Green Synthesis of Anti-bacterial Nano Silver by Polysaccharide from Bletilla Striata

The silver nanoparticle is a good antibacterial material being used as a broad-spectrum fungicide, including against some multidrug-resistant strains. Compared with the normal chemical and physical preparation methods, green synthesis has attracted wide attention, because of the pharmaceutical activities of the natural product, mild reaction conditions, and environmentally friendly, etc. In this study, the synthesis of silver nanoparticles (Ag NPs) was prepared from Bletilla striata polysaccharide (BSP) and characterized by UV-vis spectroscopy and Dynamic Light Scattering (DLS). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated the morphology of Ag NPs was subspherical with an average size of 20–35 nm. Bletilla striata polysaccharide not only can be used as a natural reducing agent, but also has good repairing ability. Moreover, the antibacterial experimental results showed its great antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli) and Candida albicans.