Graphene 'nerve string' sensor developed by Stanford University
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In the central nervous system (CNS), monoamine neurotransmitters including dopamine (DA) and serotonin (5-HT) are involved in activities such as mood, sleep and memory. Among them, dopamine is produced in the brain and plays a key role in the brain's reward mechanism, and is directly related to Parkinson's disease and addiction.
Outside of the central nervous system (peripheral nervous system), 5-HT in the gastrointestinal (GI) system, which accounts for 95% of the body's 5-HT, tightly regulates gut function and the microbiome. Gut-derived 5-HT is an integral part of the gut-brain communication system (gut-brain axis).
Life is soft, but in the current field of life science, most research tools are hard. Until now, tools to study biochemical signals in living animals and human organs have remained limited. Existing rigid probes are generally hard and fragile, which not only easily lead to device failure, but also may trigger an inflammatory response.
To solve this problem, researchers at Stanford University recently developed a flexible and stretchable graphene-based electrochemical sensor, named "nerve string". The sensor can realize real-time monitoring of the brain and gut, providing a way for further research in brain science and nervous system.
Graphene is a hot carbon material in recent years. It not only has certain catalytic properties and can redox neurotransmitters, but also has a relatively large surface area, which can adsorb small molecules and has high sensitivity. The stretchability of the sensor based on graphene alone is not very good, but it has good stretchability when it is wrapped together like a mesh and embedded in rubber.
In the experiment, the researchers used the device to conduct long-term, real-time, multi-channel and multi-channel monoamine sensing in the mouse brain, and found that the "nerve string" has superior long-term neurochemical detection stability and can monitor mouse nerves. Transmitter signaling up to 16 weeks.
In addition, in a proof-of-concept experiment, the team used nerve-string sensors to detect the release of catecholamines in the brain seconds after chocolate ingestion in mice, and observed an increase in serotonin in the colon within 30-60 minutes, which is consistent with the The typical transit time of food through the gastrointestinal tract is consistent. This result demonstrates the potential of using nerve strings to understand neurotransmitter mechanisms and their roles in the brain-gut axis.
In the future, combined with its excellent biocompatibility and sensitivity and soft stretchability, the sensor may become a powerful tool for biological signal transmission and electrophysiological signal detection.