Eco-friendly synthesis and biomedical applications of gold nanoparticles: A review

•Overview of various, green synthesis methods for gold nanoparticles (GNPs).•The indispensable role of GNPs in diseases diagnosis and bioimaging is described.•Novel green synthesis strategies for GNPs are discussed.•Discussion on the development of new clinical applications of GNPs. Nanotechnology is revolutionizing various aspects of our lives, and gold nanoparticles (GNPs) are at the forefront of this “nanotechnology revolution.” GNPs exhibit a variety of unique beneficial properties, which when harnessed and manipulated effectively, would lead to the development of materials that can be used for various applications. The use of microbes has recently emerged as a novel approach for the synthesis of GNPs with pre-defined size, shape, and composition. This has brought a new era to the field of nanomedicine and has altered the foundations of disease diagnosis, treatment, and prevention. This review provides an overview of various, green GNP synthesis methods and the indispensable role of GNPs in disease diagnosis and bioimaging. In addition, the review discusses the future directions in GNP synthesis and the development of new clinical applications of GNPs.