Fundamental Investigation of Biological Interactions for Applications in Infection Prevention and Biomaterial Development

• Main Author: Liu, Yatao
• Other Authors: Terri A. Camesano, Advisor
• Format: Others
• Published: Digital WPI 2008
• Subjects: bacterial adhesion; biomaterial development; cranberry; urinary tract infection; biological interactions; atomic force microscopy; Staphylococcus epidermidis; fimbriae
• Online Access: https://digitalcommons.wpi.edu/etd-dissertations/382; https://digitalcommons.wpi.edu/cgi/viewcontent.cgi?article=1381&context=etd-dissertations

"Bacterial infections persist as a public threat due to the ease by which bacteria adapt to commonly used antibiotics. In addition, bacteria on surfaces develop protective communities called biofilms that hinder the ability of antibiotics to completely eliminate the pathogens. The rapid development of bacterial resistance to antibiotics has made pharmaceutical companies reluctant to fund new antibiotics research. Hence, novel approaches to prevent and treat infections are needed. The development of infections can be divided into three steps: adhesion, invasion and multiplication. Antibiotics target at the latter two step and are prone to bacterial resistance as passive strategies. Bacterial adhesion to host cells/implanted medical devices is the first step leading to following invasion and multiplication. However, fundamental understanding of bacterial adhesion process is still lacking. The current studies are aimed to systematically investigate biological interactions between pathogenic bacteria and host cell, proteins and biomaterials with both macro and micro scale approaches. The macro scale methods include bacterial adhesion assay, viability studies, and thermodynamic modeling. The micro scale methods include direct adhesion force measurements, ultra surface visualization via atomic force microscopy (AFM) and surface structure modeling. Our work combines experiments and modeling aimed at understanding the initial steps of the bacterial adhesion process, focusing on two case studies: 1) Mechanisms by which cranberry can prevent urinary tract infections through interfering with bacterial adhesion; and 2) Design of anti-adhesive and antimicrobial coatings for biomaterials. We make direct adhesion force measurements between bacteria and substrates with an atomic force microscope (AFM), and combine such experiments with thermodynamic calculations, in order to develop a set of tools that allows for the prediction of whether bacteria will attach to a given surface. These fundamental investigations of the bacterial adhesion process help elucidate the underlying mechanisms behind bacterial adhesion, thus leading to improved clinical outcomes for a number of biomedical applications. "