In a study published in Nature Chemistry, Prof. QIAO Yan’s group at the Institute of Chemistry of the Chinese Academy of Sciences developed a membranization strategy for coacervate microdroplets with porous metal-organic framework (MOF) nanoparticles, enabling the mimicry of both the structure and functions of natural cells.

Complex coacervates formed through liquid-liquid phase separation have been extensively studied as models for protocells or artificial cells, owing to their ability to enrich biomolecules, establish chemical gradients, and facilitate complex biochemical reactions.

However, their inherently membraneless nature leads to low colloidal stability and limited selectivity in the recruitment of guest molecules, posing significant challenges to the construction of sophisticated protocell architectures and the development of protocellular interactions.

In this study, the interfacial assembly of zeolitic-imidazolate framework-8 (ZIF-8) nanoparticles on complex coacervate droplets was facilitated by the multivalent interactions such as electrostatic and coordination interactions between the exposed surface of ZIF-8 and the molecular components of complex coacervates.

Proteins and other biomolecules could be trapped inside the MOF or stick to its surface, similar to how proteins are arranged in cell membranes. Besides, the MOF layer helped organize these biomolecules, which could speed up, slow down, or even change the path of certain chemical reactions.

These MOF-coated coacervate droplets can be used to build more complex protocells with artificial organelles. They can even send chemical signals between different parts of the cell. When salt is added, these protocells can group together to form structures that resemble tissues.

Overall, MOF-coated coacervate protocells provide a strong and flexible platform for creating artificial cell systems where biomolecules can be precisely organized