Optimizing the sterilization of PLGA scaffolds for use in tissue engineering

There are few suitable techniques available to sterilize biodegradable poly ester three-dimensional tissue engineering scaffolds because they are susce ptible to degradation and/or morphological degeneration by high temperature and pressure. We used a novel poly(lactide-co-glycolide) scaffold (Osteofo am(TM)) to determine the optimal sterilization procedure - i.e. a sterile p roduct with minimal degradation and deformation. Initial studies, found tha t an argon plasma created at 100W for 4 min was optimal for sterilizing Ost eofoam(TM) scaffolds without affecting their morphology. The RFGD plasma st erilization method was compared to two well-established techniques - ethyle ne oxide (ETO) and gamma -irradiation (gamma) - which were in turn compared to disinfection in 70% ethanol. Disinfection in 70% ethanol serves as a us eful control because it affects neither the morphology nor the molecular we ight of the polymer; yet, ethanol is unsuitable as a sterilization method b ecause it does not adequately eliminate hydrophilic viruses and bacterial s pores. The three sterilization techniques, ETO, gamma and RFGD plasma, were compared in terms of their immediate and long-term effects on the dimensio ns, morphology, molecular weight and degradation profile of the scaffolds. Scaffolds shrank to similar to 60% of their initial volume after ETO steril ization whereas their molecular weight (Mw) decreased by similar to 50% aft er gamma -irradiation. Thus, both ETO and gamma -irradiation posed immediat e problems as sterilization techniques for 3-D biodegradable polyester scaf folds. During the in vitro degradation study, all sterilized samples showed advanced morphological and volume changes over time relative to ethanol (E tOH) disinfected samples, with the greatest changes observed for gamma -irr adiated samples. ETO, RFGD plasma sterilized and EtOH disinfected samples s howed similar changes in Mw and mass over the 8-week time frame. Overall, o f the three sterilization techniques studied, RFGD plasma was the best. (C) 2000 Elsevier Science Ltd. All rights reserved.