Synthesis of tremella-like CoS and its application in sensing of hydrogen peroxide and glucose

Controlled synthesized of ternary Cu-Co-Ni-S sulfides nanoporous network structure on carbon fiber paper: a superior catalytic electrode for highly-sensitive glucose sensing

BACKGROUND

Efficient monitoring of glucose concentration in the human body necessitates the utilization of electrochemically active sensing materials in nonenzymatic glucose sensors. However, prevailing limitations such as intricate fabrication processes, lower sensitivity, and instability impede their practical application. Herein, ternary Cu-Co-Ni-S sulfides nanoporous network structure was synthesized on carbon fiber paper (CP) by an ultrafast, facile, and controllable technique through on-step cyclic voltammetry, serving as a superior self-supporting catalytic electrode for the high-performance glucose sensor.

RESULTS

The direct growth of free-standing Cu-Co-Ni-S on the interconnected three-dimensional (3D) network of CP boosted the active site of the composites, improved ion diffusion kinetics, and significantly promoted the electron transfer rate. The multiple oxidation states and synergistic effects among Co, Ni, Cu, and S further promoted glucose electrooxidation. The well-architected Cu-Co-Ni-S/CP presented exceptional electrocatalytic properties for glucose with satisfied linearity of a broad range from 0.3 to 16,000 μM and high sensitivity of 6829 μA mM- 1 cm- 2. Furthermore, the novel sensor demonstrated excellent selectivity and storage stability, which could successfully evaluate the glucose levels in human serum. Notably, the novel Cu-Co-Ni-S/CP showed favorable biocompatibility, proving its potential for in vivo glucose monitoring.

CONCLUSION

The proposed 3D hierarchical morphology self-supported electrode sensor, which demonstrates appealing analysis behavior for glucose electrooxidation, holds great promise for the next generation of high-performance glucose sensors.

Facile preparation of a CoNiS/CF electrode by SILAR for a high sensitivity non-enzymatic glucose sensor

The nanomaterials for non-enzymatic electrochemical sensors are usually pre-synthesized and coated onto electrodes by ex situ methods. In this work, amorphous cobalt-nickel sulfide (CoNiS) nanoparticles were facilely prepared on copper foam (CF) by the in situ successive ionic layer adsorption and reaction (SILAR) method, and as-prepared CoNiS/CF was studied as an electrode for non-enzymatic glucose sensing. It was analyzed by field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX) and X-ray photoelectron spectroscopy (XPS). The electrochemical performance was investigated by cyclic voltammetry (CV) and chronoamperometry (CA). This binary sulfide electrode showed better performance toward glucose oxidation compared to the corresponding single sulfide and showed a wide linear range of 0.005 to 3.47 mM, a high sensitivity of 2298.7 μA mM-1 cm-2 and a low detection limit of 2.0 μM. The sensor exhibited high sensitivity and good repeatability and stability and was able to detect glucose in an actual sample. This work provides a simple and fast in situ electrode preparation method for a high-sensitivity glucose sensor.

In situ growth of the CoO nanoneedle array on a 3D nickel foam toward a high-performance glucose sensor

A glucose sensor with high sensitivity and low detection limit is vital for human beings' health. Herein, a CoO nanoneedle array with an unique electronic structure was successfully constructed by a hydrothermal and subsequent high-temperature calcination process. The optimized CoO-400 nanoneedles exhibit a larger electrochemical active surface area, beneficial electronic structure, favorable lattice distortion, and abundant active sites, which effectively promote electrochemical properties toward glucose sensing. The glucose sensor constructed by CoO-400 nanoneedles shows a high sensitivity of 84.23 mA cm^-2 mM^-1 and low detection limit of 4.4 × 10^-7 M, superior to the results from most previous reports. Moreover, outstanding anti-interference ability, superior long-term stability, good repeatability, and satisfactory reproducibility in glucose detection for CoO-400 nanoneedles are also demonstrated.

