DNA nanostars that self-assemble into core-shell condensate microdroplets

Area of Science:

• Biomolecular Engineering
• Synthetic Biology
• Materials Science

Background:

• Phase-separating DNA condensates offer potential for synthetic cells and microreactors but suffer from instability and uncontrolled mixing.
• Existing DNA condensates lack the stability and control needed for complex reaction pathways.
• The inherent dynamic heterogeneity of DNA condensates limits their application in precise chemical processes.

Purpose of the Study:

• To engineer stable, multi-layered DNA condensate droplets with distinct core and shell regions using DNA nanostars.
• To investigate how nanostar properties influence droplet phase-separation, stability, size, and permeability.
• To establish a method for creating controllable microscale reaction compartments for synthetic biology.

Main Methods:

• Development of multi-layered DNA droplets using DNA nanostars with different sequences for core and shell formation.
• Systematic exploration of nanostar geometry, valency, and interaction strength to optimize droplet properties.
• Analysis of phase-separation temperature differences and surfactant nanostar proportions to control shell morphology and enclosure.

Main Results:

• Successfully created core-shell DNA nanostar droplets with distinct, stable regions.
• Demonstrated control over droplet size, stability, and core permeability by tuning nanostar composition and assembly conditions.
• Identified specific conditions (e.g., >3°C phase-separation temperature difference, 16-25% surfactant nanostars) for forming membrane-like shells.
• Showcased control over droplet size and membrane thickness via thermal annealing rates.

Conclusions:

• Developed a versatile library of core-shell DNA nanostar droplets with predictable properties for microscale reaction compartments.
• These droplets exhibit enhanced stability, controlled permeability, and tunable morphology, overcoming limitations of previous DNA condensates.
• The engineered droplets provide a foundation for assembling programmable materials and synthetic microreactors with cell-like compartmentalization.