Non-enzymatic Electrochemical Biosensor Research Articles

One-pot synthesis of dendritic Pt3Ni nanoalloys as nonenzymatic electrochemical biosensors with high sensitivity and selectivity for dopamine detection

Preparation of Pt-based nanocatalysts with high catalytic activity and exploration of their novel applications have attracted significant interest in the nanoscale field. Herein, we report a facile synthesis of dendritic Pt3Ni nanoalloys and their applications for electrochemical nonenzymatic dopamine biosensors. As a result of their unique structure, the dendritic Pt3Ni nanoalloys show high electrocatalytic activity towards dopamine oxidation. Amperometric dopamine biosensors based on dendritic Pt3Ni nanoalloy microelectrode exhibit a wide linear detection ranges from 0.5 μM to 250 μM with ultrahigh sensitivity, fast response, and excellent selectivity at a potential of 0.3 V in a 0.1 M phosphate buffered solution (pH = 7.2). The limit of detection on dendritic Pt3Ni nanoalloy microelectrodes can decrease down to 10 nM, which is the least concentration of dopamine in serum samples with a value of sensitivity up to 4.6 μA mg-1Pt cm-2. This study shows an effective approach for the development of dendritic Pt3Ni nanoalloys as electrocatalysts for electrochemical nonenzymatic dopamine biosensors.

A non-enzymatic electrochemical biosensor based on SiO2–Au nanoparticles for hemoglobin detection

The novel SiO2–Au nanoparticles (SiO2–Au NPs) with excellent conductivity and biocompatibility were synthesized and used to construct non-enzymatic hemoglobin (Hb) biosensor that could be applied in the analysis of practical samples. The idea and method will provide a new approach for evaluation of quality of meat.

Nonenzymatic Glucose Sensor Based on In Situ Reduction of Ni/NiO-Graphene Nanocomposite.

Ni/NiO nanoflower modified reduced graphene oxide (rGO) nanocomposite (Ni/NiO-rGO) was introduced to screen printed electrode (SPE) for the construction of a nonenzymatic electrochemical glucose biosensor. The Ni/NiO-rGO nanocomposite was synthesized by an in situ reduction process. Graphene oxide (GO) hybrid Nafion sheets first chemical adsorbed Ni ions and assembled on the SPE. Subsequently, GO and Ni ions were reduced by hydrazine hydrate. The electrochemical properties of such a Ni/NiO-rGO modified SPE were carefully investigated. It showed a high activity for electrocatalytic oxidation of glucose in alkaline medium. The proposed nonenzymatic sensor can be utilized for quantification of glucose with a wide linear range from 29.9 μM to 6.44 mM (R = 0.9937) with a low detection limit of 1.8 μM (S/N = 3) and a high sensitivity of 1997 μA/mM∙cm−2. It also exhibited good reproducibility as well as high selectivity.

Electrodeposition of flower-like platinum on electrophoretically grown nitrogen-doped graphene as a highly sensitive electrochemical non-enzymatic biosensor for hydrogen peroxide detection

An efficient non-enzymatic biosensor electrode consisting of nitrogen-doped graphene (N-graphene) and platinum nanoflower (Pt NF) with different N-graphene loadings were fabricated on indium tin oxide (ITO) glass using a simple layer-by-layer electrophoretic and electrochemical sequential deposition approach. N-graphene was synthesized by annealing graphene oxide with urea at 900°C. The structure and morphology of the as-fabricated non-enzymatic biosensor electrodes were determined using X-ray diffraction, field emission electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectra. The as-fabricated Pt NF-N-graphene-modified ITO electrodes with different N-graphene loadings were utilized as a non-enzymatic biosensor electrode for the detection of hydrogen peroxide (H2O2). The behaviors of the hybrid electrodes towards H2O2 reduction were assessed using chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy analysis. The Pt NF-N-graphene-modified ITO electrode with a 0.05mgml−1 N-graphene loading exhibited the lowest detection limit, fastest amperometric sensing, a wide linear response range, excellent stability and reproducibility for the non-enzymatic H2O2 detection, due to the synergistic effect between the electrocatalytic activity of the Pt NF and the high conductivity and large surface area of N-graphene.

