Non-enzymatic Electrochemical Sensor Research Articles

One-step chronoamperometric synthesis of S, N co-doped graphene oxide electrodes for nonenzymatic electrochemical H2O2 sensor

One-step chronoamperometric synthesis of S, N co-doped graphene oxide electrodes for nonenzymatic electrochemical H2O2 sensor

A non-enzymatic electrochemical sensor based on zinc oxide/reduced graphene oxide (ZnO/rGO) nanocomposite for effective detection of urea

Monitoring urea levels is essential for detecting water and soil pollution and diagnosing urea cycle disorder-related diseases. The present study addresses the need for an efficient, accurate, and cost-effective detection method by developing an electrochemical sensor using ZnO/rGO nanocomposites. The sensor’s performance is evaluated through cyclic voltammetry, differential pulse voltammetry, and amperometry, with different weight ratios of ZnO and rGO (3:1, 1:1, and 1:3). The results show that the ZnO/rGO (1:1) nanocomposite modified electrode exhibits remarkable sensitivity (850.15 μA-1 mM−1 cm−2), a low limit of detection (0.07 μM), excellent selectivity, and long-term stability for urea detection. Developed sensor leverages the advantages of electrochemical sensing, including simplicity, rapid response, high sensitivity, and good selectivity, making it a promising solution for environmental monitoring and medical diagnostics.

A Multi-Channel Handheld Diagnostic Device Based on Green Biomimetic Material for Point-of-Care Testing of Vitamin C in Human Fluids.

In the era of "Great Health", maintaining an appropriate level of vitamin C is crucial for human health as it directly impacts the proper functioning of the immune system. In this study, a handheld nonenzymatic electrochemical sensor based on biomimetic material prussian blue functionalized polydopamine is proposed for point-of-care testing (POCT) of vitamin C in human fluids. Particularly, Prussian blue, known as a bio-antidote, and polydopamine, a main component of cuttlefish ink, ensure the safety and reliability of home testing. The experimental results quantitatively demonstrate that this electrochemical POCT sensor enables rapid and accurate determination of vitamin C with a wide linear detection range from 0.2 to 200µm, a low limit of detection at 0.03µm, and high sensitivity at 0.33µAµm-1cm-2. More importantly, the performance evaluation using human urine and saliva samples confirms satisfactory accuracy and recovery rates for vitamin C determination by this electrochemical POCT sensor. Thus, the proposed handheld electrochemical POCT sensor holds potential utility as an affordable tool for VC determination and home-based healthcare.

An Enzyme-Free Impedimetric Sensor Based on Flower-like NiO/Carbon Microspheres for L-Glutamic Acid Assay.

This research introduces a non-enzymatic electrochemical sensor utilizing flower-like nickel oxide/carbon (fl-NiO/C) microspheres for the precise detection of L-glutamic acid (LGA), a crucial neurotransmitter in the field of healthcare and a frequently utilized food additive and flavor enhancer. The fl-NiO/C were synthesized with controllable microstructures using metal-organic frameworks (MOFs) as precursors followed by a simple calcination process. The uniformly synthesized fl-NiO/C microspheres were further characterized using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and field emission scanning electron microscopy (FE-SEM). The fl-NiO/C was utilized as a modifier on the surface of a glassy carbon electrode, and an impedimetric sensor based on electrochemical impedance spectroscopy (EIS) was developed for the detection of LGA. The proposed sensor demonstrated excellent catalytic activity and selectivity towards LGA across a broad concentration range of 10-800 μM with a sensitivity of 486.9 µA.mM-1.cm-2 and a detection limit of 1.28 µM (S/N = 3). The sensor was also employed to identify LGA in blood plasma samples, yielding results that align with those obtained through HPLC. This achievement highlights the potential of fl-NiO/C microspheres in advancing cutting-edge biosensing applications.

A Wearable Electrochemical Sensor Based on Single-Atom Pt Anchored on Activated NiCo-LDH/Ti3C2Tx for Real-Time Monitoring of Glucose.

