Abstract
Silver nanoparticles (AgNPs) have been extensively studied by researchers due to their unique properties such as size, shape, optical, antimicrobial and electrical properties. A variety of preparation methods have been reported for the synthesis of silver nanoparticles, including laser ablation, gamma irradiation, chemical reduction, electron irradiation, microwave processing, photosynthetic methods and biological synthetic methods. AgNPs have widespread application in wastewater treatment, disease treatment, animal husbandry, fisheries and as antibacterial and antifungal agents but the toxicity of chemically synthesized AgNPs in biological system remains the concern which depends on the morphology of AgNPs. This review provides a comprehensive insight to the various techniques notably, physical, chemical and biological methods used to synthesize silver NPs. The aim of this review article is therefore to reflect the benefits of the biological techniques used for the synthesis of silver NPs and also describes some fundamental issues about non-biological techniques.