title: Supported protein G on gold electrode: characterization and immunosensor application.
abstract: In this work, we study the electrochemical properties of protein layer grafted on gold electrode for C-reactive protein detection. Two CRP-antibody immobilization methods were used: the first method is based on direct physisorption of CRP-antibody onto the gold surface and the second method is based on oriented CRP-antibody with protein G intermediate layer. The two developed immunosensors were tested against CRP antigen in phosphate buffer saline solution and in human plasma. The electrochemical characterization of each immobilized layers was achieved by cyclic voltammetry and impedance spectroscopy. The morphology of the deposited biomolecules was observed by Atomic Force Microscopy and the roughness was measured. Moreover, contact angle measurement was used for wettability studies. The response of the developed immunosensors was reproducible, rapid, and highly stable and a detection limit of 100 fg/mL and 10 pg/mL antigen was observed with and without protein G respectively. The developed immunosensors was used for CRP detection in human plasma.
authors.affiliation: Carthage University, Nanotechnology Laboratory, National Institute of Applied Science and Technology, Centre Urbain Nord, Bp676, 1080 Charguia Cedex, Tunisia.
authors.forename: Imen
authors.initials: I
authors.lastname: Hafaiedh
authors.forename: Hanen
authors.initials: H
authors.lastname: Chammem
authors.forename: Adnane
authors.initials: A
authors.lastname: Abdelghani
authors.forename: Eric
authors.initials: E
authors.lastname: Ait
authors.forename: Laurent
authors.initials: L
authors.lastname: Feldman
authors.forename: Olivier
authors.initials: O
authors.lastname: Meilhac
authors.forename: Laurence
authors.initials: L
authors.lastname: Mora
mesh_terms: D000327:Adsorption; D000906:Antibodies / Q000737:chemistry; D015374:Biosensing Techniques; D002097:C-Reactive Protein / Q000032:analysis*; D058266:Dielectric Spectroscopy; D004566:Electrodes; D019204:GTP-Binding Proteins / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry*; D007118:Immunoassay; D057230:Limit of Detection; D018625:Microscopy, Atomic Force; D011487:Protein Conformation; D015203:Reproducibility of Results; D017155:Wettability
chemical_list: D000906:Antibodies; D055767:Immobilized Proteins; D006046:Gold; D002097:C-Reactive Protein; D019204:GTP-Binding Proteins
keywords: Antigen–antibody recognition; Atomic force microscopy; C-reactive protein; Contact angle; Cyclic voltammetry; Electrochemical impedance spectroscopy