Dopamine detection is important in diagnosing a number of disorders resulting from lack or excess of the neurotransmitter - and a new detector has been developed.
A team from Penn State University in Pennsylvania and Rensselaer Polytechnic Institute in New York, together with universities in Japan and China have proposed an ultrasensitive dopamine sensor. Their study is published in the latest Science Advances journal.
A Very Sensitive and Simple-to-use Detector
"If you can develop a very sensitive, yet simple-to-use and portable, detector that can identify a wide range of dopamine concentration, for instance in sweat, that could help in non-invasive monitoring of an individual's health," said Aida Ebrahimi, a corresponding author on the study and an Assistant Professor of Electrical Engineering at Penn State.
Their ultrasensitive dopamine detector was achieved by doping a Molybdenum disulfide (MoS2) with Manganese (Mn). By adding a small and controlled amount of Mn to a MoS2, researchers were able to create a low-cost, flexible dopamine detector. Embedded in two-dimensional transition metal dichalcogenide (TMD) material, can serve as the backbone of an ultrasensitive and tunable biosensor.
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To create their Mn-doped MoS2 the research team employed a two-step approach: electrodeposition and solid-vapor deposition. An amorphous MoS2 sample is electrodeposited on pyrolytic graphite sheets (PGS), creating MoS2/PGS. To overcome the lack of crystalline bonds, solid-vapor deposition is used to add the Mn atoms and crystallize the amorphous MoS2.
"Regarding our method, electrochemical deposition is a new way of depositing these chemicals that is very simple and scalable," said Mauricio Terrones, also a corresponding author in the study and a Verne M. Willaman Professor of Physics, Materials Science and Chemistry at Penn State.
In testing the design, a team led by Humberto Terrones from RPI conducted the computational study to characterize the effect of doping an amorphous MoS2 with Mn. According to the press release from Penn State, the experimental work supported by the computational investigation was conducted at PSU's Center for Atomically Thin Multifunctional Coatings (ATOMIC).
Too Much or Too Little Dopamine
Dopamine is a neurotransmitter that plays a vital role in regulating movement and reward mechanisms in the brain. Studies have shown that too much dopamine leads to episodes of mania, hallucinations, and schizophrenia. On the other hand, very little release of dopamine is often connected to Parkinson's disease and depression.
Conventional methods for detecting and monitoring dopamine levels in patients require specialized lab equipment in time-consuming processes. Moreover, common processes are invasive, which requires drawing samples from the patient, and preparing them in procedures such as blood-plasma separation.
Novel methods of accurately detecting dopamine in patients, even against the presence of background signals and media like sweat, serum, and other buffers, have been the subject of several studies over the years.
Last 2019, a team of researchers from the University of Central Florida developed a dopamine biosensor. Their design uses an enzyme-free plasmonic neurotransmitter that also contains a microfluidic plasma separator. With this dopamine detector, the sensor is supposedly capable of in-line separation of blood and plasma, diverting it into the detection area. The presence of inorganic cerium oxide nanoparticles will bind with the dopamine, which reacts with an optical sensor, in turn creating an optical dopamine level readout.
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