Controlled synthesis of Mn₂O₃ nanowires by hydrothermal method and their bactericidal and cytotoxic impact: a promising future material.

Mn₂O₃ nanowires with diameter ~70 nm were synthesized by a simple hydrothermal method using Mn(II) nitrate as precursor. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy techniques were employed to study structural features and chemical composition of the synthesized nanowires. A biological evaluation of the antimicrobial activity and cytotoxicity of Mn₂O₃ nanowires was carried out using Escherichia coli and mouse myoblast C₂C₁₂ cells as model organism and cell lines, respectively. The antibacterial activity and the acting mechanism of Mn₂O₃ nanowires were investigated by using growth inhibition studies and analyzing the morphology of the bacterial cells following the treatment with nanowires. These results suggest that the pH is critical factor affecting the morphology and production of the Mn₂O₃ nanowires. Method developed in the present study provided optimum production of Mn₂O₃ nanowires at pH ~ 9. The Mn₂O₃ nanowires showed significant antibacterial activity against the E. coli strain, and the lowest concentration of Mn₂O₃ nanowires solution inhibiting the growth of E. coli was found to be 12.5 μg/ml. TEM analysis demonstrated that the exposure of the selected microbial strains to the nanowires led to disruption of the cell membranes and leakage of the internal contents. Furthermore, the cytotoxicity results showed that the inhibition of C₂C₁₂ increases with the increase in concentration of Mn₂O₃ nanowires. Our results for the first time highlight the cytotoxic and bactericidal potential of Mn₂O₃ nanowires which can be utilized for various biomedical applications.