title: Effect of grafted PEG chain conformation on albumin and lysozyme adsorption: A combined study using QCM-D and DPI.
abstract: In this study, elucidation of protein adsorption mechanism is performed using dual polarization interferometry (DPI) and quartz crystal microbalance with dissipation (QCM-D) to study adsorption behaviors of bovine serum albumin (BSA) and lysozyme (LYZ) on poly (ethylene glycol) (PEG) layers. From the analysis of DPI, PEG2000 and PEG5000 show tight and loose mushroom conformations, respectively. Small amount of LYZ could displace the interfacial water surrounding the tight mushroomed PEG2000 chains by hydrogen bond attraction, leading to protein adsorption. The loose mushroomed PEG5000 chains exhibit a more flexible conformation and high elastic repulsion energy that could prevent protein adsorption of all BSA and most of LYZ. From the analysis of QCM, PEG2000 and PEG5000 show tight and extended brush conformations. The LYZ adsorbed mass has critical regions of PEG2000 (0.19 chain/nm(2)) and PEG5000 (0.16 chain/nm(2)) graft density. When graft density of PEG is higher than the critical region (brush conformations), the attraction of hydrogen bonds between PEG and LYZ is the dominant factor. When graft density of PEG is lower than the critical region (mushroom conformations), elastic repulsion between PEG and proteins is driven by the high conformation entropy of PEG chains, which is the dominant force of steric repulsion in PEG-protein systems. Therefore, the adsorption of BSA is suppressed by the high elastic repulsion energy of PEG chains, whereas the adsorption of LYZ is balanced by the interactions between the repulsion of entropy elasticity and the attraction of hydrogen bonds.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Han
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Chang
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Jingchuan
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address: wjiang@ciac.ac.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address: yinjh@ciac.ac.cn.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Yin
authors.affiliation: Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, PR China.
authors.forename: Haojun
authors.initials: H
authors.lastname: Liang
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D007368:Interferometry / Q000379:methods*; D008968:Molecular Conformation; D009113:Muramidase / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D058525:Quartz Crystal Microbalance Techniques / Q000379:methods*; D012710:Serum Albumin, Bovine / Q000737:chemistry*
chemical_list: D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D009113:Muramidase
keywords: Bovine serum albumin (BSA); Dual polarization interferometry (DPI); Lysozyme (LYZ); Protein adsorption; Quartz crystal microbalance with dissipation (QCM-D)