Non-enzymatic Electrochemical Sensor Research Articles

Electrochemical sensors for the safety and quality control of cosmetics: An overview of achievements and challenges

Due to the rapid growth of the cosmetic industry in recent years, the development of new, reliable, cost-effective, ease of use and rapid methods to assay cosmetics’ quality is of particular importance. Modern electrochemistry provides powerful analytical techniques with excellent sensitivity, instrumental simplicity and portability, providing reliable alter­natives to conventional analytical methods. This review aims to give readers a clear view of advances in areas of electrode modification, successful strategies for signal amplification, and miniaturization techniques used in electro­analytical devices for cosmetics control and safety. We have summarized recent trends in the nonenzymatic electrochemical sensor sys­tems applied in the analysis of cosmetic products revealing that there are a variety of ef­ficient sensors for whitening agents, preservatives, UV filters, heavy metals, etc. In con­clu­sion, current challenges related to the sensors design and future perspectives are outlined.

A non-enzymatic, biocompatible electrochemical sensor based on N-doped graphene quantum dot-incorporated SnS2 nanosheets for in situ monitoring of hydrogen peroxide in breast cancer cells

The current study reports the design and construction of enzyme-free sensor using N-doped graphene quantum dots (N-GQDs)-decorated tin sulfide nanosheets (SnS2) for in situ monitoring of H2O2 secreted by human breast cancer cells. N-GQDs nanoparticles having a size of less than 1 nm were incorporated into SnS2 nanosheets to form an N-GQDs@SnS2 nanocomposite using a simple hydrothermal approach. The resulting hybrid material was an excellent electrocatalyst for the reduction of H2O2, owing to the combined properties of highly conductive N-GQDs and SnS2 nanosheets. The N-GQDs@SnS2-based sensing platform demonstrated substantial sensing ability, with a detection range of 0.0125–1128 µM and a limit of detection of 0.009 µM (S/N = 3). The sensing performance of N-GQDs@SnS2 was highly stable, selective, and reproducible. The practical application of the N-GQDs@SnS2 sensor was successfully demonstrated by quantifying H2O2 in lens cleaner, human urine, and saliva samples. Finally, the N-GQDs@SnS2 electrode was successfully applied for the real-time monitoring of H2O2 released from breast cancer cells and mouse fibroblasts. This study paves the way to designing efficient non-enzymatic electrochemical sensors for various biomolecule detection using a simple method.

Au Nanoparticles-Modified NiCo₂O₄ Nanowires-Supporting Co₃O₄ Dodecahedron as High-Performance Nonenzymatic Glucose Sensor

A hierarchically nanostructured active material composed of nanoparticles, microsized dodecahedron, and nanowires (NWs) has been successfully fabricated and used for glucose oxidation, in which the NiCo2O4 NWs were grown in situ on the carbon paper (CP) and used for supporting the zeolitic imidazolate framework (ZIF-67)-derived Co3O4 dodecahedron, with the Au nanoparticles (Au-Np) being further electrodeposited on their surface (Au-Np/Co3O4/NiCo2O4 NWs/CP). The NWs effectively avoid the agglomeration of Co3O4, thus providing greater surface area for loading the Au nanoparticles. The introduction of Au can decrease the oxidation potential and enhance the catalytic current, which is beneficial for the electrocatalytic oxidation of glucose. The Au-Np/Co3O4/NiCo2O4 NWs/CP-based nonenzymatic glucose sensor exhibits good sensing performance, including high sensitivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$15.3~\mu \text{A}/\mu \text{M}$ </tex-math></inline-formula> /cm2, outstanding response/recovery times of 2.5/4.0 s (toward 180- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{M}$ </tex-math></inline-formula> glucose), good reproducibility, and excellent selectivity. Therefore, constructing a hierarchical nanocomposite is a promising strategy to develop a nonenzymatic electrochemical glucose sensor.

Cost effective synthesis of Mn doped NiO/rGO nanocomposite for non-enzymatic electrochemical glucose sensor

ABSTRACT Herein, we report the synthesis, characterisation and glucose sensor study of prepared compounds and composite. The prepared samples reported here for glucose-sensing applications were doped (Mn.NiO) and un-doped metal oxide (NiO) and their composite with 2D layered material (Mn-doped-NiO/rGO). The structural analysis of the samples was done by conventional technique called as X-rays diffraction (×RD). Spectral and functional groups’ analysis was elucidated by FTIR spectroscopy. The electron microscopy (SEM) was used for morphological features study. The electrochemical measurements were carried out to analyse biosensing response. Carbon fibre cloth was used as a substrate material to fabricate Mn-doped-NiO/rGO nanocomposite-based biosensor for glucose detection. The analytical performance of the synthesised material was evaluated in terms of electrochemical sensitivity, linear response and limit of detection (LOD). The results showed that the material exhibited an excellent electrochemical sensitivity towards glucose detection with wider range of linear responses. The LOD for Mn-doped-NiO/rGO nanocomposite was 0.11 µM, regression equation for the low concentration was I(µA) = 1477.1C + 165.19 with correlation coefficient value R2 = 0.9849. Conclusively, the rGO-based Mn-doped-NiO nanocomposite experienced robust potential as non-enzymatic sensor for detection of glucose.

