title: Preparation of an aqueous suspension of stabilized TiO2 nanoparticles in primary particle form.
abstract: To prepare stabilized TiO2 nanoparticles (TiO2 NPs) in aqueous media as a suspension of the primary particles, we attempted to optimize the conditions for dispersing stable, aggregated TiO2 NPs (A-TiO2 NPs) in aqueous HCl/NaOH solutions or 5 mM pH buffered aqueous solutions. The A-TiO2 NPs with a hydrodynamic diameter (or DLS size) of 150 +/- 20 nm could be dispersed at high concentration (63.5 +/- 0.5 mg/ml) in a 5 mM phosphate buffer (PB) solution of pH 8, and a primary TiO2 (P-TiO2) NP suspension (1.2 +/- 0.3 mg/ml) with DLS size of 30 +/- 5 nm could be separated from the highly concentrated A-TiO2 NP suspension by sonication and subsequent centrifugation. It was observed by comparing the UV-Vis absorption spectra of the A-TiO2 and P-TiO2 NP suspensions that the extinction coefficient of the TiO2 NPs in the aqueous suspension depended on the degree of aggregation. The stabilized P-TiO2 NP suspension in aqueous solution can be used to study nanotoxicity as well as to characterize the physicochemical properties of TiO2 NPs.
authors.affiliation: Center for Nanobio Convergence, Korea Research Institute of Standards and Science, 209 Gajeong-Ro, Yuseong-Gu, Daejeon 305-340, Republic of Korea.
authors.forename: Na-Young
authors.initials: NY
authors.lastname: Joo
authors.forename: Jieun
authors.initials: J
authors.lastname: Lee
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Suk ho
authors.initials: Sh
authors.lastname: Hong
authors.forename: Hyun Min
authors.initials: HM
authors.lastname: Park
authors.forename: Wan Soo
authors.initials: WS
authors.lastname: Yun
authors.forename: Minjoong
authors.initials: M
authors.lastname: Yoon
authors.forename: Nam Woong
authors.initials: NW
authors.lastname: Song