Cu2O-Based Electrochemical Biosensor for Non-Invasive and Portable Glucose Detection

Electrochemical voltammetric sensors are some of the most promising types of sensors for monitoring various physiological analytes due to their implementation as non-invasive and portable devices. Advantages in reduced analysis time, cost-effectiveness, selective sensing, and simple techniques with low-powered circuits distinguish voltammetric sensors from other methods. In this work, we developed a Cu2O-based non-enzymatic portable glucose sensor on a graphene paste printed on cellulose cloth. The electron transfer of Cu2O in a NaOH alkaline medium and sweat equivalent solution at very low potential (+0.35 V) enable its implementation as a low-powered portable glucose sensor. The redox mechanism of the electrodes with the analyte solution was confirmed through cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy studies. The developed biocompatible, disposable, and reproducible sensors showed sensing performance in the range of 0.1 to 1 mM glucose, with a sensitivity of 1082.5 ± 4.7% µA mM-1 cm-2 on Cu2O coated glassy carbon electrode and 182.9 ± 8.83% µA mM-1 cm-2 on Cu2O coated graphene printed electrodes, making them a strong candidate for future portable, non-invasive glucose monitoring devices on biodegradable substrates. For portable applications we demonstrated the sensor on artificial sweat in 0.1 M NaOH solution, indicating the Cu2O nanocluster is selective to glucose from 0.0 to +0.6 V even in the presence of common interference such as urea and NaCl.

Efficient improvement in non-enzymatic glucose detection induced by the hollow prism-like NiCo2S4 electrocatalyst

Hollow prism-like NiCo2S4 materials (NiCo2S4 HNPs) were successfully fabricated by a two-step method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD) confirmed the morphology and structure of the as-prepared NiCo2S4 nanoprisms. A non-enzymatic sensor based on NiCo2S4 HNPs was constructed with outstanding electrochemical activity towards glucose oxidation in alkaline medium. The sensor showed a rapid response time (∼0.1 s), a high sensitivity of 82.9 μA mM-1 cm-2, a wide linear range (0.005-20.2 mM) and a detection limit of 0.8 μM (S/N = 3) with a good selectivity and reproducibility. Additionally, the proposed electrode also confirmed the feasibility in practical blood serum. These results indicate that NiCo2S4/ITO has great potential in the development of non-enzymatic glucose sensor applications.

Cobalt Phosphide (Co2P) with Notable Electrocatalytic Activity Designed for Sensitive and Selective Enzymeless Bioanalysis of Hydrogen Peroxide

In this work, cobalt phosphide nanoparticles (Co₂P NPs) were prepared by simple and mild hydrothermal method without the use of harmful phosphorous source. The morphological structure and surface component of Co₂P were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy measurements. Considering the excellent electrocatalytic reduction activity and good electrical conductivity of transition-metal phosphide, we fabricated Co₂P NPs on indium tin oxide (ITO) substrate (Co₂P/ITO) for H₂O₂ detection. The Co₂P/ITO transducer displayed a rapid amperometric response less than 5 s, a broader response range from 0.001 to 10.0 mM and a low detection limit of 0.65 μM. In addition, the non-enzymatic Co₂P/ITO sensor showed outstanding selectivity, reproducibility, repeatability and stability, all of which qualified the Co₂P/ITO electrode for quite a reliable and promising biosensor for H₂O₂ sensing.

Enhanced non-enzymatic glucose sensing based on porous ZIF-67 hollow nanoprisms

Porous ZIF-67 hollow nanoprisms based non-enzymatic glucose sensor was successfully prepared using Co₅(OH)₂(OAc)₈·2H₂O as a precursor by a diffusion-controlled strategy, which exhibited wide linear range and high sensitivity.

