Aravind Sivasubramanian, Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed to Be University, Thanjavur, Tamil Nadu, India.
Saisubramanian Nagarajan, Center for Research on Infectious Diseases, School of Chemical and Biotechnology, SASTRA Deemed to Be University, Thanjavur, Tamil Nadu, India.
Microb Pathog. 2019 Jul;132:178-187. doi: 10.1016/j.micpath.2019.05.005. Epub 2019 May 4.
Purified glycosides, Isoquercetin and Cassinopin from Crotalaria candicans were selected for the synthesis of biogenic copper nanoparticles (CuNPs).The designed biogenic CuNPs was characterized and when evaluated against panel of gram negative and positive bacteria, the biogenic CuNPs were found to be more effective against methicillin resistant Staphylococcus aureus (MRSA). Antibacterial, anti-biofilm effects and time kill studies confirmed the ability of biogenic CuNPs to curtail MRSA. Scanning electron microscopy, Crystal violet staining and fluorescent live-dead imaging showed that treatment with sub lethal levels of glycoside capped CuNPs resulted in greater than 50% decline in biofilm formation by MRSA, which implies that anti-biofilm effect of biogenic CuNPs is not dependent on antibacterial effect. Alizarin red assay implied that prolonged treatment of biogenic CuNPs in presence of MRSA, releases Cu(II) ions and hence antibiofilm effect is primarily mediated by NP and is not due to released Cu(II) ion. The NPs caused altered membrane permeability and reduced surface hydrophobicity, thus accounting for its antibiofilm effect.
从苦马豆中提取的纯化糖苷（异槲皮苷和苦参酮）被选作生物合成铜纳米粒子（CuNPs）的原料。设计的生物合成 CuNPs 进行了表征，当对革兰氏阴性和阳性细菌进行评估时，发现生物合成 CuNPs 对耐甲氧西林金黄色葡萄球菌（MRSA）更有效。抗菌、抗生物膜作用和时间杀伤研究证实了生物合成 CuNPs 抑制 MRSA 的能力。扫描电子显微镜、结晶紫染色和荧光死活成像显示，用亚致死浓度的糖苷封端 CuNPs 处理可使 MRSA 的生物膜形成减少 50%以上，这意味着生物合成 CuNPs 的抗生物膜作用不依赖于抗菌作用。茜素红测定表明，在存在 MRSA 的情况下，生物合成的 CuNPs 经过长时间处理会释放出 Cu(II)离子，因此，抗生物膜作用主要是由 NP 介导的，而不是由于释放出的 Cu(II)离子。这些 NPs 导致膜通透性改变和表面疏水性降低，从而解释了其抗生物膜作用。
