Over the past years the relevance of protein drugs has enormously increased due to their high therapeutic potential. However, their application is often limited by short biological half-lives due to physicochemical instability and proteolytic degradation. The incorporation of proteins into hydrogels is an excellent method to prolong their biological half-lives and control their release.In our experiments, we investigated the mobility of different model proteins in poly(ethylene glycol) (PEG) based hydrogel networks by fluorescence recovery after photobleaching (FRAP) experiments. For hydrogel preparation, branched PEG (modified with furyl and maleimide groups) was cross-linked by Diels-Alder reactions. The mobility of FITC-lysozyme, FITC-BSA and FITC-?-globulin was determined directly after cross-linking and after 24 h and 72 h of swelling.Directly after cross-linking, protein mobility was lowest because of the small hydrogel network mesh size. We observed a clear dependency between the mobility of the proteins and their hydrodymic diameter. During hydrogel swelling, the diffusion coefficients and mobile fractions increased due to the expanding network mesh size (Figure 1).   Our FRAP data suggests that hydrogel degradation will lead to a slow protein release over time. Release experiments to confirm this assumption are currently under way.Financial support from DFG, grant GO 565/16-1 is gratefully acknowledged.

Degradation controlled protein release from Diels-Alder hydrogels

246th National Meeting (2013)

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