Researchers at Yale University who are investigating the potential toxicity of SWCNTs recently announced they observed unique antimicrobial properties of the tested materials. Researchers in the study apparently removed metal contaminants from the SWCNT material to prevent false results, and then found that E. Coli test cells were killed on contact with the SWCNTs. The researchers believe that the SWCNTs’ unique shape and small size allowed them to puncture and destroy the E. Coli cells. The scientists preliminary results also indicated MWCNTs are less than toxic than SWCNTs in a lab study.