title: Electrochemical functionalization of gold and silicon surfaces by a maleimide group as a biosensor for immunological application.
abstract: In the present study we investigated the preparation of biofunctionalized surfaces using the direct electrochemical grafting of maleimidophenyl molecules with subsequent covalent immobilization of specific peptide to detect target antibody, thereby extending the application of the biosensing systems towards immunodiagnostics. Para-maleimidophenyl (p-MP) functional groups were electrochemically grafted on gold and silicon surfaces from solutions of the corresponding diazonium salt. A specially synthesized peptide modified with cysteine (Cys-peptide) was then immobilized on the p-MP grafted substrates by cross-linking between the maleimide groups and the sulfhydryl group of the cysteine residues. Accordingly, the Cys-peptide worked as an antigen that was able to bind specifically the target antibody (anti-GST antibody), while it was non-sensitive to a negative contrast antibody (i.e. anti-Flag β). The immobilization of both specific and non-specific antibodies on the Cys-peptide-modified surfaces was monitored by infrared spectroscopic ellipsometry, a quartz crystal microbalance integrated in flow injection analysis system and potentiometric response. The results obtained clearly demonstrated that the direct modification of a surface with maleimidophenyl provides a very simple and reliable way of preparing biofunctionalized surfaces suitable for the construction of immunological biosensors.
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut für Silizium-Photovoltaik, Kekuléstr. 5, 12489 Berlin, Germany.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Aleksei
authors.initials: A
authors.lastname: Tretjakov
authors.forename: Marc
authors.initials: M
authors.lastname: Hovestaedt
authors.forename: Guoguang
authors.initials: G
authors.lastname: Sun
authors.forename: Vitali
authors.initials: V
authors.lastname: Syritski
authors.forename: Jekaterina
authors.initials: J
authors.lastname: Reut
authors.forename: Rudolf
authors.initials: R
authors.lastname: Volkmer
authors.forename: Karsten
authors.initials: K
authors.lastname: Hinrichs
authors.forename: Joerg
authors.initials: J
authors.lastname: Rappich
mesh_terms: D000906:Antibodies / Q000276:immunology*; D015374:Biosensing Techniques / Q000379:methods*; D003545:Cysteine / Q000378:metabolism; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D055767:Immobilized Proteins / Q000378:metabolism; D008301:Maleimides / Q000737:chemistry*; D010455:Peptides / Q000378:metabolism; D012825:Silicon / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013499:Surface Properties
chemical_list: D000906:Antibodies; D055767:Immobilized Proteins; D008301:Maleimides; D010455:Peptides; C043592:maleimide; D006046:Gold; D003545:Cysteine; D012825:Silicon