Sensitivity For Detection Of Dopamine Research Articles

Screen-printed analytical strip constructed with bacteria-templated porous N-doped carbon nanorods/Au nanoparticles for sensitive electrochemical detection of dopamine molecules

Dopamine (DA) as an important neurotransmitter plays an important role in physiological activities, and its abnormal level can cause diseases such as Parkinson's disease. However, the clinical analysis of DA mainly relies on time-consuming and expensive liquid chromatography and molecular spectrometer. We present here a design and fabrication of inexpensive strip sensor constructed from screen printed electrodes for sensitive and selective detection of DA. The ink used for printing the strips contains Shewanella putrefaciens-templated porous N-doped carbon nanorods (N-doped CN) and Au nanoparticles (Au NPs), in which the N-doping enhances CN's negative charge to electrostatically attract the positively charged DA with strong adsorption for achieving fast electron transfer. Moreover, results indicate that the Au NPs impregnation in N-doped CN renders much more catalytic reaction sites toward DA oxidation current. The strip sensor exhibits high sensitivity for DA detection with a broad linear range of 0.02–700 μM and a low detection limit of 0.007 μM as well as good selectivity and superior flexibility for great potential in wearable applications. The strip sensor further performs an accurate detection of DA in human serum, providing a powerful analytical tool for diagnosis of DA related diseases in clinical analysis.

Hemin-doped metal-organic frameworks based nanozyme electrochemical sensor with high stability and sensitivity for dopamine detection.

This study reports a new type of artificial nanozyme based on Hemin-doped-HKUST-1 (HKUST-1, also referred to as MOF-199; a face-centered-cubic MOF containing nanochannels) as a redox mediator for the detection of dopamine (DA). Hemin-doped-HKUST-1 was successfully synthesized by one-pot hydrothermal method, which was combined with reduced graphene oxide (rGO) modified on a glassy carbon electrode (GCE) to construct a sensor (Hemin-doped HKUST-1/rGO/GCE). The morphology and structure of Hemin-doped-HKUST-1 were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and infrared spectra (IR) techniques. The Hemin-doped HKUST-1/rGO nanozyme showed an excellent electrocatalytic activity for DA oxidation, which is due to the enhanced Hemin activity through the formation of a metal–organic framework (MOFs) and the synergy between the Hemin-doped HKUST-1 and rGO in nanozyme. The resulted sensor exhibited a high sensitivity of 1.224 μA μM−1, with a lower detection limit of 3.27 × 10−8 M (S/N = 3) and a wide linear range of 0.03–10 μM for DA detection. In addition, due to the stabilizing effect of MOFs on heme, the sensor showed satisfactory stability and has been successfully applied to the detection of DA in serum samples, indicating that this work has potential value in clinical work.

Electrostatic self-assembly to fabricate ZnO nanoparticles/reduced graphene oxide composites for hypersensitivity detection of dopamine

This study introduces the self-assembly method to fabricate Zinc Oxide (ZnO) decorated reduced Graphene Oxide (ZnO-rGO) composites with higher sensitive for detection of dopamine (DA), one of the most common biomarkers of Parkinson’s disease. The approach is reported to self-assembly Graphene Oxide (GO) and ZnO nanoparticles (NPs) modified by 3-aminopropyl triethoxysilane (APTES), forming ZnO-GO composites, then ZnO-rGO composites were obtained by electrochemical reduction of ZnO-GO composites. Utilizing differential pulse voltammetry (DPV), we found ZnO-rGO composites fabricated by the method of self-assembly reduced the agglomeration of ZnO and GO and showed a higher sensitivity for detection of DA than the dopamine electrochemical sensor previously reported. The fabricated sensor showed a linear dynamic range on 5–70 μM with a LOD of 0.167 μM (S/N = 3) and a sensitivity of 458nA/μM in response to DA. Finally, the as-prepared ZnO-rGO composite displayed an excellent detection recovery of 98.8 ~ 101.2% in human serum.

Electrochemical and quantum chemical studies of cetylpyridinium bromide modified carbon electrode interface for sensor applications

In this work, both electrochemical experiments and quantum chemical simulations were performed to explore an important topic namely the cetyl pyridinium bromide (CPB) modified carbon paste electrode (CPBMCPE) employed for detection of dopamine (DA) and uric acid (UA). The electrode was found to display excellent electrocatalysis and increased surface area for simultaneously detecting DA and UA via decreasing their oxidation overpotentials when compared to the bare electrode, demonstrating high selectivity and sensitivity. Although surfactants can increase carbon-electrode sensitivity for DA detection, its mechanism remains elusive. Here, we used quantum chemical models to tackle the interface at which sensing (electron transfer) takes place. Our computational results reveal that the charged cationic head of CPBs can offer an additional electron transfer site at the CPBMCPE interface such that the sensing ability of CPE is comparatively improved after the CPB modification. Such electrodes were also applied for sensing UA in a urine sample, reaching a satisfactory of recovery up to 98%. To comprehend, we also modeled the power of electron-accepting and donating of CPB with other commonly used cationic surfactants.

