Facile Gram-Scale Synthesis of NiO Nanoflowers for Highly Selective and Sensitive Electrocatalytic Detection of Hydrazine

In situ generation of turbostratic nickel hydroxide as a nanozyme for salivary glucose sensor

Among the 3d-transition metal hydroxide series, nickel hydroxide is a well-studied electroactive catalyst. In particular, nickel hydroxide and its composite materials are well-suited for non-enzymatic glucose sensing. The electrocatalytic efficiency of nickel hydroxide is attributed to the thickness or to be precise, the thinness of the electroactive layer. Herein, we have successfully prepared metallic nickel@nickel hydroxide nanosheets through a straightforward one-pot solvothermal method. We were able to electrochemically generate a highly sensitive α-Ni(OH)2 on the nanosheets. The dynamic generation and synergy between α- and β-Ni(OH)2, imparts a glucose oxidase enzyme-like ability to the catalyst. Our proposed nickel nanozyme exhibits a good sensitivity of 683 μA mM-1 cm-2 for glucose. The sensor operates in the range of 0.001-3.1 mM, with a lower limit of detection (LOD) of 9.1 μM and exhibits a response time of ≈00.1 s. Nickel-nanozyme demonstrated better selectivity for glucose in the presence of interfering compounds. Notably, the sensor does not suffer from an interfering oxygen evolution reaction. This greatly improves sensitivity in glucose detection in lower concentrations making the sensor viable to measure salivary glucose levels. In this study, we demonstrate that our sensor can detect glucose in human saliva. The real sample analysis was carried out with saliva samples from three healthy human volunteers and one prediabetic volunteer. Our proposed sensor measurements show excellent agreement with calculated salivary glucose levels with 98% accuracy in sensing glucose in real saliva samples.

Lignosulfonate-Assisted In Situ Deposition of Palladium Nanoparticles on Carbon Nanotubes for the Electrocatalytic Sensing of Hydrazine

This paper presents a novel modified electrode for an amperometric hydrazine sensor based on multi-walled carbon nanotubes (MWCNTs) modified with lignosulfonate (LS) and decorated with palladium nanoparticles (NPds). The MWCNT/LS/NPd hybrid was characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The electrochemical properties of the electrode material were evaluated using cyclic voltammetry and chronoamperometry. The results showed that GC/MWCNT/LS/NPd possesses potent electrocatalytic properties towards the electro-oxidation of hydrazine. The electrode demonstrated exceptional electrocatalytic activity coupled with a considerable sensitivity of 0.166 μA μM-1 cm-2. The response was linear from 3.0 to 100 µM L-1 and 100 to 10,000 µM L-1, and the LOD was quantified to 0.80 µM L-1. The efficacy of the modified electrode as an electrochemical sensor was corroborated in a study of hydrazine determination in water samples.

Advances in Optical Probes for the Detection of Hydrazine in Environmental and Biological Systems

Hydrazine, as a crucial raw material in the fine chemical industry, plays an indispensable role in fuel, catalyst, pesticide and drug synthesis. Due to its good water solubility and high toxicity, hydrazine can cause irreparable damage to water and soil in the environment, and it can also be released by taking certain drugs, which brings potential risks to human health. Therefore, it is vital to develop a method that can specifically detect hydrazine in the environment and in vivo. As an effective analysis and detection tool, fluorescence probe has attracted extensive attention in recent years. In this review, we summarized and classified hydrazine fluorescence probes based on various reaction mechanisms, and discussed their structures and applications in the past ten years. At least, we briefly outline the challenges and prospects in this field.

Enhanced electrocatalytic activity of fluorine doped tin oxide (FTO) by trimetallic spinel ZnMnFeO4/CoMnFeO4 nanoparticles as a hydrazine electrochemical sensor

In the present study, ZnMnFeO₄ and CoMnFeO₄ tri-metallic spinel oxide nanoparticles (NPs) were provided using hydrothermal methods. The nanoparticles have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and electrochemical techniques. A reliable and reproducible electrochemical sensor based on ZnMnFeO₄/CoMnFeO₄/FTO was fabricated for rapid detection and highly sensitive determination of hydrazine by the DPV technique. It is observed that the modified electrode causes a sharp growth in the oxidation peak current and a decrease in the potential for oxidation, contrary to the bare electrode. The cyclic voltammetry technique showed that there is high electrocatalytic activity and excellent sensitivity in the suggested sensor for hydrazine oxidation. Under optimal experimental conditions, the DPV method was used for constructing the calibration curve, and a linear range of 1.23 × 10^-6 M to 1.8 × 10^-4 M with a limit of detection of 0.82 ± 0.09 μM was obtained. The obtained results indicate that ZnMnFeO₄/CoMnFeO₄/FTO nano sensors exhibit pleasant stability, reproducibility, and repeatability in hydrazine measurements. In addition, the suggested sensor was efficiently employed to ascertain the hydrazine in diverse samples of cigarette tobacco.

Biosynthesis and Characterization of Silver Nanoparticles Using Tribulus terrestris Seeds: Revealed Promising Antidiabetic Potentials

Green synthesis is the most effective and environmentally friendly way to produce nanoparticles. The present research aimed at the biosynthesizing of silver nanoparticles (AgNPs) using Tribulus terrestris seed extract as the reducing and stabilizing agent and investigating their anti-diabetic properties. Fourier transformation infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectroscopy were used to analyze the synthesized silver nanoparticles from Tribulus terrestris (TT-AgNPs). The spectroscopic characterization revealed a surface Plasmon resonance band at 380 nm, which verified the development of TT-AgNPs. The transmittance peaks were observed at 596, 1450, 1631, 2856, 2921, and 3422 cm^-1 through the FTIR spectrophotometer. The XRD spectrum showed four distinct diffraction peaks in the 2θ range at 20° to 60°. Intense peaks were at 26.32°, 30.70°, 44.70°, 56.07°, 53.75°, 66.28°, and 75.32°. The SEM analysis revealed that the prepared TT-AgNPs were clustered loosely with a smooth and spherical structure and were of relatively uniform size. The in vitro antidiabetic potential of TT-AgNPs was assessed by using glucose yeast uptake, glucose adsorption, and alpha-amylase assays. TT-AgNPs showed the highest activity (78.45 ± 0.84%) of glucose uptake by yeast at 80 µg/mL. In the glucose adsorption assay, the highest activity of TT-AgNPs was 10.40 ± 0.52% at 30 mM, while in the alpha-amylase assay, TT-AgNPs exhibited the maximum activity of 75.68 ± 0.11% at 100 µg/mL. The results indicate a substantial anti-diabetic effect of the TT-AgNPs. Furthermore, the in vivo antidiabetic study was performed on TT-AgNPs in streptozotocin-induced diabetic mice. After receiving TT-AgNPs treatment for 30 days, the mice were sacrificed for biochemical and histological analyses of pancreatic and liver samples, which demonstrated a good improvement when compared to the control group. Mice treated with TT-AgNPs showed a significant drop in blood sugar levels, showing that the biosynthesized TT-AgNPs have effective anti-diabetic properties.