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CPP: Chemische Physik und Polymerphysik

CPP 16: Polymere Netzwerke und Polymere mit besonderer Architektur

CPP 16.1: Vortrag

Donnerstag, 14. März 2002, 09:20–09:40, H38

Molecular structure of single DNA complexes with positively charged dendronized polymers — •Illdiko Gössl¹, Lijin Shu², A.Dieter Schlüter ², and Juergen P. Rabe¹ — ¹Department of Physics, Humboldt University Berlin, Invalidenstr. 110, 10115 Berlin, Germany. — ²Institute of Chemistry, Free University Berlin, Takustr. 3, 14195 Berlin, Germany

We determined the structure of complexes of DNA and positively charged dendronized polymers. The polymers are cylindrically shaped with protonated amine groups at the periphery. Starting with the amino-terminal dendronized polystyrene of generation one, higher generations were obtained by the so called mixed "attach-toNo-dq approach (1).Thus, the synthesised dendronized polymers of generation two, three and four possessed the same polydispersity but varying number of charges as well as radii. The obtained complexes were adsorbed on bare, negatively charged mica or on mica coated with a positively charged polymer. The analysis of scanning force microscopy data indicates that DNA wraps around the dendronized polymers resulting in a DNA pitch of 2.3 nm and 2.0 nm using dendronized polymers of generation two and four, respectively. The DNA pitch varies depending on the salt concentration of the solution for complex formation. Furthermore, the complexes were negatively charged, as predicted by the theory of spontaneous overcharging of macro-ion complexes.

1. L. Shu, A. Schäfer, A. D. Schlüter, Macromolecules 33, 4321 (2000).