Direct Growth of Polycrystalline GaN Porous Layer with Rich Nitrogen Vacancies: Application to Catalyst-Free Electrochemical Detection

It has been demonstrated that defect engineering is an effective strategy to enhance the activity of materials. Herein, a polycrystalline GaN porous layer (PGP) with high catalytic activity was grown by self-assembly on GaN-coated sapphire substrate by using low-temperature (LT) MOCVD growth. Without doping, LT growth can significantly improve the activity and electrical conductivity of PGP, owing to the presence of rich N-vacancies (∼10²⁰ cm^-3). Identification of rich N-vacancies in the PGP material was realized by using atomically resolved STEM (AR-STEM) characterization. The optimized PGP was applied to catalyst-free electrochemical detection of H₂O₂ with a limit of detection (LOD) of 50 nM, a fast response speed of 3 s, a wide linear detection range (50 nM to 12 mM), and a high stability. The LOD is exceeding 40 fold lower than that of reported metal-catalyst decorated GaN. Moreover, a quantitative relationship between the sensing performances and N-vacancy of PGP was established. To our knowledge, it is the first time that intrinsic GaN materials can exhibit high catalytic activity.

Progress of Advanced Nanomaterials in the Non-Enzymatic Electrochemical Sensing of Glucose and H2O2

Non-enzymatic sensing has been in the research limelight, and most sensors based on nanomaterials are designed to detect single analytes. The simultaneous detection of analytes that together exist in biological organisms necessitates the development of effective and efficient non-enzymatic electrodes in sensing. In this regard, the development of sensing elements for detecting glucose and hydrogen peroxide (H₂O₂) is significant. Non-enzymatic sensing is more economical and has a longer lifetime than enzymatic electrochemical sensing, but it has several drawbacks, such as high working potential, slow electrode kinetics, poisoning from intermediate species and weak sensing parameters. We comprehensively review the recent developments in non-enzymatic glucose and H₂O₂ (NEGH) sensing by focusing mainly on the sensing performance, electro catalytic mechanism, morphology and design of electrode materials. Various types of nanomaterials with metal/metal oxides and hybrid metallic nanocomposites are discussed. A comparison of glucose and H₂O₂ sensing parameters using the same electrode materials is outlined to predict the efficient sensing performance of advanced nanomaterials. Recent innovative approaches to improve the NEGH sensitivity, selectivity and stability in real-time applications are critically discussed, which have not been sufficiently addressed in the previous reviews. Finally, the challenges, future trends, and prospects associated with advanced nanomaterials for NEGH sensing are considered. We believe this article will help to understand the selection of advanced materials for dual/multi non-enzymatic sensing issues and will also be beneficial for researchers to make breakthrough progress in the area of non-enzymatic sensing of dual/multi biomolecules.

Facile preparation of Ni nanoparticle embedded on mesoporous carbon nanorods for non-enzymatic glucose detection

Transition metal doped carbon materials are recognized as promising sensing platforms for glucose detection. Herein, a simple strategy involving crystallinity, nanostructure engineering, and pyrolysis was developed for constructing well-defined Ni nanoparticle embedded on nanoporous carbon nanorods (Ni/NCNs). A three-dimensional nickel-based metal-organic framework (Ni-MOF) was used as both a self-sacrificing template and precursor. Due to the synergistic effects between the uniformly dispersed Ni nanoparticles and the nanoporous carbon matrix, the as-prepared Ni/NCNs exhibited remarkable electrochemical activity. The fabricated Ni/NCNs glucose sensor showed excellent electrocatalytic performance with ultra-low limit of detection, wide linear detection ranges, fast response times (within 1.6 s), superior stability, and anti-interference characteristics. Moreover, the Ni/NCNs sensing platform was successfully applied to analyze glucose concentrations in human blood samples. These results showed that Ni/NCNs hold potential applications in developing enzyme-free glucose sensors.

