This project seeks to revolutionize neurotransmitter sensing for the brain and gut by developing a closed-loop sensor network of advanced brain implants and gut ingestibles equipped with neurotransmitter sensors. Traditional sensors for neurotransmitters like dopamine and serotonin are limited by their discrete, tethered nature and suffer from selectivity issues, especially in freely moving animals and humans. The project’s first objective is to address these issues by developing novel nanoscale aptamer-based differential transistors. Second, with custom application-specific integrated circuits (ASICs) for brain implantation and location-aware gut ingestible, the system will enable real-time monitoring and communication between the brain and gut. Utilizing cutting-edge materials, chemistry, electronics, and fabrication techniques, the project aims to create a closed-loop system capable of precisely monitoring neurotransmitter dynamics through demonstrations in animal and human models.