In a February 15, 2010, article entitled “ZnO Particulate Matter Requires Cell Contact for Toxicity in Human Colon Cancer Cells,” researchers report their results of a comparison of the toxicity of two commercial types of zinc oxide (ZnO) to colon cells. According to the researchers, the nano-sized ZnO was more cytotoxic than micrometer-sized ZnO. The researchers state: “Unintended exposure to nano-sized zinc oxide from children accidentally eating sunscreen products is a typical public concern, motivating the study of the effects of nanomaterials in the colon.” The article will be published in Chemical Research in Toxicology.