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MA: Fachverband Magnetismus
MA 8: Magnetic Particles/ Clusters I
MA 8.1: Talk
Monday, March 14, 2011, 14:45–15:00, HSZ 103
Optical detection of the rotational dynamics of anisotropic magnetic nanoparticles — •Stefan Schrittwieser1, Joerg Schotter1, Katerina Soulantika2, Jerome Maynadie2, Sergio Lentijo Mozo2, Frank Ludwig3, Jan Dieckhoff3, Andreas Huetten4, and Hubert Brueckl1 — 1AIT Austrian Institute of Technology, Nano Systems, Vienna, Austria — 2LPCNO-INSA, Toulouse, France — 3TU Braunschweig, Braunschweig, Germany — 4Bielefeld University, Bielefeld, Germany
We introduce a novel biosensor concept, which is based on anisotropic hybrid nanoparticles consisting of magnetic nanorods encapsulated by noble metal shells. It relies on highly sensitive plasmon-optical detection of the rotational dynamics of magnetic nanoparticles immersed in the sample solution, which changes when target molecules bind to the surfaces of the nanoparticles due to the increase in their hydrodynamic radii. For alignment control of the nanoparticles in suspension, we employ constant-amplitude rotating magnetic fields. The increased hydrodynamic diameter of analyte-carrying nanoparticles translates into an easily measurable phase shift. Plain Co-nanorods dissolved in toluene solution serve as model system to verify the detection principle. Those show an optical anisotropy in polarized light, which is sufficient to optically detect their mean orientation in the solution. Along with the rotational dynamics data, we also present model calculations of both the magnetic and optical properties of suitable hybrid nanoparticles along with estimates concerning their relaxation behavior and sensitivity to molecular detection.