Dopamine Recognition Research Articles

A dual-template molecularly imprinted electrochemical sensor assisted with BO-XGBoost algorithm for simultaneous determination of dopamine and acetaminophen

The simultaneous detection of dopamine (DA) and acetaminophen (AP) is crucial for diagnosing and treating related mental disorders. However, accurately determining DA and AP in biological samples remains challenging due to the interference from other biomolecules, such as ascorbic acid (AA), uric acid (UA), epinephrine (EP), etc. Here, we present a dual-template molecularly imprinted electrochemical sensor for the selective recognition of DA and AP. Reduced graphene(rGO)-gold nanoparticles(AuNPs) composite were utilized to enhance the effective area and increase the electron transfer rate of glassy carbon electrode(GCE), thus the electrochemical response signals were amplified. This sensor combined the advantages of nanocomposites and molecularly imprinted polymer (MIP) to achieve highly sensitive and selective detection of DA and AP. However, decreases in the current response of some analytes and variations in relationships of the peak current versus analyte concentration will occur due to adsorption competition on active sites in multianalyte mixtures, rendering the detection range constrained and traditional linear fitting methods inaccurate for predicting analyte concentrations. Therefore, a concentration prediction model based on XGBoost was developed for the sensor to achieve the reliable multi-component determination of DA and AP within the identical measurement range as individual detection. In this model, nine characteristic parameters were extracted from the differential pulse voltammetry (DPV) response curve and Bayesian optimization (BO) was adopted for automatic hyperparameter search, thereby the prediction errors were reduced and the generalization ability was improved. Experiments indicated that the MIP/AuNPs/rGO/GCE exhibited a wide detection range of 2–240 μM and 3–240 μM for DA and AP, with detection limits down to 0.26 μM and 0.33 μM, respectively. In addition, the intelligent MIP/AuNPs/rGO/GCE sensor based on BO-XGBoost model provides more accurate prediction results for untrained concentration combinations obtained from fetal bovine serum samples, indicating that the proposed detection scheme holds potential in future clinical diagnosis.

In situ detection of dopamine in single living cells by molecularly imprinted polymer-functionalized nanoelectrodes

In situ detection of dopamine (DA) at single-cell level is critical for exploring neurotransmitter-related biological processes and diseases. However, the low content of DA and a variety of distractors with similar oxidation potentials as DA in cells brought great challenges. Here, a sensitive and specific electrochemical nanosensor was proposed for in situ detection of DA in single living cells based on nanodiamond (ND) and molecularly imprinted polymer (MIP)-functionalized carbon fiber nanoelectrode (ND/MIP/CFNE). Due to its excellent electrocatalytic property, ND was modified to the surface of CFNE based on amide bonding. Compared with bare CFNE, ND-modified CFNE can enhance oxidation currents of DA by about 4-fold, improving signal-to-noise ratio and detection sensitivity. MIP was further electropolymerized on the surface of nanoelectrodes to achieve specific capture and recognition of DA, which could avoid the interference of complex matrix and analogs in cells. Taking advantage of the precise positioning capability of a single-cell analyzer and micromanipulator, ND/MIP/CFNE could be precisely inserted into different locations of single cells and monitor oxidation signal of DA. The concentration of DA in the cytoplasm of single pheochromocytoma (PC12) cell was measured to be about 0.4 μM, providing a sensitive and powerful method for single-cell detection. Furthermore, the nanoelectrodes can monitor the fluctuation of intracellular DA under drug stimulation, providing new ideas and methods for new drug development and efficacy evaluation.

A novel dual recognition sensor based on molecularly imprinted polymers and photochemical aptamer for non-autofluorescence determination of dopamine

Dopamine (DA), as a neurotransmitter that plays a crucial role in neuronal communication. Abnormal levels of DA concentration in vivo are associated with severe neurological disorders such as Alzheimer’s disease and Parkinson’s disease. Highly selective and highly efficient determination of DA from complex biological samples is very important. In this work, m-MIPs@DA@ZGGC-Apt, a novel sandwich structure persistent luminescence sensor was designed based on a photochemical aptamer sensor and magnetic molecularly imprinted polymers (m-MIPs). By modifying aptamers on the surface of ZGGC persistent luminescent nanoparticles, ZGGC-Apt probes with dual capabilities (recognition and detection) were obtained, which allowed for specific recognition and autofluorescence-free detection of DA. The m-MIPs recognition probe with specific cavity captures of DA was synthesized using Fe3O4 as the imprint carrier. In the presence of both probes, a m-MIPs@DA@ZGGC-Apt sandwich structure was formed continuously in real samples with the increase in DA concentration, resulting in a strong the luminescence response. Under optimal experimental conditions, satisfactory selectivity and sensitivity were obtained by the dual recognition sensor achieved a wide linear range from 0.01 to 100 μM and a low detection limit of 0.0065 μM. Moreover, the designed sensor showed good reliability and practicability in the detection of small molecule DA in real biological samples.

