Our brushes are made with CosmeFibre® which is a man-made fibre that naturally resists microbial growth. It does not inhibit microbes as some brushes claim to do with an "antibacterial" chemical coating. Our review of those brushes test results do not convence us of the effectiveness of other such antimicrobial coatings, so we at Artis would rather offer a fibre that does not encourage microbes, but still needs to be regularly cleaned and sanitized to maximize the safe performance of the brush. We feel this is the safer and more practical approach. As antimicrobial coatings get better and safer, we will investigate the use.