Berlin 2008 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 7: Posters I
BP 7.8: Poster
Montag, 25. Februar 2008, 17:00–19:30, Poster A
Surface-Enhanced Fluorescence for microarray sensitivity improvement — •Eric Le Moal1, Emmanuel Fort2, and Sandrine Lévêque-Fort3 — 1Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstr. 12, D-53115 Bonn — 2Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot-Paris7, Bât. Condorcet, 10 rue A. Domon et L. Duquet, F-75205 Paris cedex 13 — 3Laboratoire de PhotoPhysique Moléculaire, Université Paris Sud, Bât. 210, F-91405 Orsay cedex
Fluorescence is the prevailing labeling technique in biosensors and microarrays. However, the detection of very low molecular concentrations and the precise localization of biomarkers are often limited by the weakness of the fluorescence signal. We present a new method based on sample substrates that improve in sensitivity the fluorescence detection. These active substrates consist in glass slides covered with silver and alumina films and can directly be used with common detection setups. Fluorescence enhancement affects both excitation and decay rates and is strongly dependant on the distance to the metal surface. Additional improvements are achieved by structuring the metallic layer. Surface roughness indeed allows converting into light the energy that is non-radiatively transferred by the fluorescent molecules to the substrate. We measured a signal enhancement by more than 40-fold on a DNA microarray with a commercial scanning device. Reaching a highly sensitive detection on a DNA microarray allows operating with less genetic material, which may be of major interest when this quantity is limited, e.g., in biomedical diagnosis.