Ultrasensitive Detection Of Dopamine Research Articles

Self-assembly Pt hollow nanospheres for highly selective and ultrasensitive detection of dopamine

Abnormal concentration of dopamine, one critical neurotransmitter in central nervous system, causes several neurological diseases associated with behavioral responses and brain functions in human beings. Highly sensitive detection of dopamine is of great significance yet challengeable. In this work, Pt hollow nanospheres (Pt HNSs) with a uniform diameter of 30 nm were successfully synthesized in water by self-assembly method under room temperature. The fabricated Pt hollow/Nafion nanospheres modified glassy carbon electrode (Pt HNSS/Nafion/GCE) exhibited superior electrocatalytic performance, with peak currents 2.24 and 4.54 times higher than those of Nafion-modified glassy carbon electrode (Nafion/GCE) and bare glassy carbon electrode (GCE), respectively. Theoretical calculations indicate that dopamine has an adsorption energy of −3.18 eV on the Pt(111) surface, with an electron transfer of + 1.84 |e|, aligning with the 2-electron transfer mechanism. Furthermore, the low energy barrier observed during dopamine oxidation process suggests that the Pt(111) surface is highly favorable for dopamine oxidation. Meanwhile, Pt HNSS/Nafion/GCE electrochemical sensor exhibits highly sensitive and selective response in determination of dopamine ranging from 0.01 to 250 μM with low detection limits of 0.804 nM (S/N = 3). Moreover, the electrochemical sensor shows reliable signals in real test with great anti-interference and stability during the experiments, making it a promising candidate for applications in dopamine sensing.

Pd Nanoparticles Loaded on Cu Nanoplate Sensor for Ultrasensitive Detection of Dopamine.

The detection of dopamine is of great significance for human health. Herein, Pd nanoparticles were loaded on Cu nanoplates (Pd/Cu NPTs) by a novel liquid phase reduction method. A novel dopamine (DA) electrochemical sensor based on the Pd NPs/Cu/glass carbon electrode (Pd/Cu NPTs/GCE) was constructed. This sensor showed a wide linear range of 0.047 mM to 1.122 mM and a low limit of detection (LOD) of 0.1045 μM (S/N = 3) for DA. The improved performance of this sensor is attributed to the obtained tiny Pd nanoparticles which increase the catalytic active sites and electrochemical active surface areas (ECSAs). Moreover, the larger surface area of two-dimensional Cu nanoplates can load more Pd nanoparticles, which is another reason to improve performance. The Pd/Cu NPTs/GCE sensor also showed a good reproducibility, stability, and excellent anti-interference ability.

A novel Cu–Cu2O junction structure for the ultrasensitive detection of dopamine

A novel Cu–Cu2O junction structure for the ultrasensitive detection of dopamine

Platinum nanowires/MXene nanosheets/porous carbon ternary nanocomposites for in situ monitoring of dopamine released from neuronal cells

Dopamine is an important neurotransmitter in the body and closely related to many neurodegenerative diseases. Therefore, the detection of dopamine is of great significance for the diagnosis and treatment of diseases, screening of drugs and unraveling of relevant pathogenic mechanisms. However, the low concentration of dopamine in the body and the complexity of the matrix make the accurate detection of dopamine challenging. Herein, an electrochemical sensor is constructed based on ternary nanocomposites consisting of one-dimensional Pt nanowires, two-dimensional MXene nanosheets, and three-dimensional porous carbon. The Pt nanowires exhibit excellent catalytic activity due to the abundant grain boundaries and highly undercoordinated atoms; MXene nanosheets not only facilitate the growth of Pt nanowires, but also enhance the electrical conductivity and hydrophilicity; and the porous carbon helps induce significant adsorption of dopamine on the electrode surface. In electrochemical tests, the ternary nanocomposite-based sensor achieves an ultra-sensitive detection of dopamine (S/N = 3) with a low limit of detection (LOD) of 28 nM, satisfactory selectivity and excellent stability. Furthermore, the sensor can be used for the detection of dopamine in serum and in situ monitoring of dopamine release from PC12 cells. Such a highly sensitive nanocomposite sensor can be exploited for in situ monitoring of important neurotransmitters at the cellular level, which is of great significance for related drug screening and mechanistic studies.

