Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, 741235, West Bengal, India.
Sci Rep. 2019 Oct 25;9(1):15364. doi: 10.1038/s41598-019-51906-2.
Prevalence of antibiotic-resistant bacteria demands alternatives to antibiotics. Copper-based nanoparticles with a high antibacterial property may be a solution to the problem. It is, therefore, important to understand the mode of antibacterial action of the nanoparticles (NPs). Despite reports on induction of reactive oxygen species (ROS) in bacteria by copper and copper-oxide nanoparticles and involvement of such ROS in cell killing, it is still unclear (a) if surface modification of the nanoparticles by media organics has any role on their antibacterial potency and (b) whether the bactericidal effects of these NPs are 'particle-specific' or 'ion-specific' in nature. We address these issues for cupric oxide nanoparticle (CuO-NP) in this study. Instead of nutrient medium, when E. coli bacterial cells were suspended in saline (0.9% NaCl), CuO-NP had a more anti-bacterial effect, with MBC (minimum bactericidal concentration) value of 6 µg/mL, than in nutrient medium with MBC value of 160 µg/mL. Moreover, the lysine-modified CuO-NP in saline had MBC at 130 µg/mL. Thus, unmodified CuO-NP was more efficient killer than modified one. Our finding further revealed that in saline;CuO-NP had 'particle-specific' antibacterial effect through generation of ROS and consequent oxidative damage by lipid peroxidation, protein oxidation and DNA degradation in cells.
抗生素耐药菌的流行要求寻找抗生素替代品。具有高抗菌性能的铜基纳米粒子可能是解决这一问题的方法。因此，了解纳米粒子（NPs）的抗菌作用模式非常重要。尽管有报道称铜和氧化铜纳米粒子会在细菌中诱导活性氧（ROS），并且此类 ROS 参与细胞杀伤，但仍不清楚（a）介质有机物对纳米粒子的表面修饰是否对其抗菌效力有任何影响，以及（b）这些 NPs 的杀菌作用是“颗粒特异性”还是“离子特异性”。在这项研究中，我们针对氧化铜纳米颗粒（CuO-NP）解决了这些问题。当大肠杆菌细菌细胞悬浮在盐水中（0.9%NaCl）而不是营养培养基中时，CuO-NP 的抗菌效果更好，MBC（最小杀菌浓度）值为 6μg/mL，而在营养培养基中的 MBC 值为 160μg/mL。此外，在盐水中，赖氨酸修饰的 CuO-NP 的 MBC 值为 130μg/mL。因此，未修饰的 CuO-NP 比修饰的 CuO-NP 更有效。我们的发现进一步表明，在盐水中；通过生成 ROS 以及随后通过脂质过氧化、蛋白质氧化和 DNA 降解在细胞中造成氧化损伤，CuO-NP 具有“颗粒特异性”的抗菌作用。
