Biosynthesis of iron oxide nanoparticles using plant derivatives of Lawsonia inermis (Henna) and its surface modification for biomedical application

Abstract

Metal nanoparticles are being progressively employed in several industrial sectors, and there are a growing interest and demand to develop and standardize more environmentally safe and biocompatible procedures for their synthesis. Thus, green technology has emerged as the best eco-friendly way for the synthesis of the metallic nanoparticle. The study is about plant extract-mediated green synthesis of iron oxide nanoparticles. Extract of Lawsonia inermis (Henna) was used for reduction of ferrous sulfate salt to iron oxide nanoparticles. These nanoparticles were functionalized with l-tyrosine. The biosynthetically synthesized iron oxide nanoparticles were characterized by UV–visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope and energy-dispersive X-ray spectrometer, and the results confirmed the synthesis of l-tyrosine-coated iron oxide nanoparticles. The UV–visible spectroscopy analysis confirmed the formation of nanoparticles formation indicated the surface plasmon resonance at a maximum wavelength of 224 nm. Morphology and shape of the nanoparticles were analyzed by SEM, and the result demonstrates that the particles are spherical in shape with an average size of 150–200 nm. Major functional groups present and involved in the conjugation of l-tyrosine on the surface of iron oxide nanoparticles were analyzed from FT-IR, and the results indicated that the l-tyrosine binds with O–H group of iron oxide nanoparticle to form a conjugate. The parameters were optimized by monitoring the effect of different parameters like concentration of salt, pH, temperature and reducing agent. The optimum nanoparticle synthesis parameters were found to be 0.02 M of FeSO4 concentration, 11 pH, 60 °C temperature and 4 g of reducing agent concentration. Antimicrobial activity of l-tyrosine and bare iron oxide nanoparticles were performed by well diffusion method against two pathogenic bacterial strains Staphylococcus aureus and Staphylococcus typhimurium. The positive results were observed against both S. aureus and S. typhimurium in case of l-tyrosine-functionalized iron oxide nanoparticles with an average inhibition zone of 1.6 and 1.5 cm, respectively. This indicates that the functionalized nanoparticles have great potential as an antimicrobial compound. The surface modification has increased the effectiveness of the iron oxide nanoparticles as an antimicrobial compound that has not been reported in previous studies.