title: Reversible immobilization and direct electron transfer of cytochrome c on a pH-sensitive polymer interface.
abstract: A pH-sensitive polymer interface has been used as a matrix for reversible immobilization of cytochrome c (Cyt c) on an Au surface through a dip-coating process. The pH-sensitive behavior of the polymer brush interface has been demonstrated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The reversible immobilization and electron-transfer properties of Cyt c have been investigated by in situ UV/Vis spectrophotometry and CV. The results have shown that the poly(acrylic acid) (PAA) brush acted as an excellent adsorption matrix and a good accelerant for the direct electron transfer of Cyt c, which gave redox peaks with a formal potential of 40 mV versus Ag/AgCl in pH 7.6 phosphate buffer solution. The average surface coverage of Cyt c on the PAA film was about 1.7 x 10(-10) mol cm(-2), indicating a multilayer of Cyt c. The electron-transfer rate constant was calculated to be around 0.19 s(-1) according to the CV experiments. The interface was subjected to in situ attenuated total internal reflection Fourier-transform infrared (ATR-FTIR) spectroscopic analysis, in order to further confirm the immobilization of Cyt c on the surface. This polymer-protein system may have potential applications in the design of biosensors, protein separation, interfacial engineering, biomimetics, and so on.
authors.affiliation: Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Tsinghua University, Beijing 100084, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhou
authors.forename: Xianbo
authors.initials: X
authors.lastname: Lu
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Hu
authors.forename: Jinghong
authors.initials: J
authors.lastname: Li
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000327:Adsorption; D015374:Biosensing Techniques / Q000379:methods*; D045304:Cytochromes c / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D011108:Polymers; C006903:carbopol 940; D045304:Cytochromes c