Gold Nanoparticles

The medical and pharmaceutical fields are increasingly employing green synthesis of gold nanoparticles (AuNPs) due to its sustainable and eco-friendly benefits. Physical and chemical characteristics of AuNPs render them extremely valuable in a variety of biomedical and research-related applications. Common physical methods of preparing AuNPs involve thermolysis and ultrasound, microwave, γ-ray, or electron beam irradiation that can yield nanoparticles with specific shapes and sizes. Cationic gold (III) ions can be chemically reduced by sodium citrate, ascorbic acid, or sodium borohydride. But since chemical reduction pollutes the nanoparticles with toxic residual compounds, they drastically restrict biomedical uses. For therapeutic and clinical purposes, the employment of chemically synthesized AuNPs is not sacrosanct because of toxicity as well as the resultant economic and environmental impacts. Green biosynthetic methods have emerged as an alternative to the synthesis of these gold nanoparticles. Natural plant, microbial, or other bio-sources used as reducing and capping agents in green synthesis avoid the necessity of hazardous chemicals. The process is more environmental-friendly and biocompatible. Green biosynthesis of AuNPs can control the nanoparticle stability, size, and shape. The applicability of AuNPs is to numerous biomedical applications, including drug delivery, imaging, medical diagnosis, and other developments in nanotechnology. This chapter also explores the characterization of AuNPs and some of the most recent developments in healthcare and nanomedicine.