The synthesis of PHEMA-based materials for tissue engineering applications

[Truncated abstract] The work presented herein focuses on the use of polymers based on poly(2- hydroxyethyl methacrylate) (PHEMA) to construct hydrogel scaffolds for tissue engineering purposes. The peptide-based crosslinking agents I and II were synthesized, and were both found to be degradable by collagenase. The crosslinking agents were copolymerised with HEMA, or HEMA and poly(ethylene glycol) methacrylate methyl ether (PEGMA), to form either PHEMA sponges, P[HEMA-co-MeO-PEGMA] gels, or P[HEMA-co-MeO-PEGMA] sponges. Crosslinker I was used to prepare hydrogel polymer networks. PHEMA and P[HEMA-co-MeO-PEGMA] sponges exhibited morphologies with dimensions larger than PHEMA sponges crosslinked with TEDGMA, but when I was used to prepare P[HEMA-co-MeO-PEGMA] gels, the polymers had homogeneous morphologies. The use of II as a crosslinking agent did not result in polymer networks, presumably due to differences in reactivity ratios of the methacryloyl groups from II, HEMA and PEGMA. When PHEMA sponges crosslinked with I were incubated in collagenase solution for three months, the samples showed no apparent degradation. This result was attributed to the degradation products being insoluble. The P[HEMA-co-MeO-PEGMA] gels and sponges both degraded when incubated in collagenase solutions. The P[HEMA-co- MeO-PEGMA] gels fully degraded over 28 days incubation, while only 8% dry mass of the P[HEMA-co-MeO-PEGMA] remained after 101 days incubation. The differences in the time needed for total degradation was attributed to differences in hydrogel morphologies...