A study of a biodegradable braided Mg stent for biliary reconstruction

Abstract

Aiming at deficiencies in non-degradable stents for benign common bile duct obstruction, the magnesium (Mg)-based braided stents were developed with one monofilament as a pilot research in this paper. We designed stents with the different monofilament diameter, braided-pin number and surface treatment systematically to study the mechanical and degradation behaviors. The results suggest the fluorinated Mg stents and them with polycaprolactone (PCL) coating can achieve the compression force of 3.35–11.07 N and 11.09–24.08 N, and even maintain 3.10–10.43 N for 3 days immersion and 3.11–9.37 N for 20 days immersion respectively. PCL coating on monofilament can provide significantly better compression force and corrosion resistance. By comparison with the stent in clinic, these Mg stents are expected to meet the demand of the radial compression force and implantation time. Furthermore, the degradation occurs at the ends preferentially for all stents, but for stents without PCL coating, the intersections of wire-mesh are also the area easily corroded. Additionally, the result of the compression test indicates the radial compression force is improved with the increase of monofilament diameter and pins number, but the recovery capability decreases slightly.