Light-induced magnetization detected by force microscopy: from basic concept to first applications

The aim of this proposal is to extend the existing magnetic-resonance force microscopy detection scheme by application to light-generated, short-lived triplet states as paramagnetic probes. For this purpose, initially diamagnetic chromophores are immobilized on a surface and are photo-excited into their triplet state (S = 1). This novel detection scheme potentially has the following advantages: (i) generation of triplet states by photo-excitation results in strong initial electron-spin polarization, and hence strong magnetization, on a microsecond to millisecond time scale even at comparatively high temperatures; (ii) the scheme allows repetitive photo-excitation thus leading to significantly enhanced signal-to-noise ratio; (iii) the combination of light-excitation and cantilever-detection minimizes unwanted perturbations due to light scattering or background fluorescence, and (iv) stable paramagnetic probes that are susceptible to secondary chemistry are not needed. After successful implementation of the method, we will test two applications: First, the setup will be used (i) to quantify aptamer–substrate binding constants and (ii) to scan triplet-labeled cells for protein localization purposes. With the results, we aim towards all-purpose applications.

 

S. Weber

Prof. Dr. Stefan Weber

Albert-Ludwigs-Universität Freiburg, Institut für Physikalische Chemie Albertstr. 21, 79104 Freiburg im Breisgau
Tel.: +49 761 203-6213/-14 Email: Stefan.Weber@physchem.uni-freiburg.de
Fax: +49 761 203-6222 Website: http://
E. Schleicher

Dr. Erik Schleicher

Albert-Ludwigs-Universität Freiburg, Institut für Physikalische Chemie Albertstr. 21, 79104 Freiburg im Breisgau
Tel.: +49 761 203-6204 Email: Erik.Schleicher@physchem.uni-freiburg.de
Fax: +49 761 203-6222 Website: http://
M. Havenith

Prof. Dr. Martina Havenith

Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie II 44801 Bochum
Tel.: +49 234 32-28249 Email: Martina.Havenith@rub.de
Fax: +49 234 32-14183 Website: http://