Functional Surface Self‐Assembly on Nitinol Biliary Stents for Enhanced Anti‐Fouling and Low‐Friction Behavior

ABSTRACT

Nitinol (NiTi) stents are widely used for biliary decompression, but their biofluid‐exposed metallic surfaces remain susceptible to mechanical irritation, bacterial colonization, sludge deposition, and inflammation‐associated restenosis. Inspired by the dynamic, low‐adhesion interfacial function of the native glycocalyx, we developed a self‐assembled slippery liquid‐infused porous surface (SASLIPS) for NiTi biliary stents. The modified surface formed a continuous liquid‐infused architecture, exhibited water sliding angles <0.5°, and reduced adhesion under the tested conditions. SASLIPS decreased the coefficient of friction (COF) from 0.69 (NiTi) to 0.09 (SASLIPS), reduced biliary sludge accretion, inhibited 96.98% of E. coli adhesion and biofilm formation, and attenuated inflammatory responses, while preserving macroscopic thermally induced shape recovery. Molecular dynamics simulations supported favorable interactions between perfluorooctyltrichlorosilane (PFOTS) and perfluorodecalin (PFD) and showed that the PFD‐rich interfacial region reduced water and cholesterol access to the modeled substrate. In a porcine study with independent 1‐ and 6‐month cohorts, SASLIPS‐coatedstents showed 89.92% lower sludge‐associated autofluorescence than bare NiTi stents at 1 month and no gross evidence of luminal obstruction at the 6‐month retrieval. This work established a liquid‐infused fluorinated surface strategy for engineering anti‐fouling, anti‐inflammatory, and mechanically compatible biliary stents, and offered a materials‐driven solution to persistent interfacial failure in biofluid‐rich implant environments.