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arXiv · 1712.05659

Binding branched and linear DNA structures: from isolated clusters to fully bonded gels

Javier Fernandez-Castanon·Francesca Bomboi·Francesco Sciortino
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Abstract

The proper design of DNA sequences allows for the formation of well defined supramolecular units with controlled interactions via a consecution of self-assembling processes. Here, we benefit from the controlled DNA self-assembly to experimentally realize particles with well defined valence, namely tetravalent nanostars (A) and bivalent chains (B). We specifically focus on the case in which A particles can only bind to B particles, via appropriately designed sticky-end sequences. Hence AA and BB bonds are not allowed. Such a binary mixture system reproduces with DNA-based particles the physics of poly-functional condensation, with an exquisite control over the bonding process, tuned by the ratio, r, between B and A units and by the temperature, T. We report dynamic light scattering experiments in a window of Ts ranging from 10°C to 55°C and an interval of r around the percolation transition to quantify the decay of the density correlation for the different cases. At low T, when all possible bonds are formed, the system behaves as a fully bonded network, as a percolating gel and as a cluster fluid depending on the selected r.

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Javier Fernandez-Castanon, Francesca Bomboi, Francesco Sciortino. 2017-12-15. Binding branched and linear DNA structures: from isolated clusters to fully bonded gels. https://doi.org/10.1063/1.5011720

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