Regensburg 2013 – scientific programme

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O: Fachverband Oberflächenphysik

O 43: Plasmonics and Nanooptics IV

O 43.7: Talk

Wednesday, March 13, 2013, 12:00–12:15, H31

Label-free single-protein optical sensing and imaging — •Marek Piliarik and Vahid Sandoghdar — Max Planck Institute for the Science of Light Günther-Scharowsky-Str. 1, Building 24 91058 Erlangen, Germany

To date, the sensitivity of optical detection and imaging of individual molecules is strictly limited to species with strong fluorescence or absorption properties. We report on a new approach based on the direct detection of the light scattered by biomolecular species such as proteins without the need for any labels. The underlying mechanism of our detection method is the interference between the light coherently scattered by the analyte (e.g. a protein molecule adsorbed on the substrate) and the laser beam partially reflected at the substrate-water interface. By combining this method with microfluidics and surface functionalization of the substrate, we show that it is possible to detect and image a single protein in real time and distinguish it from a large background of other scatterers. We discuss the application of our approach for ultrasensitive label-free biosensing.