Confocal fluorescence spectroscopy in microstructures

• Applicant: Professorin Dr. Petra Dittrich
• Subject Area: Biophysics
• Term: from 2001 to 2002
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5371690

SORTING OF CELLS AND SINGLE PARTICLES IN MICROSTRUCTURES. As a miniaturized alternative to FACS, we have developed a novel fluorescence based cell sorting strategy in a microfluidic device, where the possibility of high throughput rates with low sample consumption is combined with extremely sensitive analysis to enable the detection of single fluorescent cells and molecules. These microchips offer the possibility to integrate other reaction units on the same chip to build a comprehensive analysis system. Our microchip consists of a main channel, comprising the detection unit, and a perpendicular deflection channel. The fast detection of the cells and particles is realized by use of fluorescence spectroscopy in a confocal setup. Additionally, flow velocities can be precisely determined through fluorescence correlation spectroscopy measurements. Flow rates are either hydrodynamically driven by adjusting the height of water reservoirs or electroosmotically driven by set voltages determining the velocity. In the former case the switching in the deflection channel is controlled by high-speed micro-dispensing valves and in the latter by switching of the positive electrodes at the ends of the channels. Both strategies have beenutilized and compared for speed and accuracy.

• DFG Programme: Research Grants