A Review on Green Synthesis of Nanoparticles and Their Diverse Biomedical and Environmental Applications

Abstract

In recent times, metal oxide nanoparticles (NPs) have been regarded as having important commercial utility. However, the potential toxicity of these nanomaterials has also been a crucial research concern. In this regard, an important solution for ensuring lower toxicity levels and thereby facilitating an unhindered application in human consumer products is the green synthesis of these particles. Although a naïve approach, the biological synthesis of metal oxide NPs using microorganisms and plant extracts opens up immense prospects for the production of biocompatible and cost-effective particles with potential applications in the healthcare sector. An important area that calls for attention is cancer therapy and the intervention of nanotechnology to improve existing therapeutic practices. Metal oxide NPs have been identified as therapeutic agents with an extended half-life and therapeutic index and have also been reported to have lesser immunogenic properties. Currently, biosynthesized metal oxide NPs are the subject of considerable research and analysis for the early detection and treatment of tumors, but their performance in clinical experiments is yet to be determined. The present review provides a comprehensive account of recent research on the biosynthesis of metal oxide NPs, including mechanistic insights into biological production machinery, the latest reports on biogenesis, the properties of biosynthesized NPs, and directions for further improvement. In particular, scientific reports on the properties and applications of nanoparticles of the oxides of titanium, cerium, selenium, zinc, iron, and copper have been highlighted. This review discusses the significance of the green synthesis of metal oxide nanoparticles, with respect to therapeutically based pharmaceutical applications as well as energy and environmental applications, using various novel approaches including one-minute sonochemical synthesis that are capable of responding to various stimuli such as radiation, heat, and pH. This study will provide new insight into novel methods that are cost-effective and pollution free, assisted by the biodegradation of biomass.

New Green Approaches in Nanoparticles Synthesis: An Overview

“…Moreover, the involvement of bio-compounds prevents the contamination of green NPs with toxic by-products. These can be hazardous compounds that attach to the NPs during the physical and chemical synthesis [ 13 ]. However, one of the reasons for which bio-assisted synthesis has remained, so far, in the research stage is that the process involves a set of interrelated parameters (the biological reducing agent composition and concentration, initial precursor salt concentration, agitation speed, reaction time, pH, temperature and light).…”

“…The different review articles have focused on the green synthesis of NPs, considering that research interest in this subject has continuously increased in the past ten years [ 14 ]. However, some of the published reviews have not referred to the factors affecting the biological synthesis of NPs [ 15 , 16 , 17 ], while others briefly discussed them [ 13 , 18 ]. Also, the more exhaustive analyses of the green reaction parameters were limited to a single type of NP, such as silver [ 19 ], copper [ 20 ] or zinc oxide [ 21 , 22 ].…”

Synergetic Antimicrobial Effect of Silver Nanoparticles Conjugated with Iprodione against Valsa mali

“…Application of some nonmetallic nanomaterials including polymeric, lipid, etc., were summarized by Zazo [ 18 ] and Rajwade [ 19 ]. In addition, many other single [ 20 , 21 , 22 , 23 , 24 ] and compound [ 25 , 26 , 27 ] nanomaterials were also synthesized and applied by different researchers. Silver nanoparticles stand out from these nanomaterials owing to their prominent inhibition activity against various pathogens.…”

Synthesis of Silver Nanoparticles in an Eco-friendly Way using Lannea coromandelica Aqueous Bark Extract

“…The approach of eco-friendly methods in the synthesis of nanoparticles is also known as biological methods or green synthesis. Generally, this method is conducted with the help of natural ingredients such as plant extracts, fungi, yeast, bacteria, viruses, and algae, which are known to contain secondary metabolites that reduce metal ions [6,7]. Plant extract is a better synthesizer than other biological methods because of the availability of abundant plant resources compared to other forms of natural resources.…”