Metal-siloxanes derived bio-inspired superhydrophobicity and nitric oxide generation for anti-biofouling clinical...

Bio-inspired superhydrophobic surfaces are widely investigated for antibiofouling applications; however, they lack intrinsic bioactivity and provide passive resistance without eliminating planktonic or surface-adhered microbes. In this work, superhydrophobicity is integrated with bioactive nitric oxide (NO) generation from physiological levels of S-nitrosothiols (RSNOs) to provide combined antibiofouling under biologically relevant conditions. An optimized combination of non-fluorinated organosilane-modified micro- and nanosized zinc oxide (ZnO) and copper (Cu) particles within a siloxane matrix yields a durable coating on a polydimethylsiloxane substrate. The coating exhibits a surface roughness of 353 ± 26 nm and maintains water repellence following sand abrasion, water-jet, tape-peeling, and scratch test, with a contact angle >150° and hysteresis <2°. Upon exposure to physiological levels of S-nitrosoglutathione (GSNO) and glutathione (GSH), the coating demonstrates an 86.4 ± 4.0% increase in NO generation relative to controls, with fluxes matching endothelial NO production. The cytocompatible coating shows negligible metal leaching and excellent antibacterial activity, achieving ∼ 99.99% and 99.79% reductions in surface-adhered S. aureus and E. coli, respectively, and 89.43% and 69.80% reductions in planktonic S. aureus and E. coli, respectively. This work establishes a scalable strategy integrating non-adhesive superhydrophobicity with catalytic NO generation and demonstrates effective antimicrobial performance under physiologically relevant NO-generating conditions.