Antibacterial activity and possible mechanisms of one-step synthetic laminated flower-like nickelous(II) hydroxide

Abstract

It is very urgent to design and fabricate a new generation of bactericidal materials for confronting the increasing prevalence of antibacterial resistance. Here, we propose laminated flower-like nickelous(II) hydroxide as antibacterial agent and explore its possible antibacterial action. The nickelous(II) hydroxide were synthesized by simple one-step hydrothermal process. The antibacterial properties of nickelous(II) hydroxide were tested by bacterial growth curves and colonies growth on agar nutritive plates. The nickelous(II) hydroxide exhibited a strong, stable and long-term antibacterial activity and killed > 95.0% of both the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Staphylococcus aureus at 250 μg/mL. Antibacterial action was investigated by scanning electron microscopy, transmission electron microscopy, detection of Ni2+ residual, measurement of DNA and RNA release and reactive oxygen species generation analysis. Mechanistically, it killed both Gram-positive and Gram-negative bacteria through physical disruption of the cell membrane structure, causing a loss of cell viability. The antibacterial action would endow nickelous(II) hydroxide with the ability to escape some known mechanisms of antibacterial resistance as a promising long-term bactericide.