In vitro assessment of antimicrobial and genotoxic effect of metallosurfactant based nickel hydroxide nanoparticles against Escherichia coli and its genomic DNA

In the present study, we have synthesized nickel hydroxide nanosuspensions (Ns) using microemulsion technique. This approach is eco-friendly and makes use of Tween 80 (a non-ionic biocompatible surfactant) and newly synthesized metallosurfactants for the formation of uniform nanoparticles in the form of nanosuspensions (Ns). The nickel hydroxide Ns's were derived from three different metallosurfactants i.e. NiCTAC (Bishexadecyltrimethylammonium nickel tetrachloride), NiDDA (Bisdodecylamine nickel dichloride) and NiHEXA (bishexadecylamine nickel dichloride). Three different nickel-based metallosurfactants were synthesized and characterized using various methods such as CHN, (HNMR)-H-1, and FTIR. Fabrication of nanosuspension was confirmed using different characterization methods such as Transmission electron microscopy (TEM), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), pH and Zeta potential. These particles were further investigated for their genotoxic and cytotoxic effects on gram-negative bacteria, Escherichia coil (E. coli). Effect of nanosuspensions on E. coli was confirmed using colony forming unit count, agar well diffusion, and gram staining method. Through colony forming unit count method, nanosuspensions influence on the colony-forming capacity of E. coli cells was confirmed. Agar well diffusion method provides the estimation of antimicrobial activity, and the largest inhibition zone was observed for NiCTAC Ns and smallest for NiHEXA Ns which is related to maximum and minimum bactericidal properties of Ns, respectively. The interaction behavior of bacterial DNA with Ni nanosuspension was analyzed using agarose gel electrophoresis and circular dichroism. Along with, the role of different chemical scavengers was also evaluated in DNA damage using gel electrophoresis. Furthermore, the antioxidant activity of Ni nanosuspension was also confirmed using DPPH assay.