A photoelectrochemical sensor based on In2O3/In2S3/ZnIn2S4 ternary Z-scheme heterojunction for ultrasensitive detection of dopamine in sweat.

A novel ternary heterojunction material In2O3/In2S3/ZnIn2S4 was synthesized, and a photoelectrochemical sensor was fabricated for the non-invasive test of dopamine (DA) in sweat. In2O3 multihollow microtubules were synthesized and then In2S3 was formed on their surface to construct a type-I heterojunction between In2S3 and In2O3. ZnIn2S4 was further introduced to form a Z-scheme heterojunction between In2S3/ZnIn2S4. Under photoexcitation, the photogenerated holes of In2O3 transferred to the valence band of In2S3, superimposed with the holes produced by In2S3, leads to a significantly higher photocatalytic oxidation capacity of In2O3/In2S3/ZnIn2S4 ternary composites than that of In2O3/In2S3. TheZ-scheme heterojunction accelerates the transfer of photogenerated electrons accumulated on the type-I heterojunction. In the presence of DA, itis rapidly oxidized into polydopamine (PDA) by In2O3/In2S3, and the benzoquinone groups of PDA compete for the photogenerated electrons to reduce the current in the external circuit, whereby DA determination is achieved. Owing to the combination of type-I and Z-scheme heterojunction, the sensor showed extremely high sensitivity, with a detection limit of 3.94 × 10-12 mol/L. It is one of the most sensitive methods for DA detection reported and has been applied to the determination of DA in human sweat.

Ultrasensitive detecting of dopamine in complex components by field effect transistor sensor based on the synergistic enhancement effect and overcoming debye length limitations

Field effect transistor (FET) has attracted high attention in biomolecules detection. However, the sensitivity of FET-based biosensors is often limited by the charge screening effect. In addition, the facile and ultra-sensitive detection for small biomolecules, which possess weak charge or electroneutral, remains to be studied. Here, the self-assembled monolayer AuNPs/three-dimensional (3D) crumpled graphene FET is structured for a biosensor by shrinking flexible polystyrene (PS) films through heat treatment method and realized label-free and ultra-sensitive detection of dopamine (DA) using DA aptamer as probes immobilized on the AuNPs/3D crumpled graphene surface. The nanoscale deformation caused by thermal expansion effect of flexible graphene/PS can effectively reduce charge screening and the synergistic application of crumpled graphene and AuNPs can promote electron transfer and the graphene carrier concentration, leading to conductivity increase and hydrophilicity enhancement of 3D graphene. In addition, the binding of DA aptamer to DA will cause conformational changes of the aptamer molecule, which affects the charge transport properties of the sensor, thus improving its selectivity and stability. The biosensor can also easily distinguish interfering substances for DA detection in complex components (PBS, human urine, and fetal calf serum) with the detection limits as low as 60, 240 and 316 zM (10−19–10−11 M), respectively. DA released from exocytosis induced by K+ stimulation was selectively detected. The results show that the biosensor can be used as an excellent tool for ultrasensitive molecular recognition and detecting the effects of exogenous reagents on living cells, which is promising for clinical diagnosis and early disease prevention.

