Department of Zoology, Government College for Women, Thiruvananthapuram 695014, Kerala, India.
Center for Advanced Materials Research, Department of Physics, Government College for Women, Thiruvananthapuram 695014, Kerala, India.
Lett Appl Microbiol. 2024 Jun 3;77(6). doi: 10.1093/lambio/ovae053.
This study explores the eco-friendly synthesis of silver nanoparticles (AgNPs) using soil bacteria, Pseudomonas otitidis. The bio-synthesized AgNPs were characterized using various techniques, including UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). UV-visible spectroscopy revealed a distinct broad absorption band in the range of 443 nm, indicating the reduction of silver nitrate to AgNPs. XRD analysis provided evidence of the crystalline nature of the particles, with sharp peaks confirming their crystallinity and an average size of 82.76 nm. FTIR spectroscopy identified extracellular protein compounds as capping agents. SEM examination revealed spherical agglomeration of the crystalline AgNPs. The antimicrobial assay by a disc diffusion method, minimum inhibitory concentration, and minimum bactericidal concentration testing revealed that the biosynthesized AgNPs showed moderate antibacterial activity against both pathogenic Gram-negative (Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii) and Gram-positive (Bacillus cereus, Staphylococcus aureus, and Streptococcus mutans) bacterial strains. Furthermore, the AgNPs significantly disrupted the biofilm of P. aeruginosa, as confirmed by crystal violet assay and fluorescent microscopy. Overall, this study underscores the potential of microbial-synthesized nanoparticles in biomedical applications, particularly in combating pathogenic bacteria, offering a promising avenue for future research and development.
本研究探索了使用土壤细菌假单胞菌（Pseudomonas otitidis）来环保合成银纳米颗粒（AgNPs）。采用各种技术对生物合成的 AgNPs 进行了表征，包括紫外-可见光谱、傅里叶变换红外（FTIR）光谱、扫描电子显微镜（SEM）和 X 射线衍射（XRD）。紫外-可见光谱显示出在 443nm 范围内的明显宽吸收带，表明硝酸银被还原为 AgNPs。XRD 分析提供了颗粒结晶性质的证据，尖锐的峰证实了其结晶度和平均尺寸为 82.76nm。FTIR 光谱鉴定出胞外蛋白化合物作为帽状试剂。SEM 检查显示出结晶 AgNPs 的球形聚集。通过圆盘扩散法、最小抑菌浓度和最小杀菌浓度测试进行的抗菌试验表明，生物合成的 AgNPs 对革兰氏阴性（肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌）和革兰氏阳性（蜡样芽孢杆菌、金黄色葡萄球菌和变形链球菌）两种病原菌均表现出中等抗菌活性。此外，AgNPs 通过结晶紫测定和荧光显微镜证实，显著破坏了铜绿假单胞菌的生物膜。总的来说，本研究强调了微生物合成纳米粒子在生物医学应用中的潜力，特别是在对抗病原菌方面，为未来的研究和开发提供了有前途的途径。