Copper(II) Oxide Nanoparticles Embedded within a PEDOT Matrix for Hydrogen Peroxide Electrochemical Sensing

The aim of this study is the preparation of nanostructured copper(II) oxide-based materials (CuONPs) through a facile additive-free polyol procedure that consists of the hydrolysis of copper(II) acetate in 1,4-butane diol and its application in hydrogen peroxide sensing. The nonenzymatic electrochemical sensor for hydrogen peroxide determination was constructed by drop casting the CuONP sensing material on top of a glassy carbon electrode (GCE) modified by a layer of poly(3,4-ethylenedioxythiophene) conducting polymer (PEDOT). The PEDOT layer was prepared on GCE using the sinusoidal voltage method. The XRD pattern of the CuONPs reveals the formation of the monoclinic tenorite phase, CuO, with average crystallite sizes of 8.7 nm, while the estimated band gap from UV-vis spectroscopy is of 1.2 eV. The SEM, STEM, and BET analyses show the formation of quasi-prismatic microaggregates of nanoparticles, with dimensions ranging from 1 µm up to ca. 200 µm, with a mesoporous structure. The developed electrochemical sensor exhibited a linear response toward H2O2 in the concentration range from 0.04 to 10 mM, with a low detection limit of 8.5 μM of H2O2. Furthermore, the obtained sensor possessed an excellent anti-interference capability in H2O2 determination in the presence of interfering compounds such as KNO3 and KNO2.

CoAl2O4 nanoparticles modified carbon nanofibers as high-efficiency bifunctional electrocatalyst: An efficient electrochemical aqueous asymmetric supercapacitors and non-enzymatic electrochemical sensors

The thriving energy demand of the gradually increasing population and modernized life style requires development in energy storage devices for usage in commercial electronic devices. In this particular work, we have explored electrochemical performances of bimetallic oxide CoAl2O4 and tuned its performance by decorating it on the carbon nanofibers. The CoAl2O4/CNFs are synthesized by deep eutectic solvents based hydrothermal method. The synthesized CoAl2O4 nanoparticle was found electrochemically active and the incorporation of CNFs end up boosting, its electrochemical performances as battery-type electrode. The obtained nanocomposites were characterized by various techniques. The electrochemically active CoAl2O4/CNFs exhibited 2.2-fold higher charge storage capacity than CoAl2O4. The CoAl2O4/CNFs exhibited specific capacity as high as 132 C/g at a constant applied current density of 1 A/g in 1 M KOH. The asymmetric device fabricated with CoAl2O4/CNFs electrodes exhibited excellent energy density of 20 Wh/kg at power density of 3000 W/kg. The CoAl2O4/CNFs electrode long-term stability has been minutely observed; the high Coulombic efficiency of 90% and high rate of capacity retention 95 %. In this work, an enzyme-free electrochemical sensor based on CoAl2O4/CNFs composite was developed for the detection of luteolin (LUT). Further modification of CoAl2O4/CNFs composite can improve the high surface area and catalytic capability of the composites. Under the optimal detection conditions, the prepared sensor has good linearity in the detection of LUT within range 30 nM − 73.5 μM with a limit of detection (LOD) of 0.0124 μM (12.4 nM). The stability and selectivity of the sensor is high, and can be used to detect LUT in various real samples.

