was measured by CCK-8. Results The optimal porosity and degradation were found when the mass ratio of PLGA to CS was 90 ： 10, with the porosity being （28. 66± 1.35）%, water absorption being （108.65±2.27）%, tensile strength being （2.36 ±0.04） MPa, elongation at break of films being （203.64±3. 89）%, breaking power being （45. 98±2. 46） N, and degradation being （17. 60±0. 86）%. The maximum drug release was 150μg · mL^-1 · d^-1, and the effective drug release concentration lasted for 15 d, which could promote the proliferation of PLFs. Conclusion The porous PLGA/CS/nano-hydroxyapatite film prepared in the present study has optimal porosity, its degradation in vitro fit well with the tissue growth, and can create and maintain a specific space for guided periodontal tissue regeneration, allowing for steady drug release for a certain period of time.