Biological synthesis of nanoparticles: An environmentally benign approach

Scientists are expanding their interests toward synthesizing metal and metal oxide nanoparticles, as they provide unique physical, chemical, and biological properties. Conventional physical and chemical methods for synthesis of metal and metal oxide nanoparticles become accountable for various biological risks due to their general toxicity and negative impact on the environment. The plant extract is an alternative green technology used for the production of metal and metal oxide nanoparticles. Biomolecules present in plant extracts can be used to reduce metal ions to nanoparticles through a single-step green synthesis process. The present chapter discusses current trends in the plant’s extract and microorganism biosynthesis of various types of metallic and metal oxide nanoparticles and highlights the potential applications of fabricated nanoparticles. The influence of the reaction condition, such as temperature, pH, concentration of extracts, concentration of the metal salt solution, mixing ratio, and incubation time, are discussed.