Molluscicidal activity of calcium borate nanoparticles with kodom ball-flower structure on hematological, histological and biochemical parameters of Eobania vermiculata snails.

Land snails are the most harmful pests in agricultural fields. Eobania vermiculata is a widespread snail species that causes massive damage to all agricultural crops. Thus, the molluscicidal activity of calcium borate nanoparticles (CB-NPs) against Eobania vermiculata was evaluated and compared with metaldehyde (Gastrotox® E 5% G). The amorphous phase of CB-NPs was obtained after thermal treatment at a low temperature (500 °C) which conformed by X-ray diffraction (XRD) analysis. CB-NPs are composed of aggregated nano-sheets with an average thickness of 54 nm which enhanced their molluscicidal activity. These nano-sheets displayed meso-porous network architecture with pore diameters of 13.65 nm, and a 9.46 m2/g specific surface area. CB-NPs and metaldehyde (Gastrotox® E 5% G) exhibited molluscicidal effects on Eobania vermiculata snails with median lethal concentrations LC50 of 175.3 and 60.5 mg/l, respectively, after 72 h of exposure. The results also showed significant reductions of Eobania vermiculata snails hemocytes' mean total number, the levels of Testosterone (T) and Estrogen (E), alkaline phosphatase, acid phosphatase, albumin, and protein concentrations, succinate dehydrogenase, glucose, triglycerides and phospholipids levels, while significant increases in the phagocytic index and mortality index, both transaminases (ALT and AST) and glycogen phosphorylase concentration were observed after the exposure to LC50 of CB-NPs or metaldehyde (Gastrotox® E 5% G) compared to the control group. Therefore, CB-NPs could be used as an alternative molluscicide for controlling Eobania vermiculata, but further studies are needed to assess their effects on non-target organisms.

Sea urchin-like calcium borate microspheres and synergistic action with cholinesterase-inhibiting insecticides for ecofriendly Spodoptera littoralis control.

The development of nanoagrochemicals has attracted much attention in the last decade to overcome the recent agricultural and environmental challenges associated with the intensive usage of insecticides. Herein, nanostructured calcium borate materials with hierarchical sea urchin-like microspheres and microblocks have been synthesized by a facile hydrothermal method. The insecticidal activity of CaB2O4 and its synergistic combination with cholinesterase-inhibiting insecticides are explored against Spodoptera littoralis (S. littoralis) for the first time via a feeding bioassay protocol. The insecticidal efficacy of sea urchin-like microspheres (CB-A) is estimated to be LC50 = 207 mg L-1 which is two-fold higher than that of microblocks (CBM-A) with LC50 = 406 mg L-1 after eleven days of exposure. The synergistic combination of the CB-A sample with methomyl and chlorpyrifos increases the toxicity to 2.4 and 2.6-fold higher than that of the individual insecticides, respectively. Significantly, sea urchin-like CaB2O4 microspheres cause physical damage to the external insect's cuticle layer, which consequently enhances the uptake of organic insecticides. Our results revealed that calcium borate micro-/nano-structures can be employed as a multifunctional nanoagrochemical in various agricultural programs for S. littoralis control and decrease the usage of cholinesterase-inhibiting insecticides.

Pesticidal Activity of Nanostructured Metal Oxides for Generation of Alternative Pesticide Formulations.

Herein, nanostructured metal oxides of essential soil nutrient elements (i.e., CuO and CaO) with definite shape and size were simply synthesized, and their pesticidal activities against cotton leafworm ( Spodoptera littoralis) were explored for the first time. These metal oxide nanostructures represented novel economic and ecofriendly nanopesticides for sustainable plant protection and might boost the nutrient content of soil. The results showed that CuO nanoparticles (NPs) and CaO NPs exhibited potential entomotoxic effects against S. littoralis. Interestingly, CuO NPs exhibited fast entomotoxic effect with LC50 = 232.75 mg/L after 3 days, while CaO NPs showed a slow entomotoxic effect with LC50 = 129.03 mg/L after 11 days of post-treatments. The difference in the pesticidal activity of the metal oxides is related to their physical characteristics and interfacial surfaces upon insect midgut and cuticle layer of insect body wall. Thus, nanoengineered metal oxides might be utilized to generate an alternative and cost-effective pesticide formulation in the near future.

Non-enzymatic electrochemical platform for parathion pesticide sensing based on nanometer-sized nickel oxide modified screen-printed electrodes.

Nanozyme-based electrochemical sensors have attracted much attention because of their low cost, sensitivity and remarkable stability under extensive environmental and industrial conditions. Interestingly, the physical characteristics of the nanomaterials in terms of size, shape, composition, surface area and porosity dominate the electrochemical processes at electrode surfaces. Herein, we explore nickel oxide nanoplatelets (NPs) modified screen-printed electrode-based nanozyme sensors that displays high electrochemical activity including stability, sensitivity, selectivity and applicability for organophosphate pesticide (Parathion) determination. Differential pulse voltammogram of NiO-SPE in presence of parathion showed a characteristic peak current at -1.0 V (vs. Ag/AgCl). The NiO-SPE platform allows determination of parathion over the concentration range of 0.1-30 µM with a limit of detection (LOD) of 0.024 µM. The sensing platform is found to detect parathion of interferences without compromising the sensitivity of the sensor. Such interesting features offer a sensitive determination of parathion in water, urine and vegetable samples.

Large-scale production of CdO/Cd(OH)2 nanocomposites for non-enzyme sensing and supercapacitor applications.

Recent advancements in electrode design are substantially linked to state-of-the-art nanomaterial fabrications. Herein, we report a simple one-pot hydrothermal synthesis of Cd(OH)2 with a platelet-like morphology, which was subsequently annealed at relatively high temperatures to produce a CdO/Cd(OH)2 nanocomposite for the first time. It was found that the control of thermal treatment allowed tunable charge transport across the nanometre scale due to the presence of CdO and Cd(OH)2 mixed nanocrystals. The CdO/Cd(OH)2 nanocrystals offer interesting prospects for the electrocatalytic oxidation of nitrite ions and for supercapacitor applications. The CdO/Cd(OH)2 nanocomposite was blended with a trace amount of gold NPs for enhancing the electrochemical conductivity and electrocatalytic capability for nitrite oxidation with a sensitivity of 32.9 µA mM-1. It afforded a promising electrocatalyst in a wide concentration range up to 10 mM with a low detection limit of 0.87 µM. Furthermore, the CdO/Cd(OH)2 nanocomposite electrode was showed to be a highly active and stable supercapacitor, achieving a high specific capacitance in an alkaline medium of about 145 F g-1 at a discharge current of 2.0 A g-1. These results have revealed that the presence of mixed oxide/hydroxide nanocrystals in nanoscale dimensions will be very interesting for various electrochemical applications and provide for a new class of nanodevices based on electrochemistry with unique capabilities.