Protective coatings with modified silica nanoparticles defend against bacteria and fungi

The buildup of bacteria or fungi on industrial surfaces such as stainless steel, concrete and painted finishes can negatively impact human health, contaminate drinking water and perpetuate the spread of diseases. This type of contamination can lead to huge economic and environmental costs.

Yang et al. have been studying the attachment of fungi on protective coatings made from glycidoxypropyltrimethoxysilane (GPS) modified silica nanoparticles (SiNP). Their goal is to understand and optimize the defensive abilities of coatings such as these to prevent the buildup of bacteria or fungi.

The authors compared the attachment of spores from the fungus Epicoccum nigrum on four silica-based surfaces: glass, unmodified SiNP coatings, and low- and high-GPS-SiNPs coatings.

GPS-SiNP-coated surfaces were found to protect against fungi adhesion by a two-step defense mechanism. When the fungus attempts to attach by throwing out a long-range anchor, the surface first electrostatically repels the attachment of the fungus, and then, if the fungus manages to attach, a thin layer of water combined with polymer chains acts as a barrier.

Author Dan Yang explained the coatings they researched are commercially available, cost-effective, non-toxic and easy to prepare in bulk quantities.

“The coatings can be supplied as a dispersion, for example dissolved in a solution, and hence easily applied to surfaces using a range of coating techniques, such as spray coating, reel-to-reel or roll coating and just simply dipping in the solution,” said Yang.

In the future, project leader Michael Higgins intends on testing these coatings on outdoor surfaces and over long durations. He believes they show potential for biomedical applications and plans to see if they are effective in blood.

Source: “Fungal spore adhesion on glycidoxypropyltrimethoxy silane modified silica nanoparticle surfaces as revealed by single cell force spectroscopy,” by Dan Yang, Paul J. Molino, Brianna R. Knowles, Shane Maclaughlin, and Michael J. Higgins, Biointerphases (2020). The article can be accessed at https://doi.org/10.1116/6.0000142 .