Adherent microbial communities, known as biofilms, are a major contributing factor in the incidence of healthcare-associated infections (HCAIs). HCAIs are responsible for annually causing 100,000 deaths and medical expenses estimated to be $35-45 billion. Physical and chemical surface modification techniques are thought to be critical in the fight against biofilm formation within medical settings.
Nanoscale structural features have been found to have significant effects on bacterial adhesion and biofilm formation, but their effects on fungal pathogens are less explored. This thesis systematically explores the effect of surface topography in the form of nano and microscale polymeric fibers (~0.4-1.2 µm in diameter) on biofilm formation and virulence of a common HCAI-causing fungal pathogen, Candida albicans. We show that both C. albicans attachment density and differentiation to its virulent phenotype significantly vary with fiber diameter and spacing on polymeric fiber-coated surfaces. We further show that high throughput and high content techniques, such as Raman spectroscopy, can be used to track environmental and physical effects on the organism's resulting morphology and associated virulence.
Findings from this thesis will inform the design of antifouling surfaces including implantable medical devices. In a prototypical example, we demonstrate the use of fiber coating to modulate C. albicans attachment on polyurethane, silicone, and latex catheters. / Master of Science / Microbial communities that adhere to surfaces, known as biofilms, are largely associated with incidence of healthcare-associated infections (HCAIs). HCAIs are responsible for annually causing 100,000 deaths and medical expenses estimated to be $35-45 billion. Modification of surfaces using physical and chemical techniques is believed to be critical in the fight against biofilm formation on surfaces within medical settings.
Nanoscale structural features have been found to have significant effects on bacterial adhesion and biofilm formation, but their effects on fungal pathogens have not been extensively studied. This thesis focuses on the effect of surface topography, or textures, in the form of nano and microscale polymeric fibers (~0.4-1.2 µm in diameter) on biofilm formation and disease-causing ability, or virulence, of a common HCAI-causing fungal pathogen, Candida albicans. We show that both C. albicans attachment density and differentiation to its virulent form significantly vary with fiber diameter and spacing on polymeric fiber-coated surfaces. We also show that high throughput and detailed imaging techniques, such as Raman spectroscopy, can be used to track environmental and physical effects on the organism's resulting morphology and associated virulence.
Findings from this thesis can be used to aid in the design of surfaces that discourage biofilm formation, including implantable medical devices. We demonstrate the use of fiber coating to vary C. albicans attachment on polyurethane, silicone, and latex catheters in one of our studies.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/111102 |
| Date | 08 January 2021 |
| Creators | Mottley, Carolyn Yvette |
| Contributors | Department of Biomedical Engineering and Mechanics, Behkam, Bahareh, Nain, Amrinder, Senger, Ryan S. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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