The Effect of Temperature and Acidity on ‎Antimicrobial Activities of Pristine ‎MWCNTs and MWCNTs-Arg

Carbon nanotubes (CNTs) have very promising applications for inhibition of microbial growth. The aim of this study is investigation and comparison of the effect of temperature and acidity on antimicrobial activities of pristine Multiwalled Carbon nanotubes (MWCNTs) and Multiwalled Carbon nanotubes-Arginine (MWCNTs-Arg). Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were calculated in range of temperature (25, 37 and 42 ºC) and pH (4.2, 7.2, and 10) on Staphylococcus aureus. The results approved that pristine and functionalized MWCNTs have broad-spectrum antimicrobial activities against examined pathogen. Between these agents, MWCNTs-Arg and pristine MWCNTs and have the highest inhibitory activity on microbial growth, respectively. The MBC value of MWCNTs was improved by amino acid functionalization. The optimal pH for antimicrobial activity of pristine MWCNTs and MWCNTs-Arg are 4.2 and 7.2 and optimal temperatures are 42 ºC and 42 ºC, respectively. There is no change on optimal temperature of MWCNTs by this functionalization, but functionalization of MWCNTs by Arg enhanced its antimicrobial activity and led to change of optimal pH of MWCNTs for antimicrobial activity. This changes lead to suitable improvement of antimicrobial activity in neutral and biological pH.