3D Printing the Next Generation of Microsampling Probes for Neuroscience Applications

Microsampling techniques have been vital for elucidating different chemical aspects of brain function including metabolism, neurotransmitter dynamics, and cytokine signaling after brain trauma. The current trends in neuroscience research are to gather as much chemical and physical information as possible from a single experiment. The current approach of using off-the-shelf devices and parts to perform neuroscience experiments greatly limits the information content that can be obtained. The next generation of microsampling devices will be costume designed and include multiple sensing and modality platforms. The rapid capability of 3D printing technologies or additive manufacturing to make customizable devices will likely help lead the way to creating this next generation of microsampling devices. A combination of two separate 3D printing technologies has been applied in our laboratories to create microsampling probes in the shortest amount of time. A Nanoscribe GT 2-photon polymerization (2PP) stereolithographic (SLA) 3D printer, capable of 200 nm features, was used fabricate a 4 mm long microsampling needle with 6128 x 5 µm pores and a 250 µm triangular cross-section. This sampling needle is mounted to a tubing connection and handling section printed at 35 µm resolution on the Anycubic Mono 4K masked-SLA 3D printer. Solute extraction has been achieved with various test solutes. Continued design developments and device revisions will be discussed particularly related to the microporous membrane, solute recovery, and device stability.