An in vitro study of the elastic property loss of poly(L-lactic acid), PLLA, filaments undergoing hydrolysis in tissue engineering applications

The objective of the investigation was to describe the elastic property loss in a stressed PLLA filament in a scaffold for soft tissue ingrowth undergoing hydrolysis. A tissue-engineered scaffold for the liver was the theoretical example. This was a construct located in the upper mid-abdomen region able to withstand the elastic forces associated with sitting, standing, and minimal activities. For this study, fibers were melt-spun from PLLA, aged according to ASTM F 1635-95, and sterilized with gamma irradiation. Samples were mechanically tested (ASTM D 3822-96 and ASTM D 1774-94). In addition, the changes in molecular weight were followed by intrinsic viscosity (ASTM D 2857-93).; In general, the longer that most samples were aged, the lower the molecular weight. The elastic recovery did not change significantly. The breaking tenacity remained stable at least for the time of this study. In the 5.0 D_R sample, the crystallinity was low (26%). Gamma irradiation severely degraded the specimens (94% molecular weight loss). Therefore, the amount and location of the amorphous regions in the filament cross section is important in determining the rate of the degradation and the subsequent mechanical property loss.; While these define the minimal stresses on the filaments, more study on how strong the filaments are when bonded together in scaffold or fabric are required. Also, elastic and tensile testing of the samples while they are in the physiological soaking solution would keep the samples viable and as close to in vivo conditions as possible.