Synthesis, characterization of penicillin G capped silver nanoconjugates to combat β-lactamase resistance in infectious microorganism.

In the present study, a novel strategy was adopted to synthesize, β lactamase resistant penicillin G molecules by using the unique properties of silver nanoparticles. Ascorbic acid-stabilized spherical monodispersed silver nanoparticles were prepared by a simple chemical reaction. The formation processes of the silver nanoparticles were investigated by UV-vis spectroscopy and Atomic Force Microscopy (AFM). Free amine groups were introduced on the surface of native silver nanoparticles by coating a uniform layer of polyaniline and this was confirmed by FTIR spectroscopy and Scanning Electron Microscopy. Functionalized silver nanoparticles were then grafted to the C3 carboxyl group of the β lactam ring of penicillin G in the presence of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC) with a conjugation yield of 213 μg mg⁻¹. These novel silver penicillin G nanoconjugates showed a very good growth inhibition against both non-resistant Escherichia coli (gram negative) as well as toward β lactam resistant, E. coli (gram negative) and Staphylococcus aureus (gram positive).