Synthesis and characterization of Co 3 O 4 ultra-nanosheets and Co 3 O 4 ultra-nanosheet-Ni(OH) 2 as non-enzymatic electrochemical sensors for glucose detection

Advances of Transition Metal-Based Electrochemical Non-enzymatic Glucose Sensors for Glucose Analysis: A Review

Glucose concentration is a crucial parameter for assessing human health. Over recent years, non-enzymatic electrochemical glucose sensors have drawn considerable attention due to their substantial progress. This review explores the common mechanism behind the transition metal-based electrocatalytic oxidation of glucose molecules through classical electrocatalytic frameworks like the Pletcher model and the Hydrous Oxide-Adatom Mediator model (IHOAM), as well as the redox reactions at the transition metal centers. It further compiles the electrochemical characterization techniques, associated formulas, and their ensuing conclusions pertinent to transition metal-based non-enzymatic electrochemical glucose sensors. Subsequently, the review covers the latest advancements in the field of transition metal-based active materials and support materials used in non-enzymatic electrochemical glucose sensors in the last decade (2014-2023). Additionally, it presents a comprehensive classification of representative studies according to the active metal catalysts components involved.

Hydrazine High-Performance Oxidation and Sensing Using a Copper Oxide Nanosheet Electrocatalyst Prepared via a Foam-Surfactant Dual Template

This work demonstrates hydrazine electro-oxidation and sensing using an ultrathin copper oxide nanosheet (CuO-NS) architecture prepared via a versatile foam-surfactant dual template (FSDT) approach. CuO-NS was synthesised by chemical deposition of the hexagonal surfactant Brij®58 liquid crystal template containing dissolved copper ions using hydrogen foam that was concurrently generated by a sodium borohydride reducing agent. The physical characterisations of the CuO-NS showed the formation of a two-dimensional (2D) ultrathin nanosheet architecture of crystalline CuO with a specific surface area of ~39 m2/g. The electrochemical CuO-NS oxidation and sensing performance for hydrazine oxidation revealed that the CuO nanosheets had a superior oxidation performance compared with bare-CuO, and the reported state-of-the-art catalysts had a high hydrazine sensitivity of 1.47 mA/cm2 mM, a low detection limit of 15 μM (S/N = 3), and a linear concentration range of up to 45 mM. Moreover, CuO-NS shows considerable potential for the practical use of hydrazine detection in tap and bottled water samples with a good recovery achieved. Furthermore, the foam-surfactant dual template (FSDT) one-pot synthesis approach could be used to produce a wide range of nanomaterials with various compositions and nanoarchitectures at ambient conditions for boosting the electrochemical catalytic reactions.

Straw-sheaf-like Co3O4 for preparation of an electrochemical non-enzymatic glucose sensor

3D straw-sheaf-like cobalt oxide (SS-Co₃O₄) was prepared via the hydrothermal method and inert gas calcination of precursors without the assistance of any template or surfactant. It was composed of numerous nanoneedles with a length of ~ 8 µm and a diameter of ~ 30 nm strongly tied in the center. The SS-Co₃O₄ exhibited high crystallinity, a large surface area (39.01 m².g^-1), a smaller pore size (6 nm), and lower charge transfer resistance (R_ct = 9.35 Ω) at the electrode/electrolyte interface. A non-enzymatic glucose oxidizing electrode fabricated with SS-Co₃O₄ showed a high sensitivity (669 µA.mM^-1.cm^-2), wide linear range (0.04-4.85 mM), low limit of detection (0.31 µM), good selectivity, fast response time (5 s), and high reproducibility with a relative standard deviation of 2.25%. In addition, its robust structure demonstrated excellent electrochemical stability by retaining 83.8% of the initial sensitivity when its current density vs. time response was measured for 75 min in bare electrolytes prior to the glucose-sensing test. Furthermore, it demonstrated excellent repeatability performance by retaining 87.0% of the initial sensitivity when a single electrode was tested for 4 cycles. The proposed robust structured 3D SS-Co₃O₄ electrode successfully responds to the content of glucose in human saliva, which substantially proves its suitability in practical application. The synthesis technique is advantageous to prepare other metal oxides with interesting morphology and robust structure for the development of more reliable non-enzymatic glucometers and other electrochemical devices.

