With this project, we aim at performing an experimental study of interpenetrating netwokes composed of DNA nanostars (NSs) ¿ a colloidal analogue of patchy particles ¿, which have been extensively used in our group in the last years. We plan to design tetravalent DNA nanostars of two different types (A and B), such that A binds with A and B binds with B. We aim at investigating the formation of intertwisted A and B networks with (tunable) nanometric mesh size. By playing with the design of the sticky base sequences we will control the temperature range at which the two networks forms, to observe both the concurrent formation of the two lattices as well as the formation of one network in an already formed one. We will complement the experimental results with numerical simulation of the network formation process.
The present project is a first step in the direction of building interpenetrating DNA gels. The versatility of DNA nanoparticles, originating from the possibility to control in a precise way inter-particle binding and binding strength opens the possibility to control at the nanoscale the self-assembly of the networks. With the appropriate design we will be able to control the network mesh, the network dynamics, the build up of a network inside another network, the restructuring dynamics of a network inside another network.
Our previous studies[1-4]] have investigated in great details
gelation and phase-separation processes in one-component
DNA tetravalent nanostars. This model system, being well characterized, has become a standard in nanotechnology research and it is currently used by several groups
(Prof. Erika Eiser, Cambridge, Prof. Lorenzo Di MIchele, UCL London, Prof. Omar A. Saleh UC Santa Barbara USA).
With this project, we will expand the range of applicability of DNA nanostars to multicomponent systems.
Our experiments will demonstrate how a careful design of the binding energies makes it possible to control the viscoelastic properties of the gel. Controlling the number of bases involved in the binding process we will be able to modulate the build up of viscosity over a wide (or a narrow) range of temperatures. We plan to realize a material with tunable viscoelastic properties.
Finally, we will attempt to discover analogies between the
network interpenetration and the liquid-liquid transition in supercooled water. In water, it has indeed been postulated that (hydrogen bond) network interpenetration is responsible for the critical behavior[5-6]
[1] S. Biffi et al., Proc. Natl. Acad. Sci. U.S.A 110, 15633
[2] F. Bomboi et al., Nat. Commun. 7, 13191 (2016)
[3] E. Lattuada et al., Nanoscale 12, 23003 (2020)
[4] F. Bomboi et al., Nanoscale 11, 9691 (2019)
[5] P. G. Debenedetti, F. Sciortino, G. H. Zerze
Science, 369, 289-292 (2020).
[6] F. Smallenburg, L. Filion and F. Sciortino, Nature Physics 10, 653 (2014)