Guozhen He at the University of South-Eastern Norway, Faculty of Technology, Natural Sciences and Maritime Sciences (TNM) will be defending his thesis for the degree of philosophiae doctor (PhD). The title of the thesis is “Point of Care COPD Diagnostics based on Paper-based Assay and Biofluid Sensing”.
Both the trial lecture and the PhD defense are open to the public. Immediately after the defence the doctoral programme will hold a small defence reception outside Auditorium A1-39, approximately from 15:00-15:30.
Summary
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-of-care (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 and results in blocking and passivation of the sensing surface with non-specific adsorbed proteins.
This work has studied optical and electrochemical detection of COPD biomarker in human saliva by lateral flow assays (LFAs). It has also concluded a solution to practically follow progression of COPD stages with a set of chosen salivary biomarkers and their detection by LFAs as a cost-effective approach. To mitigate the “hook” effect in one-step sandwich LFA, this work introduced a strategy of controlled release of detection antibody via sucrose treatment of the LFAs. To overcome biofouling from non-specific protein adsorption, tungsten trioxide nanosheets with engineered oxygen vacancies were studied as electrode coating with a hypothesis that oxygen vacancies in the surface would affect adhesion of biofouling proteins. Tungsten trioxide rich in surface oxygen vacancies exhibited significantly 95% less adsorption from selected proteins and lower toxicity to human umbilical vein endothelial cells than its counterpart with no oxygen vacancies.