Dehydrated silk fibroin matrices as versatile delivery systems for extracellular vesicles

Extracellular vesicles (EVs) have emerged as promising alternatives to cell-based therapies due to their low immunogenicity, ability to carry therapeutic cargo, and enhanced stability. However, rapid clearance from the bloodstream and phagocytic uptake by macrophages after systemic or local administration limit their therapeutic efficacy, highlighting the need for delivery systems that enable sustained and localized EV release. In this study, a natural protein silk fibroin (SF) was selected as a biomaterial carrier due to its tunable degradation kinetics and biocompatibility. SF was produced into nonwovens and films to investigate the effect of material structure on EV delivery in dehydrated SF matrices. A mild water vapor annealing approach was applied to tune structural stability and β-sheet formation while preserving EV integrity. Gingival fibroblast (GF)-derived EVs were successfully incorporated into nonwovens and films. EV-loaded nonwovens and films demonstrated distinct release characteristics over 14 days, with nonwovens providing a more controlled release and films showing delayed but accelerated release at later time points. EV morphology was preserved after release, and the EVs were notably internalized by human umbilical vein endothelial cells (HUVECs). Both EV-loaded materials enhanced the migration in a wound healing assay. These findings highlight the potential of dehydrated SF matrices as promising EV delivery systems for future regenerative medicine applications.