Non-enzymatic electrochemical biosensor based on Pt NPs/RGO-CS-Fc nano-hybrids for the detection of hydrogen peroxide in living cells

A highly sensitive non-enzymatic electrochemical sensor based on platinum nanoparticles/reduced graphene oxide-chitosan-ferrocene carboxylic acid nano-hybrids (Pt NPs/RGO-CS-Fc biosensor) was developed for the measurement of hydrogen peroxide (H2O2). The RGO-CS-Fc nano-hybrids was prepared and characterized by UV–vis spectrum, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectrometer and electrochemical impedance spectroscopy. Under optimal experimental conditions, the Pt NPs/RGO-CS-Fc biosensor showed outstanding catalytic activity toward H2O2 reduction. The current response of the biosensor presented a linear relationship with H2O2 concentration from 2.0×10−8M to 3.0×10−6M with a correlation coefficient of R2=0.9968 and with logarithm of H2O2 concentration from 6.0×10−6M to 1.0×10−2M with a correlation coefficient of R2=0.9887, the low detection limit of 20nM was obtained at the signal/noise (S/N) ratio of 3. Moreover, the Pt NPs/RGO-CS-Fc biosensor exhibited excellent anti-interference capability and reproducibility for the detection of H2O2. The biosensor was also successfully applied for the detection of H2O2 from living cells containing normal and cancer cells. All these results prove that the Pt NPs/RGO-CS-Fc biosensor has the potential application in clinical diagnostics to evaluate oxidative stress of different living cells.

Highly sensitive non-enzymatic electrochemical glucose biosensor using a photolithography fabricated micro/nano hybrid structured electrode

In this study, a novel non-enzymatic glucose biosensor based on a simple photolithographic process is proposed. To fabricate the sensor, photoresist AZ-1518 was spin-coated onto a reclaimed silicon wafer, and then, a mask with a hexagonal close-packed circle array was employed for exposure and development to generate a hexagonal close-packed column array of AZ-1518. The diameter of each circle was set as 3μm. Subsequently, a thermal melting process was employed to convert each photoresist column into a photoresist hemisphere. A gold thin film was then sputtered onto the hemisphere array of AZ-1518 to form the sensing electrode. Finally, gold nanoparticles were deposited onto the gold thin film using a self-assembly monolayer method to enhance the sensing area. Measurements showed a 10.2-fold enhancement of the sensing area in comparison with a plain gold electrode. Actual detection of glucose demonstrated that the proposed non-enzymatic glucose biosensor can operate in a linear range of 55.6μM–13.89mM. It had a sensitivity of 749.2μAmM−1cm−2 and a detection limit of 9μM. The novel glucose biosensor proposed here has several advantages such as being enzyme free, simple to fabricate, low cost, and easy to preserve on a long-term basis. Thus, it can feasibly be used for future clinical applications.

Nonenzymatic Electrochemical Biosensor Based on Novel Hydrophilic Ferrocene‐terminated Hyperbranched Polymer and its Application in Glucose Detection

AbstractWe designed a novel water soluble topological structure polymer‐ferrocene‐ terminated hyperbranched polyurethane (HPU‐Fc) with good water solubility. The redox behaviors and the electrochemical kinetics parameters of HPU‐Fcs were explored by cyclic voltammetry (CV) according to electrochemical principle. The topological structure polymer was applied for the design and engineering of non‐enzymatic glucose sensor. The designed sensor showed good response to glucose concentration with good stability, favorable accuracy and high selectivity. The electrode was also used to detect glucose in blood samples, and the glucose contents detected by the electrode were in good agreement with those from the hospital where a common automatic biochemical analyzer (HF240–300) was used. This finding makes HPU‐Fc a promising biosensor for directly sensing glucose.

Sensitive electrochemical nonenzymatic glucose sensing based on anodized CuO nanowires on three-dimensional porous copper foam.

In this work, we proposed to utilize three-dimensional porous copper foam (CF) as conductive substrate and precursor of in-situ growth CuO nanowires (NWs) for fabricating electrochemical nonenzymatic glucose sensors. The CF supplied high surface area due to its unique three-dimensional porous foam structure, and thus resulted in high sensitivity for glucose detection. The CuO NWs/CF based nonenzymatic sensors presented reliable selectivity, good repeatability, reproducibility, and stability. In addition, the CuO NWs/CF based nonenzymatic sensors have been employed for practical applications, and the glucose concentration in human serum was measured to be 4.96 ± 0.06 mM, agreed well with the value measured from the commercial available glucose sensor in hospital, and the glucose concentration in saliva was also estimated to be 0.91 ± 0.04 mM, which indicated that the CuO NWs/CF owned the possibility for noninvasive glucose detection. The rational design of CuO NWs/CF provided an efficient strategy for fabricating of electrochemical nonenzymatic biosensors.

