Chemotactic Interactions Drive Migration of Membraneless Active Droplets

Area of Science:

• Biomimetic materials
• Synthetic biology
• Chemical engineering

Background:

• Cellular chemotaxis drives collective behavior in nature.
• Recreating in vitro chemotaxis is challenging due to cellular complexity.
• Existing methods struggle to mimic microorganism-scale cellular features.

Purpose of the Study:

• To engineer cell-sized droplets with autonomous motility and collective interaction capabilities.
• To investigate the use of pH gradients for directed droplet migration.
• To demonstrate the potential of these droplets in reconstituting protometabolic pathways.

Main Methods:

• Generation of enzymatically active, cell-sized membraneless droplets.
• Utilizing internal enzyme activity to create external pH gradients.
• Observing and controlling droplet migration along self-generated chemical gradients.
• Modulating enzyme activity to tune droplet migration speed.

Main Results:

• Enzymatically active droplets exhibited directed migration along pH gradients.
• Droplet migration was selectively directed towards neighboring droplets, demonstrating collective behavior.
• Migration speed was tunable by altering internal enzyme activity.
• The droplets facilitated the reconstitution of a simple protometabolic pathway, enhancing product generation.

Conclusions:

• Simple, stable membraneless droplets can recapitulate complex biological phenomena like chemotaxis.
• These droplets serve as versatile platforms for bioinspired materials and synthetic biology.
• The findings open new avenues for designing active soft matter systems with programmable behaviors.