“Two-step” signal amplification for ultrasensitive detection of dopamine in human serum sample using Ti3C2Tx-MXene

Two-dimensional transition-metal (Ti3C2Tx-MXene) carbide layered materials with versatile surface functional group have attracted huge interest in electrochemical sensing due to their excellent metallic conductivity, outstanding electrical and mechanical properties, high volumetric capacity, and flexibility to construct highly sensitive biosensors. Herein, we present a ultrasensitive molecular architecture for neuromolecules dopamine sensing using Ti3C2Tx-MXene multilayered materials. It was prepared through in situ polymerization of 4-APBA (4-aminophenyl boronic acid) with a scalable “two-step” approach. Additionally, its on-site application was realized by fabricating a label-free screen-printed carbon (SPC) electrode for electrochemical sensing of dopamine levels in buffer and human serum samples at the point-of-care testing (POCT). Importantly, the high specificity of Ti3C2Tx-MXene/4-APBA modification for SPC-electrode electrochemical sensing could be easily implemented with great signal drifting. As a proof of concept, this novel electrochemical sensor was found to be logically inexpensive and straightforward. It could selectively measure dopamine levels with a limit of detection (LOD) of 1.3 nM in PBS (pH 7.2) and, 1.9 nM in the human serum sample. It had a wide range of linear detection of dopamine concentrations of 40 to 500 nM, with a sensitivity of 0.0134 µA nM−1. This work paves a new path for 2D Ti3C2Tx-MXene/4-APBA modification for biomedical and biosensing applications in dopamine detection at nanomolar concentrations with high specificity, selectivity, sensitivity, stability, and reproducibility.

Ultrasensitive detection of dopamine using Au microelectrodes integrated with mesoporous silica thin films.

An electrochemical method was developed for ultrasensitive and selective detection of dopamine in human serum using mesoporous silica thin film modified gold microelectrodes. Vertically aligned mesoporous silica thin films were deposited onto Au microelectrodes by electrochemically assisted self-assembly (EASA). The mesochannels have uniform pore sizes of 2.1 nm in diameter and a negatively charged wall surface. Cyclic voltammetry reveals effective charge permselectivity through the negatively charged mesoporous channels. By using differential pulse voltammetry, the mesoporous silica thin film modified Au microelectrode can be employed for the ultrasensitive detection of dopamine with a detection limit as low as 0.084 μM. In addition, thanks to the electrostatic and steric effects of the silica mesochannels, excellent anti-interference and anti-fouling properties of the electrochemical sensors are demonstrated.

Villous 3D nanoconfined flexible carbon fibers-based electrode toward dopamine electrochemical detection

Flexible sensing interfaces for the analysis of biological samples are crucial to realize human dopamine health detection; thus, flexible sensors for biomolecular analysis have attracted considerable attention. Herein, we report a villous three-dimensional (3D) nanoconfined carbon fibers-based flexible sensor for the electrochemical analysis of dopamine (DA). Carbon nanofibers-modified carbon fibers (CNFs/CFs) with abundant nanochannels were obtained by chemical vapor deposition, and the sensing platform achieved ultra-sensitive analysis owing to the construction of nanoconfined spaces. The combination of a 3D network structure and surface N doping (N-CNFs/CFs) significantly enhanced the local enrichment of DA, thus providing a basis for ultrasensitive detection of DA. Furthermore, modified Au nanoparticles (Au/N-CNFs/CFs) exhibited s enhanced the electrocatalytic ability and electron transfer efficiency. The detection limit for DA reached 0.087 μM (S/N = 3) in the linear range of 1–800 μM. Under optimal conditions, the designed electrode material shows good performance in complex biological environments, including human serum, urine, and artificial cerebrospinal fluid). The developed Au/N-CNFs/CFs therefore provide a portable and efficient sensor for the clinical detection of biomolecules.

In-situ integrated electrodes of FeM-MIL-88/CP for simultaneous ultra-sensitive detection of dopamine and acetaminophen based on crystal engineering strategy