Wearable, noninvasive sweat sensors enable real-time monitoring of metabolites in human health management. However, the commercial enzyme-based and currently nonenzymatic glucose sensor represents sluggish glucose oxidation kinetics and a narrow sensing range. Rational design of sensitive materials is significant yet faces a huge challenge. Herein, we construct a single-atom Pt supported on NiCo-LDH/Ti3C2Tx heterostructures (Pt1-NiCo-LDH/Ti3C2Tx) as the nonenzymatic electrochemical glucose sensor sensitive materials for selective detection of glucose level in human sweat. The obtained Pt1-NiCo-LDH/Ti3C2Tx with improved structural stability and enhanced charge transfer efficiency shows a low oxidation peak potential of 0.49 V, high sensitivity of 506.6 μA mM-1 cm-2, a low detection limit of 0.035 μM, and long-term stability toward the glucose detection. The wearable sensor, coupled with a wireless transmission module and a signal processing chip, is used for real-time perspiration glucose monitoring during outdoor exercise. The result is comparable to that of high-performance liquid chromatography (HPLC). This research provides a new paradigm for designing a wearable nonenzymatic electrochemical glucose sensor, enabling noninvasive real-time monitoring of glucose concentrations in human sweat.

An electrochemical sensor for simultaneous voltammetric detection of ascorbic acid and dopamine enabled by higher electrocatalytic activity of co-modified MCM-41 mesoporous molecular sieve

It is of great value to develop effective methods for accurately and simultaneously detecting ascorbic acid (AA) and dopamine (DA) in the field of biochemistry. This work reports a nonenzymatic electrochemical sensor for the simultaneous detection of AA and DA by employing a Co-modified MCM-41 (CoMCM-41) mesoporous molecular sieve as an efficient electrocatalytic material, which was synthesized by a two-step hydrothermal method. Subsequently, the high structural organization of the CoMCM-41 mesoporous structure was characterized, and the electrocatalytic performance of CoMCM-41 toward AA and DA oxidation was then evidenced by the catalytic effect of different electrodes modified with or without CoMCM-41. By virtue of the superior electrocatalytic activity of the CoMCM-41, a much wider peak potential difference (ΔEpa) of 310 mV was obtained for the oxidation of AA and DA in their mixture solution, and the parameters that influenced the electrochemical signals of the modified electrode were also optimized. Under optimal conditions, a good linear response to AA and DA was observed on the CoMCM-41 modified electrode. For individual detection of AA and DA, the linear ranges were 7 ~ 105 μM and 5 ~ 110 μM respectively, while the linear response range was 20 ~ 100 μM for simultaneous detection of AA and DA. Satisfactory recovery results were obtained when the fabricated sensor was applied to determine AA in orange juice and DA in madopar pill samples.

Non-enzymatic electrochemical detection of sarcosine in serum of prostate cancer patients by CoNiWBO/rGO nanocomposite

Selective and sensitive sarcosine detection is crucial due to its recent endorsement as a prostate cancer (PCa) biomarker in clinical diagnosis. The reduced graphene oxide-cobalt nickel tungsten boron oxides (CoNiWBO/rGO) nanocomposite is developed as a non-enzymatic electrochemical sensor for sarcosine detection in PCa patients’ serum. CoNiWBO/rGO is synthesized by the chemical reduction method via a one-pot reduction method followed by calcination at 500 °C under a nitrogen environment for 2 h and characterized by UV-Vis, XRD, TGA, and SEM. CoNiWBO/rGO is then deposited on a glassy carbon electrode, and sarcosine sensing parameters are optimized, including concentration and pH. This non-enzymatic sensor is employed to directly determine sarcosine in serum samples. Differential pulse voltammetry (DPV) and linear sweep voltammetry (LSV) are employed to monitor the electrochemical behavior where sarcosine binding leads to oxidation. Chronoamperometric studies show the stability of the developed sensor. The results demonstrate a wide linear range from 0.1 to 50 µM and low limits of detection, i.e., 0.04 µM and 0.07 µM using DPV and LSV respectivel. Moreover, the calculated recovery of sarcosine in human serum of prostate cancer patients is 78–96%. The developed electrochemical sensor for sarcosine detection can have potential applications in clinical diagnosis.

