Biosynthesis of TiO2 nanoparticles and their superior antibacterial effect against human nosocomial bacterial pathogens

• Main Authors: Priyadarshini, S., Mainal, Azizah, Sonsudin, Faridah, Yahya, Rosiyah, Alyousef, Abdullah A., Mohammed, Arshad
• Format: Article
• Published: Springer Verlag 2020
• Subjects: Q Science (General); QD Chemistry
• Online Access: http://eprints.um.edu.my/25382/; https://doi.org/10.1007/s11164-019-03857-6

Antibacterial titanium dioxide nanoparticles (TiO2NPs) were biologically synthesized by microwave irradiation of Cissus quadrangularis extract followed by calcination at 450 °C for 3 h. As-synthesized nanoparticles were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction analysis, and high-resolution transmission electron microscopy. The bioactivity of TiO2NPs against human nosocomial Gram-positive and Gram-negative bacterial pathogens (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli) in liquid media was analyzed in the dark and under ultraviolet (UV, 365 nm) illumination. TiO2NPs demonstrated inhibitory effects against bacteria in dark, and enhanced bactericidal effect under UV illumination. Photoactivation generated holes (h+) and electrons (e−) on the surface of the TiO2NPs, inducing hydroxyl (OH−) and superoxide free radicals (.O2 −) reactive oxygen species (ROS) on the bacterial surface. Furthermore, the interaction between the pathogenic bacteria and TiO2NPs was investigated by bacterial killing assay, colony counting, and viability assay using confocal microscopy. The experimental results revealed that the photoenhanced antibacterial effect of TiO2NPs makes them worth considering as a disinfectant for hospital garments. © 2019, Springer Nature B.V.