Water-Driven PEG Shielding of Ureteral Stent for Self-Lubrication and Adhesion Resistance

The challenges of thermoplastic polyurethane (TPU) based ureteral stents are surface lubrication, bacterial adhesion, and Ca²⁺/Mg²⁺ ions deposition. In this work, a new amphiphilic copolymer for ureteral stent was reported to avoid the limitations of TPU ureteral stents. Poly(ε-caprolactone) (PCL) and polyethylene glycol (PEG) blocks were reacted with hexamethylene diisocyanate (HDI) to form amphiphilic multiblock copolymers (PCEU). The PCEU was extruded into ureteral stents (PCEU-Stent). The PEG blocks and PCL crystals aligned along the radial direction and resulted in phase-separated microstructures. The subsequent uniaxial stretching of the ureteral stents extended PCL crystals as physical crosslinkers to strengthen axial elasticity. Implantation of the stents in simulated body fluid induced surface migration of PEG, forming a PEG shielding layer around the ureteral stents. This surface reconstruction endowed the ureteral stents with excellent self-lubrication, resistance to bacterial adhesion, and effective inhibition of Ca²⁺/Mg²⁺ ions deposition.