Development of functionalized polymeric nanomaterial by organosiliconic reagent for boronate affinity-based dopamine recognition

The dopamine neurotransmitter is mainly responsible for endocrine functions in our body. The increase in the level of dopamine in the human body leads to many disorders such as schizophrenia, uncontrollable tics, addiction, increased tension, desire to act excessively, and carelessness. Decreased levels of dopamine cause problems such as malnutrition, stress, insomnia, and the use of antidepressants. Recognition of dopamine is crucial for clinical experiments. Therefore, the development of recognition surfaces of dopamine is essential for isolation, purification, and determination processes. This study, it was aimed to produce a polymeric nanomaterial that can recognize dopamine. For this purpose, p(HEMA) polymer was synthesized with surfactant-free emulsion polymerization method and silanized by organosilicon reagent (3-aminopropyl) triethoxylsilane (APTES) and modified with phenylboronic acid (PBA). Characterization of the p(HEMA)-APTES-PBA nanopolymeric system for dopamine recognition was performed with Scanning Electron Microscope(SEM), Energy Dispersive Spectrometry (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Zeta-size/zeta-potential analysis, surface area calculations. Dopamine affinity of the p(HEMA)-APTES-PBA was optimized in terms of pH, time, concentration, buffer concentration, and buffer type parameters. Dopamine adsorption of p(HEMA)-APTES-PBA nanopolymers was 4,8 times more than epinephrine in specificity analysis. After the 7 adsorption–desorption cycles, the desorption rate was found to be 74.8 %. The developed nanopolymeric system is a convenient method with high adsorption capacity which allows easy and rapid extraction, isolation, and purification of dopamine.

Simultaneous recognition of dopamine and uric acid in real samples through highly sensitive new electrode fabricated using ZnO/carbon quantum dots: bio-imaging and theoretical studies.

Dopamine (DA) and uric acid (UA), which are vital components in human metabolism, cause several health problems if they are present in altered concentrations; thus, the determination of DA and UA is essential in real samples using selective sensors. In the present study, graphite carbon paste electrodes (CPE) were fabricated using ZnO/carbon quantum dots (ZnO/CQDs) and employed as electrochemical sensors for the detection of DA and UA. These electrodes were fully characterized via different analytical techniques (XRD, SEM, TEM, XPS, and EDS). The electrochemical responses from the modified electrodes were evaluated using cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy. The results showed that the present electrode has exhibited high sensitivity towards DA, recognizing even at low concentrations (0.12 μM), and no inference was observed in the presence of UA. The ZnO/CQD electrode was applied for the simultaneous detection of co-existing DA and UA in real human urine samples and the peak potential separation between DA and UA was found to be greatly associated with the synergistic effect originated from ZnO and CQDs. The limit of detection (LOD) of the electrode was analyzed, and compared with other commercially available electrodes. Thus, the ZnO/CQD electrode was used to detect DA and UA in real samples, such as Saccharomyces cerevisiae cells.

Dopamine sensing by fluorescent carbon nanoparticles synthesized using artichoke extract.

The practical and easy detection of dopamine levels in human fluids, such as urine and saliva, is of great interest due to the correlation of dopamine concentration with several diseases. In this work, the one-step synthesis of water-soluble carbon nanoparticles (CNPs), starting from artichoke extract, containing catechol groups, for the fluorescence sensing of dopamine is reported. Size, morphology, chemical composition and electronic structure of CNPs were elucidated by DLS, AFM, XPS, FT-IR, EDX and TEM analyses. Their optical properties were then explored by UV-vis and fluorescence measurements in water. The dopamine recognition properties of these CNPs were investigated in water through fluorescence measurements and we observed the progressive enhancement of the CNP emission intensity upon the progressive addition of dopamine, with a binding affinity value of log K = 5.76 and a detection limit of 0.81 nM. Selectivity towards dopamine was tested over other interfering analytes commonly present in human saliva. Finally, in order to perform a solid point of care test, CNPs were adsorbed on a solid support and exposed to different concentrations of dopamine, thus observing a pseudo-linear response, using a smartphone as a detector. Therefore, the detection of dopamine in simulated human saliva was performed with excellent results, in terms of selectivity and a detection limit of 100 pM.

