Simultaneous Detection Of Dopamine Research Articles

Simultaneous Dopamine and Serotonin Monitoring in Freely Moving Crayfish Using a Wireless Electrochemical Sensing System.

Dopamine (DA) and serotonin (5-HT) are neurotransmitters that regulate a wide range of physiological and behavioral processes. Monitoring of both neurotransmitters with real-time analysis offers important insight into the mechanisms that shape animal behavior. However, bioelectronic tools to simultaneously monitor DA and 5-HT interactive dynamics in freely moving animals are underdeveloped. This is mainly due to the limited sensor sensitivity with miniaturized electronics. Here, we present a semi-implantable electrochemical device achieved by integrating a multi-surface-modified carbon fiber microelectrode with a miniaturized potentiostat module to detect DA and 5-HT in vivo with high sensitivity and selectivity. Specifically, carbon fiber microelectrodes were modified through electrochemical treatment and surface coatings to improve sensitivity, selectivity, and antifouling properties. A customized, lightweight potentiostat module was developed for untethered electrochemical measurements. Integrated with the microelectrode, the microsystem is compact (2.8 × 2.3 × 2.1 cm) to minimize its impacts on animal behavior and achieved simultaneous detection of DA and 5-HT with sensitivities of 48.4 and 133.0 nA/μM, respectively, within submicromolar ranges. The system was attached to the crayfish dorsal carapace, allowing electrode implantation into the heart of a crayfish to monitor DA and 5-HT dynamics, followed by drug injections. The semi-implantable biosensor system displayed a significant increase in oxidation peak currents after DA and 5-HT injections. The device successfully demonstrated the application for in vivo simultaneous monitoring of DA and 5-HT in the hemolymph (i.e., blood) of freely behaving crayfish underwater, yielding a valuable experimental tool to expand our understanding of the comodulation of DA and 5-HT.

The Simultaneous Detection of Dopamine and Uric Acid In Vivo Based on a 3D Reduced Graphene Oxide-MXene Composite Electrode.

Dopamine (DA) and uric acid (UA) are essential for many physiological processes in the human body. Abnormal levels of DA and UA can lead to multiple diseases, such as Parkinson's disease and gout. In this work, a three-dimensional reduced graphene oxide-MXene (3D rGO-Ti3C2) composite electrode was prepared using a simple one-step hydrothermal reduction process, which could separate the oxidation potentials of DA and UA, enabling the simultaneous detection of DA and UA. The 3D rGO-Ti3C2 electrode exhibited excellent electrocatalytic activity towards both DA and UA. In 0.01 M PBS solution, the linear range of DA was 0.5-500 µM with a sensitivity of 0.74 µA·µM-1·cm-2 and a detection limit of 0.056 µM (S/N = 3), while the linear range of UA was 0.5-60 µM and 80-450 µM, with sensitivity of 2.96 and 0.81 µA·µM-1·cm-2, respectively, and a detection limit of 0.086 µM (S/N = 3). In 10% fetal bovine serum (FBS) solution, the linear range of DA was 0.5-500 µM with a sensitivity of 0.41 µA·µM-1·cm-2 and a detection limit of 0.091 µM (S/N = 3). The linear range of UA was 2-500 µM with a sensitivity of 0.11 µA·µM-1·cm-2 and a detection limit of 0.6 µM (S/N = 3). The modified electrode exhibited advantages such as high sensitivity, a strong anti-interference capability, and good repeatability. Furthermore, the modified electrode was successfully used for DA measurement in vivo. This could present a simple reliable route for neurotransmitter detection in neuroscience.

