Hollow protein microspheres synthesized at the water/ionic liquid interface

Hollow microspheres of proteins are prepared by emulsion-templating technique. When aqueous protein solution was added to hydrophobic ionic liquid (C4mimPF₆) under vigorous stirring, aqueous proteins were adsorbed at the water/ionic liquid interface, which result in the formation of protein cages. Extraction of the microspheres into water was carried out by using cross-linking reaction with glutaraldehyde. Encapsulation of water-soluble functional molecules such as DNA and gold nanoparticles was easily realized by mixing of these molecules with aqueous proteins. Interfacial synthesis of protein microcapsules are widely applicable to various proteins, such as BSA, Ovalbumin, Cytc and Glucose Oxidase, and it provides general guidelines to produce functional microcapsules from biological macromolecules.