Biological Effects of Green-Synthesized Metal Nanoparticles: A Mechanistic View of Antibacterial Activity and Cytotoxicity

Recent advancements in nanotechnology have pushed the boundary of nanomaterial studies and their applications so far that almost each and every aspect of science is looking for their application based on them. The extensive studies and industrial applications have raised demand for nanomaterial in leaps and bounds. To fulfill the demand, new strategies for their synthesis and industrial preparation have been discovered and applied. However, the logarithmic expansion of production of nanomaterials, especially metal and metal oxide nanomaterials, has slowly raised the issue of their toxicity and biocompatibility with respect to ecosystems and human health. Traditional synthesis of nanomaterials by chemical and physical synthesis procedures has been reported to impose higher toxicity on both ecosystems and human health. There are regular quests for new methods to discover biocompatible nanomaterials. In view of the above facts, green synthesis of nanomaterials, using biological agents, has been shown to be a solution to this issue. However, to address this issue, discussion about their detailed biological effects is urgently needed. To illuminate these concerns, this chapter provides a brief review of the current strategies for green synthesis of nanomaterials, especially focusing on metal and metal oxide nanoparticles and their detail mechanisms of biological effects in view of their antibacterial efficacy and cytotoxicity.