Fabrication of non-enzymatic glucose sensor based on nanocomposite of MWCNTs-COOH-Poly(2-aminothiophenol)-Au NPs

A non-enzymatic electrochemical biosensor was developed as detector of glucose based on an electrode modified with MWCNTs-COOH-Poly(2-aminothiophenol)- Au nanoparticles (MWCNTs-COOH-P2AT-Au NPs). The MWCNTs-COOH-P2AT-Au nanocomposite was synthesized using an in situ reduction process. The prepared nanocomposite was characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET).The MWCNTs-COOH-P2AT-Au NPs shows a good electrochemical activity for electrocatalytic oxidation of glucose in alkaline medium. The proposed biosensor exhibits a broad linear calibration range (0.1–30mM) and a low detection limit of 3.7μM for quantification of glucose. The experiment results also demonstrated that the sensor shows good reproducibility, sensitivity, selectivity and long-term stability, as well as high selectivity. The nanocomposite modified electrode is relatively insensitive to electroactive interfering species which are commonly found in blood samples. The results demonstrated that prepared biosensor have good potential for use as ideal inexpensive amperometric glucose biosensor applicable for complex matrices.

A Novel Real-Time, Mediator-Free, Non-Enzymatic Electrochemical Biosensor for Glutamate Detection

Glutamate is the major excitatory neurotransmitter in the brain, and an excess of glutamate can cause excitotoxicity, which is a common pathological process in many neurologic disorder such as stroke, brain trauma, and brain tumor. Therefore, monitoring glutamate in real time is of critical importance. However, the existing methods for the detection and monitoring glutamate levels are limited. Here in this work, we present a novel mediator-free, non-enzymatic electrochemical biosensor for real-time glutamate monitoring, based on immobilization of genetically engineered periplasmic glutamate binding protein onto gold nanoparticle-modified screen-printed carbon electrodes. Cyclic voltammetry is performed to determine the glutamate concentration in phosphate buffer solution (pH=7.4). The results show an excellent sensitivity with 0.1µM detection limit and the linearity was investigated in the 0.1µM-1µM range of glutamate concentration. The sensor was tested with common interfering substances such as aspartate, glutamine, serine, lysine and ascorbic acid, and exhibited high selectivity toward glutamate over those substances. Figure 1

Electrodeposition of flower-like nickel oxide on CVD-grown graphene to develop an electrochemical non-enzymatic biosensor.

We demonstrated a non-enzymatic cholesterol sensor based on a nickel oxide (NiO) and high quality graphene composite for the first time. Graphene was grown by a chemical vapor deposition technique (CVD). The nanocomposite was fabricated through the electrodeposition of nickel hydroxide onto the surface of the CVD-grown graphene, which was followed by thermal annealing. The successful formation of the NiO/graphene composite was confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. The deposition of flower-like NiO onto the graphene surface was confirmed by scanning electron microscopy. Electrochemical analyses were conducted to investigate the characteristics of the sensor during the detection of cholesterol. The sensor showed a high sensitivity of 40.6 mA μM-1 cm-2, a rapid response time of 5 s, and a low detection of limit of 0.13 μM. We also investigated the effects of common interfering substances on the ability of the sensor to detect cholesterol. Furthermore, we successfully determined the cholesterol in a milk sample using the developed sensor. The composite electrode exhibited excellent detection of cholesterol with good reproducibility and long-term stability owing to the combined effects of NiO and graphene.