Designing and exploiting integrated electrodes is the current inevitable trend to realize the sustainable development of electrochemical sensors. In this work, a series of integrated electrodes prepared by in situ growing the second metal ion-modulated FeM-MIL-88 (M = Mn, Co and Ni) on carbon paper (CP) (FeM-MIL-88/CP) were constructed as the electrochemical sensing platforms for the simultaneous detection of dopamine (DA) and acetaminophen (AC). Among them, FeMn-MIL-88/CP exhibited the best sensing behaviors and achieved the trace detection for DA and AC owing to synergistic catalysis between Fe3+, Mn2+ and CP. The electrochemical sensor based on FeMn-MIL-88/CP showed ultra-high sensitivities of 2.85 and 7.46 μA μM−1 cm−2 and extremely low detection limits of 0.082 and 0.015 μM for DA and AC, respectively. The FeMn-MIL-88/CP also exhibited outstanding anti-interference ability, repeatability and stability, and satisfactory results were also obtained in the detection of actual samples. The mechanism of Mn2+ modulation on the electrocatalytic activity of FeMn-MIL-88/CP towards DA and AC was revealed for the first time through the density functional theory (DFT) calculations. Good adsorption energy and rapid electron transfer worked synergistically to improve the sensing performances of DA and AC. This work not only provided a high-performance integrated electrode for the sensing field, but also demonstrated the influencing factors of electrochemical sensing at the molecular levels, laying a theoretical foundation for the sustainable development of subsequent electrochemical sensing.

Tailoring Efficient Fluorogenic Tactic for Ultrasensitive Detection of Dopamine in Urine and Rat Brain through Real-Time and In Situ Formation of High-Performance Fluorophore.

Owing to the predominance of dopamine (DA) in controlling mental health, planning an innovative method for DA detection with simplicity and high efficacy is conducive to the assessment of neurological disorders. Herein, an efficient fluorogenic tactic has been elaborated for ultrasensitive detection of DA with remarkably enhanced turn-on response. Utilizing a twisted intramolecular charge-transfer (TICT)-suppressing strategy, a highly emissive azocine derivative 11-hydroxy-2,3,6,7,11,12,13,14-octahydro-1H,5H,10H-11,14a-methanoazocino[5',4':4,5]furo[2,3-f]pyrido[3,2,1-ij]quinolin-10-one (J-Aza) is generated via a one-step reaction between DA and 8-hydroxyjulolidine. It is marvelous that J-Aza not only possesses ideal fluorescence quantum yield (ΦF) as high as 0.956 but also exhibits bathochromic shifted fluorescence (green emissive) and stronger anti-photobleaching capacity superior to traditional azocine-derived 1,2,3,4-tetrahydro-5H-4,11a-methanobenzofuro[2,3-d]azocin-5-one (Aza) with moderate ΦF, blue fluorescence, and poor photostability. By confining the TICT process, the detection limit to DA can be reduced to 80 pM, which is competitive in contrast to previously reported fluorescence methods. Encouraged by the instant response (within 90 s), wide linear range (0.1-500 nM), great selectivity, and excellent sensitivity, this fluorogenic method has been used for the real-time measurement of DA contents in practical urine samples with satisfactory results. Furthermore, the cerebral DA level in the reserpine-induced depression rat model has also been evaluated by our designed method, demonstrating its potent analytical applicability in the biosensing field.

Electrochemical sensor based on three-dimensional Skeleton/Skin ink for the ultrasensitive detection of dopamine released from neural cells

The development of a miniaturized and low-cost platform for the simultaneous and high-sensitive detection of the nervous system metabolites has gained great interest for early diagnosis and prognostic monitoring of some diseases. Herein, a three-dimensional (3D) interpenetrating hydrogel ink synthesized through a simple hydrothermal assembly way was utilized for the sensitive detection of dopamine released from neural cells in vivo. Carbon nanotubes (CNTs) were utilized as the structural framework, while reduced graphene nanosheets were employed as the outer covering, resulting in the formation of a “skeleton/skin” structure. The attachment of hydrophilic IL molecules onto the graphene nanosheets confers distinctive hydrophilic traits on the resulting nanocomposite material. Consequently, this facilitates its effortless conversion into freestanding paper-like material via printing. The modified electrode was proved to be efficient in electrochemical detection of dopamine by means of DPV, despite the existence of interfering substances like ascorbic and uric acid. With a sensitivity of 41.86 μA μM−1 cm−2 and a low detection limit of 2 nM (S/N = 3), the paper electrode exhibited a linear response ranging from 0.01 to 50 μM. Furthermore, the rGO-CNT-IL was used to determine dopamine levels in the neural cells. The modified paper electrode can also be potentially applied for further drug detection, health monitoring and other biological applications.

