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

Abstract

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.