New biosensor can detect dopamine in unprocessed blood samples
Tool may diagnose, monitor conditions marked by abnormal dopamine levels
A newly developed biosensor that can rapidly detect and quantify levels of dopamine — a chemical messenger nerve cells use to communicate — may serve as a low-cost and efficient tool to diagnose and monitor people with Parkinson’s disease or other conditions marked by abnormal dopamine levels.
Developed by researchers at the University of Central Florida (UCF), the test works directly in unprocessed blood samples, which can make it a new tool for people in remote locations without access to complex laboratory equipment.
The sensor was described in the study “Nanoplasmonic aptasensor for sensitive, selective, and real-time detection of dopamine from unprocessed whole blood,” which was published in Science Advances.
Biosensor ‘extremely sensitive to low concentrations of biomolecules’
The “biosensor is extremely sensitive to low concentrations of biomolecules, which make them promising platform for specialized assays, point of care applications in remote locations,” Debashis Chanda, PhD, a researcher at UCF’s NanoScience Technology Center and the study’s principal investigator, said in a university news story.
Dopamine is a neurotransmitter involved in several cognitive processes such as motor function or emotions like pleasure or happiness. In people with Parkinson’s, however, the nerve cells responsible for making this chemical messenger become progressively dysfunctional, causing a reduction in dopamine levels that results in a range of motor and nonmotor symptoms.
The neurotransmitter is altered in many other neurological diseases, such as Alzheimer’s, Tourette syndrome, and bipolar disease, and it can help to diagnose certain cancer types.
However, current methods for detecting dopamine require complex preparation procedures and can take a long time for results, “making them unsuitable for point-of-care applications,” the researchers wrote.
Therefore, new methods are needed to more simply and precisely measure dopamine levels. Such tests could aid in disease diagnosis and monitoring, but may also help to advance research and the development of new medical therapies.
The new device was designed to detect dopamine via a synthetic DNA molecule, called aptamer, which coats the sensor’s active area. Aptamers are promising molecules to be used in sensors because they can bind a given target with high specificity, have good stability, and are easy to manufacture.
Sensor more cost-effective, easier to store than traditional biosensors
This approach makes the sensor more cost-effective and easier to store than traditional biosensors that use antibodies or enzymes to detect dopamine.
The biosensor is composed of a small gold pattern film that allows electrons to move in waves, called plasmons, which can be detected by measuring how they reflect light. When dopamine enters the sensor to bind an aptamer, it changes how electrons move and how light is reflected, creating an optical readout that indicates the level of dopamine.
The researchers demonstrated the sensor was able to selectively detect and quantify dopamine, even at low levels, in several biological samples. These included whole blood samples, artificial cerebrospinal fluid, which is a lab-made formulation of the liquid that surrounds the brain and spinal cord, and protein solutions.
“These results highlight the potential of plasmonic ‘aptasensors’ for developing rapid and accurate diagnostic tools for disease monitoring, medical diagnostics, and targeted therapies,” the researchers wrote.
Notably, the sensor detected dopamine directly from unprocessed blood samples, while previous methods required the plasma, or the liquid part of the blood, to separate from blood cells before analysis.
“There have been numerous demonstrations of plasmonic biosensors but all of them fall short in detecting the relevant biomarker directly from unprocessed biological fluids, such as blood,” said Aritra Biswas, PhD, the study’s lead author.
Chanda added: “There may be great interest in developing countries where access to analytical laboratories is limited.”
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