Recent progress in the green fabrication of cadmium sulfide and cadmium oxide nanoparticles: synthesis, antimicrobial and cytotoxic studies

• The cadmium undergoes bioreduction by various natural products present in bacteria, fungi, algae, and plants. • The biological synthesis gave a high control over the size distribution of nanoparticles and did not require stabilizing agents. • The antibacterial and anticancer properties of biologically produced CdO and CdS NPs are discussed. Interestingly, cadmium sulfide (CdS) and cadmium oxide (CdO) nanoparticles (NPs) are widely used as biosensors, bio-imaging, molecular pathology, solar cells, liquid crystal displays, photovoltaic cells, IR detectors and in drug delivery applications. Salts of Cd can undergo bioreduction by various natural compounds found in microorganisms, such as bacteria, fungi, algae and also in plants, to form NPs. This biological synthesis using enzyme resources has gained tremendous importance due to its environmental friendliness; however, chemical and physical synthesis techniques are frequently employed due to reproducible results in NP formation. This review provides an overview of various reports on synthesizing CdS and CdO nanoparticles and their antimicrobial and cytotoxic activities using bioreduction originating from different sources, e.g., bacteria, fungi, plants (leaves, fruit, flowers and roots), and microalgae. Furthermore, this review comprehensively discusses the significance of green nanotechnology in producing these NPs for various biomedical applications.