Immunology and Microbiology Laboratory, Department of Human Physiology with Community Health, Vidyasagar University, Midnapore-721 102, West Bengal, India.
Department of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel.
Biomed Pharmacother. 2016 Oct;83:548-558. doi: 10.1016/j.biopha.2016.07.011. Epub 2016 Jul 21.
Recently bio-inspired experimental processes for synthesis of nanoparticles are receiving significant attention in nanobiotechnology. Silver nanoparticles (Ag NPs) have been used very frequently in recent times to the wounds, burns and bacterial infections caused by drug-resistant microorganisms. Though, the antibacterial effects of Ag NPs on some multi drug-resistant bacteria specially against Gram positive bacteria has been established, but further investigation is needed to elicit its effectiveness against Gram negatives and to identify the probable mechanism of action. Thus, the present study was conducted to synthesize Ag NPs using Andrographis paniculata leaf extract and to investigate its antibacterial efficacy. After synthesis process the biosynthesized nanoparticles were purified and characterized with the help of various physical measurement techniques which raveled their purity, stability and small size range. The antimicrobial activity of Ag NPs was determined against both Gram-positive Enterococcus faecalis and Gram-negative Proteus vulgaris. Results showed comparatively higher antibacterial efficacy of Ag NPs against Gram positive Enterococcus faecalis strains. It was found that greater difference in zeta potential values between Gram positive bacteria and Ag NPs triggers better internalization of the particles. Thus the cell surface charge played vital role in cell killing which was confirmed by surface zeta potential study. Finally it may be concluded that green synthesized Ag NPs using Andrographis paniculata leaf extract can be very useful against both multi drug resistant Gram-positive and Gram-negative bacteria.
近年来，受仿生启发的纳米粒子合成实验方法在纳米生物技术领域受到了广泛关注。银纳米粒子（Ag NPs）在最近的研究中被频繁用于治疗耐药微生物引起的伤口、烧伤和细菌感染。尽管 Ag NPs 对一些多药耐药菌，特别是革兰氏阳性菌的抗菌作用已经得到证实，但仍需要进一步研究以确定其对革兰氏阴性菌的有效性，并确定其可能的作用机制。因此，本研究采用穿心莲叶提取物合成 Ag NPs，并研究其抗菌功效。在合成过程后，通过各种物理测量技术对生物合成的纳米粒子进行纯化和表征，揭示了其纯度、稳定性和小尺寸范围。Ag NPs 的抗菌活性针对革兰氏阳性粪肠球菌和革兰氏阴性普通变形杆菌进行了测定。结果表明，Ag NPs 对革兰氏阳性粪肠球菌菌株的抗菌效果较好。研究发现，革兰氏阳性菌和 Ag NPs 之间的 ζ 电位值差异越大，颗粒的内化效果越好。因此，细胞表面电荷在细胞杀伤中起着至关重要的作用，这一点通过表面 ζ 电位研究得到了证实。最后可以得出结论，使用穿心莲叶提取物合成的绿色 Ag NPs 可能对多药耐药的革兰氏阳性和革兰氏阴性菌都非常有用。