Electrochemical Sensor Based on Co-Doped FePS3 Nanosheets for Ultra-Sensitive Detection of Dopamine in Human Serum

Electrochemical dopamine (DA) sensors become important for the early diagnosis of psychiatric disorders like schizophrenia and Parkinson’s disease due to their fast response, simplicity, and portability. However, traditional electrode modification materials such as noble metals and metal oxides have shortcomings such as high cost, low conductivity, or limited catalytic performance. Two-dimensional sulfide materials contribute to the smooth electrode reaction because of their ultra-high specific superficial area and favorable electrocatalysis properties, however, their low carrier mobility and poor electroconductibility limit the detection signal. In this paper, Co-doped FePS3 nanosheets were employed for DA detection for the first time. Fe0.9Co0.1PS3 nanosheets exhibited a detection limit of 120 nM, a linear range 0.25–100 μM and 120–500 μM, and possessed high recovery and reproducible stability when applied to human serum samples. Furthermore, according to the in situ XPS characterization, S atoms located on the outmost layer of Fe0.9Co0.1PS3 nanosheets could be combined with the phenolic hydroxyl oxygen of DA, which makes electrode reaction from DA to dopamine quinone easier. Co-doping can further enhance the above effect, and increase the carrier mobility of FePS3 nanosheets. This work demonstrated electrochemical sensors based on metal phosphorus trisulfide materials have tremendous potential for future application in mental disorder diagnosis.

A photoelectrochemical sensor for ultrasensitive dopamine detection based on composites of BiOI and Au-Ag nanoparticles

A photoelectrochemical dopamine sensor based on BiOI and AuAgNPs nanoparticles modified indium tin oxide (ITO) electrode was prepared successfully. The noble metal material AuAg significantly improved the shortcomings of poor surface conductivity and easy recombination of photogenerated electron holes in BiOI. The prepared electrode generated a significantly enhanced and stable photocurrent signal under Xe lamp irradiation. In addition, in weak acidic electrolyte solution, dopamine molecules were protonated and preferent existed in the form of cations, which were easily attracted by electrostatic and adsorbed on the surface of negatively charged AuAgNPs. As an electron donor, DA is vulnerable to oxidation to DA+ by BiOI holes, resulting in an increased anodic photocurrent. The detection limit was 0.3 pM (S/N = 3) and the dopamine concentration exhibited a nice linear relationship between 1 pM and 0.1 μM under ideal circumstances. The dopamine photoelectrochemical sensor shown strong sensitivity, a broad linearity range, and good selectivity against potential uric acid and ascorbic acid interference. This work provides a promising PEC detection platform for the detection of small and medium-sized molecules in biological analysis.

DNA-modulated single-atom nanozymes with enhanced enzyme-like activity for ultrasensitive detection of dopamine.

Despite the current progress in optimizing and tailoring the performance of nanozymes through structural and synthetic adaptation, there is still a lack of dynamic modulation approaches to alter their catalytic activity. Here, we demonstrate that DNA can act as an auxiliary regulator via a straightforward incubation method with Fe-N-C single-atom nanozymes (SAzymes), causing a leap in the enzyme-like activity of Fe-N-C from moderate to a higher level. The DNA-assisted enhancement is attributed to the increased substrate affinity of Fe-N-C nanozymes through electrostatic attraction between the substrate and DNA. Based on the prepared DNA/Fe-N-C system, colorimetric sensors for dopamine (DA) detection were constructed. Surprisingly, the incorporation of DNA not only enabled the detection of DA in a low concentration range, but also greatly improved the sensitivity with a 436-fold decrease in detection limit. The quantitative determination of DA was achieved in two-segment linear ranges of 0.01-4 μM and 5-100 μM with an ultralow detection limit of 9.56 nM. The DNA/Fe-N-C system shows superior performance compared to the original Fe-N-C system, making it an ideal choice for nanozyme-based biosensors. This simple design approach has paved the way for enhancing nanozyme activity and is expected to serve as a general strategy for optimizing biosensor performance.