Nanozyme catalyzed-SERRS sensor for the recognition of dopamine based on AgNPs@PVP with oxidase-like activity

Dopamine (DA), as one of the most significant neurotransmitters, is closely related to several diseases. Achieving rapid and sensitive detection of DA remains a challenge. Herein, we proposed a simple, fast, and sensitive method for DA recognition based on surface-enhanced resonance Raman scattering (SERRS) technique. The synthesized silver nanoparticles coated with polyvinylpyrrolidone (AgNPs@PVP) with oxidase activity could not only oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) directly to produce a blue oxidation state TMB (oxTMB) but also could be used as the SERS substrate to generate a strong SERRS signal. When DA was added to the above system, the blue color faded along with the decrease in the SERRS signal. The change value of SERRS intensity was in proportion to the concentration of DA in the range of 0.1–10 μM with a limit of detection of 40 nM. This method presented great potential for the recognition of DA-related diseases.

3,5-Dihydroxybenzoic Acid-Based Selective Dopamine Detection via Subsititution-Enhanced Kinetics Differences.

The selective recognition of dopamine (DA) over other neurotransmitter analogues is difficult due to the similar molecular structure and chemical reactivity. In this study, substitution-regulated chemical reactivity of the sensing substrate is utilized to explore a novel DA detection probe with satisfying selectivity. As a case study, 3,5-dihydroxybenzoic acid (DHBA, carboxy-substituted resorcinol)-based probes have been explored for selective and ratiometric DA sensing. The carboxy substitution benefits the stabilization of the carbanion intermediate and the azamonardine product, which enhances the reaction kinetics and thermodynamics and subsequently facilitates selective DA recognition over other analogues and interferents. By exploring DHBA emission as the internal reference, ratiometric fluorescence variation is realized, which contributes to sensitive DA analysis. With the combination of logic gate and fluorometric analysis, DA detection in both low and high concentrations can be readily achieved. In addition, the DA analysis in biological samples and the enzymatic transformation of DA analogues in cerebrospinal fluid samples are achieved by the proposed DHBA probe.

From Enzymatic Dopamine Biosensors to OECT Biosensors of Dopamine.

Neurotransmitters are an important category of substances used inside the nervous system, whose detection with biosensors has been seriously addressed in the last decades. Dopamine, a neurotransmitter from the catecholamine family, was recently discovered to have implications for cardiac arrest or muscle contractions. In addition to having many other neuro-psychiatric implications, dopamine can be detected in blood, urine, and sweat. This review highlights the importance of biosensors as influential tools for dopamine recognition. The first part of this article is related to an introduction to biosensors for neurotransmitters, with a focus on dopamine. The regular methods in their detection are expensive and require high expertise personnel. A major direction of evolution of these biosensors has expanded with the integration of active biological materials suitable for molecular recognition near electronic devices. Secondly, for dopamine in particular, the miniaturized biosensors offer excellent sensitivity and specificity and offer cheaper detection than conventional spectrometry, while their linear detection ranges from the last years fall exactly on the clinical intervals. Thirdly, the applications of novel nanomaterials and biomaterials to these biosensors are discussed. Older generations, metabolism-based or enzymatic biosensors, could not detect concentrations below the micro-molar range. But new generations of biosensors combine aptamer receptors and organic electrochemical transistors, OECTs, as transducers. They have pushed the detection limit to the pico-molar and even femto-molar ranges, which fully correspond to the usual ranges of clinical detection of human dopamine in body humors that cover 0.1 ÷ 10 nM. In addition, if ten years ago the use of natural dopamine receptors on cell membranes seemed impossible for biosensors, the actual technology allows co-integrate transistors and vesicles with natural receptors of dopamine, like G protein-coupled receptors. The technology is still complicated, but the uni-molecular detection selectivity is promising.

High-Density Optophysiology Platform for Recording Intracellular and Extracellular Signals across the Brain of Free-Moving Animals.

