title: Disinfection effects of undoped and silver-doped ceria powders of nanometer crystallite size.
abstract: Being endowed with an ability of capturing and releasing oxygen, the ceria surface conventionally assumes the role of catalyzing redox reactions in chemistry. This catalytic effect also makes possible its cytotoxicity toward microorganisms at room temperature. To study this cytotoxicity, we synthesized the doped and undoped ceria particles of 8-9 nm in size using an inexpensive precipitation method and evaluated their disinfecting aptitudes with the turbidimetric and plate count methods. Among the samples being analyzed, the silver-doped ceria exhibits the highest sterilization ability, yet the undoped ceria is the most intriguing. The disinfection effect of undoped ceria is moderate in magnitude, demanding a physical contact between the ceria surface and bacteria cell wall, or the redox catalysis that can damage the cell wall and result in the cell killing. Evidently, this effect is short-range and depends strongly on dispersion of the nanoparticles. In contrast, the disinfection effects of silver-doped ceria reach out several millimeters since it releases silver ions to poison the surrounding microorganisms. Additionally, the aliovalent silver substitution creates more ceria defects. The synergetic combination, silver poisoning and heterogeneous redox catalysis, lifts and extends the disinfecting capability of silver-doped ceria to a superior level.
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
authors.forename: Dah-Shyang
authors.initials: DS
authors.lastname: Tsai
authors.affiliation: School of Dental Technology, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Biomedical Materials and Tissue Engineering, Taipei Medical University, Taipei, Taiwan.
authors.forename: Tzu-Sen
authors.initials: TS
authors.lastname: Yang
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Huang
authors.affiliation: School of Dental Technology, Taipei Medical University, Taipei, Taiwan; Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei, Taiwan.
authors.forename: Pei-Wen
authors.initials: PW
authors.lastname: Peng
authors.affiliation: Graduate Institute of Biomedical Materials and Tissue Engineering, Taipei Medical University, Taipei, Taiwan; Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei, Taiwan.
authors.forename: Keng-Liang
authors.initials: KL
authors.lastname: Ou
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D002563:Cerium / Q000494:pharmacology*; D003460:Crystallization; D004203:Disinfection / Q000379:methods*; D000067493:Dynamic Light Scattering; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D007477:Ions; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008856:Microscopy, Fluorescence; D053758:Nanoparticles / Q000737:chemistry*; D009391:Nephelometry and Turbidimetry; D010316:Particle Size; D011208:Powders; D012834:Silver / Q000494:pharmacology*; D013059:Spectrum Analysis, Raman; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development
chemical_list: D000890:Anti-Infective Agents; D007477:Ions; D011208:Powders; D002563:Cerium; D012834:Silver
keywords: antibacterial activity; ceria nanoparticle; cytotoxicity; oxygen vacancy; reactive oxygen species