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Construction of Three-Dimensional DNA Hydrogels from Linear Building Blocks

Authors


  • We thank Dr. Martin Grininger for inspiring discussions. This work has received funding from the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement n° 240544, ERC Grant agreement no. 279202, North Rhine-Westphalia, the Deutsche Forschungsgemeinschaft (DFG grant INST 221/87-1 FUGG) and the University of Siegen.

Abstract

A three-dimensional DNA hydrogel was generated by self-assembly of short linear double-stranded DNA (dsDNA) building blocks equipped with sticky ends. The resulting DNA hydrogel is thermoresponsive and the length of the supramolecular dsDNA structures varies with temperature. The average diffusion coefficients of the supramolecular dsDNA structures formed by self-assembly were determined by diffusion-ordered NMR spectroscopy (DOSY NMR) for temperatures higher than 60 °C. Temperature-dependent rheological measurements revealed a gel point of 42±1 °C. Below this temperature, the resulting material behaved as a true gel of high viscosity with values for the storage modulus G′ being significantly larger than that for the loss modulus G′′. Frequency-dependent rheological measurements at 20 °C revealed a mesh size (ξ) of 15 nm. AFM analysis of the diluted hydrogel in the dry state showed densely packed structures of entangled chains, which are also expected to contain multiple interlocked rings and catenanes.

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