In addition, these coatings exhibited efficient antibacterial activity toward Escherichia coli and Staphylococcus 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.
Researchers Develop Low-Cost Technique for Producing Antimicrobial Paints
April 1, 2008
NEW YORK - Researchers at the City College of New York (CCNY) and Rice University have developed a low-cost, environmentally friendly technique for embedding antimicrobial silver nanoparticles into vegetable oil-based paints. The method, reported in the March issue of Nature Materials, could give homes and workplaces a new defense against germs by applying a fresh coat of paint.
Silver’s antibacterial properties have been known for thousands of years, and silver nanoparticles offer superior antibacterial activity while being non-toxic. However, coatings containing antimicrobial agents have failed commercially in the past due to their complex, multi-step preparation methods and high cost of production.
The CCNY/Rice team developed a “green chemistry” approach to synthesize 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, Professor of Chemistry at CCNY and lead author of the article.
Poly-unsaturated hydrocarbons undergo auto-oxidation-induced crosslinking, 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 nanoparticle-embedded coating can be applied like traditional paints to surfaces such as metal, wood, polymers, glass and ceramics. The metal nanoparticles show characteristic color but avoid the use of short-shelf-life organic-pigment paints.