Preparation of novel whey protein-based aerogels as drug carriers for life science applications

Abstract

High-performance carriers of active compounds processed in a sustainable manner are being prospected in the health care industry and the life science sector in general. The preparation of natural product-based nanoporous materials is regarded as an upgraded process that fulfills the above requirements. The drying of covalently crosslinked protein-based hydrogels using supercritical carbon dioxide is a promising technology for generating highly porous matrices in the dry form (aerogels) susceptible to loading with high active compound contents. In this work, whey protein aerogels and cryogels were prepared by supercritical drying (SCD) and freeze drying (FD) techniques, respectively, from thermally induced protein hydrogels processed at various pH values (1.5, 3.0, 4.5, 7.0, 8.0 and 10.0). A comparative study of the properties of the resulting whey protein aerogels and cryogels was carried out. Mechanical stability as well as microstructural and textural properties of the resulting dried gels was shown to be influenced by the pH value of the hydrogel and the drying technique used. Aerogels were mesoporous (pore diameter≤27.4nm) whereas cryogels showed macroporosity (pore diameter≤200μm). Finally, the use of whey protein aerogels as carriers for active compounds was assessed using ketoprofen as the model drug. Whey protein aerogels showed a high drug loading capacity of up to 9.5% (w/w) (cryogels: 0.4–0.8%, w/w), pH-dependent swelling behaviour in aqueous media and a sustained diffusive drug release.