We present a strategy to prepare a hybrid poly(ethylene glycol) (PEG)-silk fibroin (SF) hydrogel system with chemically crosslinked PEG network and physically entrapped SF. A network of non-degradable poly(acrylate-co-NVP) chains, hydrolytically degradable thioether ester bonds, and interpenetrating SF fibrils was fabricated via visible light initiated thiol-acrylate gelation (Fig. 1A). We evaluated the impact of SF and S-SF inclusion on the properties (i.e. gel point, mesh size, etc.) of chemically crosslinked hybrid hydrogel. The fraction of SF retention in PEG hydrogels was determined and its effect on moduli and hydrolytic degradation quantified. We hypothesized that physical entrapment of SF into chemically crosslinked hydrogels will decouple the initial gel modulus from the degradation rate of the hydrogels by changing gel moduli via formation of higher order SF fibril structure in the PEG network. While SF entrapment at greater content (&gt;1.5wt %) significantly decreased crosslinking efficiency, entrapment at 1wt% negligibly affected gel crosslinking, mechanics, and degradation. The entrapment of SF and S-SF did not alter gelation of the PEG network, but significantly decreased equilibrium gel swelling and mesh size (Fig 1B). Additionally, S-SF was retained more in the hydrogels, and increased gel moduli with a minimal effect on hydrolytic degradation rate of the hybrid hydrogels (Fig 1C, 1D).

Modulating properties of chemically crosslinked PEG hydrogels via physical entrapment of silk fibroin

251st National Meeting (2016)

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