(204g) Optical Nanosensors for High Spatial and Temporal Studies of Neurotransmitter Imaging in the Brain

Information processing in the brain occurs over a broad range of spatial and temporal scales, rendering it difficult to produce tools to study brain function. Here, we discuss optical imaging technologies for the detection of neurological biomolecules that have the capacity to function concurrently on the molecular scale and on the macroscopic scale for timescales that match neurotransmitter-based information processing.

We present recent progress in the analysis of optical imaging techniques, specifically the use of infrared nanosensors for neurotransmitter imaging. In this work, we present findings from in-vitro and in-vivo experiments conducted in hydrogel based brain tissue phantoms and acute brain slices, respectively. Furthermore, we present findings from computational modeling of dopamine dynamics in the extracellular space of the brain, and discuss how computational modeling can be used to guide in-vivo neurotransmitter imaging studies. Stochastic simulations reveal that optical nanosensors can capture millisecond-scale changes during phasic and tonic firing of dopaminergic neurons. Our work scales to include a collection of neurons in defined volumes. We couple our findings to experimental results within the context of technological boundary conditions for imaging near-infrared photons. We show that single-walled carbon nanotube-based optical dopamine nanosensors can be used to detect dopamine in biologically complex and optically dense tissue phantoms, and can be rendered non-toxic for in-vivo imaging. These findings suggest that near-infrared (nIR) neurotransmitter nanosensor constructs can relay information about neurotransmission in the tissue-compatible nIR optical window, for timescales that capture single neurotransmitter synaptic release events, and for in-vivo experimentation.