title: Synthesis and characterization of visible-to-UVC upconversion antimicrobial ceramics.
abstract: The objective of this study was to develop visible-to-ultraviolet C (UVC) upconversion ceramic materials, which inactivate surface-borne microbes through frequency amplification of ambient visible light. Ceramics were formed by high-temperature sintering of compacted yttrium silicate powders doped with Pr(3+) and Li(+). In comparison to previously reported upconversion surface coatings, the ceramics were significantly more durable and had greater upconversion efficiency under both laser and low-power visible light excitation. The antimicrobial activity of the surfaces under diffuse fluorescent light was assessed by measuring the inactivation of Bacillus subtilis spores, the rate of which was nearly 4 times higher for ceramic materials compared to the previously reported films. Enhanced UVC emissions were attributed to increased material thickness as well as increased crystallite size in the ceramics. These results represent significant advancement of upconversion surfaces for sustainable, light-activated disinfection applications.
authors.affiliation: Department of Chemical and Environmental Engineering, Yale University , New Haven, Connecticut 06520-8286, United States.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Cates
authors.forename: Ezra L
authors.initials: EL
authors.lastname: Cates
authors.forename: Min
authors.initials: M
authors.lastname: Cho
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000890:Anti-Infective Agents / Q000138:chemical synthesis* / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects / Q000528:radiation effects; D002516:Ceramics / Q000138:chemical synthesis* / Q000494:pharmacology*; D049449:Luminescence; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D008855:Microscopy, Electron, Scanning; D013057:Spectrum Analysis; D013816:Thermodynamics; D014466:Ultraviolet Rays; D014961:X-Ray Diffraction
chemical_list: D000890:Anti-Infective Agents