Supramolecular functional interfacial architectures for biosensor applications

Abstract

This short review describes some of our efforts in generating bio-functional supramolecular interfacial architectures for their use as affinity coatings in biosensor development based on a recently introduced novel optical recording principle combining the resonant excitation of surface plasmon modes and fluorescence detection schemes. Examples are given for multilayer assemblies designed for surface hybridization reactions between a grafted oligonucleotide catcher probe and target strands from solution. By describing the binding behavior of fluorophore-labeled rabbit–anti-mouse IgG to surface-attached mouse IgG, the limit of detection of the surface plasmon fluorescence spectroscopy will be shown to be in the lower femtomolar concentration range. These DNA-and protein binding studies will be complemented by examples for membrane-based biosensor platforms. We will document that tethered lipid bilayer membranes can be assembled with specific capacities of Cm = 0.5μF cm−2 and specific resistivities in excess of Rm > 20 MΩ cm2. The incorporation of the synthetic ionophore valinomycin can mediate the K+-ion translocation across these tethered membranes, thus reducing the resistivity selectively and reversibly by more than four orders of magnitude.