关节假体表面壳聚糖季铵盐涂层的抗感染性能研究

目的 研制一种抑制细菌黏附和生物膜形成,同时具有良好骨生物活性的材料,用于关节假体表面涂层,以降低人工关节置换术后的感染率.方法 合成6%,18%和44%取代度的壳聚糖季铵盐,利用金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌和表皮葡萄球菌检测其抗菌性能和对生物膜形成的影响,利用骨髓间充质干细胞检测其骨生物活性.共价交联法在钛金属表面制备壳聚糖季铵盐涂层.SD大鼠股骨下端髓腔内注射表皮葡萄球菌后分组植入涂层和未涂层钛棒,通过观察术后体温和体重变化,并进行血常规、X线摄片、微生物学及组织学检测分析涂层的抗感染性能.结果 壳聚糖季铵盐的抗菌活性随着其取代度的升高而增加;取代度为18%的壳聚糖季铵盐对于干细胞具有良好的生物相容性;而取代度为44%的壳聚糖季铵盐具有一定的细胞毒性.动物实验表明,取代度为18%的壳聚糖季铵盐涂层能有效防止表皮葡萄球菌引起的骨内感染.结论 中等取代度（18%）壳聚糖季铵盐兼具较强的抑菌能力和较好的骨生物活性,具有作为关节假体表面抗感染涂层的应用前景.

Anti infective potentials of titanium joint prothesis coated with quaternized chitosan

Objective To develop a surface coating material with good bone bioactivity for the orthopedic prosthesis to prevent the bacterial colonization, biofilm formation and prosthesis associated infections. Methods A new quaternized chitosan derivative （hydroxypropyltrimethyl ammonium chloride chitosan, HACC） with different degrees of substitution of quaternary ammonium （6%, 18% and 44%） were synthesised. The antibacterial activities and the effects on biofilm formation of these polymers were evaluated in vitro. Staphylococcus aureus, Methicillin resistant Staphylococcus aureus, and Staphylococcus epidermidi were selected to the anti infection tests.. Human bone marrow derived mesenchymal stem cells （MSCs） were used to investigate the biocompatibility of the HACC. The HACC with 18% substitution was covalently bonded to the titanium implant surface. The coated and non coated implants were inserted in the medullary cavity of the rat femur which inoculated with Staphylococcus epidermidis. The body temperature, weight, X ray, blood counts, histological analysis, and microbiological analysis were determined to evaluate the anti infective potentials of the surface coating HACC. Results The antibacterial activities of the HACC with 18% or 44% substitution were significantly higher than that of the unmodified chitosan（P〈0.05） against all three bacteria.The HAAC with 6% or 18% substitution was biocompatible with the proliferation of MSCs while HAAC with 44% substitution inhibited the proliferation of MSCs. The HACC with 18% and 44% substitution also significantly prevented biofilm formation on the titanium surface. The results of animal study indicated that the coated implant with HACC 18% could prevent the development of infections in the bone marrow cavities and the adjacent bones. Conclusion The HACC with medium degree of substitution of quaternary ammonium （such as 18%） is a promising anti infective coating material which may hare better antibacterial activity and good biocompatibility.