Signal Processing Techniques Applied to Biomedical Diagnostics

Abstract

An effective way to combat cancer and infectious disease in resource-poor settings is to implement rapid and accurate diagnostic tests that can be administered at the point of care (POC). Developing such miniaturized, portable, and low-cost systems requires innovative approaches in both assay and device design. In this thesis, we construct a novel phase-sensitive "lock-in" amplifier (LIA) based on the Fast Walsh-Hadamard Transform (FWHT), and evaluate its ability to boost the signal-to-noise ratio of optical fluorescence signals. The LIA is designed to be resilient in challenging environments containing high/unpredictable ambient noise. We then develop two rapid diagnostic systems that pair this technology with isothermal CRISPR-Cas12a-based DNA/RNA amplification to detect clinically relevant targets with high specificity. Finally, we evaluate the clinical performance of our systems in detecting target genes for (1) SARS-CoV-2, the virus responsible for the COVID-19 pandemic, and (2) Human Papilloma Virus (HPV), the causal agent of cervical cancer.