title: Probing the adjustments of macromolecules during their surface adsorption.
abstract: Thiol-terminated polymers poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC-SH), poly(N,N-isopropylacrylamide) (PNIPAM-SH), and poly(tert-butyl acrylate) (PtBA-SH) were synthesized, and the polymers were grafted on the gold surfaces of quartz crystal microbalance with dissipation (QCM-D) and surface plasmon resonance (SPR) sensor chips to form brushes. The grafting process of the polymer brushes as well as protein adsorption onto the brush layers was monitored by in situ QCM-D and SPR techniques. By examining the changes in frequency and dissipation factor as well as the value of ∂D/∂f from QCM-D measurements, different stages of the polymer grafting and protein adsorption are distinguished. The most interesting discovery is the conformation change of BSA protein adsorption from a weakly adsorbed native state to a strongly immobilized denatured state on the polymer brushes. The corresponding change in BSA adsorption from a reversible state to an irreversible state was confirmed by SPR measurements. The adsorption of protein on the polymer brushes' surface relies largely on interaction between the protein and the polymers, and the stronger hydrophilicity of the surfaces is proved to be more effective to suppress the protein adsorption. Analysis of the D-f plot of QCM-D measurements helps to characterize different binding strength of protein and the underlying polymer surface.
authors.affiliation: †Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, Shaanxi 710069, China.
authors.forename: Pengxiang
authors.initials: P
authors.lastname: Jia
authors.affiliation: †Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, Shaanxi 710069, China.
authors.forename: Min
authors.initials: M
authors.lastname: He
authors.affiliation: †Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, Shaanxi 710069, China.
authors.forename: Yongkuan
authors.initials: Y
authors.lastname: Gong
authors.affiliation: †Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, Shaanxi 710069, China.|‡Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Chu
authors.affiliation: ‡Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jingfa
authors.initials: J
authors.lastname: Yang
authors.affiliation: ‡Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhao
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D057927:Hydrophobic and Hydrophilic Interactions; D011108:Polymers / Q000737:chemistry*; D058525:Quartz Crystal Microbalance Techniques; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D011108:Polymers; D012710:Serum Albumin, Bovine
keywords: QCM-D; SPR; conformation; polymer brushes; protein adsorption