Nanoparticles as antifungal additives for indoor water borne paints

•Metal nanoparticles were studied as fungal inhibitors in paints.•The silver smaller size nanoparticles were the most effective ones.•Two fungi, isolated from contaminated paints, were used as aggressive fungi.•The gloss of the paints did not change with the addition of the nanoparticles.•Color changes only appeared in the case of higher concentrations of silver. There are nanotechnology-based materials that can be used as antimicrobial additives in different applications such as water-borne paints. Antimicrobial paints are important tool in order to avoid indoor biological colonization and therefore prevent paint bio-deterioration and health problems in people and pets. These paints would have application in kitchens, bathrooms and hospitals. The present study evaluated the incorporation of silver (of two different sizes), copper and zinc oxide nanoparticles in indoor waterborne paints and the bio-resistance imparted by them. The antifungal activity of nanoparticles is a less studied topic in relation to the antibacterial activity but is no less important from the environmental point of view. Molds that grow in indoor environments contribute significantly with bioaerosol formation and therefore on air contamination and human health deterioration. In this sense, this research evaluated the nanoparticles’ antifungal activity using previously isolated fungi, Chaetomium globosum and Alternaria alternata, on solid medium. Then, the bio-resistance of acrylic paints, with nanoparticles incorporated, was evaluated in Petri dishes and observations were made using scanning electron microscopy. The better results were obtained with the paint that contained silver with the smaller size (10nm).