MasterNanosciences, nanotechnologies

General scope

In recent years, DNA has emerged as an ideal polymer to build soft materials. In addition to being mechanically robust, chemically stable and enzymatically replicable, DNA is a sequence-defined polymer. Two single-stranded DNA of complementary sequences can hybridize into the canonical double helix, forming a rigid bond. By smartly programming the monomer sequence DNA can self-assemble into almost any shape. Large structures hundreds of nanometers and hundreds of strands) of complex shapes called `DNA origami' are now routinely assembled from computer-aided design relying on the thermodynamic of DNA assembly to program a geometry.
The central objective of the present project is to bridge the gap between the macroscopic mechanical properties of gels made of DNA and the DNA strand sequences at the nanoscale.
Our research hypothesis is as follow. DNA hybridisation is highly predicable and enables the rational, automatic and reliable design of nanostructures. When connected together into a 3D network, they form a macroscopic DNA gel. Therefore, DNA sequence should encode the mechanical response of this material. However, we expect a more complex relationship between sequence and properties in the thermodynamic limit than for isolated nanostructures.

The workhorse system for DNA gels understanding is composed of only a few (e.g. 3 or 4) strands that self assemble in a simple motif called DNA nanostars (NS, see Fig). Each strand is terminated by a short palindromic sequence called `sticky end' (SE). As shown in Fig nanostars bind by their sticky ends to form a disordered network or a gel.
We propose to explore the various phase transition by using microcalorimetry, either commercial DSC or ITC, home made DSC and to explore the mechanical properties related to the nanoscale design with micro or macro rheology and in the equilibrium or out-of-equilibrium (fractures) limits.

Possible collaborations and networking

LIMMS, University of Tokyo ;  iLM Université Claude Bernard -CNRS (Lyon) , Laboratoire d’informatique et de parallélisme (LIP, ENS Lyon)