Abstract

Carbon-infiltrated carbon nanotube (CICNT) forests are carbon nanotube (CNT) forests infiltrated with pyrolytic carbon to increase durability by becoming a solid material. This material can be tuned to maintain the nanotube geometry of a CNT forest and can also be fabricated on a variety of materials and geometries. Additionally, the present work has indicated that CICNT forests may resist bacterial proliferation and biofilm formation. This phenomenon is not due to the CICNT chemistry; it is presumably due to the CICNT nanostructure morphology. Thus, both silicon and stainless steel substrates were used to investigate CICNT's structural resistance to Methicillin-resistant Staphylococcus aureus (MRSA) biofilm. From in vitro experimental testing, CICNT on both these substrates resisted MRSA cell attachment and biofilm proliferation. The discovery of this non-pharmaceutical biofilm resistance expands the potential applications of CICNT to include medical devices that are prone to infection and/or devices that contribute to infection. Two representative applications were investigated: external fixator pins and scalpel blades. CICNT-coated versions of these applications underwent additional MRSA biofilm resistance testing as well as mechanical testing. In particular, external fixator pins were identified as a high potential application of CICNT surface coating technology. Previous work on both CNT and CICNT forests has largely been performed on planar structures. However, any potential medical device applications involve curved substrates. In particular, concave curvatures are challenging due to the potential for stress-related CICNT forest defects. Thus, the present work also included a study of the incidence rates and determining factors of these defects. SEM images of the cross-sections revealed different types of microscale forest defects while the top surface showed morphologies that are largely consistent with flat substrates. CICNT forest height and substrate curvature were identified as contributing factors to CICNT forest defect incidence rates. Thus, the present work advances the understanding of bacterial resistance and microstructure-related properties of CICNT surface coatings, with applications in medical devices.

Degree

PhD

College and Department

Mechanical Engineering

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2021-04-05

Document Type

Dissertation

Handle

http://hdl.lib.byu.edu/1877/etd11549

Keywords

carbon nanotube forest, CICNT, direct growth, bacteria resistance, MRSA biofilm, medical applications, concave substrate, CNT forest defects

Language

english

Included in

Engineering Commons

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