Probing Neuropeptide Volume Transmission In Vivo by Simultaneous Near‐Infrared Light‐Triggered Release and Optical Sensing**

Abstract

Neuropeptides are abundant signaling molecules in the central nervous system. Yet remarkably little is known about their spatiotemporal spread and biological activity. Here, we developed an integrated optical approach using Plasmonic nAnovesicles and cellbased neurotransmitter fluorescent engineered reporter (CNiFER), or PACE, to probe neuropeptide signaling in the mouse neocortex. Small volumes (fL to pL) of exogenously supplied somatostatin-14 (SST) can be rapidly released under near-infrared light stimulation from nanovesicles implanted in the brain and detected by SST2 CNiFERs with nM sensitivity. Our measurements reveal reduced but synchronized SST transmission within 130 μm, and markedly smaller and delayed transmission at longer distances. These measurements enabled a quantitative estimation of the SST loss rate due to peptide degradation and binding. PACE offers a new tool for determining the spatiotemporal scales of neuropeptide volume transmission and signaling in the brain.

Glioblastoma Margin as a Diffusion Barrier Revealed by Photoactivation of Plasmonic Nanovesicles

“…The gold coating absorbs energy from near-infrared laser pulses to trigger a rapid sub-second release. 20, 21 Au-nV-Cal were characterized by UV-Vis spectrophotometry, dynamic light scattering, and transmission electronic microscopy ( Figure S1 ). We then injected Au-nV-Cal (∼175 nm) into 0.2% agarose gel as a “free” medium ( Figure 1b ).…”

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“…Nanoparticle (NP) heating has enabled many applications, [1][2][3][4] including cancer treatment, [5][6][7][8][9] neuromodulation, 10,11 molecular hyperthermia, [12][13][14][15] point-of-care diagnosis, [16][17][18] contrast agents, 19,20 controlled release, 21 energy harvesting, 22,23 and catalysis. 24,25 Janus nanoparticles (JNPs) refer to nanostructures with asymmetric structures, and have recently brought new opportunities to the eld.…”