A novel nanozyme doped ZnO/r-GO-based sensor for highly sensitive electrochemical determination of muscle-relaxant drug: cyclobenzaprine HCl

A nanocomposite of Ce-doped ZnO/r-GO was synthesized using a conventional hydrothermal method. The synthesized nanocomposites were utilized for the purpose of sensitive and selective detection of cyclobenzaprine hydrochloride (CBP). The properties of the composite were extensively analyzed, including its morphology, structure, and electrochemical behavior. This study investigates the application of a modified glassy carbon electrode for the detection of CBP, a muscle relaxant used to treat musculoskeletal diseases that cause muscle spasms. The electrode is modified with Ce-doped ZnO/r-GO. Various detection methods, such as cyclic voltammetric and square wave techniques (SWV), were utilized. The composite material showed high effectiveness as an electron transfer mediator in the oxidation of CBP. The electrode showed a good response for SWV evaluations in CBP identification, with a minimum detection limit of 1.6 × 10-8 M and a wide linear range from 10 × 10-6 M to 0.6 × 10-7 M, under ideal conditions. The rate constant for charge transfer (ks) and the estimation of the electrochemical active surface area were obtained. A developed sensor exhibited desirable selectivity, long-lasting stability, and remarkable reproducibility. A sensor was used to analyze water, human serum, and urine samples, resulting in positive recovery results.

Performance Enhancement of Self-Cleaning Cotton Fabric with ZnO NPs and Dicarboxylic Acids

In this paper, we explore the self-cleaning and washing durability of green-prepared ZnO NPs combined with cotton fabrics. Honeysuckle extract was used to prepare ZnO NPs with an average particle size of 15.3 nm. Cotton fabrics were then treated with oxalic acid (OA), tartaric acid (TA), and succinic acid (SA) as cross-linking agents, sodium hypophosphite as a catalyst, and after that, the ZnO NPs were applied to the cross-linked cotton fabrics by the padding to prepare the self-cleaning cotton fabrics. The morphology and structure of the fabric samples were characterized using FTIR, scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and XRD. The optical properties of the cotton fabric samples were discussed by UV-vis diffuse reflectance spectrum, and the self-cleaning performance, wrinkle recovery angle and ultraviolet protection performance of the cotton fabric samples were analyzed. The results showed that the carboxyl groups of TA, OA, and SA were esterified with hydroxyl groups of the cotton fiber and formed a film on the surface of the cotton fabrics. ZnO NPs were successfully loaded onto the cotton fabrics by strong electrostatic interaction, causing the improvement of the washing resistance of the cross-linked fabrics. In addition, compared with uncross-linked fabrics, the wrinkle recovery performance of the cross-linked fabrics had also been greatly improved, and the UV protection factor reached 50+, thus obtaining an excellent self-cleaning, multifunctional cotton-based textile with anti-wrinkle and anti-ultraviolet properties.

Organic-Inorganic Nanohybrid Electrochemical Sensors from Multi-Walled Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles and In-Situ Wrapped with Poly(2-methacryloyloxyethyl ferrocenecarboxylate) for Detection of the Content of Food Additives

An electrochemical sensor for detection of the content of aspartame was developed by modifying a glassy carbon electrode (GCE) with multi-walled carbon nanotubes decorated with zinc oxide nanoparticles and in-situ wrapped with poly(2-methacryloyloxyethyl ferrocenecarboxylate) (MWCNTs@ZnO/PMAEFc). MWCNTs@ZnO/PMAEFc nanohybrids were prepared through reaction of zinc acetate dihydrate with LiOH·H2O, followed by reversible addition-fragmentation chain transfer polymerization of 2-methacryloyloxyethyl ferrocenecarboxylate, and were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), scanning electron microscope (SEM), and transmission electron microscope (TEM) techniques. The electrochemical properties of the prepared nanohybrids with various composition ratios were examined by cyclic voltammetry (CV), and the trace additives in food and/or beverage was detected by using differential pulse voltammetry (DPV). The experimental results indicated that the prepared nanohybrids for fabrication of electrochemical modified electrodes possess active electroresponse, marked redox current, and good electrochemical reversibility, which could be mediated by changing the system formulations. The nanohybrid modified electrode sensors had a good peak current linear dependence on the analyte concentration with a wide detection range and a limit of detection as low as about 1.35 × 10-9 mol L-1, and the amount of aspartame was measured to be 35.36 and 40.20 µM in Coke zero, and Sprite zero, respectively. Therefore, the developed nanohybrids can potentially be used to fabricate novel electrochemical sensors for applications in the detection of beverage and food safety.

Antibacterial properties of doped nanoparticles

Nanoparticles have high potential as antibacterial agents, owing to their ability to produce reactive oxygen species (ROS). Recent studies have indicated that this ROS generation is highly affected by the modification of band structure by the introduction of various dopant materials into them. Thus, doped nanoparticles have been extensively studied in the recent literature. The types of dopants, synthesis techniques, and experimental parameters have been found to affect the overall electronic structure of the material, leading to varied antibacterial efficiency. This review summarizes some of the prominent dopant nanomaterials, various methods of synthesizing doped nanoparticles used against bacterial cells, and the main factors involved in it. Despite the extensive research on the mechanism of the antibacterial action, it is still poorly understood mainly due to the inherent complexities and dynamics in cell membranes. Some of the major proposed mechanisms of action of each kind of dopant nanomaterial have also been reported in this work, focusing on the bacterial cell structure.

Synthesis of Hydroxyapatite and ZnO Nanoparticles via Different Routes and its Comparative Analysis

Hydroxyapatite (HAp) was prepared from egg shells by various routes using hexane and acetic acid followed by heat treatment. HAp has a wide application in water treatment by removal of metal ions. XRD of the samples showed use of acetic acid followed by high temperature sintering leads to formation crystalline phases of HAp. Strong evidence of CaCO3 in calcite phase was obtained in other samples. Zinc oxide nanoparticles have also been synthesized by different methods such as sol-gel, co- precipitate and green synthesis. The effect of different synthesis methods were investigated using X-Ray Diffraction (XRD). The structural properties of nanoparticles including particle size were calculated from XRD data. The XRD reveals that the prepared ZnO samples were highly crystalline, having wurtzite crystal structure. The comparative analysis shows variations in particle size with different synthesis methods.