Design of a simple paper-based microfluidic device for fluid dilution

• Main Author: He, Zeqing
• Other Authors: Marcos
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Mechanical engineering::Fluid mechanics
• Online Access: https://hdl.handle.net/10356/150879
• Institution: Nanyang Technological University

Paper-Based Microfluidics devices ( PADs) hold a lot of potential for developing cheap, fast point-of-care diagnostic tools. These tools can drastically increase efficiency, accessibility, and personalization of healthcare for the future, particularly in resource-scarce regions. Currently, colorimetric lateral flow assays which simulate one-step simple qualitative lab assays have been successfully developed to market. To expand the applicability of paper microfluidics for multi-step quantitative time sensitive assays, further research into controlling the flow and detection methods of paper microfluidics is needed. Micromixers are one of the most used flow components in conventional microfluidics. Hence, this paper would like to investigate ways to recreate mixing on 2D paper networks. Also, incorporation of electrochemical sensors is of interest as a method to detect quantitative results from the device. The research objective is to develop a paper-based microfluidic electrochemical device for diluting NaCl saline solution and accurately measuring the resultant concentration. A logarithmic model which can predict the NaCl concentration in the range of 0.1M to 0.5M using the measured resistance response to 1MHz A.C. voltage signal was achieved. The model has a mean percentage error of 12%. Mixing ratio of the device was found to be dependent on concentration of the input solutions. While the final device is limited in terms of performing consistent and controlled mixing, the experimental trends observed and methods developed in the project can inform future research and PED design.