Preparation of in situ-forming poly(5-methyl-5-allyloxycarbonyl-1,3-dioxan-2-one)-poly(ethylene glycol) hydrogels with tuneable swelling, mechanical strength and degradability.

This work describes the preparation of a new class of in situ-forming poly(carbonate)-graft-poly(ethylene glycol) hybrid hydrogels using 'thiol-ene' photoclick chemistry. Morphological study by cryogenic Scanning Electron Microscopy (SEM) revealed that the hydrogels display characteristic macroporous and microporous distributions, the ratio of which can be tuned by varying the length of the poly(ethylene glycol) linker. Controlling the side-chain length of the poly(ethylene glycol) also allows tuning of the equilibrium water uptake, water diffusion, mechanical properties and degradability. Furthermore, we demonstrate that these hydrogels are robust materials with fracture compressive strength in the range of 27-468 kPa and are readily degraded under physiological conditions between 8 and 22 days. The swelling of the gels was also found to be thermoresponsive making them potential candidates for delivery applications.