Date of Award

Fall 2019

Document Type


Degree Name

Master of Science (MS)


Biomedical Engineering

First Advisor

Bryant Hollins


Paper-based microfluidic devices provide a light-weight, cost effective platform for diagnostic and analytical testing. The goal of this project is to enhance paper-based microfluidic mixing by incorporating fluid flow disrupting structures (referred to here as rib bones) into the microdevice design to expand the analytical capabilities of paperbased microfluidic devices. The devices are fabricated on Whatman CHR-1 chromatography paper. The devices are designed in SolidWorks and printed using a solid ink printer (ColorQube 8580). The wax is penetrated into the paper to create hydrophobic barrier regions by heating in a convection oven until the wax is fully penetrated. The parameters of the rib bone structure that were evaluated include the width of the individual rib bone (α), the spacing between the rib bones (β), and the angle of the inlet junction into the mixing channel (γ). The mixing efficiency was characterized by how well two fluids of differing colors mixed over a constant length mixing channel. The solution used for mixing is a 1:4 v/v isopropyl alcohol:water ratio with 10 drops of food coloring added for the color. Yellow and blue food coloring, which mix to form green, were used for the experiments. To quantify the effectiveness of the mixing, a digital image of the device was taken, and MATLAB was used to determine the RGB color code of the area distal to the rib bones. The outcome of this project is a fully defined mixing channel design that can be incorporated into other paper-based microfluidic designs.