title: Interaction of carboxylated single-walled carbon nanotubes with bovine serum albumin.
abstract: Carboxylated single-walled carbon nanotubes (c-SWNTs) were synthesized prosperously in order to improve dispersion of raw carbon nanotubes. Then, bovine serum albumin (BSA) was used as the template protein to study the biocompatibility of c-SWNTs by UV-Vis, fluorescence and circular dichroism (CD) spectroscopic methods at the molecular level. Results from fluorescence spectrum showed obvious decreases in fluorescence intensity of BSA induced by c-SWNTs, indicating the occurrence of interaction between BSA and c-SWNTs. Static quenching effect of c-SWNTs was verified by linear Stern-Volmer plots and K(SV) values. Thermodynamic parameters at different temperatures demonstrated that the interaction between c-SWNTs and BSA was mainly favored by hydrophobic force. In addition, Na(+) interfered with the quenching effect of c-SWNTs, which revealed that electrostatic force played a role in binding roles of BSA to c-SWNTs simultaneously. The results of UV and synchronous fluorescence spectrum validated that hydrophobicity of amino acid residues expressly increased with the addition of c-SWNTs. The content of α-helix structure in BSA decreased by 14.06% with c-SWNTs viewed from CD spectrum. Effect of SWNTs on the conformation of BSA could be controlled by the surface chemistry of SWNTs.
authors.affiliation: China Pharmaceutical University, Nanjing 210009, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Li
authors.forename: Rui
authors.initials: R
authors.lastname: Lin
authors.forename: Hua
authors.initials: H
authors.lastname: He
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Gao
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism*; D002264:Carboxylic Acids / Q000737:chemistry* / Q000378:metabolism; D002417:Cattle; D002942:Circular Dichroism; D037742:Nanotubes, Carbon / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001672:Biocompatible Materials; D002264:Carboxylic Acids; D037742:Nanotubes, Carbon; D012710:Serum Albumin, Bovine