Electron transfer correlated antibacterial activity of biocompatible graphene Nanosheets-TiO2 coatings
2020
Yang, Minggang | Liu, Hui | Qiu, Caijie | Iatsunskyi, Igor | Coy, Emerson | Moya, Sergio | Wang, Zhuo | Wu, Wenwen | Zhao, Xiaobing | Wang, Guocheng
It is a big challenge to endow a material with antibacterial functions without compromising its cytocompatibility. Respiratory electron transfer of bacterial cells play an important role in bacterial metabolism, which could be extremely useful in designing biocompatible antibacterial materials. In this study, graphene nanomaterials (GNS) were dispersed in biocompatible and chemically stable titania (TiO₂) matrix using plasma spraying technique. It was found that the electrical conductivity of TiO₂ coating was significantly enhanced due to combination of the unpaired π electrons of GNS and the Ti atoms on the surface of TiO₂. The enhanced transfer of the extruded electrons from the bacterial cell membrane to the GNS-TiO₂ and subsequent electron enrichment at the Schottky-like GNS-TiO₂ interface lead to bactericidal action. The mechanism was validated by the documented non-antibacterial efficacy of the insulating zirconia (ZrO₂) coating doped with the same amount of GNS, whose electrical conductivity was unchanged with the addition of GNS and much lower than that for GNS-TiO₂. In vitro cell culture experiments using MC3T3-E1 as a model cell proved that the proliferation and osteogenic activity of the cells cultured on TiO₂ and GNS-TiO₂ coating are comparable, indicating that the antibacterial GNS-TiO₂ coating possessed uncompromised cytocompatibility.
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