Rational Design of Bio-Inspired Nanowire Architectures for Preventing Marine Biofouling

Biofouling has a negative impact on human health and economic development. In particular, biofilms in the marine environment grow easily, adhere strongly on most surfaces, and continuously generate adhesive proteins from the living organisms in the film. However, their interactions with nanoscale structures remains unknown. Herein, we present the rational design and fabrication of ZnO/Al₂O₃ core-shell nanowire (NW) architectures to significantly reduce marine biofouling (algae: cyanobacteria and diatoms) and further suppress the biofilm formation by tuning the NW geometry (length, spacing, branching) and surface chemistryTwo mechanisms of the fouling reduction were summarized with geometric and mechanical effect of the NWs: (1) reduced effective settlement area, and (2) mechanical cell penetration. For superhydrophobic NWs, we demonstrated anti-biofouling performance for up to 22 days, which is one order of magnitude longer duration than what have been reported in the literature under biofouling environment. A mass diffusion and thermodynamic model was developed to explain and predict the anti-fouling duration on NWs in the Cassie state. Through the rational control of surface nano-architectures, the coupled relationships between wettability, transparency, and anti-biofouling performance are identified. We envision that the insights gained from the work can be used to systematically design surfaces that reduce marine biofouling in various industrial settings.