Gradient Triple-Layered ZnS/ZnO/Ta₂O₅–SiO₂ Core–Shell Nanoparticles for Enzyme-Based Electrochemical Detection of Cancer Biomarkers

Abstract

We report a methodology to fabricate unique threelayered ZnS/ZnO/Ta 2 O 5 (core)−SiO 2 (shell) nanoparticles (CSNPs) with varying compositions of ZnS, ZnO, Ta 2 O 5 , and SiO 2 in their layers (i.e., gradient structures). An electrochemical approach with better specificity and detection limit for nonneurally secreted cancer biomarker, acetylcholine (ACh), by modifying the glassy carbon electrode surface with enzyme tagged ZnS/ZnO/Ta 2 O 5 −SiO 2 CSNPs is reported. The size, composition, porosity, and morphology of CSNPs were characterized by using scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, Brunauer−Emmett−Teller (BET) surface area analysis, X-ray diffraction technique, and Fourier-transform infrared spectroscopy. A detailed discussion on the mechanism of core−shell formation and the role of ZnCl 2 in the core−shell formation is reported. We also demonstrate that the detection limit of ACh could be significantly improved by controlling the thickness of outermost shell layer. Electrochemical investigations performed using differential pulse voltammetry and cyclic voltammetry techniques displayed that the oxidation current of ACh was higher for CSNPs synthesized at 0.15 wt % of ZnCl 2 concentration. The limit of detection of ACh was found to be 11.6 nM for CSNPs prepared at 0.15 wt % ZnCl 2 concentration. Thus, the CSNPs-based electrochemical sensor platform has high potential for developing a simple, cost-effective biosensor for early detection of cancer biomarker at nanomolar concentration.

Dose-Dependent Efficacy of Umbelliferone and Gelatin-Coated ZnO/ZnS Core-Shell Nanoparticles: A Novel Arthritis Agent for Severe Knee Arthritis

“…Most of the previous studies demonstrated that the bone destruction in RA was initiated by several proinflammatory cytokines produced by macrophages, such as TNF- α and IL-1 β [ 54 ]. These findings strongly correlated with the previous reports [ 20 , 55 ].…”

“…Secondly, the subsequent transformation of ZnCl 2 to an intermediate product Zn(OH) 2 at physiological temperature leads to the formation of stable ZnO NPs at 180°C. In addition, a nonuniform transparent layer is formed by gelation on the surface of CSNPs at above 50°C, which is due to the reaction between gel and ZnO NPs [ 20 ].…”

“…To calculate organ coefficients acquired the major organs, such as the heart, liver, spleen, lung, kidney, and testis of the rate groups, which were treated with 5 and 10 mg Uf/kg of gel-ZnO-ZnS CSNPs after 28 days. The findings have shown no significant morphological changes in collected major organs [ 20 ].…”

“…Hitherto, we are first to report the most promising ZnS-ZnO core-shell nanoparticles (CSNPs) with unique properties in core and shell. The shell acts as a barrier between the core and environment, thereby controlling the charge, stability, and functionality of NPs [ 20 , 21 ]. The gelatin-coated ZnS-ZnO CSNP materials are regarded as a combination of ZnO and ZnS nanostructures to evoke umbelliferone (Uf), which successfully inhibits bone loss and inflammation with no adverse side effects in CIA rats.…”

Detection of Acetylcholine at Nanoscale NPOE/Water Liquid/Liquid Interface Electrodes

“…ACh is involved in the chemical transmission at synapses and performs functions such as regulating other neurotransmitters, controlling the opening of ligand-gated ion channels, and facilitating bursts of neuronal firing . Imbalances of ACh levels have been linked to Alzheimer’s disease, myasthenia gravis, as well as behavioral, learning, and sleep disorders. − Enzymatic detection of ACh has been achieved by the sequential use of acetylcholinesterase and choline oxidase to generate hydrogen peroxide from ACh. − ACh quantification is then achieved by electrochemical or optical detection of the hydrogen peroxide, , but other methods have also been used. − ACh has also been detected using a nickel anode electrode and electrodes that were modified with only acetylcholinesterase. − So far, all of these have been carried out at micro- and macroscales.…”