Functionalised iron nanoparticle–penicillin G conjugates: a novel strategy to combat the rapid emergence of β-lactamase resistance among infectious micro-organism

Abstract

The emergence of novel mechanisms of β-lactam resistance and their gain by infectious micro-organisms are posing a huge clinical threat to human health. It creates a need to generate novel resistant antibiotic molecules to counter their attack. In the present study, a novel strategy is developed to synthesise β-lactamase-resistant penicillin G molecules by using the unique properties of iron nanoparticles. Spherical monodispersed iron nanoparticles were prepared by a simple chemical reduction method. The formation process of the iron nanoparticles was investigated by ultraviolet–visible spectroscopy and atomic force microscopy. Free amine groups introduced on the surface of native iron nanoparticles by coating a uniform layer of polyaniline were confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy. Functionalised iron 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 with a conjugation yield of 187.7 μg mg−1. These novel iron nanoparticle–penicillin G conjugates showed a very good growth inhibition against β-lactam-resistant Staphylococcus aureus. This work thus describes a novel strategy for synthesis of nanoconjugates which can be used to design novel bactericidal materials against β-lactam-resistant infectious micro-organisms.