Holy C E, Cheng C, Davies J E, Shoichet M S
Institute of Biomaterials and Biomedical Engineering, University of Toronto, Ont, Canada.
Biomaterials. 2001 Jan;22(1):25-31. doi: 10.1016/s0142-9612(00)00136-8.
There are few suitable techniques available to sterilize biodegradable polyester three-dimensional tissue engineering scaffolds because they are susceptible to degradation and/or morphological degeneration by high temperature and pressure. We used a novel polyllactide-co-glycolide) scaffold (Osteofoam) to determine the optimal sterilization procedure--i.e. a sterile product with minimal degradation and deformation. Initial studies, found that an argon plasma created at 100W for 4min was optimal for sterilizing Osteofoam scaffolds without affecting their morphology. The RFGD plasma sterilization method was compared to two well-established techniques--ethylene oxide (ETO) and gamma-irradiation (gamma)--which were in turn compared to disinfection in 70% ethanol. Disinfection in 70% ethanol serves as a useful control because it affects neither the morphology nor the molecular weight of the polymer: yet, ethanol is unsuitable as a sterilization method because it does not adequately eliminate hydrophilic viruses and bacterial spores. The three sterilization techniques, ETO, gamma and RFGD plasma, were compared in terms of their immediate and long-term effects on the dimensions, morphology, molecular weight and degradation profile of the scaffolds. Scaffolds shrank to 60% of their initial volume after ETO sterilization whereas their molecular weight (Mw) decreased by approximately 50% after gamma-irradiation. Thus, both ETO and gamma-irradiation posed immediate problems as sterilization techniques for 3-D biodegradable polyester scaffolds. During the in vitro degradation study, all sterilized samples showed advanced morphological and volume changes over time relative to ethanol (EtOH) disinfected samples, with the greatest changes observed for gamma-irradiated samples. ETO, RFGD plasma sterilized and EtOH disinfected samples showed similar changes in Mw and mass over the 8-week time frame. Overall, of the three sterilization techniques studied, RFGD plasma was the best.
由于可生物降解的聚酯三维组织工程支架易受高温高压影响而发生降解和/或形态退变，所以几乎没有合适的技术可用于对其进行灭菌。我们使用了一种新型的聚丙交酯-乙交酯共聚物支架（Osteofoam）来确定最佳灭菌程序，即获得一种降解和变形最小的无菌产品。初步研究发现，以100W功率产生4分钟的氩等离子体最适合对Osteofoam支架进行灭菌，且不影响其形态。将射频辉光放电（RFGD）等离子体灭菌方法与两种成熟技术——环氧乙烷（ETO）和伽马射线辐照（γ）进行比较，而这两种技术又与70%乙醇消毒进行比较。70%乙醇消毒作为一个有用的对照，因为它既不影响聚合物的形态也不影响其分子量；然而，乙醇不适合作为灭菌方法，因为它不能充分消除亲水性病毒和细菌孢子。对ETO、γ和RFGD等离子体这三种灭菌技术在支架尺寸、形态、分子量和降解情况方面的即时和长期影响进行了比较。ETO灭菌后支架收缩至初始体积的60%，而伽马射线辐照后其分子量（Mw）下降了约50%。因此，ETO和伽马射线辐照作为三维可生物降解聚酯支架的灭菌技术都存在即时问题。在体外降解研究中，相对于乙醇（EtOH）消毒的样品，所有灭菌样品随时间推移都显示出更明显的形态和体积变化，伽马射线辐照的样品变化最大。在8周的时间内，ETO、RFGD等离子体灭菌和EtOH消毒的样品在Mw和质量方面显示出相似的变化。总体而言，在所研究的三种灭菌技术中，RFGD等离子体是最佳的。
