Eavesdropping on Neurochemical Signaling in Vivo
Colloquium | March 6 | 4-6 p.m. | 180 Tan Hall
Anne Andrews, Professor, UC Los Angeles
Measurements of neurotransmitters in the extracellular space are limited by combinations of poor chemical, spatial, and temporal resolution. Brain chemistries, therefore, are unable to be investigated dynamically, particularly at the level of neural circuits and across numerous signaling molecules.1 To understand neurochemical signaling at scales pertinent to encoded information, micro- to nanoscale sensors are needed for multiplexed and highly selective readouts of extracellular neurotransmitter concentrations with fast response times.1 We design, develop, and deploy sensors that approach these critical attributes. In addition to microdialysis and voltammetry approaches, we have developed electronic biosensors to investigate chemical signaling. Neurotransmitter recognition is by oligonucleotide receptors (aptamers) linked to field-effect transistor (FET) arrays for electronic transduction of binding events. Using aptamer-FETs, we have selectively detected serotonin and dopamine over five orders of magnitude with fM detection limits in artificial cerebrospinal fluid; serotonin was measured in brain tissue at physiological concentrations. We are lithographically fabricating FETs on silicon microprobes for acute, multiplexed in vivo sensing. Beyond serotonin and dopamine, we are developing sensors for a broad array of neurotransmitters and other small-molecule targets.