A Review on Silver Nanoparticles

Abstract

Nanoparticles are defined as particulate dispersions or solid particles with a size between 10 and 1000 nm. A one billionth of a metre scale is the simplest unit of measurement for nanotechnology. Silver nanoparticles superiority over silver in bulk forms is primarily due to the size, shape, composition, crystallinity, and structure of AgNPs. Silver nanoparticles synthesis can be achieved by physical, chemical and green methods. Evaporation-condensation and laser ablation processes are used in the physical synthesis of silver nanoparticle. Evaporation-condensation has been used to create a number of metal nanoparticles in the past, including fullerene, lead sulphide, cadmium sulphide, gold, and silver. Chemical reduction, photo-induced reduction, micro-emulsion, microwave-assisted synthesis, UV-initiated photo-reduction, electrochemical synthetic technique, and irradiation procedures are some of the chemical processes utilised to create nanoparticles. The temperature, pH, concentration, type of precursor, reducing and stabilising agents, and the molar ratio of surfactant and precursor are some of the reaction parameters that control how NPs form and grow in the chemical method. Utilizing biological organisms like bacteria, mould, algae, and plants allows for one-step synthesis. Proteins and enzymes found in plants and microbes are used in the reduction process to create nanoparticles. Silver nanoparticles function as nanoscale antennas at the plasmon resonant wavelength, boosting the strength of a nearby electromagnetic field. Raman spectroscopy, which uses molecules distinctive vibrational modes to identify them, is one spectroscopic method that benefits from the strengthened electromagnetic field. The plasmonic Au/Ag hollow-shelled NIR SERS probes were put together on silica nanospheres, which showed a redshift in the plasmonic extinction band in the NIR optical window region (700–900 nm). Animal tissues that were 8 mm deep showed a measurable signal in the NIR-SERS nanoprobe signals for single particle detection. Silver nanoparticles size-tunable absorption spectra can be used to multiplex optical attributes for point-of-care diagnostics. Silver nanoparticles have antimicrobial, anti-neoplastic, antioxidant, and antidiabetic activity. Silver nanoparticles also shows some kind of toxicity like Oral toxicity, Immunotoxicity, Neurotoxicity, Environmental toxicity, Reproductive toxicity etc.