title: A simultaneous electrochemical impedance and quartz crystal microbalance study on antihuman immunoglobulin G adsorption and human immunoglobulin G reaction.
abstract: The quartz crystal microbalance (QCM), in combination with electrochemical impedance spectroscopy (EIS), has been utilized to monitor in situ antihuman IgG (hIgG) adsorption on bare poly(o-phenylenediamine) (PPD)- and 1-dodecanethiol (C12SH)-modified Au electrodes and succeeding human IgG reaction, respectively. The resonant frequency (f) and the motional resistance (R(1)) of the piezoelectric quartz crystal (PQC) as well as electrochemical impedance (EI) parameters were measured and discussed. The standard heterogeneous rate constants of the ferricyanide/ferrocyanide couple before and after the antibody adsorption and antibody-antigen reactions were determined. The results show that the amount for antibody adsorption was the greatest on the most hydrophobic (1-dodecanethiol-modified) surface, while the antibody bioactivity was almost identical on the three kinds of surfaces. Two parameters simultaneously obtained, Deltaf and DeltaC(s) (interfacial capacitance), have been used for the first time to estimate both the association constant of the immunoreaction and the valence of antigen with satisfactory results. The proposed method may find wide application in interfacial biochemistry studies for its advantages in providing real-time multidimensional piezoelectric and electrochemical impedance information.
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Hunan Normal University), Ministry of Education, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: He
authors.forename: Qingji
authors.initials: Q
authors.lastname: Xie
authors.forename: Youyu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D000327:Adsorption; D000941:Antigens / Q000276:immunology; D003460:Crystallization; D017097:Electric Impedance; D004563:Electrochemistry; D004566:Electrodes; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry* / Q000276:immunology*; D010655:Phenylenediamines / Q000737:chemistry; D011791:Quartz / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D000941:Antigens; D007074:Immunoglobulin G; D010655:Phenylenediamines; D013438:Sulfhydryl Compounds; C013976:dodecylmercaptan; D011791:Quartz