Spontaneous structuration in coacervate-based protocells by polyoxometalate-mediated membrane assembly

Area of Science:

• Biomimetic chemistry
• Materials science
• Supramolecular chemistry

Background:

• Membrane-free coacervate droplets are formed from molecularly crowded, polyelectrolyte/ribonucleotide-enriched solutions.
• Developing compartmentalized structures is crucial for mimicking cellular functions and organizing biochemical reactions.

Purpose of the Study:

• To transform coacervate droplets into membrane-bounded vesicles with a three-tiered micro-compartment structure.
• To investigate the encapsulation and functionalization capabilities of these novel vesicles for biomimetic applications.

Main Methods:

• Utilizing a polyoxometalate-mediated surface-templating procedure for coacervate to vesicle transformation.
• Demonstrating the encapsulation of organic dyes, single-stranded DNA (ssDNA), magnetic nanoparticles, and enzymes within the vesicles.
• Assessing the protection of encapsulated proteins from external proteases and the spatial localization of enzyme cascade reactions.

Main Results:

• Successfully transformed coacervate micro-droplets into membrane-bounded vesicles with a distinct three-tiered structure: a polyoxometalate/polyelectrolyte outer membrane, a coacervate shell, and an aqueous lumen.
• Achieved efficient concentration of various molecules, including enzymes, within the vesicle interior via sequestration into the initial coacervate droplets.
• Demonstrated that encapsulated enzymes are protected from external proteases and can facilitate spatially localized, coupled two-enzyme cascade reactions.

Conclusions:

• The developed polyoxometalate-mediated templating offers a novel route to create functional, multi-compartmentalized hybrid vesicles from coacervates.
• These hybrid vesicles serve as versatile platforms for concentrating biomolecules and enabling spatially controlled biochemical processes, with potential applications in synthetic biology and enzyme catalysis.