A poly(l-lactic acid) braided stent with high mechanical properties during in vitro degradation in bile

In this article, the mechanical properties and physicochemical indexes of a poly(l-lactic acid) (PLLA) braided stent during in vitro degradation in bile for 270 days are characterized to investigate its applications in treating biliary strictures. The PLLA braided stent always maintains structural integrity well macroscopically without cracks or pits microscopically. During degradation, radial compressive force and chronic outward force are increased by 25.1% and 14.3%, respectively, bending stiffness and axial force are increased by 3.0% and 4.9%, respectively. These results indicate that PLLA braided stent can keep sufficient radial force and good bending performance during degradation in bile for 270 days, showing promising application prospects in treating severe benign biliary strictures demanding support for over half a year. Furthermore, almost no mass loss and 42.4% attenuation in molecular weight indicate the degradation mechanism of bulk erosion without obvious autocatalysis, causing decrease in bile pH. Degradation rate constant is 0.002 day(-1) and crystallinity is increased by 8%. These results explain that PLLA braided stent can keep high mechanical properties during degradation in bile for 270 days, which is in the early stage of degradation. This study may bring new ideas into the applications of PLLA braided stents in treating biliary strictures.

Automated summary

The study demonstrates that the PLLA braided stent maintains good mechanical properties and structural integrity during 270 days of degradation in bile, showing promising potential for the treatment of biliary strictures. High radial force and bending performance are maintained, indicating the stent's ability to provide long-term support for severe benign biliary strictures.