Glucose nano biosensor with non-enzymatic excellent sensitivity prepared with nickel-cobalt nanocomposites on f-MWCNT

NiCo (Nickel-cobalt) nanoparticles were obtained by the chemical reduction method on functionalized multi-walled carbon nanotubes. After this process, chronoamperometry, cyclic voltammetry, and amperometric methods were used to investigate the electrochemical and electrocatalytic behavior of NiCo@f-MWCNT against glucose oxidation. In addition, the NiCo@f-MWCNT nanocomposites were analyzed by characterization techniques such as X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscopy (TEM), and Atomic Force Microscopy (AFM) in terms of the morphological and atomic structure of prepared nanomaterials. The sensitivity and limit of detection the non-enzymatic glucose sensor (NiCo@f-MWCNT) were calculated as 10,015 μA/mM^-1 cm^-2 0.26 μM, respectively. As a result of these studies and experiments, the NiCo@f-MWCNT nanocomposite is a really good sensor and their stability showed that the current nanomaterials expressed to be new material for the electrochemical detection of glucose.

Fabrication of stable electrospun blended chitosan-poly(vinyl alcohol) nanofibers for designing naked-eye colorimetric glucose biosensor based on GOx/HRP

In this study, designing of a stable electrospun blended chitosan (CS)-poly(vinyl alcohol) (PVA) nanofibers for colorimetric glucose biosensing in an aqueous medium was investigated. CS and PVA solutions were blended to acquire an optimum content (CS/PVA:1/4) and electrospunned to obtain uniform and bead-free CS/PVA nanofiber structures following the optimization of the electrospinning parameters (33 kV, 20 cm, and 1.2 ml.h^-1). Crosslinking process applied subsequently provided mechanically and chemically stable nanofibers with an average diameter of 378 nm. The morphological homogeneity, high fluid absorption ability (>%50), thermal (<230 °C) and morphological stability, surface hydrophilicity and degrability properties of cross-linked CS/PVA nanofiber demonstrated their great potential to be developed as an eye-readable strip for biosensing applications. The glucose oxidase (GOx) and horseradish peroxidase (HRP) was immobilized by physical adsorption on the cross-linked CS/PVA nanofiber. The glucose assay analysis by ultraviolet-visible (UV-Vis) spectrophotometry using the same enzymatic system of the proposed glucose strips in form of absorbance versus concentration plot was found to be linear over a glucose concentration range of 2.7 to 13.8 mM. The prepared naked eye colorimetric glucose detection strips, with lower detection limit of 2.7 mM, demonstrated dramatic color change from white (0 mM) to brownish-orange (13.8 mM). The developed cross-linked CS/PVA nanofiber strips, prepared by electrospinnig procedure, could be easily adapted to a color map, as an alternative material for glucose sensing. Design of a practical, low-cost, and environmental-friendly bio-based CS/PVA testing strips for eye readable detection were presented and suggested as an applicable medium for a wide range of glucose concentrations.

Non-Enzymatic Glucose Sensors Involving Copper: An Electrochemical Perspective

Non-enzymatic glucose sensors based on the use of copper and its oxides have emerged as promising candidates to replace enzymatic glucose sensors owing to their stability, ease of fabrication, and superior sensitivity. This review explains the theories of the mechanism of glucose oxidation on copper transition metal electrodes. It also presents an overview on the development of among the best non-enzymatic copper-based glucose sensors in the past 10 years. A brief description of methods, interesting findings, and important performance parameters are provided to inspire the reader and researcher to create new improvements in sensor design. Finally, several important considerations that pertain to the nano-structuring of the electrode surface is provided.

Developments of the Electroactive Materials for Non-Enzymatic Glucose Sensing and Their Mechanisms

A comprehensive review of the electroactive materials for non-enzymatic glucose sensing and sensing devices has been performed in this work. A general introduction for glucose sensing, a facile electrochemical technique for glucose detection, and explanations of fundamental mechanisms for the electro-oxidation of glucose via the electrochemical technique are conducted. The glucose sensing materials are classified into five major systems: (1) mono-metallic materials, (2) bi-metallic materials, (3) metallic-oxide compounds, (4) metallic-hydroxide materials, and (5) metal-metal derivatives. The performances of various systems within this decade have been compared and explained in terms of sensitivity, linear regime, the limit of detection (LOD), and detection potentials. Some promising materials and practicable methodologies for the further developments of glucose sensors have been proposed. Firstly, the atomic deposition of alloys is expected to enhance the selectivity, which is considered to be lacking in non-enzymatic glucose sensing. Secondly, by using the modification of the hydrophilicity of the metallic-oxides, a promoted current response from the electro-oxidation of glucose is expected. Lastly, by taking the advantage of the redistribution phenomenon of the oxide particles, the usage of the noble metals is foreseen to be reduced.

