Flexibility defines structure in crystals of amphiphilic DNA nanostars

TL;DR

This study shows that flexibility, rather than rigidity, in amphiphilic DNA nanostars is essential for their crystallization, challenging traditional design principles for DNA-based crystalline materials.

Contribution

It reveals that flexible amphiphilic DNA motifs can form crystalline structures without relying on structural rigidity, expanding design possibilities.

Findings

Flexibility is crucial for DNA nanostar crystallization.

Amphiphilic motifs do not require high rigidity for long-range order.

Small angle X-ray scattering and simulations support the role of flexibility.

Abstract

DNA nanostructures with programmable shape and interactions can be used as building blocks for the self-assembly of crystalline materials with prescribed nanoscale features, holding a vast technological potential. Structural rigidity and bond directionality have been recognised as key design features for DNA motifs to sustain long-range order in 3D, but the practical challenges associated with prescribing building-block geometry with sufficient accuracy have limited the variety of available designs. We have recently introduced a novel platform for the one-pot preparation of crystalline DNA frameworks supported by a combination of Watson-Crick base pairing and hydrophobic forces [Nano Lett., 17(5):3276-3281, 2017]. Here we use small angle X-ray scattering and coarse-grained molecular simulations to demonstrate that, as opposed to available all- DNA approaches, amphiphilic motifs do not rely on structural rigidity to support long-range order. Instead, the flexibility of amphiphilic DNA building-blocks is a crucial feature for successful crystallisation.