FUNCTIONAL 3-D CELLULOSE & NITROCELLULOSE PAPER-BASED, MULITPLEX DIAGNOSTIC PLATFORMS WITHOUT COUPLING AGENTS

Abstract

The purpose of this thesis was to demonstrate device functionality of 3-D paperbased, multiplex platforms, µPADs, without the use of coupling agents between layers. Previously, these platforms were fabricated with double-sided tape and cellulose powder to try to augment proper fluid routing, but difficulties with this method occurred. An acrylic housing unit with strategically placed pressure tabs was designed to aid horizontal and vertical fluid routing through the platform, thus eliminating the inconsistencies associated with coupling agents. Channel characterization studies, a COMSOL TM simulation, and development time studies were performed to aid device design and demonstrate device functionality. The implementation of this µPAD platform as a diagnostic instrument was validated via lateral flow immunoassays utilizing both biotinylated antibodies and biotinylated aptamers as capture reagents. Successful detection of the target analyte, IgE, as well as successful fluid routing through multiple layers of membrane was demonstrated by immunoassays performed on 3-D, multiplex platforms. Another important result determined the aptamers' ability to detect IgE to be statistically the same as the antibodies' ability; thus confirming aptamers as viable capture reagent alternatives to antibodies in lateral flow assays. Overall, this research project was performed to develop and validate via experiment a prototype paper-based microfluidic diagnostic device, µPAD, with the capability to detect multiple biomarkers on one platform.

Functional 3-D Cellulose and Nitrocellulose Paper-based, Microfluidic Device Utilizing ELISA Technology for the Detection/Distinction Between Hemorrhagic and Ischemic Strokes

“…This minimizes lateral flow by eliminating the need for long fluid-routing channels, which are typically used to connect layers. Based on the combined results from Jennifer Ward and Mackenzie Tageson's theses, the optimal channel widths appeared to be 1.6 mm to 2.5 mm [19,34]. For this chip, the detection layer and fluid-routing layer were designed to have circular channels with diameters of 2.5 mm.…”

“…The AutoCAD design of the top and bottom components of the housing for the first circular chip can be seen in Figure 8. 34 The details of the dimensions for this housing can be found in Appendix A. Once this design was finalized, the housing was fabricated using a laser cutter in the IME lab on Cal Poly's campus.…”