Low Fouling Marine Coatings Based on Nitric Oxide-Releasing Polysaccharide-Based Hybrid Materials

Abstract

Diethylenetriamine-modified heparin and alginates as well as unmodified polysaccharides were combined using sol–gel chemistry to construct hybrid material thin-film coatings. Due to the high density of amine groups, the hybrid material coatings are capable of binding nitric oxide when exposed to NO at elevated pressures, which were characterized by UV–Vis and ATR-FTIR spectroscopy. When exposed to aqueous environments, the hybrid material coatings showed nitrogen oxide release rates between 17 and 30 pmol·cm–2·s–1. Marine antifouling properties were tested against the marine bacterium Cobetia marina and the diatom Navicula perminuta. The diatom assays revealed a lower settlement on the nitric oxide-loaded hybrid materials compared to hybrid materials without nitrogen oxide release. All coatings readily suppressed attachment of the marine bacterium C. marina. The advantages of hybrid materials, composed purely of polysaccharides and siloxanes, are that their building blocks are environmentally friendly, biodegradable, and biocompatible. This makes them interesting candidates for environmentally benign marine protective coating applications. In particular, the binding of nitric oxide and release of nitrogen oxide species as naturally occurring signaling molecules were found to be promising mechanisms to add additional fouling inhibiting functionality to deter marine organisms from settlement.