Mechanotransduction-associated osteogenesis on a superwicking SiO₂-ZnO coating: A dual-functional strategy for antibacterial bone implants

Surface properties of biomedical implants play a key role in regulating cell behavior and tissue integration. Here, we developed a silicon dioxide–zinc oxide (SiO₂-ZnO) superwicking coating using a simple sandpaper-templating strategy combined with nanoscale spray coating. The resulting hierarchical micro/nanostructured surface exhibited high roughness (Ra > 50 μm) and extreme superhydrophilicity (water contact angle ≈ 0°). Incorporation of trace ZnO (500 ppm) endowed the coating with strong antibacterial activity, achieving >99% reduction against both Escherichia coli and Staphylococcus aureus under a standard 24 h assay. In vitro cell experiments showed that the modified surface enhanced MC3T3-E1 proliferation, spreading, and osteogenic mineralization compared with the control surface. Immunofluorescence and Western blot analyses further showed enhanced Paxillin/F-actin organization and increased phosphorylation of focal adhesion kinase (FAK) and proto-oncogene tyrosine-protein kinase Src (SRC), suggesting the involvement of FAK/SRC-associated mechanotransduction in these cellular responses. Overall, this dual-functional coating integrates hierarchical micro/nanotopography, superwicking behavior, and ZnO-mediated antibacterial functionality, providing a low-cost proof-of-concept strategy for antibacterial implant-related surface engineering.