Antimicrobial Properties of Infrared to Ultraviolet Upconverting Lanthanide Doped Zirconia Material Systems
Open Access
- Author:
- Lauer, Pete
- Area of Honors:
- Materials Science and Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Douglas Edward Wolfe, Thesis Supervisor
Robert Allen Kimel, Thesis Honors Advisor - Keywords:
- Lanthanide
Ceramics
Antimicrobial
Upconversion - Abstract:
- The increase in antibiotic-resistant bacteria and nosocomial infections pose a serious risk to the long-term health of society. To prevent this spread of disease in hospitals without the reliance on antibiotics, novel material systems that self-sterilize are being investigated. This effort discusses the development of one such antimicrobial system. This material system consists of a zirconia host lattice co-doped with ytterbium and thulium or europium ions that is capable of emitting ultraviolet electromagnetic radiation following the excitation from an infra-red-light source. Two sets of samples were fabricated and tested to elucidate the antimicrobial response of this material system. The first set of samples were ceramic pellets which consisted of 4 different stoichiometries of the aforementioned host lattice and dopants. These samples’ antimicrobial properties were tested both with and without the presence of a light source. When illuminated, all the doped compositions showed a strong antimicrobial response after 6 hours of light stimulation (99.68% to 99.93% reduction in E. coli cultures) and a total reduction of detectable E. coli after 9 hours. When tested in the absence of light, the samples showed an increase in bacterial inoculum density after 6 hours (157.6% to 608.1% increase in E. coli cultures). The second set of samples consisted of thin films deposited via electron-beam physical vapor deposition, the target of which had the same composition as the bulk ceramics previously investigated. These films were tested under light stimulation and exhibited a variable antimicrobial response over a 6 and 24 hour incubation period, depending on their position in the deposition mask.