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CPP: Chemische Physik und Polymerphysik

CPP 22: SYMPOSIUM Microfluidics II: Soft objects in flow, open geometries

CPP 22.1: Hauptvortrag

Donnerstag, 30. März 2006, 14:00–14:30, ZEU 160

Confinement and manipulation of single molecules in micro- and nanochannels — •Petra Schwille, Fedor Malik, Petra S. Dittrich, and Madhavi Krishnan — Institute for Biophysics, Biotechnology Center, Technical University Dresden

Micro- and nanofluidic structures are ideally suited to observe and manipulate minute amounts of biomolecules under close-to-native conditions without tedious and error-prone immobilization to surfaces. In particular, soft polymer structures such as PDMS can be easily adapted to host several manipulation steps, e.g. for solution mixing and cell or particle sorting on one chip, and at the same time allow to analyze the solution by high resolution optics such as single molecule fluorescence spectroscopy. We discuss several successful and promising microfluidic applications, such as for enzyme kinetics, particle sorting, and the design of a chip allowing for the generation of ∼5µm sized homodisperse droplets that contain the reaction mixture for cell-free protein expression, as a basic model for what could be developed into artificial cells.

Recently, we devised a strategy to quantitatively study the translocation of DNA binding proteins, such as helicases, restriction endonucleases and exonculeases at the single molecule level by scaling down the structure sizes to nanochannels whose dimensions approach the persistence length of DNA (50-60 nm). The method is based on the entropic stretching of DNA in confined structures, and the subsequent application of fluorescence techniques such as bright field fluorescence microscopy and/or Fluorescence Correlation Spectroscopy to quantify transport coefficients of enzymes that translocate along the DNA backbone