Morphology-Driven Antiadhesion, Antibacterial and Cytotoxic Effects in Superhydrophobic Surfaces.

Superhydrophobic surfaces (SHSs), inspired by water-repellent biostructures, hold promise across biomedical, industrial, and environmental domains. Here, we systematically compare PTFE-based SHSs with microstructured (MS), nanostructured (NS), and micro-nano hierarchical (MN) morphologies for liquid repellency, antifouling, antibacterial performance, and cytocompatibility. MN surfaces provided the strongest antiadhesion, maintaining low sliding angles for challenging high-viscosity/high-solids liquids (glycerol, egg white, and yogurt) by minimizing solid-liquid contact and elevating energy barriers to pinning. Antibacterial testing (ISO 22196-equivalent) showed morphology-dependent efficacy: MS and MN reduced Staphylococcus aureus by >80% and Escherichia coli by ≈40%, whereas NS showed negligible activity. Cytotoxicity toward L929 fibroblasts followed a similar trend: MN modestly reduced viability (≈70%), while NS on PTFE/PET maintained >95% viability. Collectively, the data indicate that mechano-bactericidal effects arising from microscale confinement combined with nanoscale protrusionsnot an air-cushion barrier alonegovern SHS bioactivity. These findings clarify performance-biocompatibility trade-offs and provide design guidelines for medical devices, antifouling coatings, and transparent coatings for optical/food-contact surfaces.