Point of Care COPD Diagnostics Based on Paper-based Assay and Biofluid Sensing

Abstract

Chronic obstructive pulmonary disease (COPD) has always been the one of the top four major death causes during the last ten years. During the era of covid-19 pandemic, COPD patients faced higher mortality rates than ever before. Inefficiency in COPD diagnosis and exacerbation monitoring leads to tremendous medical costs and economic burden. Decentralized point-ofcare (PoC) diagnostics based on disposable paper-based biosensors emerge as a cost-effective approach, which requires sensitive detection of COPD biomarkers in human saliva and blood as a prerequisite. When testing biological samples, it also needs to consider matrix effects resulted from samples and handling protocols. Biofouling is the most noticeable and deleterious effect of untreated saliva or serum that happens simultaneously on most interfaces that results in blocking and passivation of the sensing surface with non-specific adsorbed proteins. This dissertation work focuses on the following challenges: (i) demonstrate sensitive electrochemical and optical biosensing of COPD biomarkers in human saliva based on lateral flow assays; (ii) investigate solutions to resolve hook effect in sandwich LFAs and redesign the LFA structure; (iii) control defects in emerging nanomaterials, taken 2-dimensional black phosphorus as an example, for the development of future biosensors that contact human saliva and blood; and (iv) an anti-biofouling strategy to overcome non-specific protein adsorption and matrix effect of body fluids.