Diverse, Distinct, and Densely Packed DNA Droplets

TL;DR

This study demonstrates the creation of multiple distinct DNA-based liquid droplets through sequence design, revealing how thermal processing influences their morphology and dynamics, with implications for understanding biomolecular phase separation.

Contribution

We experimentally engineered up to nine distinct DNA nanostar phases and analyzed how temperature quenching affects their structure and behavior, advancing control over complex biomolecular condensates.

Findings

Created nine non-adhering DNA nanostar phases.

Rapid temperature quench induces densely packed droplet layers.

Observed glassy dynamics and phase caging effects.

Abstract

The liquid-liquid phase separation of biomolecules is an important process for intracellular organization. Biomolecular sequence combinatorics leads to a large variety of proteins and nucleic acids which can interact to form a diversity of dense liquid (`condensate') phases. The relationship between sequence design and the diversity of the resultant phases is therefore of interest. Here, we explore this question using the DNA nanostar system which permits the creation of multi-phase condensate droplets through sequence engineering of the sticky end bonds that drive particle-particle attraction. We explore the theoretical limits of nanostar phase diversity, then experimentally demonstrate the ability to create 9 distinct, non-adhering nanostar phases that do not share components. We further study how thermal processing affects the morphology and dynamics of such a highly diverse condensate system. We particularly show that a rapid temperature quench leads to the formation of a densely packed 2-D layer of droplets that is transiently stabilized by caging effects enabled by the phase diversity, leading to glassy dynamics, such as slow coarsening and dynamic heterogeneity. Generally, our work provides experimental insight into the thermodynamics of phase separation of complex mixtures and demonstrates the rational engineering of complex, long-range, multi-phase droplet structures.