The facile synthesis of a Co3O4-NiNP composite as an electrochemical non-enzymatic sensing platform for small chemical molecules

In this paper, a new Co3O4-Ni nanocomposite-modified glassy carbon electrode (Co3O4-NiNPs/GCE) was successfully constructed and used to detect glucose and hydrogen peroxide (H2O2). The morphologies and structures of the Co3O4 and Co3O4-Ni nanocomposites were characterized via transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The construction process of the modified electrode was characterized via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. Co3O4-NiNPs/GCE shows more excellent electrocatalytic activity for the detection of glucose and H2O2 compared with Co3O4/GCE and NiNPs/GCE. The amperometric i-t method was used for the quantitative analysis of glucose and H2O2. The plots of current difference versus concentration of glucose and H2O2 were linear in the range of 0.3-550 μM and 0.5-89 μM, respectively. The corresponding limits of detection (LODs) were 0.086 μM and 0.23 μM for glucose and H2O2, respectively. This recommended sensor was successfully applied for the quantitative analysis of glucose in fruit and H2O2 in water samples.

Sensitive and Enzyme-Free Glucose Sensor Based on Copper Nanowires/Polyaniline/Reduced Graphene Oxide Nanocomposite Ink

In this paper, we report the preparation and characterization of a sensitive and reusable nonenzymatic glucose (NEG) sensor based on copper nanowires (CuNWs)/polyaniline (PANI)/reduced graphene oxide (rGO) nanocomposite ink. The CuNWs/PANI/rGO nanocomposite ink was prepared by solvothermal mixing of CuNWs, PANI, rGO and binders. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier Transform Infra-Red (FT-IR) spectroscopy techniques were used to assess the structural and morphological parameters of prepared nanocomposite ink. The cyclic voltammetry (CV) technique was used to estimate the electrochemical behavior of prepared NEG sensor. The structural, morphological and spectroscopy results confirmed the change in morphological and oxidation state of CuNWs to CuO nanostructures as a constituent of nanocomposite ink. The CuO nanostructures supported on PANI/rGO demonstrated good electrochemical stability and great electrocatalytic activity toward glucose oxidation. At a glucose oxidation potential of 0.64V, the prepared NEG sensor exhibited great electrocatalytic ability by offering a high sensitivity of 843.06[Formula: see text]AmM[Formula: see text]cm[Formula: see text] in the linear glucose range 0–4mM with a lower detection limit of 1.6mM. In addition to these outstanding performance characteristics, CuNWs/PANI/rGO nanocomposite ink-based NEG sensor has the advantages of ease of fabrication, low cost and reusability.

3D NiCo-Layered double Hydroxide@Ni nanotube networks as integrated free-standing electrodes for nonenzymatic glucose sensing

Nickel cobalt layered double hydroxide (NiCo-LDH)-based materials have recently emerged as catalysts for important electrochemical applications. However, they frequently suffer from low electrical conductivity and agglomeration, which in turn impairs their performance. Herein, we present a catalyst design based on integrated, self-supported nickel nanotube networks (Ni-NTNWs) loaded with NiCo-LDH nanosheets, which represents a binder-free, hierarchically nanostructured electrode architecture combining continuous conduction paths and openly accessible macropores of low tortuosity with an ultrahigh density of active sites. Similar to macroscale metallic foams, the NTNWs serve as three-dimensionally interconnected, robust frameworks for the deposition of active material, but are structured in the submicron range. Our synthesis is solely based on scalable approaches, namely templating with commercial track-etched membranes, electroless plating, and electrodeposition. Morphological and compositional characterization proved the successful decoration of the inner and outer nanotube surfaces with a conformal NiCo-LDH layer. Ni-NTNW electrodes and hydroxide-decorated variants showed excellent performance in glucose sensing. The highest activity was achieved for the catalyst augmented with NiCo-LDH nanosheets, which surpassed the modification with pure Ni(OH)₂. Despite its low thickness of 20 µm, the optimized catalyst layer provided an outstanding sensitivity of 4.6 mA mM^-1 cm^-2, a low detection limit of 0.2 µM, a fast response time of 5.3 s, high selectivity and stability, and two linear ranges covering four orders of magnitude, up to 2.5 mM analyte. As such, derivatized interconnected metal nano-networks represent a promising design paradigm for highly miniaturized yet effective catalyst electrodes and electrochemical sensors.