Cobalt-generated reactive oxygen species promoted FeS2/CoS2 for electrochemical detection of acetaminophen with the widest linear range and simultaneous detection of dopamine

It is crucial to investigate the variables that impact the electrooxidation of acetaminophen (AP) to develop sensors for acetaminophen with outstanding performance. Considering the ability of hydroxyl adsorption to produce reactive oxygen species in the catalytic system is an important factor affecting the performance of the acetaminophen sensor. Herein, FeS2/CoS2 nanohybrids were prepared by incorporating cobalt. The relationship between the reactive oxygen generation capacity and the detection linear range during the oxidation of acetaminophen was studied. It was found that when the ratio of iron to cobalt was 7:3, the reactive oxygen generation activity of the catalyst was the largest and its linear range was the widest (1 μM-27 mM). Additionally, we found that catalysts with an iron to cobalt ratio of 7:3 had the widest linear range (1 μM-24 mM) for dopamine detection compared with other comparison samples. The limits of detection were calculated to be 0.88 μM and 1.1 μM for acetaminophen and dopamine. Moreover, the simultaneous detection of acetaminophen and dopamine was exhibited which showed two separate oxidation peaks.

Sensitive sensing platform based on Co, Mo doped electrospun nanofibers for simultaneous electrochemical detection of dopamine and uric acid

Abnormal levels of dopamine (DA) and uric acid (UA) in the human body are valuable indicators for monitoring human health, as they are associated with certain diseases. Therefore, it is crucial to develop sensitive and simultaneous analytical techniques for DA and UA in diagnosing the related diseases. Herein, the Co- and Mo- doped carbon nanofibers (Co, Mo@CNFs) electrochemical biosensor was developed successfully for the sensitive and accurate simultaneous detection of DA and UA. A straightforward electrospinning technique followed by a carbonization process was employed for the synthesis of Co, Mo@CNFs, and the encapsulation of Co and Mo within CNFs served to not only prevent nanoparticle agglomeration, thus providing more active sites, but also to facilitate rapid electron transfer. By incorporating Co and Mo into CNFs, the electrocatalytic activity of the modified electrode was greatly improved due to the beneficial conductivity and synergistic effects of transition metals. This enhancement effectively addressed issues such as the overlapping anodic peaks that occur when DA and UA are oxidized concurrently. Due to the mentioned synergistic contributions, the modified Co, Mo@CNFs electrode (Co, Mo@CNFs/GCE) achieved remarkable sensitivity for the simultaneous detection of DA and UA, while also exhibiting strong anti-interference ability. The detection limits for DA and UA were 2.35 nmol L−1 and 0.16 μmol L−1, respectively. We applied the developed Co, Mo@CNFs/GCE electrochemical biosensor to detect DA and UA in 50-fold diluted serum and urine samples. The results affirm the biosensor's reliability and precision. Moreover, the developed Co, Mo@CNFs/GCE biosensor demonstrated excellent performance in simultaneously detecting DA and UA, providing an efficient and dependable detection approach for clinical diagnosis and bioanalysis.

A disposable sensor based on one-pot synthesized tungsten oxide nanostructure-modified screen printed electrodes for selective detection of dopamine and uric acid.

Here, screen-printed carbon electrodes (SPCEs) were modified with ultrafine and mainly mono-disperse sea urchin-like tungsten oxide (SUWO3) nanostructures synthesized by a simple one-pot hydrothermal method for non-enzymatic detection of dopamine (DA) and uric acid (UA) in synthetic urine. Sea urchin-like nanostructures were clearly observed in scanning electron microscope images and WO3 composition was confirmed with XRD, Raman,FTIR and UV-Vis spectrophotometer. Modification of SPCEs with SUWO3 nanostructures via the drop-casting method clearly reduced the Rct value of the electrodes, lowered the ∆Ep and enhanced the DA oxidation current due to high electrocatalytic activity. As a result, SUWO3/SPCEs enabled highly sensitive non-enzymatic detection of DA (LOD: 51.4nM and sensitivity: 127µAmM-1cm-2) and UA (LOD: 253nM and sensitivity: 55.9µAmM-1cm-2) at low concentration. Lastly, SUWO3/SPCEs were tested with synthetic urine, in which acceptable recoveries for both molecules (94.02-105.8%) were obtained. Given the high selectivity, the sensor has the potential to be used for highly sensitive simultaneous detection of DA and UA in real biological samples.

