(379h) Hands-on Microfluidic Glucose Sensor Module for the Enhancement of Engineering Courses

Riley Fosbre,1 David B. Thiessen,1 Prashanta Dutta,2, Olusola Adesope3 and Bernard Van Wie,1, (1) Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, (2) School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, (3) Educational Psychology, Washington State University, Pullman, WA

This project focuses on teaching microtechnology and microfluidics topics to the next generation of engineers by increasing the number of interactive experiences. Microfluidics deals with the processing of micro-scale quantities of fluids through micron-sized channels, allowing for the rapid emergence of breakthrough technologies meant for experimentation and analysis, such as point-of-care diagnostics and multiple clinical applications. These technologies have radically impacted chemical and biological analyses, allowing for improved understanding of cellular biology, disease diagnosis and progression, as well as fluid mechanics, while producing economical and disposable micro-devices due to advancement in soft lithography techniques. Unfortunately, robust teaching of these concepts has been challenging due to the topic’s interdisciplinary nature.

Microfluidics encompasses several scientific fundamentals, including materials science, chemistry, physics, and biology, requiring training in all of them to take full advantage of multiple concepts. Currently, a significant gap exists in engineering curricula due to the engineering students’ lack of robust understanding of microfluidics and its core principle. The long-term goal of this project is to address this gap with a low cost, hands-on educational series of modules, meant to advance knowledge of this complex topic while enhancing student engagement. In the short term, this means designing and implementing micro-devices which display the phenomena in question as well as accompanying educational material for use in chemical (ChE), mechanical (ME), and biomedical (BME) engineering courses at WSU (Washington State University) and WVU (West Virginia University). In addition, we seek to conduct ongoing assessments of this approach on student learning and engagement. An example of one of these modules currently in development is a glucose enzymatic analyzer, a micro-device which relies on microfluidic principles and a common compound analyzed in the medical field, glucose, to cover several scientific topics at once, including microfluidic mixing, reaction kinetics, and absorption spectroscopy based on Beer’s law.

Glucose is commonly measured in blood chemistries because it is a key indicator for many medical conditions, such as diabetes and other metabolic diseases. The concentration of glucose in blood can be measured via a reaction in which glucose is first oxidized into gluconolactone and peroxide, the latter of which is then detected by reacting with 4-amino antipyrine in the presence of the enzyme peroxidase, which yields a final violet-red dye product, quinonimine, that absorbs over a characteristic wavelength range as an indicator of the concentration of glucose.

To that end, the experimental set up is simple. Students will inject reagent and sample into a Y-shaped chip with an on-off valve at the intersection. From there, the sample and reagent will be mixed within a micro-channel via an oscillating electric field. This leads to a color change reaction with a faint pink for low concentration, deep red for high. From there, the sample will pass into an opaque black box with a clear slit on the front side and a green plastic sheet on the other. This allows green light to pass through the sample when backlit. The green light that passes through the slit can be measured using a smartphone app, and with Beer’s law, students can determine the concentration of glucose in the sample based off the measured intensity. Student comprehension of the concepts related to the experiment will be examined using accompanying worksheets, where the reaction kinetics and scientific principles can be tied in with the course. This experiment would work well with biomedical and reaction engineering courses.

After completing and testing the initial design, modules are planned for implementation by ChE, BE, and ME faculty at WSU and WVU using the modules, guided worksheets and accompanying assessment materials to assess learning of microfluidic concepts in relation to existing curricula. We will manufacture using simple and inexpensive 3D printing technology for rapid prototyping, allowing for fabrication of devices tailored to the unique needs of the intended course or experiment desired by the instructor.

We will present details on design construction and building of guided inquiry exercises and concept and motivational assessment instruments. We will also outline content for conducting surveys and interviews with instructors. This will provide the necessary feedback to ensure the integration of this additional curricula is well implemented by instructors.

The long-term goal of this program of research is the propagation and widespread adoption of new, more effective pedagogical tools and cutting-edge engineering technologies for teaching these complex topics - microtechnology and microfluidics.