Dose-dependent cytotoxicity has also been observed in some animal/human biomass-derived CDs.154,177,201,208,220,243–245 For example, the low cytotoxicity of cow manure-derived PBA-CDs at a concentration of 0.01 mg mL−1 to B16F10 (murine melanoma cells) and NIH3T3 (fibroblast cells) cells was explained based on the surface-confined negative charges present in the boronic groups. The gene discussed is CDS1; the disease is melanoma.