7 - Green synthesis of metal nanoparticles by plant extracts and biopolymers

Abstract

Metallic nanoparticles have been employed in many different nanotechnological applications including medical diagnosis, drug/bioactive delivery, wound healing, and sensors. In particular, gold and silver nanoparticles have been industrially applied due to their unique properties. Although many methodologies have been used for the synthesis of metal nanoparticles, most of them involve the use of hazardous reactants, evidencing that the development of new green protocols is urgent. To be called green, each step of the procedure should employ both environment-friendly solvents and reagents, as well as reduce energy consumption. In other words, green methods focus on the production of nanoparticles by employing natural compounds as reducing and capping agents and decrease, or ideally eliminate, the use or production of hazardous substances during nanoparticle fabrication and/or application. This chapter will present some aspects of the chemistry procedures focused on the protocols developed for the green synthesis of silver and gold nanoparticles, discussing the main role of each biocompound and how they can add new features or even modify the properties of metal nanoparticles, allowing for several applications in different fields of science and technology.