Innovative coating based on graphene and their decorated nanoparticles for medical stent applications.

Novel coating for stainless steel stent was developed. Graphene sheets were exfoliated directly in chitosan solution as biopolymer and then decorated with TiO2 nanoparticles of an average size of 21 nm. Coating solutions of chitosan, graphene sheets and graphene sheets decorated TiO2NPs were coated on stainless steel stent in uniform form. The average thickness of the coated layer was found to be 6 and 10.6 µm for graphene and TiO2NPs decorated graphene coatings, respectively. The mechanical properties and hematological properties of the developed coated and uncoated stents were studied. The graphene sheets based coated stent showed good mechanical properties compared to chitosan and decorated coated stents. Furthermore, the mechanical properties of the coating layer based graphene on stent surface were investigated reflecting very good mechanical properties compared to graphene nanoparticles decorated coating layer. Also, the coated stent based on graphene sheets reflects very good behaviour regarding no platelets adhesion in healthy and diabetic human blood compared to uncoated, chitosan and TiO2NPs decorated graphene coated stents. The graphene sheets and their decorated composites with TiO2NPs were characterized using transmission electron microscopy. Also, the uncoated and coated stents morphologies were evaluated using scanning electron microscopy. This study presents new approach for developing and engineering medical stent using green and cost-effective graphene sheets for enhancing its performance.