Bactericidal Effects of Single-walled Carbon Nanotubes on E.coli

Abstract

In this work, the effects of Single-walled carbon nanotubes (SWNTs), 4-Chloro-3, 5-Dimethylphenol (PCMX) adsorbed SWNTs (named SWNTs-PCMX) and Poly-hexamethylene Biguanide Hydrochloride (PHMB) adsorbed SWNTs (named SWNTs-PHMB) on growth of Escherichia coli (E. coli) were investigated. The results showed that low concentration (0.1g/L) of SWNTs had no significant effect on the growth of E. coli, while 1g/L SWNTs inhibited E. coli. Within 25min, the killing log (KL) of SWNTs-PCMX (450mg/L) was 8.66 folds of KL without PCMX, in contrast the bactericidal activity was still lower than PCMX. The results of Fourier Transform Infrared Spectroscopy (FTIR) showed that the functional groups of PCMX in SWNTs-PCMX were adsorbed into the cavity of SWNTs, which led to the decrease of bactericidal effect. However, with the increase of time, the bactericidal activity of SWNTs-PCMX was enhanced, and it had a slow release effect. To further improve the bactericidal effect of SWNTs, the PCMX was replaced by PHMB, the KL of SWNTs-PHMB (320mg/L) was 2.7 folds than that of SWNTs-PCMX (450mg/L).