title: Bovine serum albumin adsorption on SiO2and TiO2nanoparticle surfaces at circumneutral and acidic pH: A tale of two nano-bio surface interactions.
abstract: The interaction of a model protein, bovine serum albumin (BSA) with two different metal oxide nanoparticles, TiO2(∼22nm) and SiO2(∼14nm), was studied at both physiological and acidic pH. The pH- and nanoparticle-dependent differences in protein structure and protein adsorption were determined using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA). The results indicated that the surface coverage of BSA decreases with decreasing pH on both TiO2and SiO2surfaces, and BSA coverage is higher by a factor of ca. 3-10times more on TiO2compared to SiO2. The secondary structure of BSA changes upon adsorption to either nanoparticle surface at both pH 7.4 and 2. At acidic pH, BSA appears to completely unfold on TiO2nanoparticles whereas it assumes an extended conformation on SiO2. These differences highlight for the first time the extent to which the protein corona structure is significantly impacted by protein-nanoparticle interactions which depend on the interplay between pH and specific nanoparticle surface chemistry.
authors.affiliation: Department of Chemical & Biochemical Engineering, University of Iowa, Iowa City, IA 52242, United States.
authors.forename: Brittany E
authors.initials: BE
authors.lastname: Givens
authors.affiliation: Department of Chemistry & Biochemistry, University of California San Diego, La Jolla, CA 92093, United States.
authors.forename: Zhenzhu
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Chemical & Biochemical Engineering, University of Iowa, Iowa City, IA 52242, United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Fiegel
authors.affiliation: Departments of Chemistry & Biochemistry, Nanoengineering and Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, United States. Electronic address: vhgrassian@ucsd.edu.
authors.forename: Vicki H
authors.initials: VH
authors.lastname: Grassian
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000737:chemistry*; D011487:Protein Conformation; D058767:Protein Unfolding; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D012710:Serum Albumin, Bovine; D012822:Silicon Dioxide; D014025:Titanium
keywords: Nanoparticles; Protein adsorption; Surface chemistry