A Systematic Review of Biosynthesized Metallic Nanoparticles as a Promising Anti-Cancer-Strategy

Simple Summary Cancer is one of the major public health burdens in the world. To date, various conventional cancer therapies have been used, but these therapies are less effective and have severe side effects. Currently, in order to find a better cure for cancer, researchers have tried to explore new approaches with minimal toxicity and fewer side effects. In recent years, nanotechnology has been widely used in diseases management and holds a promising future in curing complex incurable diseases, in particular cancer. Biosynthesized metallic nanoparticles are eco-friendly and biocompatible, and can be used in cancer diagnostics, novel treatments, and drug delivery systems. This review gives an overview of the recent advancements in the biosynthesis of metallic nanoparticles (silver (Ag), gold (Au), zinc (Zn) and copper (Cu)) and their possible anti-cancer activities, with particular emphasis on the mechanisms of action, and future research prospects of nano-therapeutics are also discussed. Cancer is one of the foremost causes of death worldwide. Cancer develops because of mutation in genes that regulate normal cell cycle and cell division, thereby resulting in uncontrolled division and proliferation of cells. Various drugs have been used to treat cancer thus far; however, conventional chemotherapeutic drugs have lower bioavailability, rapid renal clearance, unequal delivery, and severe side effects. In the recent years, nanotechnology has flourished rapidly and has a multitude of applications in the biomedical field. Bio-mediated nanoparticles (NPs) are cost effective, safe, and biocompatible and have got substantial attention from researchers around the globe. Due to their safe profile and fewer side effects, these nanoscale materials offer a promising cure for cancer. Currently, various metallic NPs have been designed to cure or diagnose cancer; among these, silver (Ag), gold (Au), zinc (Zn) and copper (Cu) are the leading anti-cancer NPs. The anticancer potential of these NPs is attributed to the production of reactive oxygen species (ROS) in cellular compartments that eventually leads to activation of autophagic, apoptotic and necrotic death pathways. In this review, we summarized the recent advancements in the biosynthesis of Ag, Au, Zn and Cu NPs with emphasis on their mechanism of action. Moreover, nanotoxicity, as well as the future prospects and opportunities of nano-therapeutics, are also highlighted.