Developing a novel tool capable of real-time monitoring and simultaneously quantifying of both intra/extracellular chemical signals across the large-scale brain is the key bottleneck for understanding the interactions between the molecules inside and outside neurons. Here we built up a high-density intra/extracellular optophysiology platform, together with developing two probes for specific recognition of L-cysteine (Cys) and dopamine (DA), for simultaneously quantifying of both intracellular Cys and extracellular DA with high selectivity and accuracy across the brain of freely moving animals, as well as recording electrical signals. Using this powerful tool, it was found that intracellular Cys regulated extracellular DA through inducing the expression of tyrosine hydroxylase in the depressed mice brain. We also established the functional networks of Cys and DA across 32 brain regions in freely moving animals. More importantly, it was discovered that depression reduced the correlations between adjacent brain regions, which was recovered by the treatment of N-acetyl-l-cysteine.

Label-Free Electrogenerated Chemiluminescence Aptasensing Method for Highly Sensitive Determination of Dopamine via Target-Induced DNA Conformational Change.

A label-free electrogenerated chemiluminescence (ECL) aptasensing method for highly sensitive determination of dopamine (DA) was developed based on target-induced DNA conformational change. After anti-DA specific aptamer, as molecular recognition element, was hybridized with a capture ss-DNA (complementary with the aptamer), the formed double-strand DNA (ds-DNA) was self-assembled onto the surface of a gold electrode, and then Ru(phen)32+, as ECL reagent, was intercalated into ds-DNA to form an ECL biosensing platform. In the presence of DA, DA bound with its aptamer and target-induced DNA conformational change occurred, resulting in the dissociation of ds-DNA, the release of intercalated Ru(phen)32+ from the electrode surface, and the decrease of ECL intensity. For comparison, an ECL aptamer-based biosensing method using an ECL reagent-labeled aptamer was also developed for DA assay based on target-induced DNA conformational change. Because of the increase in the amount of ECL reagent into ds-DNA over that of the single-site ECL reagent-labeled aptamer, an obvious increase of ECL intensity was found at the ds-DNA modified electrode over the aptamer modified electrode. DA can be sensitively detected with a lower detection limit of 0.05 nM in the range from 0.1 to 100 nM. With the recognition of the aptamer for DA, DA can be selectively and sensitively detected in artificial cerebrospinal fluid and serum samples without interference from common small molecules. This work demonstrates that the combination of the direct transduction of specific recognition of DA and its aptamer into an ECL signal with Ru(phen)32+ intercalated ds-DNA amplification provides a promising strategy for the development of a simple, sensitive, and selective method for DA assay, which is of great importance in neurochemical assays and clinical diagnosis.

Smartphone-Based Dopamine Detection by Fluorescent Supramolecular Sensor.

Supramolecular recognition of dopamine by two quinoxaline cavitands was studied in solution by fluorescence titrations, ESI-MS and ROESY measurements. In addition, the tetraquinoxaline cavitand was dropped onto a siloxane-based polymeric solid support, obtaining a sensor able to detect dopamine in a linear range of concentrations 10 Mm-100 pM, with a detection limit of 1 pM, much lower than the normal concentration values in the common human fluids (plasma, urine and saliva), by using a simple smartphone as detector. This sensor shows also good selectivity for dopamine respect to the other common analytes contained in a saliva sample and can be reused after acid-base cycles, paving the way for the realization of real practical sensor for human dopamine detection.

Electrochemical determination of dopamine and uric acid with covalent organic frameworks and Ox-MWCNT co-modified glassy carbon electrode

Covalent organic frameworks (COFs) have received tremendous interest due to their structural diversity and versatility. These unique physicochemical properties make them exhibit great application potential in the field of electrochemical sensor. In this study, an imine bond-linked COF with porosity and large specific surface area was fabricated by a dehydration condensation reaction between 1, 3, 5-tris(4-formylphenyl)benzene (TFPB) and 1, 3, 5-tris(4-aminophenyl) benzene (TAPB) and combined with high electrical conductivity of oxidized multi-walled carbon nanotube (Ox-MWCNT). The structure of the COF and the resulted composite material were confirmed through a series of characterization techniques, including Fourier-transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and thermogravimetric analysis, then a co-modified glassy carbon electrode was constructed for simple, sensitive and selective electrochemical recognition of dopamine (DA) and uric acid (UA). The fabricated electrochemical sensor displayed a strong current response to both DA and UA in the phosphate buffer solution (PBS) at pH = 6.5. The synergistic effect between COFs and Ox-MWCNT effectively improved the analytical sensitivity for the target analytes. Under optimized experimental conditions, the method showed good performance for DA and UA in the concentration range of 0.6–250.0 μM with low detection limits of 0.073 μM and 0.063 μM (S/N = 3), respectively. Moreover, the proposed sensor exhibited high selectivity, longtime stability, desirable repeatability and acceptable reproducibility and can be used to analyze simultaneously DA and UA in biological and medicine samples with satisfactory results. Our work not only provides a simple way to detect DA and UA quantitatively in real samples, but also offers a new platform for COF-based composite application in electrochemical sensing . • TFPB-TAPB-COF is prepared via a simple solvothermal method. • TFPB-TAPB-COF/Ox-MWCNT/GCE is fabricated for sensing of dopamine (DA) and uric acid (UA). • The sensor has low detection limits and wide linear ranges for detection DA and UA. • The sensor is successfully applied to the determination of DA and UA in real samples.

