title: Acceleration of suspending single-walled carbon nanotubes in BSA aqueous solution induced by amino acid molecules.
abstract: Single-walled carbon nanotube (SWCNT) suspensions in aqueous media were prepared using bovine serum albumin (BSA) and amino acid molecules. It was found that the amino acid molecules clearly decreased the time required for suspending the SWCNTs in BSA aqueous solutions. Dynamic light scattering measurements revealed that the particle sizes of the SWCNTs suspended in aqueous media with and without amino acid molecules were approximately the same and stable for more than one week. The zeta potential values of the BSA molecules in pure water and amino acid aqueous solutions were different, and these values were also reflected in the surface potential of colloidal SWCNT particles in the corresponding aqueous media, thus inducing different dispersibility of SWCNTs in aqueous media. Pulsed field gradient nuclear magnetic resonance measurements showed that the interactions between the SWCNTs and the amino acid molecules are weak and comprise chemical exchange interactions and not bonding interactions. Amino acid molecules play a fascinating role in the preparation of SWCNT suspensions in BSA aqueous media by increasing electrostatic repulsive interactions between SWCNT colloidal particles and consequently enhancing the dispersion ability of the BSA molecules.
authors.affiliation: 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. Electronic address: H-kato@aist.go.jp.
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Kato
authors.affiliation: 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.
authors.forename: Ayako
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: Health Research Institute (HRI), AIST, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Horie
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D000818:Animals; D037742:Nanotubes, Carbon / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry
chemical_list: D000596:Amino Acids; D037742:Nanotubes, Carbon; D012996:Solutions; D014867:Water; D012710:Serum Albumin, Bovine
keywords: Amino acid; Dispersibility; Dynamic light scattering; PFG-NMR; SWCNT; Suspending; Zeta potential