OrientaÃÃo de anticorpos em alumÃnio empregando monocamadas auto-organizadas para produÃÃo de microssensores capacitativos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

There is a growing demand for in situ monitoring of antigen-antibody interaction. Immunosensors based on antigenâantibody interaction have attracted great interest in recent years in various areas. Numerous techniques such as optical, mass-sensitive and electrochemical have been employed for this purpose. Among the electrochemical techniques, a capacitive measurement has also been investigated as a highly sensitive approach. Capacitive immunosensor is based on changes in dielectric properties, charge distribution, dimension and shape, when an antibody / antigen complex formed on the surface of an electrode. These devices present advantages such as reduced influence Faradic currents, nonnecessity labeled or tracer to output signal. In this work, a novel platform of capacitive sensor based on interdigited devices principle was purposed. In addiction, aluminum supports were employed to antibody immobilization using âself assembled-monolayerâ (SAM) and its efficiency were evaluated by immunoenzymatic methods. The microelectrodes was performed by thermal evaporation on the backside of silicon wafer, the aluminum-deposited silicon wafer was annealed for the purpose of performing ohmic contact between two strips (with area approximately 3mm2). The purposed microelectrode was coupled to a Parameter Analyser (Hewllet-Packer,USA) for potentiostatic capacitance measurements. The capacitive sensor consisted of self-assembled of thiols compounds on aluminum strips to which antibodies towards. As model of antibodies was used immunoglobulin G (anti-IgG). The selfassembled monolayer onto electrodes was obtained by immersing of the silicon wafers in a cysteamine solution (25mM) followed by glutaraldehyde for cross linking immobilization of anti-IgG. The results suggest that the antigen-antibody interactions can be measured as proportional to the capacitance increase. This developed platform can be applied for several immunoassay systems due to rapid and low cost advantaging. Then, this work opens perspectives for the development of novel imunossensores applied to the human and animal health, in the ambient diagnosis and other assays based on the interaction antigen-antibody

ASSUNTO(S)

monocamada auto-organizada self-assembled monolayer imunossensor capacitivo aluminum bioquimica alumÃnio immunosensor capacitive

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