Laser-induced graphene sensor enables dopamine detection in tears
Researchers from Brazil's Federal University of Pelotas and Federal University of Rio Grande do Sul have developed a laser-induced graphene sensor capable of detecting dopamine in tear fluid with high sensitivity. This advancement could lead to noninvasive monitoring of neurological disorders, utilizing the electroactive properties of graphene to provide a compact and scalable alternative to traditional methods that often require blood or implanted devices.
Researchers from Brazil's Federal University of Pelotas and Federal University of Rio Grande do Sul have developed a laser-induced graphene sensor capable of detecting dopamine with high sensitivity in tear fluid. This advancement suggests a potential noninvasive method for monitoring neurological disorders.
Dopamine plays a crucial role in movement, cognition, and emotional regulation, with abnormal levels linked to disorders such as Parkinson’s disease and schizophrenia. Traditional monitoring methods often require blood, urine, or implanted devices. The research team focused on tears as a faster and less invasive alternative. They constructed the sensor using laser-induced graphene, enhanced with nickel nitrate and urea. This combination increased active sites, improved electron transfer, and amplified the oxidation signal from dopamine, the key electrochemical event measured by the sensor.
The sensor demonstrated strong analytical performance. In phosphate-buffered saline, it showed a linear detection range of 0.25–16.44 μmol·L–1, a detection limit of 17.86 nmol·L–1, and a quantification limit of 54.14 nmol·L–1, with 𝑅2=0.98. In synthetic tear fluid, it maintained a reliable response across 3.23–9.32 μmol·L–1, with recovery in real-sample analysis close to 100%.
The concentration range is significant as previously reported dopamine levels in tears are approximately 3.38 μmol·L–1, which fits within the sensor’s operational window. The device also showed high selectivity in complex tear-like media, accurately detecting dopamine even in the presence of other common tear components.
This development results in a compact, low-cost, nonenzymatic sensing platform that combines scalable laser fabrication with robust electrochemical performance. By utilizing the electroactive graphene structure and nickel-based surface chemistry, the sensor generates a measurable current response, potentially making it suitable for future point-of-care tear-based diagnostics.
Source: Graphene Feed