Current Green Chemistry - Volume 8, Issue 3, 2021

Nowadays, nanoparticles are gaining enormous importance in a wide variety of disciplines due to their unambiguous physical and chemical properties. There are lots of physical and chemical approaches available for the synthesis of metal nanoparticles. But there are certain disadvantages associated with these methods, such as adsorption of hazardous toxins on the surface of the material, high capital investment, high manufacturing energy demand, etc., which make their effective implementation almost impossible. An alternative method of synthesizing nanoparticles to avoid the aforementioned disadvantages is to use different parts of the plant under aqueous conditions. Plant-mediated approach for the synthesis of nanoparticles is becoming increasingly popular due to its faster reaction rate, easily affordable, eco-friendly nature and rich diversity of plants. Chemical compositions of plant extracts are examined using the liquid chromatography-mass spectrometry technique. Noble metals such as Silver, Gold, Iron, Copper, Platinum, Zinc, Palladium, and their oxides are used for the fabrication of metal nanoparticles, due to their enormous potential applications. In a single-step green synthesis process, the phytochemical constituents which are present in plant extract reduce metal salts into metal nanoparticles. This article gives an overview of plant-mediated synthesized metal and metal oxide nanoparticles and their characterization by using different techniques, together with their properties and applications in numerous fields.

Super Critical Fluid is the emerging technique that consists of super solvent, which is considered a benefit over many other conventional solvents. The main component utilized in it is Carbon Dioxide [CO2], which possesses dual state properties such as effusion through solid and other dissolving materials like liquid which results in unique applications bidden with no limitations. The varying temperature and pressure are the important parameters optimized and thus enhance its solvent properties. Higher Co-efficient of diffusion, reduction in time, higher compressibility, etc. is some of the major advantages of SCF-CO2 over the conventional solvents. Over and above, it is a green approach and a super solvent. Here we have discussed the multifarious applications of the SCF-CO2 extraction in fields and areas extended, but not limited to, Food, Environmental, Analysis, Metal-Cation Extraction, as well as Extractions, Forensics, Pharmaceuticals, Toxins, and Botanical Samples.

Nanotechnology studies the various phenomena of physio-chemical procedures and biological properties for the generation of nanosized particles, and their rising challenges in the various sectors, like medicine, engineering, agriculture, electronic, and environmental studies. The nanosized particles exhibit good anti-microbial, anti-inflammatory, cytotoxic, drug delivery, anti-parasitic, anti-coagulant and catalytic properties because of their unique dimensions with large surface area, chemical stability and higher binding density for the accumulation of various bio-constituents on their surfaces. Biological approaches for the synthesis of silver nanoparticles (AgNPs) have been reviewed because it is an easy and single-step protocol and a viable substitute for the synthetic chemical-based procedures. Physical and chemical approaches for the production of AgNPs are also mentioned herein. Biological synthesis has drawn attention because it is cost-effective, faster, non-pathogenic, environment-friendly, easy to scale-up for large-scale synthesis, and having no demand for usage of high pressure, energy, temperature, or noxious chemical ingredients, and safe for human therapeutic use. Therefore, the collaboration of nanomaterials with bio-green approaches could extend the utilization of biological and cytological properties compatible with AgNPs. In this perspective, there is an immediate need to develop ecofriendly and biocompatible techniques, which strengthen efficacy against microbes and minimize toxicity for human cells. The present study introduces the biological synthesis of silver nanoparticles, and their potential biomedical applications have also been reviewed.