On-Demand Release of Hydrosoluble Drugs from a Paramagnetic Porous Collagen-Based Scaffold

The design of a collagen scaffold containing iron oxide nanostructures capped by a TiO₂ (anatase) layer is reported. The TiO₂ shell is proposed to perform a dual role: 1) as an innovative and biocompatible cross-linker agent, providing binding sites to the protein moiety, through the well-known TiO₂ chemical affinity towards carboxyl groups, and 2) as a protective surface layer for the paramagnetic core against oxidation. Simultaneously, the presence of the nanostructures confers to the collagen gel sensitivity to an external stimulus; that is, the application of a magnetic field. The hybrid biomaterial was demonstrated to be nontoxic and is proposed as a smart scaffold for the release of bioactive compounds on demand. The tuneable release of a model protein (myoglobin) upon application of a magnetic field was investigated. Myoglobin was loaded in the microporous material and discharge was induced by consecutive magnet applications, leading to release of the protein with high spatio-temporal and dosage control.