Processing and characterization of electrospun graphene oxide/polyurethane composite nanofibers for stent coating

Cracking or delaminating with insufficient mechanical strength of biocompatible polymer layer applied for stent coating is a major limiting factor in stent coating technology. Novel strategies and smart materials are therefore required to develop stable polymeric layer on the surface of stent. In this study, an in situ polymerization technique is applied to fabricate graphene oxide (GO) loaded electrospun PU fibers. Viscous solution of in situ polymerized GO/PU composite in mixed solvent system of DMF/MEK (1:1 by wt) was applied to fabricate GO/PU composite fibers and its application on nonvascular stent coating was performed. Microscopic analysis shows that GO sheets are evenly distributed throughout the composite nanofibers. Spectroscopic analysis indicated the formation of chemically bonded GO-PU composite fibers. Mechanical performance evaluation and water contact angle measurement of pristine and composite PU electrospun membranes (obtained from the same method) showed that a 1. wt% GO containing PU fibrous mat is far better in mechanical properties and hydrophilicity compared to the pristine PU mat. The improved properties of composite PU fibers on the surface of nonvascular stent were evaluated using durability test. Results showed that as-synthesized composite PU fibrous membrane coated on the surface of stent has no crack or delaminate upon repeated cyclic stress during standard stent durability test. Therefore, the proposed coating material and processing technology will be a promising approach for the development of hybrid stent.