Two-dimensional inorganic nanosheets: production and utility in the development of novel electrochemical (bio)sensors and gas-sensing applications

This review (with 178 references) focuses on inorganic layered materials (ILMs) and the use of their two-dimensional nanosheets in the development of novel electrochemical (bio)sensors, analytical devices, and gas-phase sensing applications. The text is organized in three main sections including the presentation of the most important families of ILMs, a comprehensive outline of various "bottom-up", "top-down," and hydro(solvo)thermal methods that have been used for the production of ILM nanosheets, and finally an evaluative survey on their utility for the determination of analytes with interest in different sectors of contemporary analysis. Critical discussion on the effect of the production method on their electronic properties, the suitability of each nanomaterial in different sensing technologies along with an assessment of the performance of the (bio)sensors and devices that have been proposed within the last 5 years, is enclosed. The perspectives of further improving the utility of 2D inorganic nanosheets in sensing applications, in real-world samples, are also discussed.

Non-Enzymatic Glucose Sensing Based on Incorporation of Carbon Nanotube into Zn-Co-S Ball-in-Ball Hollow Sphere

Zn-Co-S ball-in-ball hollow sphere (BHS) was successfully prepared by solvothermal sulfurization method. An efficient strategy to synthesize Zn-Co-S BHS consisted of multilevel structures by controlling the ionic exchange reaction was applied to obtain great performance electrode material. Carbon nanotubes (CNTs) as a conductive agent were uniformly introduced with Zn-Co-S BHS to form Zn-Co-S BHS/CNTs and expedited the considerable electrocatalytic behavior toward glucose electro-oxidation in alkaline medium. In this study, characterization with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) was used for investigating the morphological and physical/chemical properties and further evaluating the feasibility of Zn-Co-S BHS/CNTs in non-enzymatic glucose sensing. Electrochemical methods (cyclic voltammetry (CV) and chronoamperometry (CA)) were performed to investigate the glucose sensing performance of Zn-Co-S BHS/CNTs. The synergistic effect of Faradaic redox couple species of Zn-Co-S BHS and unique conductive network of CNTs exhibited excellent electrochemical catalytic ability towards the glucose electro-oxidation, which revealed linear range from 5 to 100 μM with high sensitivity of 2734.4 μA mM^-1 cm^-2, excellent detection limit of 2.98 μM, and great selectivity in the presence of dopamine, uric acid, ascorbic acid, and fructose. Thus, Zn-Co-S BHS/CNTs would be expected to be a promising material for non-enzymatic glucose sensing.

A facile and sensitive electrochemical sensor for non-enzymatic glucose detection based on three-dimensional flexible polyurethane sponge decorated with nickel hydroxide

A novel three-dimensional nickel hydroxide/polyurethane (Ni(OH)₂/PU) electrode was prepared by a simple and environmentally friendly method and used for non-enzymatic detection of glucose. The Ni(OH)₂/PU electrode was obtained by one-pot hydrothermal method of loading nickel hydroxide on a cheap, easily available and flexible polyurethane sponge, which is facile and energy-saving. The porous structure of the polyurethane sponge provides a large surface area and a rich electrochemical active site for the electrode, which is beneficial to the oxidation reaction of glucose on the surface of the electrode with Ni(OH)₂. The Ni(OH)₂/PU electrode structure was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The cyclic voltammetry test was used to study the catalytic performance of Ni(OH)₂/PU electrode for oxidation of glucose and the chronoamperometry was used to investigate the detection performance of Ni(OH)₂/PU electrode on glucose. The results indicate that this non-enzymatic glucose sensor had a high sensitivity of 2845 μA mM^-1 cm^-2, a low detection limit of 0.32 μM (S/N = 3), a detection range of 0.01-2.06 mM and response time of less than 5 s. In addition, the Ni(OH)₂/PU electrode had excellent selectivity, reproducibility and stability and also exhibited effective detection of glucose in fetal bovine serum (FBS). In summary, Ni(OH)₂/PU electrode had broad prospects as an excellent candidate for non-enzymatic glucose sensors. The study also opens up a facile and energy-saving approach for preparing three-dimensional (3D) functionalized polymer electrode via hydrothermal method as electrochemical sensors.

