不同灭菌法对组织工程支架降解性和力学特性的影响

目的　研究不同灭菌方法对组织工程聚合物支架的灭菌效果以及灭菌处理对聚合物支架降解性和力学特性的影响。方法　选择聚合物支架PGA编织网和PLGA纤维 ,经环氧乙烷、紫外线、75 %酒精浸泡和γ射线照射 4种方法灭菌后 ,用细菌培养检测灭菌效果 ;用粘度法测定聚合物粘度 ,以观察聚合物的降解性 ;用拉伸实验测定聚合物支架的力学特性。结果　经 4种方法灭菌后 ,聚合物支架PGA编织网细菌检测均为阴性 ,都可达到灭菌目的。辐射剂量为 15kGy的γ射线照射和紫外线照射灭菌都可导致PLGA粘度下降 ,且均具有显著性差异 (P <0 .0 5 ) ,即这两种灭菌方法使PLGA的降解明显 ;相反 ,75 %酒精和环氧乙烷灭菌对PL GA粘度下降的影响没有显著性意义 (P >0 .0 5 ) ,即降解不明显。各种灭菌方法处理后支架的断裂伸长率差异无显著性意义 (P >0 .0 5 ) ;经 15kGy的γ射线照射和紫外线灭菌后 ,支架的最大载荷、断裂能量及抗拉强度均降低 ,差异具有显著性意义 (P <0 .0 5 ) ;经环氧乙烷和酒精浸泡灭菌方法处理的支架其最大载荷、断裂能量、抗拉强度均无明显改变 ,差异无显著性意义 (P >0 .0 5 )。结论　环氧乙烷和酒精浸泡灭菌对支架降解性和力学特性影响均较小 ,是可降解聚合物支架较理想的灭菌方法。

Effect of different sterilization techniques on degradation and mechanical properties of tissue engineering scaffolds

Objective To elucidate the effect of different sterilization methods on degradation and mechanical properties of tissue engineering scaffolds.Methods PGA meshes and PLGA fibers were sterilized with ethylene oxide, ultraviolet exposure, alcohol and gamma irradiation from a 60Co source, respectively. The bacterial culture, polymer viscosity and mechanical properties of the scaffolds were examined.Results Negative bacterial cultivation was noted for all the scaffolds after sterilization with each of the 4 sterilization methods. The reduction of viscosity, or degradation of scaffolds after gamma irradiation(15 kGy) or ultraviolet exposure was significantly greater than that sterilized with ethylene oxide or 75% alcohol (P<0.05). In addition, scaffolds sterilized with ethylene oxide or 75% alcohol almost maintained their normal maximum load, energy at break and tensile strength. However, the irradiation with gamma ray or ultraviolet exposure of the scaffolds resulted in significant decline of maximum load, energy at break and tensile strength (P<0.05). ConclusionThe results suggest that among the 4 different sterilization methods, the sterilization with ethylene oxide or 75% alcohol may be the better methods for the degradable polymers.