Highly responsive sensor on a nanostructured surface via the self-assembly of a biomolecule with an evanescent wave technique

A self-assembled biomolecule was used to create a highly sensitive sensor surface for detecting toxic chemical species (polychlorinated biphenyls, PCBs). We fabricated the nanostructured sensor surface via the self-assembly of cytochrome c on a Au thin film. Surface plasmon resonance (SPR), an evanescent wave technique possessing maximum sensitivity on the surface and characterized by an exponential decay of sensitivity with distance from the surface, was utilized as the principle for signal transduction. When this sensor surface was used for the detection of PCB, even trace amounts of PCB (from 0.1 ppb to 8.0 ppb) in an aqueous solution were readily detectable.