Preparation and evaluation of a UV-curing hydrophilic semi-IPN coating for medical guidewires

Guidewires have crucial roles in intravascular, critical care, and urological applications. In recent years, the demand for guidewires with lower friction surfaces has arisen for medical applications. Among various surface lubrication strategies for guidewires, the most promising is the use of a hydrophilic coating. However, obtaining a hydrophilic coating on guidewires with strong adhesion remains difficult owing to the surface energy difference between the substrate and hydrophilic coating. Herein, we present a UV-curing semi-interpenetrating polymer network coating for medical thermoplastic polyurethane (TPU)-sheathed nitinol guidewires. A polyurethane acrylate (PUA) was synthesized and cured as a transition layer on the TPU substrate to provide strong adhesion. Then, polyvinyl pyrrolidone (PVP) and polyethylene glycol diacrylate (PEGDA) permeated into the PUA layer and cured to form the composite coating. The PUA–PEGDA–PVP coating exhibited excellent lubricity and satisfactory adhesion force. The surface coefficient of friction decreased to approximately 0.02 after modification with the coating, and the coating was stable during long-term soaking in water and repeated friction. In vitro toxicity tests revealed that the coating had good biocompatibility. Thus, our PUA–PEGDA–PVP coating has the potential for application as super-lubricity guidewires and other medical devices.