IMMOBILIZATION OF ANTIMICROBIAL PEPTIDES ON SILVER NANOPARTICLES

Abstract

The aim behind this project is to investigate the synergistic action of a food grade antimicrobial peptide with silver nanoparticles. The goal is to develop double edged weapons against food spoilage and pathogenic bacteria. Silver nanoparticles were synthesised by Turkevich Method. Characterisation of the samples was performed, using SEM, AFM, Zeta seizer, AAS, FTIR and UV-Visible spectroscopy. Silver nanoparticles and nisin in combination were subjected to inhibition testing on various bacteria viz such as E.coli, Bacillus sp, Salmonella sp. It was observed that the nisin in combination with silver nanoparticles show enhanced antimicrobial activity against both Gram-positive and Gram-negative bacteria. They also exhibited lower minimum inhibitory concentration compared to either nisin or silver nanoparticles alone. Once refined, this idea can find wide variety of applications in medicine and pharmacological studies. The other approach in this project was synthesis of silver nanoparticles using Polymyxin B sulphate. In this silver nitrate and the polymyxin B sulphate were mixed in methanol in defined concentrations and kept under the visible light for an hour. The light induced reduction of silver nitrate and thus formed silver nanoparticles were capped with polymyxin B sulphate thus confining the size of the silver nanoparticles. The silver nanoparticles thus obtained were characterized by UV-Visible spectroscopy, AFM, SEM, FTIR, Zeta-seizer and AAS. It was observed that the compounds exhibited antimicrobial activity. These silver nanoparticles showed a broad spectrum activity on both Gram-positive as well as Gram-negative bacteria.