Loading and release of a model protein from porous silicon powders

Porous silicon (p‐Si) has been investigated as a novel delivery system for protein therapeutics. The loading of a model hydrophilic protein, Papain into anodised and stain etched p‐Si powders has been investigated using X‐ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR) and correlations made with the release kinetics. Variation in specific Papain (Amide I/II) and p‐Si (Si–Hx ) functional group absorbances with Papain loading level was characterised using FTIR, while the surface chemical distribution was assessed using XPS. A combination of burst release and sustained release of Papain was observed from p‐Si powders; this was dependent on p‐Si type and the Papain loading level. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)