One-Step Fabrication of Coconut-Like Capsules via Competitive Reactions at an All-Aqueous Interface for Enzyme Immobilization

A concept of interfacial competitive reaction between biomineralization and alginate gelation at an all-aqueous single-emulsion droplet interface to prepare robust coconut-like capsules (inner hard wall and outer soft wall) is developed. The concept is further applied for enzyme immobilization with high encapsulation efficiency, enzyme loading, mass transfer coefficient, and recyclability. The thickness and swelling properties of the shell are simply tunable by a competitive reaction. Our platform may open a green, facile, and efficient way to prepare organic–inorganic hybrid sustainable materials with tailored compositions and structures.