Researchers have developed an inexpensive electrochemical sensor capable of detecting dopamine changes in tears, which could pave the way for early detection of diseases such as Parkinson's before troublesome symptoms appear.
Dopamine is a key neurotransmitter that controls movement, learning, and emotional motivation, and any imbalance in its levels is associated with serious neurological and psychological disorders.
In Parkinson's disease, for example, dopamine levels gradually decrease, while in some other cases they increase.
Current monitoring methods, such as blood and urine tests or implanted devices, are either time-consuming or require surgical intervention, making them impractical for regular follow-up. This is where tears come in; they can be collected easily and painlessly, offering a promising window into brain health.
A research team led by Naftali Lenin-Viarr-Real Carreño, whose study was published in the journal ACS Omega, developed a postage stamp-sized sensor made from a thin plastic film partially transformed into the electrically conductive material graphene using a laser. The device works by generating an electrical signal when dopamine interacts with the graphene, allowing for precise measurement of its concentration.
In laboratory experiments, researchers added dopamine to artificial human tears and found that the sensor detected concentrations with high accuracy, including levels similar to those recorded in the tears of Parkinson's patients. The device also performed efficiently even in the presence of other compounds common in tears.
Co-author Lucas Menge Gonsalves says the sensor can detect dopamine levels from well below the normal healthy level, up to three times lower, allowing for the identification of the initial drop in dopamine at a very early stage, which allows for therapeutic intervention before the condition worsens.
The team believes that these results provide a solid foundation for future studies using real human tear samples, and will help in developing simple diagnostic devices that can be used in clinics or homes to monitor neurological indicators using only a tear sample, without any pain or complication.
