Tuning of SPR for Colocalized Characterization of Biomolecules Using Nanoparticle-Containing Multilayers

Abstract

In this contribution, we quantify the fine-tuning of surface plasmon resonance via nanoparticle coating of gold SPR chips. We target preparation of atomically flat surface with defined charge, needed for scanning probe characterization of biomolecules, with simultaneous optimization of in situ SPR sensitivity during immobilization of these molecules. Using total internal reflection ellipsometry, we show that the goal can be achieved by combination of charge-stabilized silver nanoparticles over underlying gold chip of reduced thickness. The provided formulas for optimal silver to gold thickness relation are valid for arbitrary analyte and the method was experimentally verified on binding of Rtt103 protein.