Physicochemical Characterization of Polymer‐Stabilized Coacervate Protocells

• Published in: Chembiochem : a European journal of chemical biology 2019-10, Vol.20 (20), p.2643-2652
• Main Authors: Yewdall, N. Amy, Buddingh, Bastiaan C., Altenburg, Wiggert J., Timmermans, Suzanne B. P. E., Vervoort, Daan F. M., Abdelmohsen, Loai K. E. A., Mason, Alexander F., Hest, Jan C. M.
• Format: Article
• Language: English
• Subjects: Artificial Cells - chemistry; Artificial Cells - cytology; block copolymers; Cargo; Catalytic activity; complex coacervates; Cytosol; macromolecular crowding; Macromolecular Substances - chemistry; Macromolecules; Membrane permeability; Membranes; Physicochemical properties; Polymers; Polymers - chemistry; Properties (attributes); Proteins; Proteins - chemistry; self-assembly; synthetic cells
• ISSN: 1439-4227; 1439-7633
• DOI: 10.1002/cbic.201900195

The bottom‐up construction of cell mimics has produced a range of membrane‐bound protocells that have been endowed with functionality and biochemical processes reminiscent of living systems. The contents of these compartments, however, experience semidilute conditions, whereas macromolecules in the cytosol exist in protein‐rich, crowded environments that affect their physicochemical properties, such as diffusion and catalytic activity. Recently, complex coacervates have emerged as attractive protocellular models because their condensed interiors would be expected to mimic this crowding better. Here we explore some relevant physicochemical properties of a recently developed polymer‐stabilized coacervate system, such as the diffusion of macromolecules in the condensed coacervate phase, relative to in dilute solutions, the buffering capacity of the core, the molecular organization of the polymer membrane, the permeability characteristics of this membrane towards a wide range of compounds, and the behavior of a simple enzymatic reaction. In addition, either the coacervate charge or the cargo charge is engineered to allow the selective loading of protein cargo into the coacervate protocells. Our in‐depth characterization has revealed that these polymer‐stabilized coacervate protocells have many desirable properties, thus making them attractive candidates for the investigation of biochemical processes in stable, controlled, tunable, and increasingly cell‐like environments. It′s a lot like life: The physicochemical characterization of polymer‐stabilized coacervate protocells (such as macromolecular diffusion and buffering capacity within the core, structure and permeability of the polymer membrane) were explored, thus establishing this system as an attractive platform for investigating biochemical processes and enzymatic reactions in stable, tunable, and increasingly cell‐like environments.