Study on Polyurethane Dipping Double-Layer Membrane Coating Method for Developing Polymer-Covered Stents

A stent is a medical device that is inserted into a narrowed or blocked area to normalize the flow when blood or body fluids do not flow smoothly. Covered stents coated with various materials such as silicone and expanded polytetrafluoroethylene (e-PTFE) are mainly used. However, these materials have various disadvantages, such as difficulty adding drugs or applying them to blood vessels. Electrospinning technology offers advantages in multifunctionality, including drug release and biodegradability. However, when coating a stent with an electrospun membrane, there are unresolved problems such as delamination of the membrane during stent surgery due to the weak nature and contraction of the electrospun fiber. Therefore, we studied fabricating by combining the dipping method and the electrospinning method a covered stent composed of a double-layer membrane using polyurethane (PU). It was confirmed that the double-layer membrane developed in this study has high mechanical properties, excellent adhesion to the stent, and can significantly improve the mechanical properties of the stent. This method is expected to overcome the limitations of existing cover stents manufactured using the electrospinning method by increasing the adhesive strength between the stent wire and the membrane.