Date of Award


Document Type



Santa Clara University

First Advisor

Unyoung (Ashley) Kim


There is a significant and urgent need for affordable, fast, and accurate pathogen detection methods in resource-limited settings. Currently, accurate pathogen detection methods are dependent upon special equipment or reagents, specialized training to operate such equipment, electricity or cold storage, or sterile environments not feasible outside of the laboratory. Here we present a functionalized cellulose paper device towards an autonomous 3- dimensional microfluidics chip to detect bacterial pathogens. The microfluidic device utilizes a nucleic acid sandwich assay that detects the presence of bacterial RNA through complementary strand binding. An oligonucleotide “capture strand” immobilizes the targeted RNA sequence to the device, while a “detection strand” produces a visible colorimetric change due to gold nanoparticle conglomeration. A smart phone application and camera quantifies the concentration of the bacterial RNA present in the sample. This detection method can determine concentrations in the lower limits of the femtomolar range. The microfluidic device was fabricated using wax printing on cellulose filter paper, which was then folded into a final 3-D configuration. The simplicity and specificity of this paper-based assay was verified by the detection of E. Coli target oligonucleotide.