title: Physicochemical properties of surface charge-modified ZnO nanoparticles with different particle sizes.
abstract: In this study, four types of standardized ZnO nanoparticles were prepared for assessment of their potential biological risk. Powder-phased ZnO nanoparticles with different particle sizes (20 nm and 100 nm) were coated with citrate or L-serine to induce a negative or positive surface charge, respectively. The four types of coated ZnO nanoparticles were subjected to physicochemical evaluation according to the guidelines published by the Organisation for Economic Cooperation and Development. All four samples had a well crystallized Wurtzite phase, with particle sizes of ∼30 nm and ∼70 nm after coating with organic molecules. The coating agents were determined to have attached to the ZnO surfaces through either electrostatic interaction or partial coordination bonding. Electrokinetic measurements showed that the surface charges of the ZnO nanoparticles were successfully modified to be negative (about -40 mV) or positive (about +25 mV). Although all the four types of ZnO nanoparticles showed some agglomeration when suspended in water according to dynamic light scattering analysis, they had clearly distinguishable particle size and surface charge parameters and well defined physicochemical properties.
authors.affiliation: Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Gangwon-do, South Korea.
authors.forename: Kyoung-Min
authors.initials: KM
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Kyungpook National University, Taegu, South Korea.
authors.forename: Mun-Hyoung
authors.initials: MH
authors.lastname: Choi
authors.affiliation: Toxicological Research Division, National Institute of Food and Drug Safety Evaluation, Chungchungbuk-do, South Korea.
authors.forename: Jong-Kwon
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Toxicological Research Division, National Institute of Food and Drug Safety Evaluation, Chungchungbuk-do, South Korea.
authors.forename: Jayoung
authors.initials: J
authors.lastname: Jeong
authors.affiliation: Department of Biochemistry and Molecular Biology, Korea University Medical School and College, Seoul, South Korea.
authors.forename: Yu-Ri
authors.initials: YR
authors.lastname: Kim
authors.affiliation: Department of Biochemistry and Molecular Biology, Korea University Medical School and College, Seoul, South Korea.
authors.forename: Meyoung-Kon
authors.initials: MK
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Kyungpook National University, Taegu, South Korea.
authors.forename: Seung-Min
authors.initials: SM
authors.lastname: Paek
authors.affiliation: Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Gangwon-do, South Korea.
authors.forename: Jae-Min
authors.initials: JM
authors.lastname: Oh
mesh_terms: D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D055672:Static Electricity; D013499:Surface Properties; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D015034:Zinc Oxide
keywords: ZnO nanoparticles; particle size; physicochemical properties; surface charge; surface coating