• A thermoplastic carbon composite electrode using Ecoflex and graphite was fabricated. • The thermoplastic sensor presented an excellent electrochemical performance for glucose sensing. • The modified Ecoflex:graphite/Au@GQDs device enables sensitive detection of glucose. • The thermoplastic electrochemical device presents portable and disposable features. There is an increasing demand for robust, affordable, and sensitive analytical devices for clinical diagnostics. Herein, we describe a simple route to produce biodegradable and disposable thermoplastic composite electrodes using the commercial polymer (Ecoflex®) and graphite microparticles. The surface of the carbon composite electrode was modified with gold nanoparticles conjugated with graphene quantum dots (Au@GQDs) for sensitive and non-enzymatic glucose sensing. The morphological and structural characterizations of the modified electrochemical device revealed a hydrophilic rough composite surface, with high dispersion of graphite in the polymer matrix and confirmed the successful superficial modification of the working electrode with spherical Au@GQDs nanoparticles. Cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) were used to electrochemically characterize the modified and nonmodified thermoplastic sensor, demonstrating a 4.5-fold enhancement of the electroactive area, higher heterogeneous electron transfer kinetics, and electrocatalytic properties for glucose sensing when the sensor was modified with Au@GQDs. The electrochemical determination of the glucose was carried out using an amperometric method applying -0.15 V in alkaline conditions (0.1 mol L − 1 NaOH). Under optimized conditions, the proposed method presented a high sensitivity (4.85 A L mol −1 ) and a low limit of detection (LOD) of 9.12 µmol L − 1 . The Ecoflex:graphite/Au@GQDs sensor was applied for glucose sensing in synthetic saliva samples with recovery values ranging from 97.84% to 105.20%, highlighting the excellent accuracy of the proposed method. Finally, the electrode was subjected to thermal and biological degradation studies and presented disposable and eco-friendly characteristics. Based on these results, we believe that this new thermoplastic composite sensor modified with Au@GQDs can be an excellent candidate for a disposable, low-cost, and enzymeless electrochemical glucose sensor. 

Enzymeless glucose sensor based on disposable Ecoflex®/graphite thermoplastic composite substrate modified with Au@GQDs

Nickel-based catalysts for non-enzymatic electrochemical sensing of glucose: A review

Nickel–cobalt-based bimetallic oxide compound (NiCo 2 O 4 ) as a highly sensitive and selective platform for the detection of flutamide in biological fluids. 

A low-cost and facile electrochemical sensor for the trace-level recognition of flutamide in biofluids using large-area bimetallic NiCo<sub>2</sub>O<sub>4</sub> micro flowers

Graphene-oxide-based metal hybrids (GM) are used for the rapid and efficient reduction and removal of toxic adulterants in the environment. The exceptionally high specific surface area, versatile surface chemistry, and exceptional customization efficiency of graphene oxide nanosheets combined with the adaptable chemistry of metal nanoparticles enable the formation of GM hybrid nanocomposites. However, little is known about the architecture of GM nanocomposite engineering, interaction mechanisms, and environmental compatibility. This review aims to describe the environmental performance of graphene oxide–metal hybrids for the removal of environmental pollutants, carbon capture, EMI shielding efficiency, and microbial elimination of engineered graphene oxide composites anchored with metal particles. We also developed an essential link between the material properties of GM nanohybrids and their performance, which identified the fundamental parameters that influence the contaminant removal capability and EMI resistance efficiency. The influence of the thermodynamic parameters of GM on the adsorption of radioisotopes, heavy metals, organic pollutants, and dyes was considered. Finally, we comment on the remaining challenges and provide suggestions for future developments in this field.

https://www.mdpi.com/2076-3298/9/12/153/pdf?version=1670553775

Progress in Graphene Oxide Hybrids for Environmental Applications

Diabetes mellitus is one of the most rapidly rising chronic diseases around the globe. To combat these rising numbers, active research has been done in recent years to enhance the sensitivity, selectivity, and specificity of glucose biosensors. Despite the easy availability of these enzymatic glucose sensors, these have demonstrated limitations like low stability, short shelf-life, and being easily altered by physical and chemical environmental factors. To overcome these limitations, non-enzymatic sensors, also called fourth-generation glucose sensors, have been developed. These sensors use nanomaterials and do not employ any enzymes therefore exhibit better shelf life, improved sensitivity, and allow for quick detection of glucose without needing additional steps. In recent years, bimetallic nanocomposite-based fourth-generation glucose sensors have gained widespread attention from the scientific community. Owing to the synergistic effect of two distinct metal nanomaterials, these sensors show enhanced reproducibility and excellent stability as compared to monometallic nanomaterials. In this review, we aim to represent a comprehensive overview of the recent developments in the development of bimetallic nanocomposite-based glucose sensors for rapid and accurate glucose detection. After a brief introduction, we discussed the various bimetallic nanomaterials developed in recent years, followed by a discussion on the mechanism of action of such sensors. We then briefly discussed the industrial challenges of developing such sensors and discussed the advantages and disadvantages of bimetallic nanomaterial-based sensors. We finally concluded the review by highlighting the future perspectives of this new and upcoming field. 

Trends in bimetallic nanomaterials and methods for fourth-generation glucose sensors

In this work, Ni–Cu bimetallic alloy nanoparticles supported on reduced graphene oxide (Ni–Cu ANPs/RGO) was successfully fabricated through a one-step hydrothermal synthesis method, where simultaneous reduction of graphene oxide, nickel salt and copper salt was performed, and relevant characterization studies were executed. This synthetic method does not require surfactants and high temperature treatment, and is recommended as a green, convenient and effective way to produce composites. The unique two-dimensional architecture of the RGO provides a large specific surface area, contributing to loading more Ni–Cu ANPs, while the uniformly distributed Ni–Cu bimetallic alloy nanoparticles enhance the electrocatalytic performance of glucose oxidation. The non-enzymatic glucose biosensor based on Ni–Cu ANPs/RGO showed a wide linear range (from 0.01 μM to 30 μM), low detection limit (0.005 μM), and excellent sensitivity (1754.72 μA mM−1 cm−2). More importantly, the high reliability and the excellent selectivity in actual sample detection will broaden its practical application in electrochemical sensing.

Non-enzymatic electrochemical detection of glucose using Ni-Cu bimetallic alloy nanoparticles loaded on reduced graphene oxide through a one-step synthesis strategy.

Rong Tan

Papers

Non-enzymatic electrochemical detection of glucose using Ni-Cu bimetallic alloy nanoparticles loaded on reduced graphene oxide through a one-step synthesis strategy.