Grant: Alliance Grants

Biofouling, the settlement and development of unwanted aquatic species, is a significant challenge for maritime industries including the transportation and aquaculture sectors. Marine fouling affects hull hydrodynamic resistance to reduce speed while increasing fuel consumption by as much as 20%. Biofouling also poses a significant economic barrier to fish production, contributing 5-10% of productions costs. Currently, much marine transportation and aquaculture biofouling is controlled with the use of highly effective copper or copper alloy-based compounds, but their effectiveness is due to non-specific toxicity of leaching copper ions, which may affect food safety. The proposed project will develop environmentally friendly anti-fouling treatments based on black titanium dioxide (bTiO2) and layered double hydroxide (LDH) composites with naturally sourced biomaterials, evaluate their efficacy to inhibit adhering film-forming microorganisms by the biomolecules' innate properties and the nanomaterials generation of electron holes and oxyradicals. Anti-biofouling efficiency will be measured by immersing substrates in seawater with nutrient augmentation to accelerate biofilm growth. Ecotoxicity of nanocomposite/biomaterial coatings and their uptake by filter feeders will be evaluated by tissue dissections and staining with elimination assessed through collection of oyster and mussel feces/pseudofeces. Combining visible light-exploiting bTiO2 nanomaterials which generate reactive oxygen species underwater in low-light conditions (where UV is rapidly scattered with depth) with natural biomaterials that passively inhibit biofilm formation may produce surface coatings rivalling effectiveness of legacy and current metal-based antifouling strategies. Regulators cannot ban copper-based anti-fouling treatments in the absence of a viable commercial replacement as aquaculture is an increasingly important source of protein, and fouling is the chief logistical and economic challenge facing aquaculture. Commercialization of such products will foster a vital competitive edge for Canadian aquaculture in the international marketplace, while improving ecosystem and human health in Canada.