Coordination-driven antifouling spray coating using a sulfated polysaccharide Fucoidan

Surface contamination and infection caused by bacteria are recognized as acute problems in daily life and human health. To address these issues, surface coatings with antifouling materials to hinder bacterial adhesion and growth on surfaces have been widely used. Although synthetic polymers have their own merits, natural polysaccharides have recently attracted considerable interest for use as antifouling coatings owing to their sustain ability and natural abundance. Metal coordination has recently been utilized to achieve stable antifouling polysaccharide coatings. However, there is an unmet need to fabricate antifouling polysaccharide coatings in a direct way without surface primer layer. Herein, fucoidan, a brown algae-derived polysaccharide, was employed as an antifouling surface coating. For efficient coating, fucoidan was conjugated with catechol groups to produce fucoidan catechol (FD-C). Co-spraying FD-C and ferric (Fe-III) ions onto surfaces enabled the application of coordination-driven antifouling coatings without any surface primer layer in a thickness-controllable manner. Compared with the control, the FD-C/Fe-III coatings achieved 99.2% and 95.6% reduction in E. coli and S. aureus adhesion, respectively, demonstrating the antifouling effects of the coatings. Remarkably, spray-based antifouling coatings have long-term durability, retaining excellent antifouling performance for up to six weeks. Coordination-driven spray coatings can be applied to various substrates including titanium dioxide (a material with medical applications), stainless steel, and seat handles (used in public transportation systems). Given its facile and versatile coating capability, we believe that direct FD-C/Fe-III co-spraying can serve as an effective approach to suppress bacterial contamination and resultant infections.

Automated summary

The researchers developed a direct method to fabricate antifouling polysaccharide coatings that can hinder bacterial adhesion and growth. Fucoidan catechol (FD-C), a conjugate of fucoidan and catechol groups, was co-sprayed with ferric (Fe-III) ions to form coordination-driven antifouling coatings on surfaces. The FD-C/Fe-III coatings achieved significant reduction in E. coli and S. aureus adhesion. The spray-based coatings also exhibited long-term durability and flexibility for various substrates.