ZnFe(PBA)@Ti3C2Tx nanohybrid-based highly sensitive non-enzymatic electrochemical sensor for the detection of glucose in human sweat

The ZnFe prussian blue analogue [ZnFe(PBA)] was infused with Ti3C2Tx (MXene) denoted as ZnFe(PBA)@Ti3C2Tx and was prepared by an in-situ sonication method to use as a non-enzymatic screen printed electrode sensor. The advantage of non-enzymatic sensors is their excellent sensitivity, rapid detection, low cost and simple design. The synthesized ZnFe(PBA)@Ti3C2Tx was characterized for its physical and chemical characterization by XRD, Raman, XPS, EDAX, and FESEM analysis. It possessed multiple functionalized layers and a cubic structure in the nanohybrid. Further, the sensor was investigated by using electroanalytical studies such as cyclic voltammetry and chronoamperometry analysis. The enhanced surface area with a cubic structure of ZnFe(PBA) and the excellent electrical response of Ti3C2 nanosheet support the advancement of a non-enzymatic electrochemical glucose sensor with improved sensitivity of 973.42 µA mM−1 cm−2 with the limit of detection (LOD) of 3.036 µM (S/N = 3) and linear detection range (LDR) from 0.01 to 1 mM.

Fabrication of a novel non-enzymatic glucose sensor based on ruthenium supported by a combination of PBA nanocubes and MOF nanosheets

The development of novel catalysts with high catalytic activity is of high importance of electrochemical non-enzymatic glucose sensing. Herein, a sensitive non-enzymatic electrochemical sensor (Ru@NiCo-MOF/NiFe-PBA) has been synthesized using a fast, simple and eco-friendly method. The high stability of PBA and the large specific surface area (two-dimensional nanosheet structure) of MOF support the excellent electrochemical performance, while the incorporation of the highly active metal Ru enhances the electrochemical activity even more. The results reveal that the sensitivities of the sensor are 1070.77 and 487.62 μA mM−1 cm−2, corresponding to linear ranges of 0.01–0.67 mM and 0.67–5.07 mM, respectively. Meanwhile, the sensor has a low detection limit (0.446 μM) and a short response time (2 s), making it a strong candidate for non-enzymatic glucose sensors. The successful detection of glucose in saliva further demonstrates its potential for practical applications. Therefore, Ru@NiCo-MOF/NiFe-PBA will make an impact in the field of glucose monitoring and detection.

Highly Specific Non-Enzymatic Electrochemical Sensor for the Detection of Uric Acid Using Carboxylated Multiwalled Carbon Nanotubes Intertwined with GdS-Gd2O3 Nanoplates in Human Urine and Serum.

Herein, the electrochemical sensing efficacy of carboxylic acid functionalized multiwalled carbon nanotubes (C-MWCNT) intertwined with coexisting phases of gadolinium monosulfide (GdS) and gadolinium oxide (Gd2O3) nanosheets is explored for the first time. The nanocomposite demonstrated splendid specificity for nonenzymatic electrochemical detection of uric acid (UA) in biological samples. It was synthesized using the coprecipitation method and thoroughly characterized. The presence of functional groups and disorder in the as-synthesized nanocomposite are confirmed using Fourier transform infrared spectroscopy and Raman spectroscopy. Furthermore, field emission scanning electron microscopy, high-resolution transmission electron microscope, X-ray powder diffraction, and X-ray photoelectron spectroscopy provides a clear understanding of the morphology, coexisting phases, and elemental composition of the as-synthesized nanocomposites. The differential pulse voltammetry technique was utilized to elaborate the electrochemical sensing of UA using a GdS-Gd2O3/C-MWCNT modified glassy carbon electrode (GCE), The sensor showed an enhanced current response by more than 2-fold compared to bare GCE. Also, the sensor's performance was further improved by dispersing the nanocomposite in an ionic liquid with the exceptional reproducibility (SD = 0.0025, n = 3). The fabricated UA sensor GdS-Gd2O3/C-MWCNT/IL/GCE demonstrated a wide linear detection range from 0.5-30 μM and 30-2000 μM, effectively covering the entire physiological range of UA in biological fluids with a limit of detection (LOD) of 0.380 μM (+3SD of blank) and a sensitivity of 356.125 μA mM-1 cm-2. Moreover, the electrodes exhibited storage stability for 2 weeks with decrease in zero-day current by only 4.5%. The sensor was validated by quantifying UA in 12 unprocessed clinical human urine and serum samples, and its comparison with the gold standard test yielded remarkable results (p < 0.05). Hence, the proposed nonenzymatic electrochemical UA sensor is selective, sensitive, reproducible, and stable, making it reliable for point-of-care diagnostics.