Ultrasensitive dopamine detection with graphene aptasensor multitransistor arrays

Detecting physiological levels of neurotransmitters in biological samples can advance our understanding of brain disorders and lead to improved diagnostics and therapeutics. However, neurotransmitter sensors for real-world applications must reliably detect low concentrations of target analytes from small volume working samples. Herein, a platform for robust and ultrasensitive detection of dopamine, an essential neurotransmitter that underlies several brain disorders, based on graphene multitransistor arrays (gMTAs) functionalized with a selective DNA aptamer is presented. High-yield scalable methodologies optimized at the wafer level were employed to integrate multiple graphene transistors on small-size chips (4.5 × 4.5 mm). The multiple sensor array configuration permits independent and simultaneous replicate measurements of the same sample that produce robust average data, reducing sources of measurement variability. This procedure allowed sensitive and reproducible dopamine detection in ultra-low concentrations from small volume samples across physiological buffers and high ionic strength complex biological samples. The obtained limit-of-detection was 1 aM (10–18) with dynamic detection ranges spanning 10 orders of magnitude up to 100 µM (10–8), and a 22 mV/decade peak sensitivity in artificial cerebral spinal fluid. Dopamine detection in dopamine-depleted brain homogenates spiked with dopamine was also possible with a LOD of 1 aM, overcoming sensitivity losses typically observed in ion-sensitive sensors in complex biological samples. Furthermore, we show that our gMTAs platform can detect minimal changes in dopamine concentrations in small working volume samples (2 µL) of cerebral spinal fluid samples obtained from a mouse model of Parkinson’s Disease. The platform presented in this work can lead the way to graphene-based neurotransmitter sensors suitable for real-world academic and pre-clinical pharmaceutical research as well as clinical diagnosis.

Surface modification of MoS2 nanosheets by single Ni atom for ultrasensitive dopamine detection

Surface modification of MoS2 nanosheets by single Ni atom for ultrasensitive dopamine detection

Electrodeposited copper nanocubes on multi-layer graphene: A novel nanozyme for ultrasensitive dopamine detection from biological samples

In this paper, copper nanocubes (CuNCs) were grown on top of few-layer and multi-layer graphene (FLG and MLG) nanomaterial by electrodeposition, to develop a sensitive and selective nanozyme based electrochemical sensor for the determination of dopamine from plasma samples. The copper electrodeposition process was intensively studied and optimized to obtain cubic shape CuNPs on top of graphene that increased the active area of the sensor. The surface of the nanomaterial was investigated with several microphysical characterization techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), and Fourier-transform infrared (FTIR), Raman, and X-ray photoemission spectroscopies (XPS). Further, the nanozyme sensor based on CuNCs-Gr/SPCE was electrochemically characterized using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), and the response towards the oxidation of DA was investigated using the differential pulse voltammetry (DPV) technique. The signal recorded with CuNCs-Gr/SPCE was linear in a wide range (0.001 – 100 µM), with a low limit of detection of 0.33 nM and a very high sensitivity of 196 mA/moL-1. The developed sensor showed high selectivity towards DA in presence of other neurotransmitters. The detection of DA in human plasma samples was obtained with 95.8–100.2 % recovery percentage, proving the reliability of the method.

