Unconventional Physical Methods for Synthesis of Metal and Non-metal Nanoparticles: A Review

Current Methods for Synthesis and Potential Applications of Cobalt Nanoparticles: A Review

Cobalt nanoparticles (CoNPs) are promising nanomaterials with exceptional catalytic magnetic, electronic, and chemical properties. The nano size and developed surface open a wide range of applications of cobalt nanoparticles in biomedicine along with those properties. The present review assessed the current environmentally friendly synthesis methods used to synthesize CoNPs with various properties, such as size, zeta potential, surface area, and magnetic properties. We systematized several methods and provided some examples to illustrate the synthetic process of CoNPs, along with the properties, the chemical formula of obtained CoNPs, and their method of analysis. In addition, we also looked at the potential application of CoNPs from water purification cytostatic agents against cancer to theranostic and diagnostic agents. Moreover, CoNPs also can be used as contrast agents in magnetic resonance imaging and photoacoustic methods. This review features a comprehensive understanding of the synthesis methods and applications of CoNPs, which will help guide future studies on CoNPs.

Applications of Fusarium solani YMM20 in bioremediation of heavy metals via enhancing extracellular green synthesis of nanoparticles

A novel technique for removing metals from water, by converting them into nanoparticles using the culture filtrate of Fusarium solani YMM20, followed by their removal by centrifugation was developed in this study. It is a promising, simple, and eco-friendly process for the bioremediation of wastewater. This method is built on the reduction of metal ions by cell-free fungal filtrate protein(s). The chitosan and chitosan nanoparticles were used as adsorbents for the removal of Cu²⁺ , Pb²⁺ , Co²⁺ , Cd²⁺ , Ni²⁺ , and Fe²⁺ , separately. In addition, fungal filtrate and chitosan nanoparticles loaded with fungal filtrate were used for the biosynthesis of metal nanoparticles of Cu²⁺ , Pb²⁺ , Co²⁺ , Cd²⁺ , Ni²⁺ , and Fe²⁺ , separately for their removal. The fungal filtrate approach has the highest metal removal (%) for most metals. Among the six metal ions, the fungal filtrate, chitosan nanoparticles loaded with fungal filtrate, chitosan, and chitosan nanoparticles showed the highest removal (%) for Pb²⁺ and the lowest removal (%) for Co²⁺ . Techniques such as transmission electron microscopy, scanning electron microscopy, and Zeta potential measurements were used to characterize the obtained nanoparticles. The average size of the spherical nanoparticles observed by transmission electron microscopy was from 18.938 ± 2.269 nm to 60.175 ± 4.973 nm.

Synthesis Methods of Obtaining Materials for Hydrogen Sensors

The development of hydrogen sensors has acquired a great interest from researchers for safety in fields such as chemical industry, metallurgy, pharmaceutics or power generation, as well as due to hydrogen’s introduction as fuel in vehicles. Several types of sensors have been developed for hydrogen detection, including resistive, surface acoustic wave, optical or conductometric sensors. The properties of the material of the sensitive area of the sensor are of great importance for establishing its performance. Besides the nature of the material, an important role for its final properties is played by the synthesis method used and the parameters used during the synthesis. The present paper highlights recent results in the field of hydrogen detection, obtained using four of the well-known synthesis and deposition methods: sol-gel, co-precipitation, spin-coating and pulsed laser deposition (PLD). Sensors with very good results have been achieved by these methods, which gives an encouraging perspective for their use in obtaining commercial hydrogen sensors and their application in common areas for society.

Cerium oxide nanoparticles: green synthesis using Banana peel, cytotoxic effect, UV protection and their photocatalytic activity

Nanomaterials, as an active ingredient, have been widely deployed in various science and technological applications with zinc and titanium oxides nanoparticles being commonly applied in sunscreens. On similar lines, cerium oxide nanoparticles (CeO₂-NPs) were synthesized using Musa sapientum peel extract, to investigate its cytotoxic effects, UV protection and photocatalytic activity. The synthesized nanoparticles were identified through Raman, Powder X-ray Diffraction (PXRD), Fourier-Transform Infrared spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FESEM) and Energy-Dispersive Spectroscopy (EDX). FESEM results showed that the size of synthesized nanoparticles is in the range 4-13 nm. Their cytotoxic activity revealed a non-toxic behavior in concentrations below 500 μg/mL on lung (A549) cell lines. The Sun protection factor (SPF) was estimated approximately ~ 40 for synthesized CeO₂-NPs. The survey of photocatalytic activity showed that synthesized nanoparticles can remove 81.7% of AO7 in 180 min under visible light.

Gold, Silver, and Palladium Nanoparticles: A Chemical Tool for Biomedical Applications

Herein, the role of metal-based nanoparticles (NPs) in biomedical analysis and the treatment of critical deceases been highlighted. In the world of nanotechnology, noble elements such as the gold/silver/palladium (Au/Ag/Pd) NPs are the most promising emerging trend to design bioengineering materials that could to be employed as modern diagnostic tools and devices to combat serious diseases. NPs are considered a powerful and advanced chemical tool to diagnose and to cure critical ailments such as HIV, cancer, and other types of infectious illnesses. The treatment of cancer is the most significant application of nanotechnology which is based on premature tumor detection and analysis of cancer cells through Nano-devices. The fascinating characteristic properties of NPs-such as high surface area, high surface Plasmon resonance, multi-functionalization, highly stable nature, and easy processing-make them more prolific for nanotechnology. In this review article, the multifunctional roles of Au/Ag/Pd NPs in the field of medical science, the physicochemical toxicity dependent properties, and the interaction mechanism is highlighted. Due to the cytotoxicity of Ag/Au/Pd NPs, the conclusion and future remarks emphasize the need for further research to minimize the toxicity of NPs in the bio-medicinal field.

Metal Nanoparticles as Green Catalysts

Nanoparticles play a significant role in various fields ranging from electronics to composite materials development. Among them, metal nanoparticles have attracted much attention in recent decades due to their high surface area, selectivity, tunable morphologies, and remarkable catalytic activity. In this review, we discuss various possibilities for the synthesis of different metal nanoparticles; specifically, we address some of the green synthesis approaches. In the second part of the paper, we review the catalytic performance of the most commonly used metal nanoparticles and we explore a few roadblocks to the commercialization of the developed metal nanoparticles as efficient catalysts.