Regensburg 2004 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 14: SYMPOSIUM: Understanding and Controlling Complex Structures: From Synthetic Polymers to Biomaterials II

CPP 14.3: Talk

Tuesday, March 9, 2004, 15:00–15:15, H 37

Biorelevant Reactions in Microchannel Mixing Devices Observed by Microbeam-SAXS — •Alexander Otten¹, Sarah Köster¹, Bernd Struth², Anatoly Snigirev², and Thomas Pfohl¹ — ¹Angewandte Physik, Universität Ulm, Albert Einstein Allee 11, D-89069 Ulm — ²ESRF, 6 Rue Horowitz, 38043 Grenoble Cedex, France

The application of microfluidic devices does not only allow to analyze small volume fractions of e.g. biomaterial solutions but also gives access to faster observations and improved sample characterization. We use a microchannel device consisting of two crossed channels to examine the behavior of biomacromolecules in elongational flow as well as for studies on biomaterial aggregation. In our microfluidic focussing device a microjet flow is achieved by hydrodynamically focussing a center stream by two symmetric side streams. The elongational flow and the biomaterial aggregation were studied by using the microbeam-SAXS (small angle X-ray scattering) technique. To achieve a spatial resolution of ≈20µm, the x-ray beam was focussed by compound refractive lenses. We present SAXS data on the elongation of DNA molecules in semi-dilute solutions and the increased orientation in the microjet flow. Furthermore, we studied DNA condensation by positively charged countermolecules, G4-Dendrimers. The mixing and the achieved aggregates in respect to different DNA/Dendrimer concentrations were examined and several structural phases were observed.