Electrogenerated indium tin oxide-coated glass surface with photosensitive interfaces: Surface analysis

We present herein a photo-immobilization technique for the localized and specific conjugation of biochip platforms with different proteinaceous bioreceptors, such as antigen or antibodies. This methodology based on a photoactivable electrogenerated polymer film, pyrrole-benzophenone, allows the covalent immobilization of biomolecules through light mediation. The surface-conductive glass platform electropolymerized with poly(pyrrole-benzophenone) thin film may then be used to affinity-coat the chip with molecular recognition probes. This glass chip electroconductive surface modification is done by the deposition of a thin layer of indium tin oxide (ITO). Thereafter, pyrrole-benzophenone monomers are electropolymerized onto the conductive metal oxide surface and then exposed to an antigen Staphylococcal Enterotoxin B (SEB)) solution and illuminated with UV light (wavelength ∼345 nm) through a mask. As a result of the photochemical reaction, a pattern thin layer of the antigen was covalently bound to the benzophenone-modified surface. Then the sample to be analyzed, along with its specific target antibody (anti-SEB antibodies), is introduced onto the glass surface and left to react with the previously photo-immobilized antigen. When the immuno-reaction is completed, the specifically attached immunoglobulin analytes are detected by using secondary antibodies conjugated with Fluorescein isothiocyanate (FITC). The fluorescence signal emanating from the biochip surface is then quantified by two methods, using a filtered intensified charge-coupled device (CCD) camera and a grating spectrometer.