EFFECT of SHORT MULTIWALLED CARBON NANOTUBES on ESCHERICHIA COLI K-12 STRAIN

Abstract

Objective: Multi-walled carbon nanotubes (MWNTs) are obtained by rolling up the graphene structure to form multi-walled cylindrical structures, find wide usage areas in different areas with their large surface areas, hydrophobicity, and high electron conductivity. Evaluation of antibacterial effects has become very important in recent years. In this study, it was aimed to evaluate the antibacterial effect of MWNTs on E. coli K12 strain, which are shorter than most of the MWNTs in the literature, which we have previously applied to different cell lines, nematodes, and which have a very limited toxic effect up to high concentrations. Methods: Different concentrations ranging from 20 to 100 µg/ml were prepared from MWNTs and applied to E. coli K12 strain. Colony count, optical density measurement, and microscopic images were evaluated. Results: Compared to control, it was observed that MWNTs affected the proliferation at every concentration from 10 µg/ml to 100 µg/ml, and the antibacterial effect was most pronounced at 50 and 100 µg/ml concentrations. There was no significant difference in inhibition dose between 10 and 20 µg/ml. Growth inhibition was observed to be greater than 20% after 90 minutes at high doses. Conclusion: Bacteria grown in liquid and solid agar revealed different inhibition properties at low and high concentrations. Depending on the concentration, it was determined that the absorbance and viability values of E. coli cells decreased in both experiments. In addition, decreases in bacterial colonies, and the bacterial activity performed with DAPI staining and image analyzes are quite evident. Keywords: Multi-walled carbon nanotube, E. coli, inhibition, density, antibacterial effect