Facile fabrication of microspheres and microcapsules from a recombinant spider eggcase silk protein for drug delivery

Spider silk is renowned for its exceptional mechanical properties, and compatibility and biodegradability for various functional applications, such as drug delivery. By a facile HFIP (1,1,1,3,3,3-hexafluoro-2-propanol)-on-Oil method, microspheres and microcapsules were assembled from a recombinant spider eggcase silk protein. Doxorubicin (Dox) can be loaded into microspheres or microcapsules before or after their preparation, while maintaining morphological integrity. The isoelectric point of the silk proteins was 4.8, which affected the drug loading of silk spheres for different pH media. For enzyme-assisted drug delivery, Dox-loaded silk spheres effectively released the drug under enzymatic degradation by addition of proteinase K.