Modification-free pumpless laser-induced graphene multichannel open microfluidic electrode chip for simultaneous quantification of dual targets

Pumpless surface fluid transport technology has attracted concerns in the field of electroanalysis. However, the combination of surface wettability-controlled multichannel fluid transport and flexible three-electrode systems has been rarely reported for electrochemical detection. Here, we have developed a modification-free pumpless laser-induced graphene multichannel open microfluidic electrode chip (LIG-MOMEC) for simultaneous quantification of dual targets. The LIG-MOMEC enables rapid sample distribution to four addressable locations for multiple parallel tests on a single chip and simultaneous detection of dopamine (DA) and uric acid (UA) using differential pulsed voltammetry. The flexible polyimide templated by laser parameters supports a programmable electrochemical sensing surface with desired conductivity and optimal surface wettability without post-chemical modification, effectively avoiding the tedious multi-step processing and time-consuming surface modification of conventional modified electrodes. The LIG-MOMEC has a linear detection range of 0.91 ∼ 171.15 μM for DA and 0.83 ∼ 250.04 μM for UA with the LODs of 72 nM and 48 nM. Due to the advantages of superior selectivity, anti-interference and reliable stability, the LIG-MOMEC could be reversibly used 30 times with high reproducibility and attain satisfactory recovery in human serum samples. The LIG-MOMEC provides great potential for the rapid detection of biomolecules in clinical diagnostics and biochemical analysis.

Bimetallic cobalt–nickel supported on carbon fiber for electrochemical simultaneous determination of dopamine and hydroquinone

Bimetallic cobalt–nickel supported on carbon fiber (Co-Ni@CF) was synthesized by a straightforward homogeneous co-precipitation approach. Electrochemical results demonstrated that the modified Co-Ni@CF electrode demonstrated excellent electrooxidation activity toward dopamine (DA) and hydroquinone (HQ) without any other activating treatments, which could be modified as an electrochemical biosensor for DA and HQ detection simultaneously. The as-proposed biosensor was developed for simultaneous detection of DA and HQ, featuring low detection limits (LODs) of 0.4698 μM for DA and 0.2388 mM for HQ, respectively. The sensor also offers broad linear ranges for DA (5.0–30 μM), and HQ (0.5–5.0 mM). Along with these attractive features, the Co-Ni@CF electrode also performed good long-term stability and reproducibility, making it a promising candidate for electrochemical biosensing of DA and HQ.

Electrochemical sensors for simultaneous detection of dopamine and uric acid based on a composite of electrochemically reduced graphene oxide and PEDOT:PSS-modified glassy carbon electrode

Herein, we report the development of a successful electrochemical sensor based on a composite of electrochemically reduced graphene oxide (ErGO) and poly(3,4-ethylenedioxythiophene):poly(styrene-4-sulphonate) (PEDOT:PSS) for the simultaneous detection of dopamine (DA) and uric acid (UA). A glassy carbon electrode was modified with a composite of ErGO and PEDOT:PSS and further characterized using Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy. The obtained composition of weight ratio between ErGO and PEDOT:PSS as 7:3 demonstrated the highest electrocatalytic activity for the simultaneous detection of DA and UA when it was investigated using differential pulse voltammetry technique under optimized experimental conditions. The developed sensor also exhibited two separate well-defined anodic peaks of both analytes with a linear response over the concentration range of 3–33 µM for DA and 10–110 µM for UA. The limits of detection for DA and UA were 0.4 and 0.5 µM, respectively. The proposed sensor also displayed good stability and reproducibility for the simultaneous detection of DA and UA for five consecutive days of measurements. In addition, the developed sensor exhibited a good selectivity for the simultaneous detection of DA and UA against several potential interferences, such as K+, Cl−, C2O42−, PO43−, ascorbic acid, glucose, and urea, with % recovery values of 97%–101% for DA and 97%–103% for UA, which are acceptable in the analytical range. Furthermore, this sensor was successfully used in detecting DA and UA in real human samples using standard addition techniques and thus may have a potency to be further employed in practical applications.

