Schematic of the sensitive and highly selective dopamine detector based on molybdenum disulfide. Image: Derrick Butler, Penn State.
Schematic of the sensitive and highly selective dopamine detector based on molybdenum disulfide. Image: Derrick Butler, Penn State.

A supersensitive dopamine detector based on a 2D material could help in the early diagnosis of several disorders that result from too much or too little dopamine in the brain, say a group led by researchers at Penn State. Dopamine is an important neurotransmitter that plays a role in disorders such as Parkinson's disease, Alzheimer's disease and schizophrenia.

"If you can develop a very sensitive, yet simple-to-use and portable, detector that can identify a wide range of dopamine concentrations, for instance in sweat, that could help in non-invasive monitoring of an individual's health," said Aida Ebrahimi, assistant professor of electrical engineering at Penn State and corresponding author of a paper on this work in Science Advances.

In the paper, the researchers report that adding a small amount of manganese to a 2D layered material known as molybdenum disulfide (MoS2) improves its sensitivity as a dopamine detector by many orders of magnitude compared to other reported results, while also achieving high specificity. Importantly, their detector is low-cost and flexible, and can detect dopamine in background media including buffer, serum and sweat, and in real-time.

"Regarding our method, electrochemical deposition is a new way of depositing these chemicals that is very simple and scalable," said Mauricio Terrones, professor of physics, materials science and chemistry at Penn State and the second corresponding author. "The Air Force is interested in these neurotransmitters that are markers of stress. I envision this as a wearable sensor."

Humberto Terrones and his group at Rensselaer Polytechnic Institute performed the computational investigation that allowed them to explain how addition of manganese enhances the response to dopamine. The experimental work was performed within the Center for Atomically Thin Multifunctional Coatings (ATOMIC) at Penn State.

"Combining the experimental results with computational studies proved to be very insightful, and I think we all learned much more throughout this project because of that," said Derrick Butler, co-lead author on the paper and a doctoral student at Penn State. "Developing these materials and applying them in a way that could improve the health and well-being of others makes the work especially enjoyable and rewarding."

"One challenge is to develop a scalable method to bridge fundamental studies and practical applications," added co-lead author and Penn State doctoral candidate Yu Lei. "Our method is based on electrodeposition, which has been widely used in industry, thus providing a scalable route to functionalize MoS2 in a scalable way. Also, I believe this multidisciplinary team is the key to find the right way to functionalize MoS2 for ultrasensitive dopamine detection."

In further work, the group hopes to find alternative material combinations to detect a variety of other biomarkers with the specificity of their current sensor. Creating such a ‘toolkit’ that combines experimental investigations with computational methods will lead to new materials with multifunctional capabilities. This might be useful beyond human health, such as for detecting noxious gases, water contamination or biodefense agents.

"In future, we can envision a combined sensor/actuator that can detect the dopamine and provide therapy at the same time. The sensors can be integrated with miniaturized chips for integration of sensing, actuating, control and data processing," Ebrahimi said.

This story is adapted from material from Penn State, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.