Fluidic Membrane-Bound Protocells Enabling Versatile Assembly of Functional Nanomaterials for Biomedical Applications.

The development of membrane-bound protocells, which process cascade biochemical reactions in distinct microcompartments, marks a significant advancement in soft systems. However, many synthesized protocells with cell membrane-like structures are prone to rupturing in biological environments and are challenging to functionalize, limiting their biomedical applications. In this study, we explore the liquid-liquid phase separation of tannic acid (TA) and polyethylene glycol (PEG) to form coacervate droplets. Upon introducing polyvinylpyrrolidone (PVP) molecules, a dense hydrogen bonding network spontaneously forms at the surfaces of the coacervate droplets, resulting in robust fluidic membrane-bound protocells (FMPs). These protocells can be flexibly postfunctionalized to incorporate functional nanomaterials via electrostatic attraction, enabling the design of cascade reactions for biomedical applications. To demonstrate this, nanozymes (Pt/CeO2) are assembled onto Fe3+/FMPs, resulting in functional FMPs (Pt/CeO2@Fe3+/FMPs) capable of catalyzing the degradation of uric acid and its harmful byproduct, H2O2, offering potential treatments for gout.