Green synthesis of metal nanoparticles: Characterization and their antibacterial efficacy

Abstract

The global emergence and spread of multi-drug resistance in bacterial pathogens has led the researchers to focus on the development of alternative measures or therapeutic agents to combat microbial infections caused by drug-resistant bacteria. Recent advances in nanotechnology have given a new hope for the development of novel nano-based formulations to address the problem. Green synthesis of metal nanoparticles has advantages over other chemical and physical methods such as, reduced toxicity, one-step process, cost-effectiveness, eco-friendliness, and does not require additional capping or stabilizing agents. The techniques employed for the characterization of nanoparticles are UV-Vis spectroscopy, XRD, FTIR, SEM, EDX, TEM, AFM, DLS, zeta potential, and TGA etc. The antibacterial nanoparticles studied most widely are metal nanoparticles. Metal nanoparticles have demonstrated potent antibacterial activity in vitro with promising therapeutic potential in wound dressings, medical implant coatings, drug delivery, tumour detection, and photoimaging. Many bioagents such as bacteria, fungi, plant extracts, etc. have been exploited for green synthesis of nanoparticles. Medicinal plants as bio-templates for the synthesis of metal nanoparticles might show an immense impact in biomedicine. However, toxicity of nanoparticles to the host is a major concern that needs to be scrutinized properly to monitor its long-term impact. Still, recently developed nano-based formulations, including metal nanoparticles, are expected to become the next generation therapeutic agents against bacterial pathogens, especially against MDR bacteria. In this chapter, we have reviewed the role of medicinal plants in metal nanoparticle synthesis, characterization techniques, and their efficacy against bacterial pathogens.