Electrochemical detection of gliclazide and glibenclamide on ZnIn2S4 nanoparticles-modified carbon ionic liquid electrode

Electrochemical Assays for the Determination of Antidiabetic Drugs-A Review

This article presents the current state of knowledge regarding electrochemical methods for determining the active substances within drugs that are used in the treatment of type 1 and type 2 diabetes. Electrochemical methods of analysis, due to their sensitivity and easiness, are a great alternative to other, usually more expensive analytical assays. The determination of active substances mentioned in this review is based on oxidation or reduction processes on the surface of the working electrode. A wide variety of working electrodes, often modified with materials such as nanoparticles or conducting polymers, have been used for the highly sensitive analysis of antidiabetic drugs. The presented assays allow us to determine the compounds of interest in various samples, such as pharmaceutical products or different human bodily fluids.

A dual-emission ratiometric fluorescent biosensor for ultrasensitive detection of glibenclamide using S-CDs/CdS quantum dots

In the present work, sulfide-doped carbon dots (S-CDs)/cadmium sulfide quantum dots (CdS QDs) ratiometric fluorescent nanosensor has been developed for sensitive and selective determination of glibenclamide (GLC) in biological fluids. The method was based on the quenching effect of GLC on the dual-emission intensity of the S-CDs/CdS QDs system at 420 nm and 650 nm, which are related to S-CDs and CdS QDs, respectively. The fluorimetric data analysis indicated that the fluorescence signals of the system were quenched by adding GLC in a concentration-dependent manner. A good linear relationship was observed between GLC concentration and the quenched fluorescence intensity of the S-CDs/CdS QDs in the range of 0.3 nM-10.0 μM. The limit of detection (LOD) value was estimated to be 0.12 nM. Furthermore, under optimum conditions, GLC was detected in spiked human serum sample (as real media) using the developed ratiometric nanosensor with an accuracy of 99.6%. According to the results, the developed dual-emission system can be used as a reliable method for the quantitative detection of GLC in biological samples.

Glycopolymer-Based Materials: Synthesis, Properties, and Biosensing Applications

Glycopolymer materials have emerged as a significant biopolymer class that has piqued the scientific community's attention due to their potential applications. Recently, they have been found to be a unique synthetic biomaterial; glycopolymer materials have also been used for various applications, including direct therapeutic methods, medical adhesives, drug/gene delivery systems, and biosensor applications. Therefore, for the next stage of biomaterial research, it is essential to understand current breakthroughs in glycopolymer-based materials research. This review discusses the most widely utilized synthetic methodologies for glycopolymer-based materials, their properties based on structure–function interactions, and the significance of these materials in biosensing applications, among other topics. When creating glycopolymer materials, contemporary polymerization methods allow precise control over molecular weight, molecular weight distribution, chemical activity, and polymer architecture. This review concludes with a discussion of the challenges and complexities of glycopolymer-based biosensors, in addition to their potential applications in the future.

Highly sensitive and convenient aptasensor based on Au NPs@Ce-TpBpy COF for quantitative determination of zearalenone

In this work, an aptasensor based on a portable U-disk electrochemical workstation in combination with a screen-printed electrode (SPE) is demonstrated for the quantitative determination of zearalenone (ZEN). The aptamer is immobilized on Au NPs@Ce-TpBpy COF (Covalent organic frameworks), which is modified on the surface of glassy carbon electrode. ZEN specifically binds to ZEN aptamer, which hinders the electron transfer and decreases the catalytic current of Au NPs@Ce-TpBpy COF for the reduction of hydrogen peroxide, measured by chronoamperometry (i-t). The quantitative detection of ZEN toxin is realized by a decrease of the catalytic current (ΔI). Under the optimal experimental conditions, the aptamer sensor exhibited excellent sensitivity, selectivity, reproducibility. A wide linear range of 1 pg mL^-1-10.0 ng mL^-1 with a detection limit of 0.389 pg mL^-1 (at 3σ) was obtained. The linear equation is ΔI = 0.401 lg c + 1.948 with a correlation coefficient of 0.9906. The recovery is in the range of 93.0-104.7% for the cornflour samples. The proposed method offers a new strategy for the rapid, inexpensive, and real-time detection of ZEN.

Label-Free ZnIn2S4/UiO-66-NH2 Modified Glassy Carbon Electrode for Electrochemically Assessing Fish Freshness by Monitoring Xanthine and Hypoxanthine

Considering that simultaneous detection of xanthine (XA) and hypoxanthine (HXA) has been proved to be a reliable and feasible method for assessing fish freshness, a novel electrochemical sensing platform based on the ZnIn2S4/UiO-66-NH2 modified glassy carbon electrode (GCE) was constructed in this study for XA and HXA determination. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) were performed to exhibit the morphology and structural characteristics of ZnIn2S4/UiO-66-NH2. The Brunauer–Emmett–Teller (BET) displayed that the introduction of UiO-66-NH2 can improve the specific surface area of the hybrid. Besides, the electrochemical sensing performance of ZnIn2S4/UiO-66-NH2 was evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). For simultaneously detecting XA and HXA, the fabricated electrochemical sensor shows wide linear ranges (0.025–40 µM and 0.3–40 µM) with low detection limits (0.0083 µM and 0.1 µM). This sensor also has 96–103% recovery in detecting XA and HXA content in large yellow croaker meat samples, demonstrating a promising application in the marine food industry.

Fabrication of ionic liquid stabilized MXene interface for electrochemical dopamine detection

Development of MXene (Ti3C2Cl2)-based sensing platforms by exploiting their inherent active electrochemistry is highly challenging due to their characteristic poor stability in air and water. Herein, we report a cost-effective methodology to deposit MXene on a conductive graphitic pencil electrode (GPE). MXenes can provide active surface area due to their clever morphology of accordion-like sheets; however, the disposition to stack together limits their potential applications. A task-specific ionic liquid (1-methyl imidazolium acetate) is utilized as a multiplex host material to engineer MXene interface via π-π interactions as well as to act as a selective binding site for biomolecules. The resulting IL-MXene/GPE interface proved to be a highly stable interface owing to good interactions between MXene and IL that inhibited electrode leaching and boosted electron transfer at the electrode-electrolyte interface. It resulted in robust dopamine (DA) oxidation with amplified faradaic response and enhanced sensitivity (9.61 µA µM-1 cm-2) for DA detection. This fabricated sensor demonstrated large linear range (10 µM - 2000 µM), low detection limit (702 nM), high reproducibility, and good selectivity. We anticipate that such platform will pave the way for the development of stable and economically viable MXene-based sensors without sacrificing their inherent properties. Scheme 1 Schematic illustration of the IL-MXene/GPE fabrication and oxidative process towards non-enzymatic dopamine sensor.