Photoelectrochemical sensor based on zinc phthalocyanine semiconducting polymer dots for ultrasensitive detection of dopamine

Developing materials with excellent photoelectric activity is critical to improving the sensitivity of photoelectrochemical (PEC) sensors. Herein, we reported a convenience method to synthesize phthalocyanine polymer dots (Pdots), which dope zinc phthalocyanine (ZnPc) into a conjugated polymer poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo{2,1,3}thiadia-zol-4,8-diyl)] (P8BT). The synthesized materials were characterized by energy dispersive spectrometry (EDS), electrochemical impedance spectroscopy (EIS), fluorescence (FL) spectroscopy, transmission electron microscopy (TEM), ultraviolet-visible diffuse reflectance spectroscopy (UV–vis DRS), and dynamic light scattering (DLS). Then, ZnPc-P8BT-Pdots were modified on an indium tin oxide (ITO) electrode by repeated immersion to develop an ultrasensitive PEC sensor for dopamine (DA) detection. Semiconducting polymers in ZnPc-doped forms exhibit a typical photocurrent reduction in comparison with the original polymers. As the photocurrent was weakened, energy was transferred from the conjugated polymers to ZnPc. The photocurrent intensity of ZnPc-P8BT-Pdots/ITO increases as the concentration of DA increases under blue light irradiation. Under the best experimental conditions, the PEC sensor realized the detection of DA (2.5 nM-125 μM) with a limit of detection (LOD) of 1.69 nM (S/N = 3). Moreover, the ZnPc-P8BT-Pdots/ITO sensor for the detection of DA exhibited superior PEC performance, high sensitivity, rapid response, and favorable stability. This study indicated that ZnPc-P8BT-Pdots possess the promising potential to construct PEC sensors for pharmaceutical analysis.

Nitrogen and sulfur co-doped Nb2C-MXene nanosheets for the ultrasensitive electrochemical detection dopamine under acidic conditions in gastric juice

Nitrogen and sulfur co-doped Nb 2 C MXene (NS-Nb 2 C) which successfully synthesized in a one-step treatment of Nb 2 C using thiourea as N,S resource is used as a stable and high-performance sensing material for highly sensitive detection of dopamine (DA) in gastric juice under acidic conditions. The NS-Nb 2 C is more electrochemically active than multilayered Nb 2 C nanosheets (ML-Nb 2 C) and delaminated Nb 2 C nanosheets (DL-Nb 2 C) under acidic conditions due to the provision of active sites, high surface area and enhanced conductivity caused by the heteroatom doping strategy. • A novel electrochemical sensor based on nitrogen and sulfur co-doped Nb 2 C MXene is proposed for DA detection in gastric juice. • NS-Nb 2 C is more electrochemically active than multilayered Nb 2 C nanosheets and delaminated Nb 2 C nanosheets. • This work provides a new direction for the application of Nb-based MXene in the electrochemical sensing applications. • Nitrogen and sulfur co-doping is an effective method to improve the electrochemical performance of MXene. This work reports the synthesis and application of nitrogen and sulfur co-doped Nb 2 C MXene (NS-Nb 2 C) for the sensing of dopamine (DA) in gastric juice. NS-Nb 2 C MXene was successfully synthesized in a one-step treatment of Nb 2 C using thiourea as N,S resource. The heteroatom doping strategy enables introduction of N,S into MXene nanosheets and simultaneously induces the increased interlayer spacing, high surface area, and enhanced electrical conductivity. It was found that NS-Nb 2 C is more electrochemically active than multilayered Nb 2 C nanosheets (ML-Nb 2 C) and delaminated Nb 2 C nanosheets (DL-Nb 2 C). Based on this, the as-prepared NS-Nb 2 C/Nafion/GCE was used to study the electrochemical behavior of dopamine in pH = 3.0. The sensing interface not only utilizes the unique two-dimensional (2D) nanosheet morphology of Nb 2 C that has a larger surface area and conductive network, but also takes advantage of the more active sites provided by doping. This enables the sensor to achieve ultra-sensitive detection of dopamine (S/N = 3) with a low limit of detection (LOD) of 0.12 µM. In addition, the prepared sensor has good stability and selectivity, and the results of detecting DA in simulated gastric juice is satisfactory. The results indicated that the Nb-based MXenes provided a promising tool for acidic electrochemical sensing applications.