Vertical growth of leaf-like Co-metal organic framework on carbon fiber cloth as integrated electrode for sensitive detection of dopamine and uric acid

Application of metal organic framework (MOF) in electrochemical sensors usually suffer from poor conductivity, low electrocatalysis, material aggregation and complex electrode fabrication. Here, leaf-like Co-MOF (L-Co-MOF) vertically grown on carbon cloth (CC) was prepared as integrated electrode for electrochemical detection. The L-Co-MOF/CC with interlaced Co-MOF nanosheets as building blocks greatly reduces aggregation, provides large surface area and highly exposed active sites to interact with analyte. The synergy between L-Co-MOF and CC endows the composite greatly enhanced electrocatalysis on oxidation of dopamine (DA) and uric acid (UA) compared with those of ordinary polyhedral Co-MOF or 2D Co-MOF grown in solution. The L-Co-MOF/CC can be directly used as working electrode without further modification, and it achieved the separate detection of DA and UA in the range of 5.6 nM-70 μM, and 21 nM-350 μM, respectively. Simultaneous detection of DA and UA was also performed with a LOD of 2.5 nM for DA and 7 nM for UA, respectively. The sensor with high reproducibility and good anti-interference properties also achieved practical sensing of DA and UA in serum with recoveries of 83.3–104.0%. Such integrated 2D-MOF-carbon material composite with unique structure and high electrocatalysis hold great promise in electrochemical device.

Simultaneous detection of dopamine and ascorbic acid by using a thread-based microfluidic device and multiple pulse amperometry.

This study presents a novel approach for the simultaneous detection of ascorbic acid (AA) and dopamine (DA) using an affordable and user-friendly microfluidic device. Microfluidic devices, when combined with electrochemical detectors like screen-printed electrodes (SPEs), offer numerous advantages such as portability, high sample throughput, and low reagent consumption. In this study, a 3D-printed microfluidic device called a μTED was developed, utilizing textile threads as microfluidic channels and an unmodified SPE as the amperometric detector. The method employed multiple pulse amperometry (MPA) with carefully selected potential values (+0.65 V and -0.10 V). The reduction current signals generated by dopamine o-quinone were used to calculate a correction factor for the oxidation signals of ascorbic acid, enabling simultaneous quantification. The developed microfluidic device ensured a stable flow rate of the carrier solution at 1.19 μL s-1, minimizing the consumption of samples and reagents (injection volume of 2.0 μL). Under the optimized experimental conditions, a linear range from 50 to 900 μmol L-1 was achieved for both DA and AA. The obtained sensitivities were 2.24 μA L mmol-1 for AA and 5.09 μA L mmol-1 for DA, with corresponding limits of detection (LOD) of 2.60 μmol L-1 and 1.54 μmol L-1, respectively. To confirm the effectiveness of the proposed method, it was successfully applied to analyze AA and DA in a commercial blood serum sample spiked at three different concentration levels, with a medium recovery rate of 70%. Furthermore, the MPA technique demonstrated its simplicity by enabling the simultaneous determination of AA and DA without the need for prior separation steps or the use of chemically modified electrodes.

Simultaneous Detection of Dopamine and Paracetamol on Electroreduced Graphene Oxide–Cobalt Phthalocyanine Polymer Nanocomposite Electrode

Simultaneous Detection of Dopamine and Paracetamol on Electroreduced Graphene Oxide–Cobalt Phthalocyanine Polymer Nanocomposite Electrode

Comparison of Carbon Nanomaterials for Simultaneous Detection of Neurotransmitters in the Presence of Interfering Species

