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BP: Fachverband Biologische Physik

BP 18: Functionalized Nanoparticles

BP 18.3: Vortrag

Mittwoch, 28. März 2007, 14:30–14:45, H43

Core-Shell Nanoparticle Layers for Label-Free Biosensing in Array Format — •Reiner Dahint¹, Elka Trileva¹, Hatice Acunman¹, Ulrike Konrad¹, Martin Zimmer¹, Volker Stadler², and Michael Himmelhaus¹ — ¹Angewandte Physikalische Chemie, Universität Heidelberg — ²DKFZ Heidelberg

A novel complex material has been prepared with combined biological and optical functionalities. It consists of biofunctionalized gold-coated nanoparticles self-assembled on surfaces, which locally change their optical absorption properties in response to biospecific interactions. For the preparation of the layers, nanoparticles of about 400 nm in diameter are self-assembled on a gold-coated substrate to form a random-close-packed monolayer. Afterwards, the nanoparticle layer is covered with a metal film by deposition of gold colloid prior to an electroless plating step. The resulting surface exhibits a pronounced optical extinction upon reflection of white light. When organic molecules bind to the surface, the peak position of this extinction shows a strong red-shift. It is demonstrated that sensitivity towards molecule adsorption can be significantly enhanced compared to conventional surface plasmon resonance based techniques. By immobilizing a pattern of different peptides on the nanoparticle layers and reacting the surface with specific antibodies label-free detection of biospecific interactions in array format has been shown. In the future we intend to immobilize high-density peptide libraries on the nanoparticle layers by combinatorial synthesis to facilitate in situ, parallel, time-resolved, and label-free screening of biospecific binding processes.