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.

通过微波辐射Cissus quadrangularis提取物，然后在450°C下煅烧3 h ，生物合成抗菌二氧化钛纳米颗粒（TiO ₂ NPs）。通过傅立叶变换红外光谱，X射线衍射分析和高分辨率透射电子显微镜对合成后的纳米颗粒进行表征。在黑暗和紫外线（UV，365 nm）照明下分析了液体介质中TiO ₂ NPs对人类医院革兰氏阳性和革兰氏阴性细菌病原体（金黄色葡萄球菌，枯草芽孢杆菌和大肠杆菌）的生物活性。二氧化钛₂NPs在黑暗中表现出对细菌的抑制作用，并在紫外线照射下增强了杀菌作用。光活化产生的空穴（h ⁺）和电子（e ^- ）在TiO的表面上₂的NP，诱导羟基（OH ^- ）和超氧自由基（·O ₂ ^{- ）}的细菌表面上的活性氧物种（ROS）。此外，使用共聚焦显微镜通过细菌杀灭测定，菌落计数和生存力测定研究了致病细菌与TiO ₂ NPs之间的相互作用。实验结果表明，TiO ₂具有光增强抗菌作用。NP使他们值得考虑作为医院服装的消毒剂。