Characterization of self-assembled redox polymer and antibody molecules on thiolated gold electrodes.
Multilayer immobilization of antibody and redox polymer molecules on a gold electrode was achieved, as a strategy for the potential development of an amperometric immunosensor. The step-by-step assembly of antibiotin IgG on Os(bpy)(2)ClPyCH(2)NH poly(allylamine) redox polymer (PAH-Os) adsorbed on thiolated gold electrodes was proved by quartz crystal microbalance (QCM) and atomic force microscopy (AFM) experiments, confirming the electrochemical evidence. The increase of redox charge during the layer-by-layer deposition demonstrated that charge propagation within the layers is feasible. The multilayer structure proved to be effective for the molecular recognition of horseradish peroxidase-biotin conjugate (HRP-biotin), as confirmed by the QCM measurements and the electrocatalytic reduction current obtained upon H(2)O(2) addition. The catalytic current resulting from PAH-Os mediation was shown to increase with the number of assembled layers. Furthermore, the inventory of IgG molecules on the supramolecular self-assembled structure and the specific and non-specific binding of HRP-biotin conjugate were confirmed by the QCM transient studies, giving information on the kinetics of IgG deposition and HRP-biotin conjugate binding to the IgG.
Calvo
E J
EJ
INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria AR-1428, Buenos Aires, Argentina. calvo@q1.fcen.uba.ar
Danilowicz
C
C
Lagier
C M
CM
Manrique
J
J
Otero
M
M
D000906:Antibodies; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D006046:Gold; D007118:Immunoassay / Q000295:instrumentation; D007700:Kinetics; D018625:Microscopy, Atomic Force; D010084:Oxidation-Reduction; D011108:Polymers
D000906:Antibodies; D011108:Polymers; D006046:Gold