Competition between self-assembly and phase separation governs high-temperature condensation of a DNA liquid

Abstract

In many biopolymer solutions, attractive interactions that stabilize finite-sized clusters at low concentrations also promote phase separation at high concentrations. Here we study a model biopolymer system that exhibits the opposite behavior: Self-assembly of DNA oligonucleotides into finite-sized, stoichiometric clusters, known as "DNA nanostars", tends to inhibit phase separation of the oligonucleotides at high temperatures. We use microfluidics-based experiments to map the phase behavior of DNA nanostars at high concentrations of divalent cations, revealing a novel phase transition in which the oligonucleotides condense upon increasing temperature. We then show that a theoretical model of competition between self-assembly and phase separation quantitatively predicts changes in experimental phase diagrams arising from DNA sequence perturbations. Our results point to a general mechanism by which self-assembly shapes phase boundaries in complex biopolymer solutions.

arXiv commentIncludes supplementary information

References in corpus (8)

• Phase behavior and morphology of multicomponent liquid mixtures
• Rational design of self-assembly pathways for complex multicomponent structures
• Accurate phase diagram of tetravalent DNA nanostars
• Self-assembly in chains, rings and branches: a single component system with two critical points
• Reentrant phase behaviour for systems with competition between phase separation and self-assembly
• Controlling composition of coexisting phases via molecular transitions
• Linker-mediated phase behavior of DNA-coated colloids
• Interplay between self-assembly and phase separation in a polymer-complex model

Cited by in corpus (2)

• Emergence of multiphase condensates from a limited set of chemical building blocks
• Cooperation and competition of basepairing and electrostatic interactions in mixtures of DNA nanostars and polylysine