Alexandre Dmitriev

Alexandre Dmitriev is an Assistant professor at the Department of Applied Physics, Chalmers University of Technology (Göteborg, Sweden). He graduated from Rostov State University (Rostov-on-Don, Russia) with MSc in Physics (1997) and obtained his PhD (2003) at Max-Planck-Insitute for Solid State Research (Stuttgart, Germany) jointly with École Polytechnique Fédérale de Lausanne (EPFL, Switzerland), developing novel strategies for supramolecular self-assembly and 2D metal-organic coordination at surfaces. In 2004 he joined Chalmers as a Marie Curie Fellow working on nanoplasmonic materials and optical biosensing. His research up to date resulted in more than 30 papers in peer-reviewed scientific journals, grossing more than 1100 citations (http://www.chalmers.se/ap/EN/research/bionanophotonics/research/functional ).

Single-molecule nanoplasmonic sensing in the near- and far-field

In this lecture we’ll discuss possibilities for the optical single-molecule sensing with the help of localized plasmonic resonances – collective charge density oscillations that are supported in the nanoscopic metal particles, illuminated by light: metallic nanostructures show resonant behaviour (enhanced scattering and absorption) upon the illumination with light in the visible and near-IR spectral range. As a result, strongly enhanced electromagnetic (EM) fields, which are extremely sensitive to the dielectric properties of the medium, are created in the direct proximity of the illuminated nanostructures. Positioning chemical and biological species in the regions of the enhanced EM fields changes the dielectric properties of these regions. In general, two possible strategies are available for the optical label-free biochemosensing – sensing in the near- and far-field. In the former the ‘reporter’ is positioned directly in the proximity of the entities we want to detect (analytes) – this can be a sharp (plasmonic) tip of the AFM so single biomolecules can be addressed with high spatial resolution. In the far-field, mostly the dark-field scattering from the plasmonic structure, carrying the bound analyte, is detected, and the analyte is specifically bound to the exclusive regions of very high EM field enhancement, so we yield the binding detection one molecule at a time.