AbstractThe main hurdle in simultaneous analysis of dopamine and serotonin is not only their similar detection potential but also the polymerization of dopamine at physiological pH, which results in sensitivity loss. In this work, we investigated glassy carbon electrodes and electrodes modified with carbon black, graphene oxide, and carbon nanodots in terms of their ability to detect 5 neurobiologically relevant analytes (dopamine, serotonin, epinephrine, norepinephrine, and 3,4‐dihydroxyphenylacetic acid). We proved that simultaneous detection of dopamine and serotonin in the presence of uric and ascorbic acids is possible on electrodes modified with carbon black and graphene oxide, both in buffer solution and cell medium. Graphene oxide‐modified electrodes have shown the highest sensitivity towards all tested neurotransmitters. Moreover, a considerable shift of epinephrine, norepinephrine, and 3,4‐dihydroxyphenylacetic acid peaks towards more negative potentials was observed for electrodes modified with carbon black and graphene oxide as compared with glassy carbon electrodes. Electrodes covered with carbon nanodots were proven inappropriate due to their surface functionalization with ethylenediamine.

Eco-friendly surface modification of oxidized carbon nanotubes with curcumin for simultaneous electrochemical detection of dopamine and serotonin

Here we report a surface modification of oxidized carbon nanotubes (oCNTs) pre-modified on a glassy carbon electrode (GCE) with electrodeposited curcumin (CM) as a metal-free platform for simultaneous detection of dopamine (DA) and serotonin (SE). CM dissolved in an alkaline medium, was electrodeposited on various carbon-based materials and its activity towards detection of DA and SE was verified. Excellent synergy was observed between CM and oCNT towards simultaneous detection of DA and SE in pH 7 phosphate buffer saline (PBS) at 0.2 V and 0.34 V, respectively. DFT calculations also showed higher stabilization energy of the oxidized CM i.e., curcumin semiquinone (CMQ) with oCNT (3.35 eV) compared to bare CNT (2.87 eV). The CM-oCNT on a glassy carbon electrode (GCE) exhibited 4.42 times higher surface area and 60 times enhanced anodic current compared to bare GCE towards highly selective oxidative response of DA and SE with a potential difference of 158 mV. Linear calibration curves were obtained for DA and SE ranging from 10 to 170 μM and 10 to 130 μM, respectively. The research outcomes point towards possible metal-free combinations of organic moieties and carbon materials for detection of vital biomolecules in the future.

Novel lanthanum vanadate-based nanocomposite for simultaneously electrochemical detection of dopamine and uric acid in fetal bovine serum

The abnormal levels of two biological molecules, dopamine (DA) and Uric acid (UA), in human body are symptoms of diseases such as Parkinson's disease and arrhythmia. A novel lanthanum vanadate and multi-walled carbon nanotubes (LaV-MWCNTs) composite modified glassy carbon electrode (GCE) was developed and utilized as an efficient electrochemical sensor for the simultaneous detection of DA and UA. LaV-MWCNTs composite was successfully fabricated by a facile ultrasonic self-assembly method and identified by means of a series of successive measurements including XPS, XRD, FT-IR and FE-SEM. The LaV-MWCNTs modified GCE shows the concentration linear ranges of DA and UA are 2–100 μΜ using DPV. The limits of detection (LODs; signal-to-noise ratio of 3, S/N = 3) of the LaV-MWCNTs modified GCE sensor for DA and UA were calculated to be 0.046 μM and 0.025 μM, respectively. The feasibility of using the LaV-MWCNTs modified GCE sensor to detect DA and UA in a typical biological fluid, fetal bovine serum, was also evaluated by the standard addition method.

