Green nanotechnology has made the synthesis of nanoparticles a possible approach. Nanotechnology has a significant impact on several scientific domains and has diverse applications in different commercial areas. The current study aimed to develop a novel and green approach for the biosynthesis of silver oxide nanoparticles (Ag2ONPs) utilizing Parieteria alsinaefolia leaves extract as a reducing, stabilizing and capping agent. The change in color of the reaction mixture from light brown to reddish black determines the synthesis of Ag2ONPs. Further, different techniques were used to confirm the synthesis of Ag2ONPs, including UV-Visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX), zeta potential and dynamic light scattering (DLS) analyses. The Scherrer equation determined a mean crystallite size of ~22.23 nm for Ag2ONPs. Additionally, different in vitro biological activities have been investigated and determined significant therapeutic potentials. Radical scavenging DPPH assay (79.4%), reducing power assay (62.68 ± 1.77%) and total antioxidant capacity (87.5 ± 4.8%) were evaluated to assess the antioxidative potential of Ag2ONPs. The disc diffusion method was adopted to evaluate the antibacterial and antifungal potentials of Ag2ONPs using different concentrations (125–1000 μg/mL). Moreover, the brine shrimp cytotoxicity assay was investigated and the LC50 value was calculated as 2.21 μg/mL. The biocompatibility assay using red blood cells (<200 μg/mL) confirmed the biosafe and biocompatible nature of Ag2ONPs. Alpha-amylase inhibition assay was performed and reported 66% inhibition. In conclusion, currently synthesized Ag2ONPs have exhibited strong biological potential and proved as an attractive eco-friendly candidate. In the future, this preliminary research work will be a helpful source and will open new avenues in diverse fields, including the pharmaceutical, biomedical and pharmacological sectors.

Novel catalytic materials are under investigation to find convincing energy alternatives. In this context, transition metal selenides (TMSes) are found to be feasible, ecofriendly, and effective electrocatalysts with futuristic characteristics. A deep and comprehensive investigation on metal selenides for energy conversion and storage application is summarized in this review article. Different methods such as hydrothermal, solvothermal, coprecipitation, hot injection, successive ionic layer adsorption reaction, polyol, and others can be used for the synthesis of metal selenides based electrocatalysts, with different morphologies and compositions. The morphology of metal selenides is strongly controlled by factors such as reaction time, temperature, pH of the reaction medium, and surfactant. The electrochemical applications of metal selenides are governed by morphology, active spots for reaction, surface engineering, and confinement. It is concluded that TMSes deliver high performance with large surface area, which is possible due to their porous or 3D morphology. The TMSes with multimetal or with doping metal/nonmetals perform better compared to single atoms. It is concluded that the reaction mechanism of hydrogen evolution reaction and oxygen evolution reaction is a primary tool to better understand the system to develop more efficient catalysts for practical application.

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Heavy metal stress, including lead, adversely affects the growth and yield of several economically important crops, leading to food challenges and significant economic losses. Ameliorating plant responses to various environmental stresses is one of the promising areas of research for sustainable agriculture. In this study, we evaluated the effect of aspartic acid-functionalized copper nanoparticles on the photosynthetic efficiency and antioxidation system of maize plants under Pb toxicity. The ion reduction method was employed for the synthesis of CuNPs, using ascorbic acid as the reducing agent and aspartic acid as the surface functionalizing agent. Isolated experiments under laboratory and field conditions were performed using a randomized complete block design (RCBD). Seeds primed in water, 1.0, 5.0, and 10 µg/mL of Asp-CuNPs were sown under 0, 500, and 1000 mg/L Pb stress in laboratory conditions, while primed seeds along with foliar-applied Asp-CuNP plants were grown in a field under applied Pb stress, and the obtained data were statistically analyzed using TWANOVA. The laboratory experiment shows that Asp-CuNPs act both as a plant growth regulator (PGR) and plant growth inhibitor (PGI), depending upon their concentration, whereby Asp-CuNPs act as a PGR at a concentration of 1 µg/mL ≤ X ≤10 µg/mL. The field experiment confirms that seed priming and foliar spraying with Asp-CuNPs activate embryos and enhance plant growth in a dose-dependent manner. In addition, Asp-CuNPs (10 µg/mL) significantly increase chlorophyll content to 0.87 mg/g from 0.53 mg/g (untreated) when plants were exposed to Pb toxicity at 1000 mg/kg of soil. It is noteworthy that Asp-CuNPs induce resilience to Pb toxicity (1000 mg/kg of soil) in plants by reducing its root absorption from 3.68 mg/kg (0 µg/mL Asp-CuNPs) to 1.72 mg/kg with the application of 10 µg/mL Asp-CuNPs. Additionally, histochemical analyses with NBT and hydrogen peroxide revealed that ROS accretion in plants treated with Asp-CuNPs declined because of the augmentation of antioxidant enzyme (POD, SOD, APOX, etc.) activities under Pb toxicity. Our findings suggest that amino acid-functionalized copper nanoparticles regulate plant defensive mechanisms related to lead tolerance, which is a promising approach for the induction of resistivity to heavy metal stress.