Sono-Assembly of Polyphenol–Protein Capsules for Enhanced Biocatalytic Cascades

We report a versatile approach for engineering protein capsules by harnessing the ultrasonication-mediated assembly (sono-assembly) of protein-stabilized emulsions for cascade biocatalysis. The capsules are assembled by coating volatile perfluorohexane emulsion with proteins aided by ultrasonication, followed by cross-linking proteins with polyphenols (e.g., tannic acid) and subsequent evaporation of the oil phase. When multiple enzymes are used as stabilizers for emulsion preparation, the resulting capsules can be utilized for biocatalytic cascades. The protein capsules as interfacial biocatalytic platforms can increase the interfacial area and maintain enzyme activity. Compared to capsules composed of a single type of enzymes, those incorporated with multiple enzymes demonstrate faster and more sensitive visual detection of substances (e.g., glucose). Moreover, the introduction of polyphenols not only enhances the stability of capsules but also participates in enzyme cascade reactions through the coordination of metal ions, generating reactive oxygen species (e.g., •OH) in tumor cells, potentiallly useful for chemodynamic therapy. The facile and scalable nature of the sono-assembly process, combined with the biocatalytic cascade properties, make these capsules promising candidates as microreactors for advanced biological and biomedical applications.