Research Team Develops Low-cost Antimicrobial Paint

Researchers at The City College of New York and Rice University have developed a low-cost, environmentally friendly technique for embedding antimicrobial silver nanoparticles into vegetable oil-based paints. The method, to be reported in the March issue (online January 20) of Nature Materials, could give homes and workplaces a new defense against germs by applying a fresh coat of paint.

Silver nanoparticles offer superior antibacterial activity while being non-toxic. Coatings containing antimicrobial agents have failed commercially in the past, however, due to their complex, multi-step preparation methods and high cost of production.

The research team synthesized metal nanoparticles in common household paints in situ without using hazardous reagents and solvents. “We extensively worked on poly-unsaturated hydrocarbon chain containing polymers/oils to devise a novel approach to nanoparticle formation,” said George John, PhD., professor of chemistry at City College and lead author of the article.

Polyunsaturated hydrocarbons undergo auto-oxidation-induced cross-linking, which is similar to lipid peroxidation, the process by which fatty acids are oxidized in biological systems. During this process, a variety of chemically active species called ‘free radicals’ are generated. These were used by the group as a tool to prepare metal nano-particles in situ in the oil medium.

“The simplicity of the process and economics should allow us to commercialize these paints as a versatile coating material for health and environmental applications” said Pulickel M. Ajayan, PhD., professor of mechanical engineering and materials science at Houston-based Rice University and co-author.

The nanoparticle embedded coating can be applied like traditional paints to such surfaces as metal, wood, polymers, glass, and ceramics.  The metal nanoparticles show characteristic color but avoid the use of short shelf-life organic pigment paints.

The coatings exhibited efficient antibacterial activity toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The antibacterial property is important for hospitals and other public buildings that are prone to bacterial growth, a main cause of infection and disease.

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