title: Diazonium-protein adducts for graphite electrode microarrays modification: direct and addressed electrochemical immobilization.
abstract: Diazonium cation electrodeposition was investigated for the direct and electro-addressed immobilization of proteins. For the first time, this reaction was triggered directly onto diazonium-modified proteins. Screen-printed (SP) graphite electrode microarrays were studied as active support for this immobilization. A 10-microelectrode (eight working electrodes, 0.2 mm2 each; one reference; and one auxiliary) setup was used to study the addressing possibilities of the method. These electrode microarrays were shown to be able to covalently graft diazonium cations through electrochemical reduction. Cyclic voltammetry and X-ray photoelectron spectroscopy were used to characterize the electrochemical grafting onto our SP graphite surface and suggested that a diazonium monolayer was deposited. Rabbit and human immunoglobulins (IgGs) were then chemically coupled to an aniline derivative (4-carboxymethylaniline), followed by diazotation to form an aryl diazonium function available for the electrodeposition. These modified proteins were both successfully electro-addressed at the surface of the graphite electrodes without cross-talk or interference. The immuno-biochip obtained using this novel approach enabled the specific detection of anti-rabbit IgG antibodies with a detection limit of 50 fmol of protein. A promising strategy to immobilize markedly different biological entities was then presented, providing an excellent spatial specificity of the electro-addressing.
authors.affiliation: Laboratoire de Génie Enzymatique et Biomoléculaire, UMR 5013 EMB2, CNRS Université Claude Bernard Lyon 1, Bât CPE, 43, boulevard du 11 Novembre 1918, 69622 Villeurbanne, Cedex, France.
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Corgier
authors.forename: Christophe A
authors.initials: CA
authors.lastname: Marquette
authors.forename: Loïc J
authors.initials: LJ
authors.lastname: Blum
mesh_terms: D000818:Animals; D000906:Antibodies / Q000032:analysis* / Q000737:chemistry; D003979:Diazonium Compounds / Q000737:chemistry*; D004566:Electrodes; D006108:Graphite / Q000737:chemistry; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry* / Q000276:immunology; D040081:Protein Array Analysis / Q000379:methods*; D011817:Rabbits; D014052:Toluidines / Q000737:chemistry
chemical_list: D000906:Antibodies; D003979:Diazonium Compounds; D007074:Immunoglobulin G; D014052:Toluidines; D006108:Graphite