Recombinant Spider Silk Gels Derived from Aqueous-Organic Solvents as Depots for Drugs.

Hydrogels are widely used in various biomedical applications, as they cannot only serve as materials for biofabrication but also as depots for the administration of drugs. However, the possibilities of formulation of water-insoluble drugs in hydrogels are rather limited. Herein, we assembled recombinant spider silk gels using a new processing route with aqueous-organic co-solvents, and the properties of these gels could be controlled by the choice of the co-solvent. The presence of the organic co-solvent further enabled the incorporation of hydrophobic drugs as exemplarily shown for 6-mercaptopurine. The developed gels showed shear-thinning behaviour and could be easily injected to serve, for example, as drug depots, and they could even be 3D printed to serve as scaffolds for biofabrication. With this new processing route, the formulation of water-insoluble drugs in spider silk-based depots is possible, circumventing common pharmaceutical solubility issues.