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 that can detect dopamine with high sensitivity in tear fluid, pointing to a possible noninvasive route for monitoring neurological disorders.

Dopamine is central to movement, cognition, and emotional regulation, and abnormal levels are linked to disorders including Parkinson’s disease and schizophrenia. Because current monitoring methods often rely on blood, urine, or implanted devices, the researchers focused on tears as a faster and less invasive alternative. The team built the sensor using laser-induced graphene and then functionalized it with nickel nitrate and urea. This combination increased the number of active sites, improved electron transfer, and boosted the oxidation signal from dopamine, which is the key electrochemical event the sensor measures.