Amine-Reactive Augmentation of Silk Fibroin Mats for Increasing Cargo Retention Capabilities

Silk fibroin (SF) is an ideal biomaterial for next-generation clinical wound dressings due to its biocompatibility and tunable mechanical properties. Cell therapies for wound healing have explored using SF as the base for delivering beneficial cargo; however, retention is poor due to exudate "wash out." To address concerns with the premature release of cargo from SF-fabricated wound dressings, we utilized amine-reactive chemistry to conjugate SF mats with azido-reactive dibenzocyclooctyne (DBCO) that can then attach complementary azido-tagged cargo through chemoselective immobilization. SF mats were made using electrospinning of a 1:1 SF/PCL solution and were then conjugated with N-Hydroxysuccinimide-dibenzocyclooctyne ester (DBCO). PBS soaking was used for control SF mats. SF mats were then imaged and characterized using the following metrics: pore size, fiber alignment, fiber distribution, fiber diameter, ultimate tensile strength, tangent modulus, proteolytic degradation, absorption, and retention. Successful DBCO conjugation of SF mats was confirmed through the presence of the Az-Cy5 dye while exhibiting no significant changes to the DBCO SF mats in any of the tested metrics compared to controls. Our results provide evidence that the amine chemistry responsible for the DBCO conjugation does not alter important SF mat properties. This confirms that DBCO augmentation paired with Az-Cy5 tags may be a viable approach for immobilizing different therapeutic cargoes to aid wound healing efforts.