Designing and Optimizing 3D Printed Microfluidic Devices Coupled with Electrochemical Detection for use in Undergraduate Laboratories

Microfluidic total systems (aka Lab-on-a-Chip) are well known for lowering costs, scaling down experiments increasing efficiency, and decreasing time to analyze. However, implementation of microfluidic systems in undergraduate teaching laboratories has proven to be difficult due to the highly technical fabrication and reproduction procedures required for effective experiments. Recent 3D printing methods expedite the process of designing integrated flow systems and provide major advantages by allowing one device to contain multiple integrated parts, so as to increase efficiency, cost, reduce fabrication labor, and—importantly, in the context of undergraduate laboratories—reproducibility. Although 3D printing poses obvious advantages to the field of microfluidics and as analytical tools, the use of such devices in teaching laboratory settings has not yet been utilized and students lack exposure to this significant scientific innovation. This paper highlights 3D printing as a teaching tool for undergraduate students in research projects, which eventually produce parts to the total analytical system to be used in teaching laboratory. We focus primarily on the use of Autodesk Inventor to design a simple microfluidic chip and a four-port injection valve to serve as a flow injection analysis (FIA) system. The total system is then coupled to electrochemical detection via embedment of electrodes into commercial fittings and optimized for its performance. Reproducible detection at a 100 µm diameter Pt electrode of sample analyte catechol resulted in a linear correlation over a range of concentrations (r2 = 0.99, 25 µM - 100 µM) with limit of detection at 21nM. The total 3D printed system serves as an instrumental method to electrochemically study analytes of interest in an undergraduate laboratory context.