Salient degradation features of a 50: 50 PLA/PGA scaffold for tissue engineering

An implant system that undergoes a gradual, time-dependent, nontoxic degradation process may offer an efficacious, safe, and desirable alternative to metallic materials used in the treatment of various musculoskeletal conditions. Such a scaffold may also be a suitable vehicle for growing cells and tissue in the laboratory for tissue engineering applications. We have used a scaffold of this type previously in animal studies for biological resurfacing of large articular cartilage defects. This study examined important in vitro degradation characteristics of a 50:50 polylactic acid/polyglycolic acid (PLG) implant during an 8-week period. It was determined that this particular implant degraded in a biphasic fashion. The initial phase occurred during the first 2 weeks with a decrease in molecular weight and surface axial strain, coupled with an increase in percent porosity. The second phase demonstrated a decline in surface axial strain by 4 weeks and an ongoing decline in molecular weight. Loss of gross structural properties was not evident until the start of the second phase and was complete at 8 weeks. This study demonstrated the potential uses for this implant as a means of providing structural support for cells and tissue ingrowth for up to 8 weeks. Further studies need to be conducted in order to determine the biological effects of the degrading polymer byproducts on host tissues.