Neurons perform numerous complex tasks by communicating with each other via small messenger molecules called neurotransmitters. Accurately detecting them is crucial to understanding the functioning of our brain. To this end, researchers have demonstrated that fluorescent nanoparticles imprinted with the molecular structure of a target neurotransmitter, immobilized on glass beads at a controlled surface density, can detect specific neurotransmitters based on their expansion during interaction with the target transmitters.