Blood compatible and noncytotoxic superhydrophobic graphene/titanium dioxide coating with antibacterial and antibiofilm properties

The potential of superhydrophobic surfaces has gained vast attention in medical settings due to their self-cleaning effect (including bacterial colonization reduction), minimized cell-to-surface interaction, and anti-biofouling effect. These valuable features allow the vanquishment of some limitations accompanying the blood-contacting medical devices that are widely used in clinical practice. The extracorporeal circulation used to perform hemodialysis, for instance, as well as the blood collection sets, these essential blood-contacting medical devices are frequently associated with bacterial infection and hemolysis. Within this study, superhydrophobic surface was substantiated to enhance the biocompatibility. Herein, the graphene (Gr) and titanium dioxide (TiO2) nanoparticles were dip-coated on poly(lactic acid) (PLA) film to produce a superhydrophobic surface. The uniform distribution of the Gr/TiO2 nanoparticles of the coating enhanced the surface roughness and therefore promoted superhydrophobic properties. Co-occurrence of the Cassie-Baxter regime and Wenzel regime was suggested to induce the low surface wettability. The superhydrophobic Gr/TiO2 demonstrated significant inhibition of biofilm formation and antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. Besides, the in vitro blood compatibility assay showed a hemolysis rate lower than 2%, which was categorized as nonhemolytic. The exposure of human heart cells and kidney cells to the Gr/TiO2-coated PLA film did not significantly affect the cell viability. The findings herein showed promising results for the superhydrophobic Gr/TiO2-coated PLA film to act as a potential biomaterial for single-use blood-contacting medical devices. This study also provided insight for future medical applications that require superhydrophobic coatings.