Sterilized poly(L-lactic acid) braided stents with stable mechanical properties and fast degradation rates for benign...

In this paper, the in vitro degradation behaviors of two types of sterilized poly(L-lactic acid) (PLLA) braided stents differing in monofilament diameter are studied in a bile immersion environment with the aim of assessing their potential clinical applications. The results indicate that both stent variants preserve their macroscopic structural integrity, microscopic surface morphology, and mechanical stability over a 180-day degradation period. Stent with larger monofilament diameter exhibits enhanced radial supporting performance but reduced axial flexibility. Besides, both sterilized stents demonstrate accelerated degradation rates compared with the unsterilized counterpart reported in our previous study, a phenomenon primarily attributed to the reduced molecular weight resulting from the sterilization process. It is predicted that mechanical failure will occur in both sterilized stents after about 8 months of degradation, suggesting their suitability for managing common benign biliary strictures that require support for up to 6 months. The gradual increase in crystallinity observed over the 180 days of degradation indicates that degradation remains in an early stage, proceeding via a bulk erosion mechanism accompanied by mild autocatalysis. These findings offer valuable insights into the development of PLLA braided stents with controllable mechanical properties and degradation profiles tailored to meet the diverse therapeutic requirements of benign biliary strictures.