title: Comparison of interactions between human serum albumin and silver nanoparticles of different sizes using spectroscopic methods.
abstract: Three different sizes (15.9 ± 2.1 nm, 26.4 ± 3.2 nm and 39.8 ± 4.0 nm, respectively) of citrate-coated silver nanoparticles (SNPs) have been synthesized and characterized. The interactions of the synthesized SNPs with human serum albumin (HSA) at physiological pH have been systematically studied by UV-vis absorption spectroscopy, fluorescence spectroscopy, synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy and circular dichroism (CD) spectroscopy. The results indicate that the SNPs can bind to HSA with high affinity and quench the intrinsic fluorescence of HSA. The binding constants and quenching rate constants were calculated. The apparent association constants (Kapp ) values are 2.14 × 10(4) M(-1) for 15.9 nm SNP, 1.65 × 10(4) M(-1) for 26.4 nm SNP and 1.37 × 10(4) M(-1) for 39.8 nm SNP, respectively. The values of binding constant obtained from the fluorescence quenching data match well with that determined from the absorption spectral changes. These results suggest that the smaller SNPs have stronger interactions to HSA than the larger ones at the same concentrations. Synchronous fluorescence, three-dimensional fluorescence and CD spectroscopy studies show that the synthesized SNPs can induce slight conformational changes in HSA.
authors.affiliation: State Key Laboratory of Virology & Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, People's Republic of China; Hubei Key Laboratory for Processing and Application of Catalytic Materials, Huanggang Normal University, Huanggang, 438000, People's Republic of China.
authors.forename: Wanju
authors.initials: W
authors.lastname: Zhang
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Zhang
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Lian
authors.initials: L
authors.lastname: Yuan
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Xu
authors.forename: Fenglei
authors.initials: F
authors.lastname: Jiang
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
mesh_terms: D002942:Circular Dichroism; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013056:Spectrophotometry, Ultraviolet
chemical_list: D012709:Serum Albumin; D012834:Silver
keywords: fluorescence spectroscopy; human serum albumin; interaction; silver nanoparticles