Non-Enzymatic Electrochemical Sensor Based on ZIF-67 and Mwcnts-ZIF-67 Nanocomposites for Detection of Uric Acid in Human Urea

Metal-Organic Frameworks (MOFs) have much interest in the catalytic research community but are less attracted by the sensor society for their poor conductivity. In the present work, we report a novel Zeolitic Imidazolate Framework-67 (ZIF-67) and MWCNT’s-ZIF-67 nanocomposites based on non-enzymatic electrochemical sensors for sensing uric acid in human urea. The conductivity and binding affinity of ZIF-67 are improved by the addition of MWCNTs. Initially, ZIF-67 powders were prepared by facile in-situ synthesis method and then the MWCNTs were introduced into ZIF-67 powders. To achieve better bonding between the carbon and the ZIF-67, MWCNT’s functionalized to attach hydroxyl, carboxyl, and carbonyl groups on the surface of the carbon tubes. The obtained nanopowders were spectroscopically analyzed by using X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) spectroscopy, FESEM, and Raman analysis. The MWCNTs-ZIF-67 modified electrode offered the detection limit of uric acid with 1.18 µM and a sensitivity of 97.9 nA µM-1. The sensitivity was performed within two seconds with a linear response (R2=0.99). Fifteen repeated cyclic voltammetric responses were recorded to 0.1M of uric acid to analyze the stability and reproducibility of the electrode. All the sensor responses were determined in comparison with ZIF-67 with MWCNT-ZIF-67 modified electrode performance. In the present work, the catalytic MOFs with low conductivity was modified with MWCNTs and used for ultra-fast and highly-sensitive sensing of uric acid. Keywords: ZIF-67, MWCNTs, Modified Electrode, Uric Acid, and Functionalization

A novel gold-decorated porous silicon-poly(3-hexylthiophene) ternary nanocomposite as a highly sensitive and selective non-enzymatic dopamine electrochemical sensor

As a key biomolecule for neurotransmission, dopamine (DA) is responsible for many neurological syndromes. Hence, effective DA detection is vital for the rapid-diagnosis of diseases caused by irregular DA levels. Therefore, we designed a non-enzymatic DA sensor using the novel gold-decorated porous silicon-poly-3-hexylthiophene (Au@PSi-P3HT) nanocomposite fabricated glassy carbon electrode. We employed a simple stain etching technique followed by ultra-sonication and photo-reduction techniques to synthesize this novel Au@PSi-P3HT nanocomposite. The structural, morphological, and surface characterizations of the Au@PSi-P3HT nanocomposite were performed using various analytical tools. TEM and FESEM images revealed that gold nanoparticles were randomly dispersed onto the PSi-P3HT sheet-like structure. In the electrochemical investigations, the Au@PSi-P3HT/GCE sensor showed excellent sensitivity (0.5112 μAμM−1cm−2), wide linear dynamic range (LDR = 1.0–460 μM), and reasonably low detection limit (LOD ∼0.63 μM). This newly designed DA sensor was also employed to check the potential chemical interference using several common biomolecules and the obtained results confirmed its selectivity during DA detection. The Au@PSi-P3HT/GCE sensor also exhibited satisfactory results in detecting DA levels in human blood serum and dopamine hydrochloride injection samples. Besides, the Au@PSi-P3HT/GCE sensor displayed superb reproducibility, repeatability, and stability. This novel Au@PSi-P3HT nanocomposite-modified GCE may emerge as a successful means for further designing effective non-enzymatic electrochemical sensors.

A novel and ultrasensitive non-enzymatic electrochemical glucose sensor in real human blood samples based on facile one-step electrochemical synthesis of nickel hydroxides nanoparticles onto a three-dimensional Inconel 625 foam

A novel and ultrasensitive non-enzymatic electrochemical glucose sensor in real human blood samples based on facile one-step electrochemical synthesis of nickel hydroxides nanoparticles onto a three-dimensional Inconel 625 foam

Effects of nickel–cobalt material properties on glucose catalysis

The development of non-enzymatic glucose sensors becomes even more significant as the number of diabetics worldwide continues to increase. Ni–Co alloy can be fabricated by electrodeposition and used as a catalyst for glucose so that it is a suitable electrode material for non-enzymatic electrochemical glucose sensors. The results of material analyses reveal that the catalytic performance for glucose is related to the crystallographic structure of Ni–Co alloy. A Ni–Co based non-enzymatic glucose sensor with a majority of hexagonal close packed (hcp) lattice exhibits better catalytic performance and, moreover, the catalysis of glucose is a quasi-reversible redox process, either in film-type or nanowire-type alloy. However, the nanowire-type Ni–Co glucose sensor has a wider sensing range than the film-type sensor. Ni–Co glucose sensor possesses excellent anti-interference without being influenced by the chemicals coexisting with glucose. These results demonstrate the effect of the crystal structure of Ni–Co on glucose catalysis and suggest the electroplating conditions for the preparation of Ni–Co non-enzymatic glucose sensor with good catalytic performance and excellent anti-interference ability.

