A novel approach of silver-sericin nanoparticles synthesis and their potential as microbicide candidates.

Silver nanoparticles have widely applied for biomedical areas due to its potent antiviral and anti-bacterial activity. Synthesis of silver nanoparticles using biomacromoleculesis more efficient, environment-friendly and cost-saving compare with traditional approach. In this paper, a novel approach was developed to establish a reaction system with Ag+ -BH4- -sericin to synthesize silver nanoparticles conjugated to sericin (AgNPs-Sericin). Sericin could be as a good dispersant and stabilizing agent, which is able to modify nanoscale-silver particles, the average diameter of which was only 3.78±1.14nm prepared in 0.3mg/mL sericin solution. The characterizations of the AgNPs-Sericin were determined by FTIR, TG and XRD. The results showed that the synthesized silver nanoparticle conjugated with sericin as organic phase. Via SAED and XRD analysis, it was showed that these silver particles formed polycrystalline powder with face-centered cubic (fcc) structure of bulk metals. Also, we investigated the antiviral and anti-bacterial activities of AgNPs-Sericin, and the results showed that AgNPs-Sericin exhibited potent anti-HIV-1 activity against CCR5-tropic and CXCR4-tropic strains,but no significant cytotoxicity was found to human genital epithelial cells compared with free silver ions which is accepted as a commonly-used potent antimicrobial agent. Also, its anti-bacterial activity was determined via flow cytometry counting. And the results showed that AgNPs-Sericin could suppress gram-negative ( E.coli ) and gram-positive ( S. aureus ) bacteria, but more potent for gram-negative one. We concluded that our AgNPs-Sericin could be a potential candidate as a microbicide or antimicrobial agent to prevent sexually transmitted infection.