[Zurück]

C. Jochum, N. Adzić, G. Kahl, C. N. Likos:
"Conformation characteristics of DNA-based dendrimers in electrolyte solutions";
Poster: Jülich Soft Matter Days 2018, Jülich; 20.11.2018 - 23.11.2018; in: "Jülich Soft Matter Days 2018 Book of Abstracts", (2018), S. 107.

Conformation characteristics of DNA-based dendrimers in
electrolyte solutions

C. Jochum, N. Adzić, E. Stiakakis, G. Kahl, C. N. Likos

Dendrimers are synthetic macromolecules possessing a highly branched and regular internal
structure. Charging these dendrimers leads to conformational responsiveness, i.e. one of the
most important ingredients for their envisioned applications, which is essentially lacking for
their neutral counterparts. Recently, Luo and his co-workers at Cornell University synthesized
dendrimer-like DNA (DL-DNA) via enzymatic ligation of Y-shaped DNA building blocks [1].
These charged DNA-based dendrimers are novel macromolecule aggregates, which hold high
promise in bringing about targeted self-assembly of soft-matter systems in the bulk and at in-
terfaces. Inspired by these findings, we present a joint theoretical-experimental study of this
novel class of macromolecules. We employ a bead-spring model in order to describe such den-
drimers of varying generation numbers and we performed Molecular Dynamics Simulations
to determine equilibrium properties and conformational characteristics of all-DNA dendrimers.
The obtained results are compared to dynamic and static light scattering experiments. Our
computational and experimental results show that DL-DNAs are rigid objects with low internal
bead concentration and a high percentage of absorbed counterions. Furthermore, both experi-
mental as well as computational results reveal that varying the salt concentration barely affects
the molecule´s conformation and does not cause any backfolding of dendritic arms [2]. In or-
der to simulate large ensembles of DL-DNAs, we calculate a coarse-grained potential for the
dendrimers within the framework of the introduced model. This is achieved by employing
an approach based on the Widom particle-insertion method as well as the umbrella sampling
method [3]. With this coarse-grained potential at hand, we investigate the phenomenon of clus-
ter crystals of DL-DNA in the bulk [4], a novel form of solids with multiple site occupancy. The
study of these charged dendrimer systems is an important field of research in the area of soft
matter due to their potential role for various interdisciplinary applications, ranging from molec-
ular cages and carriers for drug delivery in a living organism to the development of dendrimer-
and dendron-based ultra- thin films in the area of nanotechnology [5].
References
[1] Y. Li, Y. Tseng, and D. Luo, Nat. Mater. 3, 38, (2004)
[2] C. Jochum, N. Adzić, E. Stiakakis, T. L. Derrien, D. Luo, G. Kahl, and C. N. Likos,
submitted to RSC Nanoscale, (2018)
[3] B. Mladek and D. Frenkel, Soft Matter, 7, 1450, (2011)
[4] B. Mladek, M. Neumann, G. Kahl, and C. Likos, Phys. Rev. Lett. 96, 045701, (2006)
[5] C. Lee, J. MacKay, J. FrÃl´chet, and F. Szoka, Nat. Biotechnol., 23, 1517, (2005)

Projektleitung Gerhard Kahl:
DFS