A fully degradable and photocrosslinked polysaccharide-polyphosphate hydrogel for tissue engineering

Extracellular matrix degradability meditates cell behaviors and gains increasing importance in the development of implantation materials for tissue engineering. Here, we developed a fully biodegradable hydrogel combining the unique features of synthetic polyphosphate polymer and natural polysaccharide polymer. Polyphosphate copolymer poly(butynyl phospholane)-random-poly(ethylethylene phosphate) (PBYP-r-PEEP) bearing pendent alkynes was synthesized through a facile one-pot reaction. Subsequently, thiol-yne click reaction was employed to fabricate the fully degradable and photocrosslinked hydrogel by mixing PBYP-r-PEEP with thiolated biodegradable hyaluronic acid (HA-SH). The generated HA/PPE hydrogels show viscoelastic properties and enzymatic biodegradability, supporting the growth of human mesenchymal stem cells (hMSCs). HA/PPE hydrogel is permissive to the covalent conjugation of cell-adhesive peptide RGD, which can enhance the cell-cell interactions. This HA/PPE hydrogel system provides a fully biodegradable platform that can support hMSCs growth and facilitate the formation of cell clustering, expanding the range of fully degradable materials for tissue engineering and regenerative medicine.