A Porphyrin‐functionalized Graphene Oxide Nanocomposite for Simultaneous Detection of Dopamine and Uric Acid

AbstractCarbon nanomaterials combined with porphyrins having the similar electrocatalytic active center to heme protein are quite promising for high‐performance nonenzymatic electrochemical sensor. Herein, the catalytic tetra(4‐aminophenyl) porphyrin (TAPP) molecules are covalent immobilized on the conductive graphene oxide (GO) surface (TAPP@GO) by a simple one‐pot method. TAPP@GO as a novel electrochemical sensor successfully realized the sensitive detection of dopamine (DA) and uric acid (UA) in nM level with high stability and repeatability. The detection limit (LOD) for DA and UA is as low as 38 and 47 nM, and sensitivity up to 40.3 and 54.2 μA mM−1 in a wide detection range from 0.1 to 350 μM, respectively. Impressively, both DA and UA in the coexistence system can be simultaneously determined with the LOD of 51 and 64 nM for DA and UA, which is further confirmed by accurate determination of both in urine samples. This work represents not only the first example of electrochemical sensor based on organic porphyrin molecules covalent linked on GO surface, but more importantly provides an effective method for developing high‐performance sensing materials.

Preparation of cuprous oxide-supported silver-modified reduced graphene oxide nanocomposites for non-enzymatic electrochemical sensor

Abstract We constructed a non-enzymatic H2O2 sensor based on cuprous oxide-supported silver-modified reduced graphene oxide nanocomposites. It was found that the sensor exhibited good performances for sensing H2O2 with a detection limit of 0.34 μM and a wide detection range of 1–310 μM. The combination of graphene with silver and cuprous oxide improved the sensor’s sensitivity for detecting H2O2, with good repeatability, selectivity, and stability. The synthesis method of this nanocomposite provides a new idea for the green preparation of graphene-based nanocomposites and a new method for the construction of a new electrochemical sensor platform.

AuNPs and graphdiyne nanocomposite as robust electrocatalyst for methyl parathion detection in real samples.

The present work describes a simple and rapid synthesis method of gold nanoparticles and graphdiyne (AuNPs@GDY) nanocomposites including porous structure. Moreover, the synthesized AuNPs@GDY material was decorated on the glassy carbon electrode (GCE) with a drop coating method to construct a non-enzymatic electrochemical pesticides sensor. The micro-morphology and elemental composition of the materials were characterized by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The electrocatalysis and conductivity of the material were studied with cyclic voltammetry (CV) and impedance method, respectively. The properties of the sensor were investigated by CV and differential pulse voltammetry (DPV). The results showed that AuNPs@GDY exhibited excellent electrocatalytic ability for methyl parathion in a wide linear range (from 0.25ng/mL to 24.43μg/mL) and low limit of detection value (6.2pg/mL). Furthermore, the DPV method used in this paper was accurate and sensitive, and could be used for routine quality control of methyl parathion in kiwi fruit and tomato samples.

Comparison of Polyacrylonitrile-and Polypyrrole-based Electrochemical Sensors for Detection of Propamocarb in Food Samples

Food safety is a crucial issue; all countries have struggled against pesticides for years. In this study, Polypyrrole (PPy)- and Polyacrylonitrile (PAN)-based non-enzymatic electrochemical sensors were investigated to detect the pesticide propamocarb (PM) in food samples. Under the experimental conditions, the proposed strategy exhibited a high selectivity of the disposable PPy-based and PAN-based sensors for the determination of propamocarb pesticide in the concentration of 1 μM with a rapid detection within 1 min at pH 7.4 and 25 °C. We demonstrated the detection of PM residues on cucumber and tomato samples with good electrochemical performances towards the real-time usability on real food samples. PAN-based non-enzymatic electrochemical sensor has good sensitivity, higher selectivity, and stability than PPy-based non-enzymatic electrochemical sensor. The prepared PAN-based non-enzymatic electrochemical sensor is a potential candidate to be used in devices which perform food safety in agricultural products.

Zn–Co Bimetallic Zeolitic Imidazolate Frameworks as Nonenzymatic Electrochemical Glucose Sensors with Enhanced Sensitivity and Chemical Stability

Zn–Co Bimetallic Zeolitic Imidazolate Frameworks as Nonenzymatic Electrochemical Glucose Sensors with Enhanced Sensitivity and Chemical Stability

Electrochemical Biosensor for SARS-CoV-2 cDNA Detection Using AuPs-Modified 3D-Printed Graphene Electrodes.

