Direct encapsulation of BSA and DNA into silica microcapsules (hollow spheres)

We reported before that silica hollow spheres (microcapsules) are prepared by interfacial reaction method that W/O emulsion with the aqueous solution of sodium silicate and n-hexane solution of Tween 80 and Span 80 is combined with another aqueous solution of silica precipitant such as NH4HCO3 and NH4CI. This procedure using W/O/W emulsion fabricates the hollow structures of silica particles directly, and additional steps such as the removal of core parts, that are often essential for the preparation of hollow particles via core-shell materials, are not required. When biomacromolecules such as protein and nucleic acid are mixed in the aqueous solution of sodium silicate, these macromolecules can be encapsulated into the microcapsules. We succeeded the direct encapsulation of bovine serum albumin (BSA) and duplex DNA. Most of encapsulated BSA and DNA cannot be released from the microcapsules without the destruction of microcapsule shell. These microcapsule materials encapsulating biomacromolecules will be applied to biotechnologies such as immobilized enzyme and so on. (c) 2006 Wiley Periodicals, Inc. J Biomed Mater Res 81A: 103-112, 2007.