Redesigned Silk: A New Macroporous Biomaterial Platform for Antimicrobial Dermal Patches with Unique Exudate Wicking Ability

Silk is one of the most important materials in the history of medical practice. Owing to its excellent strength, biocompatibility and degradability, silk from Bombyx mori – which is structured as a concentric assembly of silk fibroin (SF) coated by a sheath of sericin (SS) – has long been used for wound treatment. Here, we recapitulate for the first time the topology of native silk fibers using a radically new materials design-oriented approach to achieve unprecedented porous dermal patches suitable for controlled drug delivery. The method implies four steps: (1) removing SS; (2) creating anisotropic macroporosity in SF via ice templating; (3) stabilizing the SF foam with a methanolic solution of Rifamycin (Rif) antibiotic; and (4) coating Rif-loaded redesigned SF foams with a SS sheath. The core-shell SS@SF foams exhibit water wicking properties accommodate up to ~20% lateral deformation. Moreover, monitoring of antibacterial activity against Staphylococcus aureus revealed that the SS@SF foams’ Rif release extended up to 9 days. We anticipate that reverse-engineering of silk foams opens exciting new avenues towards the fabrication of advanced drug eluting silk-based biomaterial platforms with improved performance. The present approach can be generalizable to re-build multicomponent biological materials with tunable porosity.