Green synthesis of gold and silver nanoparticles: Updates on research, patents, and future prospects

Abstract

Metal nanoparticles (NPs) exhibit distinctive attributes and continue to entice researchers to investigate new dimensions of their worth. Amongst the different noble metal NPs, silver (Ag) and gold (Au) NPs have stolen the limelight. AgNPs and AuNPs are typically synthesized using hazardous chemicals, which affect the environment and human health. This necessitated the development of environment-friendly techniques and gave rise to the green synthesis methodology. Plant-based biological molecules in the form of extracts are the backbone of plant-mediated production of NPs, which outperforms conventional chemical techniques. These natural molecules undergo a strictly regulated assembling process to make them appropriate for forming metal NPs. These plant-based metallic NPs also display well-known biological characteristics, such as antitumor, antioxidant, antibacterial, wound repair, etc. The remarkable benefits of this environmentally friendly technique have also opened the door for fascinating advancements in the synthesis of NPs. The current review highlights the plant's plethora that can be employed to quickly generate a nanoparticulate system adhering to green principles than conventional ones. In addition, a comprehensive overview of the most recent patents and research articles on the synthesis, applications, environmental effects, and future prospects of Ag and AuNPs is provided. Conclusively, it's imperative to focus on creating engineered NPs that are less toxic, have controllable size, shape, and improved health benefits, and expand their applications in related industries.