Palladium doped α-MnO2 nanorods on graphene as an electrochemical sensor for simultaneous determination of dopamine and paracetamol

Defect engineering at the atomic level has been one of the most prevalent research topics in the field of catalysis because defects act as superior active sites. However, defects are difficult to create, recognize, and fully comprehend. In this study, for the first time, we demonstrate that the defects creation by palladium atom on the surface of α-MnO2 nanorods supported graphene (Pd@α-MnO2/G). These defects significantly altered the electronic and crystalline structures of the as-prepared material, as well as improving the surface/interface properties for biomolecule determination. As a result, Pd@α-MnO2/G exhibited a higher electroactive surface area, conductivity, and synergistic effect in the simultaneous detection of dopamine (DA) and paracetamol (PA) owing to its defective nature. For instance, it showed wide detection ranges from 0.2 to 425 µM and from 0.1 to 375 µM with lower limits of detection of 0.086 and 0.059 µM for DA and PA, respectively. It also showed high sensitivity (0.0591 and 0.0854 µA µM−1 for DA and PA, respectively) and experienced no interference from the presence of a 100-fold excess of interferents. Importantly, we discussed the 2H+/2e– reaction mechanism of DA and PA oxidation on the Pd@α-MnO2/G surface, for an in-depth understanding of the process.

A Double-Deck Structure of Reduced Graphene Oxide Modified Porous Ti3C2Tx Electrode towards Ultrasensitive and Simultaneous Detection of Dopamine and Uric Acid.

Considering the vital physiological functions of dopamine (DA) and uric acid (UA) and their coexistence in the biological matrix, the development of biosensing techniques for their simultaneous and sensitive detection is highly desirable for diagnostic and analytical applications. Therefore, Ti3C2Tx/rGO heterostructure with a double-deck layer was fabricated through electrochemical reduction. The rGO was modified on a porous Ti3C2Tx electrode as the biosensor for the detection of DA and UA simultaneously. Debye length was regulated by the alteration of rGO mass on the surface of the Ti3C2Tx electrode. Debye length decreased with respect to the rGO electrode modified with further rGO mass, indicating that fewer DA molecules were capable of surpassing the equilibrium double layer and reaching the surface of rGO to achieve the voltammetric response of DA. Thus, the proposed Ti3C2Tx/rGO sensor presented an excellent performance in detecting DA and UA with a wide linear range of 0.1–100 μM and 1–1000 μM and a low detection limit of 9.5 nM and 0.3 μM, respectively. Additionally, the proposed Ti3C2Tx/rGO electrode displayed good repeatability, selectivity, and proved to be available for real sample analysis.

Overoxidized poly(3,4-ethylenedioxythiophene)–gold nanoparticles–graphene-modified electrode for the simultaneous detection of dopamine and uric acid in the presence of ascorbic acid

An innovative, ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene) (OPEDOT), gold nanoparticles (AuNPs), and electrochemically reduced graphene oxide (ERGO) was prepared on a glassy carbon electrode (GCE) (OPEDOT–AuNPs–ERGO/GCE) through homogeneous chemical reactions and heterogeneous electrochemical methods. The morphology, composition, and structure of this nanocomposite were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical properties of the OPEDOT–AuNPs–ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(III) chloride redox probe systems. This modified electrode shows excellent electro-catalytic activity for dopamine (DA) and uric acid (UA) under physiological pH conditions, but inhibits the oxidation of ascorbic acid (AA). Linear voltammetric responses were obtained when DA concentrations of approximately 4.0–100 μM and UA concentrations of approximately 20–100 μM were used. The detection limits (S/N=3) for DA and UA were 1.0 and 5.0 μM, respectively, under physiological conditions and in the presence of 1.0 mM of AA. This developed method was applied to the simultaneous detection of DA and UA in human urine, where satisfactory recoveries from 96.7% to 105.0% were observed. This work demonstrates that the developed OPEDOT–AuNPs–ERGO ternary nanocomposite, with its excellent ion-selectivity and electro-catalytic activity, is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies.

A covalent organic polymer-TiO2/Ti3C2 heterostructure as nonenzymatic biosensor for voltammetric detection of dopamine and uric acid.

