Biosensor Platform Development for Studying Carbohydrate-Mediated Bacterial Adhesion

Abstract

Infectious diseases are the second leading cause of mortality worldwide, accounting for 14.9 million deaths each year. Diarrheal diseases, usually a result of infection by enteric pathogens, cause 1.8 million of these deaths, a disproportionate number of which are infants and children. Pathogen adhesion to host tissue is a prerequisite for a majority of infectious diseases, so these adhesion mechanisms are of primary concern to understand the pathogenesis of infectious disease and to develop strategies to combat these ailments. Of the many adhesion mechanisms that pathogens have evolved, cell surface glycoconjugates are one of the most common targets. A biosensor capable of screening pathogens against many carbohydrate structures at one time would help address the challenges of identifying binding partners, understanding bacterial adhesion, and developing anti-adhesives. To better understand the challenges associated with studying whole cell binding with biosensors, as well as to maximize opportunities, two very different biosensing platforms were chosen as promising technologies for studying bacterial adhesion: (1) a complementary metal oxide semiconductor (CMOS)-based microelectrode array and (2) an instrument based on silicon photonic microring resonators. For each of these platforms, we developed and implemented functionalization techniques and experimental protocols to enable the study of carbohydrate-mediated bacterial interactions. In the case of the microelectrode array, a polypyrrole functionalization technique was used to evaluate bacterial adhesion to glyconconjugates immobilized on the microelectrodes, and the dose-dependent inhibition of <italic>Salmonella enterica</italic> binding demonstrated a real-world application of this platform. Achieving carbohydrate-mediated bacterial adhesion on the microring resonators proved elusive, but significant advancements were made on this emerging biosensor platform in the form of several different functionalization techniques and antibody-based capture of <italic>Campylobacter jejuni</italic>.