Study on the performance of MoS2/Au composites for non-enzymatic electrochemical glucose detection

Abstract Glucose concentration is considered an indicator for the diagnosis of diabetes, highlighting the importance of accurate glucose detection. Non-enzymatic electrochemical sensors have been extensively studied for glucose detection applications, with nanocomposites composed of molybdenum disulfide (MoS2) and gold nanoparticles (Au NPs) demonstrating high catalytic activity. In this study, a nanocomposite material composed of MoS2 and Au NPs (MoS2/Au) was synthesized and employed to construct a non-enzymatic electrochemical glucose biosensor. The detection limit of this sensor was explored, reaching as low as 1 mM. Additionally, compared to MoS2, the MoS2/Au nanocomposite exhibited a higher linear correlation coefficient and sensitivity, with a linear range of 1–25 mM and a sensitivity of 417.556 μA mM−1 cm−2. The sensor demonstrated excellent performance within the range of human blood glucose concentrations, showing potential for real-time monitoring and precise measurement of glucose levels. Furthermore, it exhibited good stability and reproducibility. These findings indicate the potential applications of MoS2/Au in biosensors and immunoassays.

Dibenzosuberenone-based non-enzymatic electrochemical sensors

Dibenzosuberenone-based non-enzymatic electrochemical sensors

Gold Microflower Modified Screen‐Printed Carbon Electrode for the Electrochemical Detection of Lactic Acid in Blood and Sweat

AbstractA nonenzymatic electrochemical lactic acid sensor was fabricated by electrodepositing gold microflowers on a screen‐printed carbon electrode and used to determine lactic acid in human serum and sweat quantitatively. Extensive voltammetric studies with lactic acid in phosphate‐buffer saline (PBS) and the analysis of the reduction product proved beyond doubt that lactic acid undergoes two‐electron reduction to form lactaldehyde. The reduction current increased quantitively with lactic acid concentration from 0.5–8.5 mM in 0.1 M PBS. The sensor showed excellent sensitivities of 1243 μA mM−1 cm−2 and 2752 μA mM−1 cm−2 in two linear ranges, 0.5–2.5 mM and 2.5–8.5 mM, respectively with a detection limit of 0.012±0.0014 mM. The performance of the sensor was validated by estimating lactic acid in human serum and the sweat generated through physical exercise. The estimated lactic acid concentrations are in good agreement with clinical analysis data. This indicates the potential applicability of the sensor in the point‐of‐care detection of lactic acid.

Development Of Non-Enzymatic Electrochemical P-Nitrophenol Sensor Based On Carboxylated Graphene Oxide Modified Glassy Carbon Electrode

The current work reports a new electrochemical p-nitrophenol (p-NP) sensor which depends upon the carboxyl functionalized graphene oxide (GO-COOH) modified of glassy carbon electrode (GCE). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were performed to examine the morphology of GO-COOH. The GO-COOH/GCE sensor was electrochemically characterized by means of chronoamperometry, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). A distinct cathodic peak of p-NP was seen on the GO-COOH/GCE in 0.1 M phosphate buffer solution (pH 6.5). The sensor displayed three dynamic linear ranges for p-NP under optimum conductions. The linear detection ranges were 2.0×10-7 - 2.95×10-6 M, 2.95×10-6 – 2.74×10-4 M, and 2.74×10-4 – 7.25×10-4 M with the sensitivities of 39622.1 A/Mm2, 9959.3 A/Mm2, and 6395 A/Mm2, respectively. It was found that detection limit (LOD) was 5.3×10-8 M at a signal to noise ratio of 3. The GO-COOH/GCE demonstrated satisfactory performance factors such as selectivity and repeatability. Additionally, the GO-COOH/GCE sensor was demonstrated to be utilized to electrochemically determine p-NP in a variety of water samples.

