Hydrogels of collagen-inspired telechelic triblock copolymers for the sustained release of proteins.

We studied the release of entrapped protein from transient gels made of thermosensitive, collagen-inspired ABA triblock copolymers with tailorable properties and with mid blocks of two different lengths (~37 kDa and ~73 kDa). These polymers were produced as heterologous proteins in recombinant yeast. By varying polymer length and concentration, the elastic properties of the hydrogels as well as their mesh size, swelling and erosion could be tuned. Whereas the volume of the investigated dense networks decreased in time as a result of temperature- and polymer concentration-dependent surface erosion, the release of entrapped protein was governed by a combination of gel erosion and protein diffusion. The prevalence of one or the other was strongly dependent on polymer concentration. Most importantly, the encapsulated protein was quantitatively released, which demonstrates that these hydrogels offer great potential as drug delivery systems.