NANOSTRUCTURED Pt–Ir NON-ENZYMATIC GLUCOSE SENSORS

Over the past decade, the development of non-enzymatic electrochemical biosensors had thriven at a considerable rate. Compared with the traditional enzymatic electrochemical biosensors, the non-enzymatic electrochemical biosensors have the advantages of higher sensitivity and stability. Recently, plenty of researches have devoted to synthesizing new materials, such as bimetallic nanoparticles, and also develop specific nanostructures on the sensor surface to solve the problem of poisoning and increase the selectivity. This work develops two non-enzymatic glucose sensors that are based on nanostructured Pt – Ir films which were deposited by electrodeposition. Because of the relatively high deposition current density, bubbles produced vigorously on the working electrode surface. This phenomenon results in leaf-like nanostructure formed naturally on the surface of the working electrode and further increased the catalytic reaction area. Besides, as determined by the sampling analysis method that is developed herein, the presented Pt – Ir sensors mitigate the current drifting problem which is easily observed when a constant potential is applied in an amperometric glucose detection. Furthermore, the presented Pt – Ir sensors show high sensitivity and stability in 1X PBS (0.15 M NaCl ) at 37°C in the glucose concentration range of 1–12 mM. Therefore, the presented non-enzymatic glucose sensors not only provide great potential in biomedical applications, such as homecare products, but can also be adapted for the biological application, such as continuous cell culture monitoring.

Preparation of nickel nanoparticle/graphene composites for non-enzymatic electrochemical glucose biosensor applications

A novel non-enzymatic electrochemical sensor device was fabricated for glucose detection based on nickel nanoparticles/graphene nanosheets (NiNPs/GNs) composites, which were synthesized through in situ chemical reduction procedure. The NiNPs/GNs composites modified electrode exhibited high electrocatalytic activity and good response toward the oxidation of glucose in alkaline solution, attributing to the synergistic effect of GNs and NiNPs. At detection potential of +0.5V, the biosensor exhibited high sensitivity of 865μAmM−1cm−2 for glucose with a wide linear range from 5μM to 550μM as well as a low detection limit of 1.85μM (at a signal-to-noise ratio(S/N) of 3). The good analytical performance, low cost and simple fabrication procedure make this novel electrode material promising for the development of effective non-enzymatic glucose sensor.

Synthesis of CuO/graphene nanocomposites for nonenzymatic electrochemical glucose biosensor applications

Glucose detection is of great importance in the fields of biological, environmental, and clinical analyses. In this study, CuO/graphene nanocomposites have been synthesized for nonenzymatic electrochemical glucose biosensors to avoid the disadvantages of enzymatic sensors. Transmission electron microscopy images show that the spherical and size-selected CuO nanoparticles were well dispersed on the surface of graphene. For the amperometric glucose detection, the low detection limit of 1μmolL−1 with wide linear range from 1μmolL−1 to 8mmolL−1 can be obtained using the CuO/graphene (CuOG)-modified glassy carbon (GC) electrode with a low loading. Under the applied potential of +0.60V vs. Ag/AgCl, the optimal CuOG-modified GC electrode exhibits a sensitivity of 1065μAmmol−1Lcm−2. With such good analytical performance from simple process, it is believed that CuO/graphene nanocomposites are promising for the development of cost-effective nonenzymatic electrochemical glucose biosensors.

In situ spontaneous reduction synthesis of spherical Pd@Cys-C60nanoparticles and its application in nonenzymatic glucose biosensors

Novel spherical Pd@Cys-C(60) nanoparticles were synthesized using an in situ spontaneous reduction process without any other reducing agent. A nonenzymatic electrochemical biosensor was developed for the detection of glucose based on the spherical nanoparticles film.

Synthesis of Graphene/Pt Nanocomposites for Nonenzymatic Electrochemical Glucose Biosensor Applications

not Available.

In situ synthesis of palladium nanoparticle–graphene nanohybrids and their application in nonenzymatic glucose biosensors

A nonenzymatic electrochemical biosensor was developed for the detection of glucose based on an electrode modified with palladium nanoparticles (PdNPs)-functioned graphene (nafion–graphene). The palladium nanoparticle–graphene nanohybrids were synthesized using an in situ reduction process. Nafion–graphene was first assembled onto an electrode to chemically adsorb Pd 2+. And Pd 2+ was subsequently reduced by hydrazine hydrate to form PdNPs in situ. Such a PdNPs–graphene nanohybrids-based electrode shows a very high electrochemical activity for electrocatalytic oxidation of glucose in alkaline medium. The proposed biosensor can be applied to the quantification of glucose with a wide linear range covering from 10 μM to 5 mM ( R = 0.998) with a low detection limit of 1 μM. The experiment results also showed that the sensor exhibits good reproducibility and long-term stability, as well as high selectivity with no interference from other potential competing species.

Nonenzymatic Electrochemical Glucose Biosensor Based on Ionic Liquid and Nickel Nanoparticles

Nonenzymatic Electrochemical Glucose Biosensor Based on Ionic Liquid and Nickel Nanoparticles