Preparation of SnS2/MWCNTs chemically modified electrode and its electrochemical detection of H2O2

Considering the importance of hydrogen peroxide (H₂O₂) rapid detection, a SnS₂/MWCNTs composite was prepared by loading tin disulfide (SnS₂) nanoparticles on a three-dimensional conductive network composed of multi-walled carbon nanotubes (MWCNTs). The obtained SnS₂/MWCNTs composite was used as the modified material to prepare a chemically modified electrode (CME), which was used for the rapid detection of H₂O₂. The morphology and structure of the obtained samples were characterized and analyzed by scanning electron microscopy, X-ray diffraction, and energy-dispersive spectroscopy. The electrochemical performance of the modified electrode was researched by cyclic voltammetry, amperometric i-t curves, and AC impedance techniques. The results show that SnS₂ nanoparticles with a size of about 33 nm are evenly dispersed on the surface of MWCNTs. The obtained SnS₂/MWCNTs-CME has a strong current response to H₂O₂: it has a good linear relationship during the range of 0.248 ~ 16.423 mmol L^-1, and its linear regression equation is I_pa (mA) = (-0.94 ± 0.05) × 10^-2 + (- 0.43 ± 0.06) × 10^-2c (mmol L^-1) (R² = 0.997) with a sensitivity of 87.84 μA mmol^-1 L cm^-2. The corresponding detection limit is 1.04 μmol L^-1 (S/N = 3). At the same time, the SnS₂/MWCNTs-CME has good selectivity, reproducibility, and stability. Graphical abstract Uniformly distributed SnS₂/CNTs composite is used to prepare a chemically modified electrode for H₂O₂ detection. The prepared electrode has a strong electrochemical response to H₂O₂ due to the excellent conductivity and support of CNTs. And the SnS₂/CNTs electrode shows high sensitivity and selectivity for the electrochemical detection of H₂O₂.

Controlled synthesis of flower-like cobalt phosphate microsheet arrays supported on Ni foam as a highly efficient 3D integrated anode for non-enzymatic glucose sensing

CoPO MA/NF was synthesized in a controlled way and utilized as an efficient 3D integrated electrode for enzyme-free glucose sensing.

Metabolic Syndrome-An Emerging Constellation of Risk Factors: Electrochemical Detection Strategies

Metabolic syndrome is a condition that results from dysfunction of different metabolic pathways leading to increased risk of disorders such as hyperglycemia, atherosclerosis, cardiovascular diseases, cancer, neurodegenerative disorders etc. As this condition cannot be diagnosed based on a single marker, multiple markers need to be detected and quantified to assess the risk facing an individual of metabolic syndrome. In this context, chemical- and bio-sensors capable of detecting multiple analytes may provide an appropriate diagnostic strategy. Research in this field has resulted in the evolution of sensors from the first generation to a fourth generation of 'smart' sensors. A shift in the sensing paradigm involving the sensing element and transduction strategy has also resulted in remarkable advancements in biomedical diagnostics particularly in terms of higher sensitivity and selectivity towards analyte molecule and rapid response time. This review encapsulates the significant advancements reported so far in the field of sensors developed for biomarkers of metabolic syndrome.

Recent advances in electrochemical non-enzymatic glucose sensors - A review

This review encompasses the mechanisms of electrochemical glucose detection and recent advances in non-enzymatic glucose sensors based on a variety of materials ranging from platinum, gold, metal alloys/adatom, non-precious transition metal/metal oxides to glucose-specific organic materials. It shows that the discovery of new materials based on unique nanostructures have not only provided the detailed insight into non-enzymatic glucose oxidation, but also demonstrated the possibility of direct detection in whole blood or interstitial fluids. We critically evaluate various aspects of non-enzymatic electrochemical glucose sensors in terms of significance as well as performance. Beyond laboratory tests, the prospect of commercialization of non-enzymatic glucose sensors is discussed.

A controllable honeycomb-like amorphous cobalt sulfide architecture directly grown on the reduced graphene oxide–poly(3,4-ethylenedioxythiophene) composite through electrodeposition for non-enzyme glucose sensing

A facile, controllable two-step electrodeposition route was developed, whereby a honeycomb-like amorphous Co_xS_y architecture was obtained via direct growth on rGO–PEDOT/GCE as an electrode for glucose detection.