Ultrasensitive and Selective Electrochemical Detection of Dopamine Based on CuO/PVA Nanocomposite-Modified GC Electrode

At present, the determination of dopamine (DA) is enormously necessary for the human body. Since then, it has played a crucial role in the brain that affects mood, sleep, memory, learning, and concentration. Dopamine insufficiency is a threat to human health. Dopamine recognition is important to avoid this problem. Copper oxide (CuO) nanoparticles are one of the potentials which can be used in the detection of dopamine level in the sample. In this work, CuO was synthesized by a simple chemical precipitation technique and modified by polyvinyl alcohol (PVA) as a capping agent. The nanomaterials manufactured are used for the detection of dopamine in 0.1 M PBS medium at room temperature. The CuO/PVA-modified electrode shows better electrocatalytic activity than CuO/GCE (glassy carbon electrode). The constructed dopamine biosensor of copper oxide-PVA nanocomposites also has extraordinary selectivity, stability, sensitivity (183.12 μA mM-1 cm-2), and a minimum level detection limit of 0.017 μM, is inexpensive, and has minimal effort and rapid detection of dopamine.

A novel three-dimensional molecularly imprinted polypyrrole electrochemical sensor based on MOF derived porous carbon and nitrogen doped graphene for ultrasensitive determination of dopamine.

Herein, a novel molecular imprinting polypyrrole electrochemical sensor was fabricated based on a zirconia and carbon core-shell structure (ZrO2@C) and a nitrogen-doped graphene (NPG) modified glassy carbon electrode (GCE) for ultrasensitive recognition of dopamine (DA). The NPG was prepared by a sacrificial-template-assisted pyrolysis method and ZrO2@C was synthesized via annealing treatment of a zirconium-based metal-organic framework (UiO-66). A convenient electropolymerization method was used to prepare the pyrrole (Py) conductive molecularly imprinted polymer (MIP) in the presence of DA. The elution process of DA was performed by a simple overoxidation process under alkaline conditions. Differential pulse voltammetry (DPV) was used to assess the electrochemical performance of the sensors. The MIP-based electrochemical sensor with specific binding sites could be used for selective recognition of DA. Under the optimal conditions, the linear range of such a sensor was 5.0 × 10-9-1.0 × 10-4 mol L-1 and the detection limit was 3.3 × 10-10 mol L-1 (S/N = 3). This sensor exhibited suitable selectivity, stability, and reproducibility, which suggested that it could be a promising candidate for rapid diagnostic methods in dopamine investigations.

Fast screening test for molecular recognition of levodopa and dopamine in biological samples using 3D printed stochastic microsensors

The simultaneous assay of levodopa and dopamine is essential for diagnosis and treatment of neurodegenerative diseases and brain cancer. 3D stochastic microsensors based on multi-walled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs) and 1-adamantyloleamide (AOA) was used for the simultaneous molecular recognition of levodopa and dopamine in biological samples (whole blood, urine, and brain tissue). The proposed 3D stochastic microsensors presented low limits of quantification, and high sensitivities. High selectivity was recorded versus neurotransmitters such as epinephrine, norepinephrine, serotonin, and glutamate. High recoveries were obtained for the assay of both levodopa and dopamine in whole blood, urine, and tumor tissue samples.

One-pot hydrothermal synthesis of NiCoZn a ternary mixed metal oxide nanorod based electrochemical sensor for trace level recognition of dopamine in biofluids

Here, we present a facile, one-pot hydrothermal synthesis of NiCoZn (NCZ) ternary metal oxide nanorods adapted glassy carbon electrode (GCE) for trace level recognition of dopamine (DA) in biofluids. The NCZ-MMO/GCE sensor exhibits a low limit of detection (LOD) of 0.01 nM with a linear range of detection from 1 nM to 500 μM. The sensor exhibits excellent selectivity and stability with the successful determination of DA in human blood serum with good recovery percentages ranging from ∼96.43% to 103.91%. Thus, proving it as a promising low-cost, reliable platform for a wide variety of bioanalytical applications.