Timed Electrodeposition of PEDOT:Nafion onto Carbon Fiber-Microelectrodes Enhances Dopamine Detection in Zebrafish Retina

Carbon fiber-microelectrodes (CFMEs) are one of the standards for the detection of neurotransmitters such as dopamine (DA). In this study, we demonstrate that CFMEs electrodeposited with poly (3,4-ethylenedioxythiophene) (PEDOT) in the presence of Nafion exhibit enhanced sensitivity for DA detection. Scanning electron microscopy (SEM) revealed the smooth outer surface morphologies of polymer coatings, which filled in the ridges and grooves of the bare unmodified carbon electrode and energy-dispersive X-ray spectroscopy (EDX) confirmed PEDOT:Nafion incorporation. PEDOT:Nafion coated CMFEs exhibited a statistically enhanced two-fold increase in DA sensitivity compared to unmodified microelectrodes, with stability and integrity of the coated microelectrodes maintained for at least 4 h. A scan rate test revealed a linear relationship with peak DA oxidative current (5 μM), indicating adsorption control of DA to the surface of the PEDOT:Nafion electrode. As proof of principle, PEDOT:Nafion coated electrodes were used to detect potassium chloride (KCl)-induced DA release in zebrafish (Danio rerio) retinal tissue ex vivo, thus illustrating their applicability as biosensors.

A novel popamine-imprinted chitosan/CuCo2O4@carbon/three-dimensional macroporous carbon integrated electrode

A novel Cu–Co-zeolite imidazole framework (Cu–Co-ZIF)-derived CuCo2O4@carbon nanocomposites supported on three-dimensional porous carbon (3D-KSC) were prepared to develop molecularly imprinted electrochemical sensors for sensing dopamine (DA). Firstly, polyhedral Cu–Co-ZIF was synthesized at room temperature and uniformly arrayed on 3D-KSC, and then the CuCo2O4@carbon nanostructure was obtained by high-temperature carbonization under nitrogen atmosphere. Finally, the molecularly imprinted polymer (MIPs) DA-imprinted chitosan was covered by potentiostatic electrodeposition to obtain the MIPs/CuCo2O4@carbon/3D-KSC integrated electrode. The results showed 15 μm-sized polyhedral Cu–Co-ZIF crystals were transformed into smaller irregular porous CuCo2O4@carbon nanocomposites with rough surface by calcination. Here, the produced 5 nm-sized CuCo2O4 crystals were uniformly embedded into the N-doped porous carbon frameworks. Various experimental conditions including the amount of Cu–Co-ZIF grew on 3D-KSC, calcination temperature, electrodepositing time of MIPs, the eluted time of template molecule and the pH of electrolyte were explored. The as-prepared MIPs/CuCo2O4@carbon/3D-KSC integrated electrode exhibited excellent anti-interference ability and good stability. The sensitivity for DA detection was 720.8 μA mM−1cm−2, the detection range was 0.51 μM–1.95 mM, and the detection limit was 0.16 μM.

High Temporal Resolution Bio-Sensing Using Nitrogen-Incorporated Nanodiamond Ultra-Microelectrode Array by Fast Scan Cyclic Voltammetry

Microelectrodes have several benefits over macroelectrodes by virtue of their size. Their advantages include lower capacitance and uncompensated resistance loss, enhanced temporal and spatial resolution, usability in highly resistive media, increased signal to noise ratio. An array of microelectrodes can deliver these benefits along with signal amplification. Neurotransmitters, such as dopamine, undergo rapid fluctuations in concentrations occurring at a sub-second time scale. Real-time monitoring and measurement of these concentration changes, in-vivo or in-vitro, requires the use of ultra-microelectrode arrays (UMEAs). A nitrogen incorporated nanodiamond UMEA was fabricated using silicon microfabrication technology and microwave PECVD process. The array of 2500 UMEs, projects above the SiO2 insulating matrix, thus providing a 3-dimensional surface. Fast scan cyclic voltammetry at 300V/s was used to examine the temporal response and sensitivity for dopamine detection. A large negative holding potential was employed to promote DA pre-concentration in between the voltage scans.

Selective detection of dopamine on poly(indole-5-carboxylic acid)/tyrosinase electrode

We report here on a simple tyrosinase (TYR) modified electrode designed through the covalent bonding of the enzyme with poly (indole-5-carboxylic acid) (PIn5COOH) conducting polymer. This electrode was applied to the amperometric detection of dopamine (DA) in the presence of ascorbic acid (AA), uric acid (UA) and their mixtures, in the concentration range and ratios similar to those found in blood serum. Our experiments demonstrate that the presence of these interferents (AA, UA) does not affect the selectivity of such electrode towards dopamine with linear concentration dependence in the range of 0.5–20 μM, depending on the experimental conditions, however its sensitivity depends on the type and amount of interferent present. The lower limit of detection of DA in the presence of high AA (1000 fold) or UA (500 fold) concentration was found to be 0.1–0.5 μM. The sensitivity for DA detection is 6.2 A/M cm 2 with UA and 2.3 A/M cm 2 with AA present as interfering agents. For both interferents present in the ratio 12.5:1 (AA:UA), the sensitivity drops to the value of ca. 1.3 A/M cm 2. The Michaelis–Menten ( K M) constant and I max values were evaluated, showing improved electrode sensitivity towards dopamine as judged from the decrease of the Michaelis–Menten constant.