Preparation of co-Co3 O4 /carbon nanotube/carbon foam for glucose sensor

Co-Co₃ O₄ /carbon nanotube/carbon foam (Co-Co₃ O₄ /CNT/CF) nanocomposites were prepared by soaking melamine foam into a solution of Co(NO₃ )₂ ·6H₂ O, followed by calcination in N₂ and air in sequence. The obtained Co-Co₃ O₄ /CNT/CF nanocomposites were characterized with scanning electron microscopy and cyclic voltammetry. It was found that Co₃ O₄ nanoparticles were grown on the external of CF successfully, while CNTs were grown on the surfaces of CF in a large amount, which further improved the electrical conductivity of the. The prepared Co-Co₃ O₄ /CNT/CF nanocomposites were then used to construct nonenzymatic sensor to detect glucose in alkaline solution. The sensor showed detection range from 1.2 μM to 2.29 mM with a detection limit of 0.4 μM (S/N =3) and a high sensitivity of 637.5 μA^-1 cm^-2 . The developed sensor also showed an instant response, favorable reproducibility, and high selectivity. The results attest that Co-Co₃ O₄ /CNT/CF composites have great potential in the development of nonenzymatic sensors for glucose.

Hierarchical core-shell structured Ni3S2/NiMoO4 nanowires: a high-performance and reusable electrochemical sensor for glucose detection

Designing highly active electrode is important for the fabrication of electrochemical sensing platforms, and core-shell nanostructures with large specific surface areas and ease of accessibility are effective probes for the detection of biomolecules. In this work, we report the development of hierarchical core-shell Ni3S2/NiMoO4 nanowires on a nickel foam substrate (Ni-Ni3S2/NiMoO4) as a non-noble metal catalyst electrode for the electrochemical oxidation of glucose in alkaline electrolyte. As an electrochemical sensor for glucose detection, the fabricated hierarchical Ni-Ni3S2/NiMoO4 core-shell nanowires display an enhanced catalytic response, a fast response time of 1 s with a limit of detection (LOD) of 0.055 μM (S/N = 3), and a higher sensitivity of 10.49 μA μM-1 cm-2. Unlike Ni3S2 or NiMoO4 electrodes, the observed superior catalytic activity towards glucose is mainly due to the promotional effect of NiMoO4 nanosheets on the Ni3S2 nanowires, which can increase the large active surface area and generate numerous active sites within and on the surface walls of the nanowire structures. The developed Ni-Ni3S2/NiMoO4 nanowire electrode can selectively detect glucose in the presence of other carbohydrates, such as fructose, sucrose, lactose, maltose, galactose, mannose, and xylose, indicating potential anti-interference properties. The Ni-Ni3S2/NiMoO4 nanowire electrode is highly stable for reuse and its practical application is demonstrated using real blood serum samples. These results demonstrate that hierarchical core-shell Ni3S2/NiMoO4 nanowires show potential for application in the development of low-cost applied glucose sensors.

A non-enzymatic glucose sensor based on a CoNi2Se4/rGO nanocomposite with ultrahigh sensitivity at low working potential

A CoNi₂Se₄–rGO nanocomposite fabricated on Ni foam shows excellent efficiency for non-enzymatic glucose sensing at low applied potential.

