Researchers have developed a nanocomposite-based electrochemical sensor that can detect dopamine with unprecedented sensitivity and selectivity. The device, built from platinum nanoparticles (PtNPs) integrated with carbon nanotubes (CNTs) and polypyrrole (PPy), offers a scalable, environmentally friendly platform for monitoring neurological health.
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Dopamine is a vital neurotransmitter involved in mood regulation, motor control, and cognition. Abnormal levels are linked to a range of disorders such as Parkinson’s disease, depression, and schizophrenia, making accurate detection essential for diagnosis and treatment.
Conventional detection methods, including high-performance liquid chromatography and mass spectrometry, provide reliable results but are costly, complex, and impractical for real-time or point-of-care applications. Electrochemical sensors, by contrast, offer a faster, lower-cost solution, especially when enhanced with nanomaterials.
Building a Smarter Sensor with Nanotechnology
Nanotechnology has transformed sensor design by introducing materials with high surface area and unique electrochemical properties. Recently introduced in Electrochemical Science Advances, researchers have engineered a ternary nanocomposite PtNPs@CNTs/PPy-C, using a simple two-step method.
First, they combined CNTs with PPy using ultrasonication, creating a conductive matrix. Then, Pt(IV) chloride was photochemically reduced under a mercury lamp in the presence of methanol, forming Pt nanoparticles anchored to the CNT/PPy network. This dispersant-free process simplified the nano synthesis, lowering its cost and environmental impact.
Once formed, the nanocomposite was extensively characterized using XRD, XPS, FTIR, and TEM, confirming uniform PtNP distribution and a stable structure. Electrochemical testing was performed with a glassy carbon electrode modified by drop-casting the composite. Its performance was evaluated via cyclic voltammetry and differential pulse voltammetry.
Sensitivity, Selectivity, Stability
The sensor demonstrated a wide detection range with detection limits as low as 0.034 µM for low dopamine concentrations and 0.146 µM at higher levels. The calibration curve revealed two linear regions, with higher sensitivity at low concentrations—a common phenomenon due to surface blocking at higher analyte levels.
Electrochemical analysis confirmed adsorption-controlled DA oxidation, with a heterogeneous electron transfer rate constant of 8.37 s-1. The PtNPs increased the electroactive surface area, leading to sharper current peaks and a reduced peak separation of 71 mV compared to unmodified electrodes.
Most importantly, the sensor displayed excellent selectivity against interfering compounds such as ascorbic and uric acid, two problematic molecules in biological samples. Repeatability tests demonstrated remarkable stability, with a relative standard deviation of just 1.18 % and minimal signal loss after repeated cycles.
Clinical and Practical Applications
The PtNPs@CNTs/PPy-C sensor’s high sensitivity and stability make it an attractive candidate for biomedical diagnostics, particularly in monitoring dopamine levels in patients with neurological disorders. Its simple, scalable synthesis process also supports wider clinical adoption.
Beyond dopamine, the platform could be adapted to detect other neurotransmitters and biomolecules, opening new avenues in personalized medicine, pharmaceutical analysis, and continuous biosensing.
Journal Reference
S, N, I, Nayem., et al. (2025). Highly Sensitive Dopamine Electrochemical Sensor Using Pt Nanoparticles on CNTs/Polypyrrole Nanocomposites. Electrochemical Science Advances, e70011. DOI: 10.1002/elsa.70011, https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/elsa.70011
