Thiol stabilized copper nanoparticles exert antimicrobial properties by preventing cell division in Escherichia coli

The uses of metallic nanoparticles have gained importance as one of the therapeutic options to treat infections. Here, we synthesized stable copper nanoparticles (CuNPs) using Thiosalicylic acid and assessed their antimicrobial activities against various Gram-negative bacteria. The synthesized CuNPs had absorption maxima of 570 nM with a size range of 5-11 nM and face-centred cubic (Fcc) crystal structure. The bacterial cells in their planktonic and sessile forms were susceptible to CuNPs. The nanoparticles did not show any cytotoxicity to murine macrophages (RAW264.7) below 60 µg/mL. However, the expression of oxidative stress defence gene ahpC revealed the possibility of ROS generation upon treatment with CuNPs. Interestingly, the cell division proteins like, FtsZ and FtsI were destabilized in the presence of CuNPs which in turn inhibited bacterial cell division. In conclusion, it may be stated that the synthesized CuNPs can kill bacteria by arresting cell division and/or by ROS generation