Three-Dimensional Porous Nickel Frameworks Anchored with Cross-Linked Ni(OH)2 Nanosheets as a Highly Sensitive Nonenzymatic Glucose Sensor

A facile and scalable in situ microelectrolysis nanofabrication technique is developed for preparing cross-linked Ni(OH)₂ nanosheets on a novel three-dimensional porous nickel template (Ni(OH)₂@3DPN). For the constructed template, the porogen of NaCl particles not only induces a self-limiting surficial hot corrosion to claim the "start engine stop" mechanism but also serves as the primary battery electrolyte to greatly accelerate the growth of Ni(OH)₂. As far as we know, the microelectrolysis nanofabrication is superior to the other reported Ni(OH)₂ synthesis methods due to the mild condition (60 °C, 6 h, NaCl solution, ambient environment) and without any post-treatment. The integrated Ni(OH)₂@3DPN electrode with a highly suitable microstructure and a porous architecture implies a potential application in electrochemistry. As a proof-of-concept demonstration, the electrode was employed for nonenzymatic glucose sensing, which exhibits an outstanding sensitivity of 2761.6 μA mM^-1 cm^-2 ranging from 0.46 to 2100 μM, a fast response, and a low detection limit. The microelectrolysis nanofabrication is a one-step, binder-free, entirely green, and therefore it has a distinct advantage to improve clean production and reduce energy consumption.

Two-Dimensional Oxides: Recent Progress in Nanosheets

Two-dimensional (2D) materials have been widely investigated for the last few years, introducing nanosheets and ultrathin films. The often superior electrical, optical and mechanical properties in contrast to their three-dimensional (3D) bulk counterparts offer a promising field of opportunities. Especially new research fields for already existing and novel applications are opened by downsizing and improving the materials at the same time. Some of the most promising application fields are namely supercapacitors, electrochromic devices, (bio-) chemical sensors, photovoltaic devices, thermoelectrics, (photo-) catalysts and membranes. The role of oxides in this field of materials deserves a closer look due to their availability, durability and further advantages. Here, recent progress in oxidic nanosheets is highlighted and the benefit of 2D oxides for applications discussed in-depth. Therefore, different synthesis techniques and microstructures are compared more closely.

Highly sensitive and selective non-enzymatic monosaccharide and disaccharide sugar sensing based on carbon paste electrodes modified with perforated NiO nanosheets

Fabrication and characterization of enzyme-free electrochemical sensor for the sensing of monosaccharide and disaccharide sugars based on perforated NiO nanosheets (NSs).

In situ fabrication of Ni nanoparticles on N-doped TiO2 nanowire arrays by nitridation of NiTiO3 for highly sensitive and enzyme-free glucose sensing

A novel strategy for Ni NPs/TiO_xN_y NWAs by nitridation of NiTiO₃ NWAs is designed for highly sensitive and selective non-enzymatic glucose sensing.

Nano-composite of Co3O4 and Cu with enhanced stability and catalytic performance for non-enzymatic electrochemical glucose sensors

A non-enzymatic glucose sensor (Co₃O₄–CuNPs/Pt) was successfully constructed by a dropping method and a potentiostatic deposition technology. This sensor was used successfully for the quantitative analysis of trace glucose in serum sample.

Enhanced amperometric sensing using a NiCo2O4/nitrogen-doped reduced graphene oxide/ionic liquid ternary composite for enzyme-free detection of glucose

Schematic illustration of the fabrication of NiCo₂O₄/N-rGO/ILs/GCE.

Flower-like Copper Cobaltite Nanosheets on Graphite Paper as High-Performance Supercapacitor Electrodes and Enzymeless Glucose Sensors

Flower-like copper cobaltite (CuCo2O4) nanosheets anchored on graphite paper have been synthesized using a facile hydrothermal method followed by a postannealing treatment. Supercapacitor electrodes employing CuCo2O4 nanosheets exhibit an enhanced capacitance of 1131 F g(-1) at a current density of 1 A g(-1) compared with previously reported supercapacitor electrodes. The CuCo2O4 electrode delivers a specific capacitance of up to 409 F g(-1) at a current density of as high as 50 A g(-1), and a good long-term cycling stability, with 79.7% of its specific capacitance retained after 5000 cycles at 10 A g(-1). Furthermore, the as-prepared CuCo2O4 nanosheets on graphite paper can be fabricated as electrodes and used as enzymeless glucose sensors, which exhibit good sensitivity (3.625 μA μM(-1) cm(-2)) and an extraordinary linear response ranging up to 320 μM with a low detection limit (5 μM).

A novel sensitive and selective electrochemical sensor based on molecularly imprinted polymer on a nanoporous gold leaf modified electrode for warfarin sodium determination

A novel electrochemical sensor was facilely fabricated by coupling nanoporous gold leaf (NPGL) with molecularly imprinted polymer (MIP), and afforded ultrasensitive and selective determination of warfarin sodium (WFS).