Phenylalanine: Amino Acid Metal Non-Enzymatic Electrochemical Voltammetric Sensors

This study presents a comparative analysis of non-enzymatic electrochemical voltammetric sensors, utilizing phenylalanine amino acid metal complexes (M: Ni, Zn, and Co) Polyaniline (PANI) nanocomposites (NCs). The PANI: Zn(Phala)2 NCs-based sensor detected dopamine (DA) with a sensitivity of 101.18 μAμM−1 cm−2. The limit of detection (LOD) for the PANI: Zn(Phala)2 NCs-based sensor was calculated as 0.391 μM. This exceptional sensitivity makes the PANI: Zn(Phala)2 NCs-based sensor highly promising for potential integration into biomedical test kits. To gain deeper insights into the structural properties of the PANI NCs, scanning electron microscopy (SEM), artificial-intelligence-based SEM, and Fourier transform infrared spectroscopy (FTIR) were employed for characterization. FTIR characterization provided insights into the functional groups of the NCs. The results of this comparative investigation a significant advancement in the field of PANI-based electrochemical sensors designed for DA sensing. The PANI: Zn(Phala)2 NCs-based sensor show great promise for a range of advanced sensing applications. The Z value of the PANI: Zn(Phala)2 NCs-based sensor is the lowest among the tested materials, indicating that the conductivity of the PANI: Zn(Phala)2 layer is higher than that of other active layers. Consequently, the PANI: Zn(Phala)2 NCs-based sensor achieved higher sensitivity in DA detection.

Highly stable and selective determination of glucose by a modified glassy carbon electrode based on micro-rods [Ni(HL)NCS] complex as a novel modifier

Non-enzymatic glucose sensors have acquired a lot of attention, where the modifier materials perform as an electrocatalyst instead of an enzyme on the surface of electrodes. More active sites, increased synergistic reactions, and expanded contacts between the electrolyte and the catalyst are essential to enhance catalytic performances. Numerous efforts have been made to fabricate novel non-enzymatic glucose sensors with electrode modification strategies. Herein, a non-enzymatic electrochemical glucose sensor was constructed by a modified glassy carbon electrode (GCE) based on micro-rods [Ni(HL)NCS] complex (MR-NiC/GCE) as a novel modifier for the glucose detection. In alkali media, the non-enzymatic glucose sensor showed a linear dynamic range (LDR) of 100-1100 µM with an excellent limit of detection (LOD) of 15.8 μM (S/N= 3). The proposed sensor demonstrated remarkable stability (after recording 50 continuous cycles), good reproducibility, and significant anti-interference performance toward fructose (Fru), ascorbic acid (AA), dopamine (DA), citric acid (CA), uric acid (UA) and sucrose. According to this study, complexes can be an excellent suggestion to fabricate non-enzymatic glucose sensors.

A novel Au-NPs/DBTTA nanocomposite-based electrochemical sensor for the detection of ascorbic acid (AA)

PurposeAscorbic acid, a water-soluble antioxidant, is an essential component of the human diet and is known for its potent antioxidant properties against several diseases. In recent years, there has been increasing interest in the development of nonenzymatic sensors due to their simplicity, efficiency and excellent selectivity. The aim of this study is to present a selective and sensitive method for the detection of ascorbic acid in aqueous system using a new electrochemical non-enzymatic sensor based on a gold nanoparticles Au-NPs-1,3-di(4-bromophényl)-5-tert-butyl-1,3,5-triazinane (DBTTA) composite.Design/methodology/approachUsing the square wave voltammetry (SWV) technique, a series of Au-NPs-DBTTA composites were successfully developed and investigated. First, DBTTA was synthesized via the condensation of tert-butylamine and a4-bromoaniline. The structure obtained was identified by IR, 1H NMR and 13C NMR analysis. A glassy carbon electrode (GCE) was modified with 10–1 M DBTTA dissolved in an aqueous solution by cyclic voltammetry in the potential range of 1–1.4 V. Au-NPs were then deposited on the DBTTA/GCE by a chronoamperometric technique. SWV was used to study the electrochemical behavior of the modified electrode (DBTTA/Au-NPs/GCEs). To observe the effect of nanoparticles, ascorbic acid in a buffer solution was analyzed by SWV at the modified electrode with and without gold nanoparticles (Au-NPs).FindingsThe DBTTA/Au-NPs/GCE showed better electroanalytical results. The detection limit of 10–5 M was obtained and the electrode was proportional to the logarithm of the AA concentration in the range of 5 × 10−3 M to 1 × 10−1 with very good correlation parameters.Originality/valueIt was also found that the elaborated sensor exhibited reproducibility and excellent selectivity against interfering molecules such as uric acid, aspartic acid and glucose. The proposed sensor was tested for the recognition of AA in orange, and satisfactory results were obtained.

