Development of a 3D printed microdialysis-based microsampling probe

by Pysz, Patrick Michael; Hoskins, Julia K.; Zou, Min; Stenken, Julie Ann

Microdialysis sampling is an established technique for in vivo collection of samples to quantify various biol. signaling mols., such as neurotransmitters, cytokines, and bacterial quorum sensing. Com. probes have not changed significantly in the last 40 years. Modern in vivo device design leans toward open flow devices with the need to collect larger mol. weight proteins and vesicles. Most probes are still fabricated using microbore tubing and hollow fiber membranes. There are no com. devices that use advanced photolithog.-based fabrication techniques common to the development of microfluidic systems. In the past decade, photolithog. techniques have produced numerous microfabricated sampling probes in different research groups. In parallel, significant progress has been made developing multi-modal biosensors that combine chem. delivery, optogenetic, and electrophysiol. detection methods for real-time data at increasingly smaller spatial resolutions Photolithog. is inherently limited in geometric complexity to simple 2D planar designs with slow prototyping cycles. Stereolithog. (SLA) 3D printing is a powerful fabrication alternative capable of manufacturing sub-micron features approaching those of standard photolithog. techniques, while offering nearly limitless geometric complexity. 3D printing is an ideal method for fabricating microsampling probes to take advantage of complex geometries not previously possible. The presentation will discuss the development of a fully 3D printed microsampling device fabricated by multiple 3D printing technologies. The Nanoscribe GT 2-photon polymerization SLA 3D printer, capable of 200 nm features, is 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. The combination of using two 3D printing technologies allows for the rapid prototyping of highly customized and complex microsampling probes that are otherwise possible individually.