NEAR-INFRARED SURFACE-PLASMON RESONANCE IN SILICON-BASED SENSOR - NEWOPPORTUNITIES IN SENSITIVE DETECTION OF BIOMOLECULES FROM AQUEOUS-SOLUTIONS BY APPLYING MICROSTEP FOR DISCRIMINATING SPECIFIC AND NONSPECIFIC-BINDING

We report the application of near-infrared surface plasmon spectroscop y to study the sensitive detection of the binding of proteins to funct ionalized surfaces, Working at 1300 nm, where both water and silicon a re transparent, the method is of particular interest for biosensors ba sed on silicon technology. We describe the application of thin functio nalization layers forming a step on the sensor surface. Employment of such a step for discriminating specific and non-specific binding of bi omolecules is suggested: measuring surface plasmon resonance (SPR) wit h a single near-infrared laser and detector chip on a single sensor sp ot shows simultaneously adsorption to one surface in comparison to a r eference surface. As a model for this step, a few monolayers of phthal ocyaninatopolysiloxane, a 'hairy' rod-like polymer, are deposited by t he Langmuir-Blodgett technique. As a model system, we use the binding behaviour of bovine serum albumin to two different kinds of surface.