title: Characterization of fullerene colloidal suspension in a cell culture medium for in vitro toxicity assessment.
abstract: To elucidate important parameters for in vitro toxicity assessment of C(60) and C(70) fullerene colloidal particles, experiments were carried out in culture medium using pulsed field gradient nuclear magnetic resonance (PFG-NMR), asymmetrical flow field-flow fractionation (AFFFF), and dynamic light scattering (DLS) methods. First, the amounts of total and bulk bovine serum albumin (BSA) molecules in C(60) and C(70) fullerene colloidal suspensions were determined using the PFG-NMR and AFFFF methods. Because the amount of bulk BSA molecules in the cell culture medium is a significant factor in inducing cell growth and because BSA can strongly adsorb onto the fullerene particles, this value is an important parameter for toxicological assessment. It was found that most of the BSA molecules are freely diffusing for both fullerene colloidal suspensions, at least in the range of fullerene concentration from 0.0025-0.15 mg mL(-1). Second, structural analysis of the fullerene colloidal nanoparticles was successfully performed using AFFFF-multi angle light scattering (MALS) and DLS methods. Based on the observed light scattering profiles obtained from a narrow size distribution of colloidal particles collected after AFFFF separation, it was estimated that the fullerene colloidal nanoparticles of both C(60) and C(70) did not adopt a hard spherical structure in the culture medium. The results from combined analysis using the AFFFF-MALS and DLS methods also supported this conclusion and indicated that the fullerene colloidal particles adopted a more flexible structure in culture medium. Since carbon nanomaterials with different geometric structures exhibit quite different cytotoxicity and bioactivity, these results are important for in vitro toxicity assessment.
authors.affiliation: Polymer Standards Section Japan (PSSJ), National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, Higashi 1-1-1, Tsukuba, Ibaraki, 305-8565 Japan. h-kato@aist.go.jp
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Kato
authors.forename: Naohide
authors.initials: N
authors.lastname: Shinohara
authors.forename: Ayako
authors.initials: A
authors.lastname: Nakamura
authors.forename: Masanori
authors.initials: M
authors.lastname: Horie
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Fujita
authors.forename: Kayori
authors.initials: K
authors.lastname: Takahashi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Iwahashi
authors.forename: Shigehisa
authors.initials: S
authors.lastname: Endoh
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kinugasa
mesh_terms: D000465:Algorithms; D000818:Animals; D002417:Cattle; D003102:Colloids / Q000032:analysis / Q000737:chemistry; D003470:Culture Media / Q000032:analysis* / Q000737:chemistry; D037741:Fullerenes / Q000032:analysis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D053758:Nanoparticles / Q000032:analysis* / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet; D013535:Suspensions / Q000032:analysis / Q000737:chemistry
chemical_list: D003102:Colloids; D003470:Culture Media; D037741:Fullerenes; D013535:Suspensions; D012710:Serum Albumin, Bovine