title: Recombinant albumin adsorption on mica studied by AFM and streaming potential measurements.
abstract: Recombinant human serum albumin (rHSA) in monomeric state is widely used in pharmaceutical industry as a drug excipient and for preparing coatings for medical devices. In this work the adsorption process of rHSA on model mica surface at pH 3.5 was studied using the atomic force microscopy (AFM) and in situ streaming potential measurements. The kinetics of albumin adsorption was determined by a direct enumeration of single molecules over various substrate areas. These results were consistent with streaming potential measurements carried out for the parallel-plate channel flow and with theoretical predictions derived from the random sequential adsorption (RSA) model. Desorption kinetics of albumin under flow conditions was also evaluated via the streaming potential measurements. In this way, the amount of irreversibly bound albumin was quantitatively evaluated to be 0.64 and 1.2 mg m(-2) for ionic strength of 0.01 and 0.15 M, respectively. This agrees with previous results obtained for HSA and theoretical calculations derived from the RSA model. Additionally, it was demonstrated that there existed a fraction of reversibly bound albumin that can be fully eluted within a few hours. The binding energy of these fraction of molecules was -18 kT that is consistent with the electrostatic controlled adsorption mechanism of albumin at this pH. It was concluded that the rHSA monolayers of well-defined coverage can find applications for quantitatively analyzing ligand binding and for performing efficient biomaterials and immunological tests.
authors: J Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, Cracow, 30-239 Poland.
authors: Marta
authors: M
authors: Kujda
authors: J Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, Cracow, 30-239 Poland. Electronic address: ncadamcz@cyf-kr.edu.pl.
authors: Zbigniew
authors: Z
authors: Adamczyk
authors: J Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, Cracow, 30-239 Poland.
authors: Maria
authors: M
authors: Morga
authors: Kamila
authors: K
authors: Sofińska
mesh_terms: D000327:Adsorption; D000418:Albumins / Q000378:metabolism*; D000538:Aluminum Silicates / Q000737:chemistry*; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D018625:Microscopy, Atomic Force; D009994:Osmolar Concentration; D011994:Recombinant Proteins / Q000378:metabolism*; D055672:Static Electricity
chemical_list: D000418:Albumins; D000538:Aluminum Silicates; D011994:Recombinant Proteins; C011934:mica
keywords: AFM measurements of recombinant albumin adsorption; Monolayers of recombinant albumin on mica; Recombinant albumin adsorption on mica; Streaming potential of albumin adsorption; Zeta potential of albumin covered mica