NiCo layered double hydroxide nanosheet arrays constructed via in-situ plasma etching as non-enzymatic electrochemical sensor for glucose in food

The design and construction of an efficient non-enzymatic glucose electrochemical sensor is of great significance for food quality assessment. Here, we have developed a method to fabricate highly efficient catalytic electrodes for glucose sensing in alkaline. This method utilizes microplasma assistance during the in-situ etching of NiCo layered double hydroxide nanosheet arrays on nickel foam (NiCo-LDH/NF). The NiCo-LDH nanosheets possessed uniform dispersion without agglomeration, high electrochemically active surface area, and excellent electron transfer efficiency (the electron transfer coefficient (α) up to 0.91, the catalytic rate constant (k) was 2.44 × 106 cm3 mol−1 s−1). The NiCo-LDH/NF-based non-enzymatic glucose sensor exhibits the broad linear range (0.4–150 μM), high sensitivity (98000 μA mM−1 cm−2), and the low detection limits (48.76 nM) with satisfactory reproducibility and selectivity. This work developed a simple and rapid in-situ approach for constructing non-enzymatic electrochemical sensors with high sensitivity.

Direct detection of ethyl carbamate in baijiu by molecularly imprinted electrochemical sensors based on perovskite and graphene oxide

Ethyl carbamate (EC), a carcinogen commonly found in Baijiu, requires an efficient detection method for quality control and monitoring. This study introduces a novel molecularly imprinted electrochemical sensor for sensitive and selective EC detection. We proposed a simple sol-gel method for the growth of perovskite-structured lanthanum manganate (LaMnO3) on graphene oxide (GO). A non-enzymatic electrochemical sensor was developed by coating a molecularly imprinted polymer synthesized via precipitation polymerization onto the surface of LaMnO3@GO. LaMnO3, with its superior three-dimensional nanocube structure, demonstrated excellent electrocatalytic activity, while the addition of GO provided a large specific surface area. The results indicate that the developed sensor exhibits exceptional recognition ability and electrochemical activity, which is attributed to the high affinity of LaMnO3@GO@MIP for EC. The sensor displays a broad linear range from 10 to 2000 μM, with a detection limit as low as 2.18 μM and long-term durability of 28 days. Notably, it demonstrates excellent selectivity, reproducibility, and stability even under different interference conditions. The sensor was successfully used to determine EC in real Baijiu samples. Overall, the sensor has broad application prospects for detecting trace contaminants in the field of food safety.

Sensor for Real-Time Glucose Measurement in Aqueous Media based on Nanomaterials Incorporating an Artificial Neural Network Algorithm on a System-On-Chip

The aim of this paper is to present the development of a real-time measurement system for glucose in aqueous media. The proposed system incorporates two lines of research: i) design, synthesis, and implementation of a non-enzymatic electrochemical sensor of Multi-Walled Carbon Nanotubes with Copper nanoparticles (MWCNT-Cu) and ii) design and implementation of a machine learning algorithm based on an Artificial Neural Network Multilayer Perceptron (ANN-MLP), which is embedded in an ESP32 SoC (System on Chip). From the current data that is extracted in real-time during the oxidation-reduction process to which an aqueous medium is subjected, it feeds the algorithm embedded in the ESP32 SoC to estimate the glucose value. The experimental results show that the nanostructured sensor improves the resolution in the amperometric response by identifying an ideal place for data collection. For its part, the incorporation of the algorithm based on an ANN embedded in a SoC provides a level of 97.8 % accuracy in the measurements. It is concluded that incorporating machine learning algorithms embedded in low-cost SoC in complex experimental processes improves data manipulation, increases the reliability of results, and adds portability.