A low-cost and disposable graphene polylactic (G-PLA) 3D-printed electrode modified with gold particles (AuPs) was explored to detect the cDNA of SARS-CoV-2 and creatinine, a potential biomarker for COVID-19. For that, a simple, non-enzymatic electrochemical sensor, based on a Au-modified G-PLA platform was applied. The AuPs deposited on the electrode were involved in a complexation reaction with creatinine, resulting in a decrease in the analytical response, and thus providing a fast and simple electroanalytical device. Physicochemical characterizations were performed by SEM, EIS, FTIR, and cyclic voltammetry. Square wave voltammetry was employed for the creatinine detection, and the sensor presented a linear response with a detection limit of 0.016 mmol L−1. Finally, a biosensor for the detection of SARS-CoV-2 was developed based on the immobilization of a capture sequence of the viral cDNA upon the Au-modified 3D-printed electrode. The concentration, immobilization time, and hybridization time were evaluated in presence of the DNA target, resulting in a biosensor with rapid and low-cost analysis, capable of sensing the cDNA of the virus with a good limit of detection (0.30 µmol L−1), and high sensitivity (0.583 µA µmol−1 L). Reproducible results were obtained (RSD = 1.14%, n = 3), attesting to the potentiality of 3D-printed platforms for the production of biosensors.

High-Performance Non-Enzymatic Electrochemical Dopamine Sensors Based on Metal-Organic Framework Derived Co-C-Matrix Nanoplatforms

A facile electrochemical sensing nanoplatform for detection of ultralow dopamine (DA) concentrations is developed through modification of cobalt-benzene tricarboxylic acid (Co-BTC) derived cobalt-carbon-matrix (Co-C-matrix). To enhance surface reactions and enzyme-like activities involved in interaction with DA, the structural integration of hybrid Co-C-matrix into Co-BTC as metal-organic framework (MOF) is investigated, resulting in nanostructured transducing media with high sensitivity and selectivity as catalyst. The Co-C-matrix nanoplatform exhibited the improved performance based on electrocatalytic oxidation of DA with high sensitivity of 7176 μA mM−1 cm−2 and low detection limit of 10 nM. Furthermore, the linearity of an amperometry peak toward DA concentration over wide concentration range from 10 nM to 25 μM was observed under optimal conditions. Excellent selectivity in the presence of potential interferents and operational stability in ambient air for 30 days as well as under environmental conditions for the electrochemical oxidation of dopamine were achieved. The practical feasibility of these non-enzymatic biosensors is demonstrated on real samples, where DA is detected in human serum with outstanding recovery of up to 100%. The synergetic effect of Co atoms dispersed in the matrix of the carbon nanohybrid results in abundant active sites for DA oxidation and electron transfer pathways.

Cover Feature: Direct Laser Writing of Poly(furfuryl Alcohol)/Graphene Oxide Electrodes for Electrochemical Determination of Ascorbic Acid (ChemElectroChem 17/2022)

The Cover Feature illustrates the use of a biomass-derived polymer for the direct laser writing fabrication of carbon-based electrodes for a non-enzymatic electrochemical sensor of ascorbic acid. More information can be found in the Research Article by L. Fernandes Loguercio et al.

Synthesis of Cu–CdIn2O4 nanoparticles decorated on nickel foam as a sensitive non-enzymatic electrochemical sensor for glucose detection

Synthesis of Cu–CdIn2O4 nanoparticles decorated on nickel foam as a sensitive non-enzymatic electrochemical sensor for glucose detection

Facile synthesis of copper and carbon co-doped peanut shell-like Mo2C/Mo3P electrocatalysts for ultra-sensitive amperometric detection of hydrogen peroxide

The rapid and precise detection of hydrogen peroxide has recently been a hot research in non-enzymatic electrochemical sensors. Herein, peanut shell-like Cu-Mo2C/Mo3P/C composite was simply prepared by in-situ simultaneous phosphorization and carbonization of [Cu(P4Mo6)]-based metal–organic framework (MOF) under N2/H2 atmosphere. Then, the above nanomaterials were deposited on glassy carbon electrode (GCE) surface through facile drop coating method, thus fabricating a highly efficient non-enzymatic H2O2 electrochemical sensor. In phosphate buffer solution (PBS, pH = 7.4), the Cu-Mo2C/Mo3P/C/GCE exhibits high sensitivity (653.2 μA mM−1 cm−2) and low detection limit (37 nM) to H2O2. Its amperometric response is 1.94, 3.27 and 4.71 times bigger than that of Mo2C/Mo3P/C/GCE, Mo3P/GCE and Mo2C/GCE. Such good electrochemical sensing performance is mainly ascribed to the synergism of unique microstructure, platinum-like Mo2C and Mo3P co-combination, together with copper and carbon dual-doping. Moreover, it can realize the satisfactory detection of H2O2 in human serum, disinfectant and contact lens solution, indicating the potential application in the fields of environmental monitoring and biochemical analysis.