Heterostructures have potential to blend the advantages of each material, even exhibiting the evolutionary performance due to synergistic effects. Herein, covalent organic polymers (NUF) are integrated with a TiO2/Ti3C2Tx nanocomposite (TiO2/TiCT) to form TiO2/TiCT-NUF heterojunctions as an enlarged nonenzymatic biosensor for dopamine (DA) and uric acid (UA). Detection is performed by differential pulse voltammetry (DPV). TheTiO2/TiCT/NUF exhibits high sensing activity with low detection limits of 0.2 and 0.18nM (S/N = 3) inthe concentration ranges from 0.002 to 100μM and 0.001 to 60μM for simultaneous determination of DA and UA, respectively. In addition, the TiO2/TiCT/NUF provides good selectivityand reproducibility for DA and UA detection in urine and serum samples with recoveries of 98.4 to 100.9%. The proposed heterojunctions manifest an intriguing potential as a candidate of an electrochemical sensor for sole and simultaneous detection of DA and UA.

Polycrystalline boron-doped diamond-based electrochemical biosensor for simultaneous detection of dopamine and melatonin

In this study, boron-doped diamond (BDD) electrodes with varied B contents are prepared to determine the feasibility of the direct usage of BDD as an electrochemical biosensor without any modification. The electrochemical performance of the electrodes was investigated through the characterization of electrochemical impedance spectroscopy for potassium ferricyanide/potassium ferrocyanide (K3Fe(CN)6/K4Fe(CN)6) redox couples, as well as through qualitative and quantitative analysis of the two biomolecules dopamine (DA) and melatonin (MLT). The results show that the B content of BDD is the primary parameter for controlling the electrocatalytic current, that is, the response sensitivity. However, the abundant crystal planes and low background current are the key factors in improving the selectivity of the biomarkers to identify multiple analytes. Considering the catalytic current and its ability to distinguish the biomolecules, BDD with a B source carrier gas flow rate of 18 sccm is used as the sensing electrode for the simultaneous detection of DA and MLT. The response peak potential difference reaches 500 mV, and the linear concentration range for the two analytes is 0.4–600 μM, with detection limits of 0.1 μM for DA and 0.003 μM for MLT. These results match those observed for electrochemical sensors modified by various sensitive materials. BDD electrodes show good chemical resistance, good stability, and no pollution and are suitable for long-term usage as biomarker sensors.

Designing C-Fe-O bonded MIL-88B(Fe)/jasmine petal-derived-carbon composite biosensor for the simultaneous detection of dopamine and uric acid

C-Fe-O bonded MIL-88B(Fe)/carbon composite was designed to enhance the sensitivity and resolution for the simultaneous detection of dopamine (DA) and uric acid (UA) based on the “adsorption enhancement and distinguished potential regulation” strategy. Fe loaded Jasmine petal derived biocarbon (Fe-JPBC) was implanted in MIL-88B(Fe) through C-Fe-O bonding, resulting in a novel composite biosensor (MIL(Fe)/Fe-JPBC). MIL-88B(Fe) exhibited improved analyte capture ability via adsorption enhancement, which significantly enhanced signal sensitivity and lowered the limit of detection (LOD). In addition, the enhanced signal transmission capacity for DA and UA was attributed to the strong interface between MOF and Fe-JPBC via C-Fe-O bond. Interestingly, the presence of this unique interface showed different catalytic properties for the redox reaction of DA and UA, and broadened the oxidation potential discrepancy between them. The MIL(Fe)/Fe-JPBC biosensor therefore exhibited well-resolved potential peaks of 240 mV for DA and UA with respective LOD of 42.0 nM and 5.6 nM. Cyclic voltammetry, adsorption kinetics and molecular simulation results revealed that compared to DA, the utilization of MIL(Fe)/Fe-JPBC to detect UA was a reaction-controlled process with higher affinity and faster adsorption rate, leading to its much lower LOD than DA. MIL(Fe)/Fe-JPBC also exhibited high anti-interference and reproducibility in the detection of simulated and real serum samples. The novel strategy of adsorption enhancement and distinguished potential regulation via C-Fe-O bond for designing composite biosensors with significantly increased sensitivity and resolution for the simultaneous detection of DA and UA could be deemed of great potential on large applications.