BC-78 Affordable Microfluidics for Resource-Limited Environments: Leveraging 3D Printing and Microcontroller Technology to Expand Access to Advanced Research

This project presents the development of a cost-effective, open-source spin coater and microfluidic molds using 3D printing technologies and advanced microcontroller techniques. These new technologies enable us to overcome the high cost of microfluidic device development, which limits their adoption in economically depressed areas. The spin coater, constructed from 3D-printed parts made of Acrylonitrile butadiene styrene (ABS) resin, utilizes a repurposed PC fan motor with external magnets for precise RPM monitoring via a Hall effect sensor. An Arduino microcontroller regulates speed, with real-time feedback displayed on an LCD. The system’s robustness was enhanced by evolving the circuit design from a breadboard prototype to a soldered perf board. By integrating a microcontroller to control spin RPM and time and using AutoCAD Inventor for design, the spin coater facilitates photolithography of silicon wafers coating with photoresist. Calibration with a laser tachometer ensures accurate speed readings. The photoresist layers were measured using optical profilometry to measure the depth of the microstructures. The photoresist-coated wafer is then patterned through photolithography to give a mold master to create microfluidic devices. The resulting polydimethylsiloxane (PDMS) microfluidic devices are intended for point-of-care testing (POCT) for diseases such as Lyme disease. We compared our low-cost open-source spin coater film thickness to the manufacturer's model behavior from a high-cost spin coater with their expected values. Our data shows a high R2 agreement with the model film thickness. Additionally, we will show examples of how the DIY spin coater can be used to create microfluidic devices in a resource-limited setting. Open-source microcontrollers like Arduino, microcontroller code, and 3D printable library parts make this technology accessible to researchers, educators, and open-source scientists. The Arduino code and 3D-printed part designs will be publicly available, providing an affordable solution for thin-film deposition and microfluidic device fabrication in resource-limited settings.