Polypyrrole-Oligosaccharide Microarray for the Measurement of Biomolecular Interactions by Surface P

The polypyrrole approach initially developed for the construction of DNA chips, has been extended to other biochemical compounds such as proteins and more recently oligosaccharides. The copolymerization of a pyrrole monomer with a biomolecule bearing a pyrrole group by an electrochemical process allows a very fast coupling of the biomolecule (probe) to a gold layer used as a working electrode. Fluorescence-based detection is the reference method to detect interactions on biochips; however an alternative label free method, could be more convenient for rapid screening of biointeractions. Surface Plasmon Resonance (SPRi) is a typical label-free method for real time detection of the binding of biological molecules onto functionalized surfaces. This surface sensitive optical method is based upon evanescent wave sensing on a thin metal layer. The SPR approach described herein is performed in an imaging geometry that allows simultaneous monitoring of biorecognition reactions occurring on an array of immobilized probes (chip). In a SPR imaging experiment, local changes in the reflectivity are recorded with a CCD camera and are exploited to monitor up to 100 different biological reactions occurring onto the molecules linked to the polypyrrole matrix. This method will be applied to oligosaccharide recognition.