Solid Phase Microextraction-Based Miniaturized Probe and Protocol for Extraction of Neurotransmitters from Brains in Vivo

Despite the importance of monitoring and correlating neurotransmitter concentrations in the brain with observable behavior and brain areas in which they act, in vivo measurement of multiple neurochemicals in the brain remains a challenge. Here, we propose an alternative solid phase microextraction-based (SPME) chemical biopsy approach as a viable method for acquirement of quantitative information on multiple neurotransmitters by one device within a single sampling event, with multisite measurement capabilities and minimized invasiveness, as no tissue is removed. The miniaturized SPME probe developed for integrated in vivo sampling/sample preparation has been thoroughly optimized with respect to probe shape, desorption solvent, and extracting phase tailored for extraction of small hydrophilic molecules via synthesis and functionalization of the SPME coating. Experimental evaluations of sampling time and storage strategy led to achieving appropriate temporal resolution versus recovery balance as well as lit...