The Ames test utilizes several different tester strains of Salmonella typhimurium to measure two classes of gene mutation, base pair substitution and small frameshifts [13] and [14]. Six of the eight Ames tests on nanomaterials thus far reported in the literature were negative. Titanium dioxide (TiO2) nanoparticles [15] and zinc oxide nanoparticles [16], with or without UV light irradiation, were negative in S. typhimurium (and Escherichia coli) tester strains. Also, TiO2 nanoparticles [17] and silica-overcoated magnetic nanoparticles labeled with rhodamine B isothiocyanate [18] t