Friday, May 9, 2025
5/9/2025
Portable Microsampling Backpack with Integrated Sensing System - Project Summary This work aims to create an important sampling tool for the neuroscience research community that will allow for microsampling within the brain in a completely unrestrained rat. The backpack/sampling system that will be developed for rats will address a significant capability gap by incorporating portable advanced fluidic handling platforms useful for neuroscience research. The proposed backpack serves as an initial development platform to further integrate electrophysiological measurements, optogenetic capability and other chemical sensors. This research consists of a two-stage objective that (1) aims to develop a portable/backpack sampling platform for integration with commercial microdialysis probes, and (2) verification of backpack functionality under multiple sampling conditions to include durability testing, in vivo sampling from the rat brain via coupling to microdialysis probes, and integration with prototype 3D printed microsampling probes created using two-photon polymerization stereolithography (Nanoscribe instrument). This backpack will be portable, battery-powered, and includes on- board data processing, integrated fluid pumping and fluid management, with robust real-time chemical sensing. The prototype backpacks consist of four key components: (1) custom microcontroller board, (2) fluidic pumping mechanism, (3) microfluidic chip, and (4) an integrated UV-vis sensor. The goal is to have a closed loop fluidic system where a pumping mechanism drives fluid through microfluidic channels from the probe to the sensor array and back to the probe. A secondary goal is to allow for selective off-loading of fluid for quantifying solutes externally via LC-MS or other methods. Finally, expansion of the pumping mechanism (to multiple pumps) to allow for use with multiple probes for simultaneous sampling from different brain regions. All these features will be balanced in size, power, and weight as to allow for sufficiently long sampling times (>5 hours initially) and to not burden the animal. The backpack prototypes will be tested using metronidazole, a strongly UV-VIS absorbing drug, as well as caffeine. Subsequent backpack prototypes with the 3D printed microsampling probes will be used for dopamine and glutamate detection that will be performed with the off-loading fluidic mechanism. Completion of this proposed work will lead to an initial portable battery-powered backpack sampling platform that can integrate with commercial microdialysis probes along with in-house 3D printed probes and serves as a steppingstone for addition of other sensing or modulating devices.
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