Simultaneous Recognition of Dopamine and Uric Acid in the Presence of Ascorbic Acid via an Intercalated MXene/PPy Nanocomposite.

Two-dimensional (2D) MXenes have shown a great potential for chemical sensing due to their electric properties. In this work, a Ti3C2Tx/polypyrrole (MXene/PPy) nanocomposite has been synthesized and immobilized into a glassy carbon electrode to enable the simultaneous recognition of dopamine (DA) and uric acid (UA) under the interference of ascorbic acid (AA). The multilayer Ti3C2Tx MXene was prepared via the aqueous acid etching method and delaminated to a single layer nanosheet, benefiting the in-situ growth of PPy nanowires. The controllable preparation strategy and the compounding of PPy material remain great challenges for further practical application. A facile chemical oxidation method was proposed to regulate magnitude and density during the forming process of PPy nanowire, which promotes the conductivity and the electrochemical active site of this as-prepared nanomaterial. The MXene/PPy nanocomposite-modified electrode exhibited the selective determination of DA and UA in the presence of a high concentration of AA, as well as a wide linear range (DA: 12.5–125 μM, UA: 50–500 μM) and a low detection limit (DA: 0.37 μM, UA: 0.15 μM). More importantly, the simultaneous sensing for the co-existence of DA and UA was successfully achieved via the as-prepared sensor.

Development of a novel sensing platform based on molecularly imprinted polymer and closed bipolar electrochemiluminescence for sensitive detection of dopamine

Abstract Electrochemiluminescence (ECL) is widely used in bioanalysis due to its outstanding performance. In this work, we proposed a new ECL sensing strategy through the combination of molecular imprinting technology (MIT) and bipolar electrode (BPE). We use 3-aminophenyl boronic acid (APBA) as the monomer and dopamine (DA) as the template molecule to fabricate the MIP sensor through one-step electropolymerization. DA was encapsulated within the polymer film during the polymerization and subsequently removed to form a molecularly imprinted polymer (MIP) for DA recognition. The MIP modified electrode was applied as the sensing electrode, which could generate the oxidation current in the presence of DA, enabling the ECL signal change of reporting cell containing Ru(bpy)32+/TPrA in the BPECL system. Therefore, the rapid analysis of DA was achieved via this c-MIP-BPECL platform. The closed BPE simplifies sample pretreatment due to the relative independence of sensing and detecting, and the enrichment and precise identification of the analytes by MIP greatly improve the sensitivity, selectivity, and stability of the bipolar system. The established platform exhibits great sensing performance for DA with a linear range of 2 × 10−7–2.6 × 10−4 M and 2.6–6.2 × 10−4 M, respectively, with the low limit of detection (LOD) of 1 × 10−7 M.

A digital SERS sensing platform using 3D nanolaminate plasmonic crystals coupled with Au nanoparticles for accurate quantitative detection of dopamine.

We report a digital surface-enhanced Raman spectroscopy (SERS) sensing platform using the arrays of 3D nanolaminate plasmonic crystals (NLPC) coupled with Au nanoparticles and digital (on/off) SERS signal analysis for the accurate quantitative detection of dopamine (DA) at ultralow concentrations. 3D NLPC SERS substrates were fabricated to support the optically dense arrays of vertically-stacked multi-nanogap hotspots and combined with Raman tag-conjugated Au nanoparticles for NLPC-based dual-recognition structures. We demonstrate that the 3D NLPC-based dual-recognition structures including Au nanoparticle-induced additional hotspots can enable more effective SERS enhancement through the molecular recognition of DA. For the accurate quantification of DA at ultralow concentrations, we conducted digital SERS analysis to reduce stochastic signal variation due to various microscopic effects, including molecular orientation/position variation and the spatial distribution of nanoparticle-coupled hotspots. The digital SERS analysis allowed the SERS mapping results from the DA-specific dual-recognition structures to be converted into binary "On/Off" states; the number of "On" events was directly correlated with low-abundance DA molecules down to 1 pM. Therefore, the digital SERS platform using the 3D NLPC-based dual-recognition structures coupled with Au nanoparticles and digital SERS signal analysis can be used not only for the ultrasensitive, accurate, and quantitative determination of DA, but also for the practical and rapid analysis of various molecules on nanostructured surfaces.