Fabrication Of A Self-rolling And Shape Memory Hydrogel And Its Application

In this study, we synthesized mechanically strong hydrogels, termed as PBVP, byphotopolymerization of2-vinyl-4,6-diamino-1,3,5-triazine (VDT), poly(ethyleneglycol) methacrylate (PEGMA526) and disulfide-containing crosslinker,N’N-bis(acryloyl)cystamine (BAC). The multiple hydrogen bondings ofdiaminotriazine-strengthened hydrogels exhibited the tensile strengths of350-650KPa and compressive strengths of2-16MPa with equilibrated water contents rangingfrom78-85%. The PBVP hydrogels displayed a pH sensitive shape memory behavior,due to the reversible breakage and reformation process of the hydrogen bonds amongdiaminotriazine residues, which were shown to firmly lock the temporary shape of thegel. Breaking of hydrogen bonds by acid solution could facilitate the recovery ofpermanent shape. A bilayer PBVP hydrogel with distinct crosslinking density wasshown to self-roll into a3D tube which could still be well reinforced by hydrogenbondings, upon exposing reductants such as1,4-dithio-DL-threitol (DTT) orL-glutathione (GSH), because the redox-induced cleavage of disulfide bonds resultedin the imbalanced internal shrinking stress between two layers. At an intracellularlevel of GSH, model L929cells-seeded bilayer gel sheet could curl up into a3Dtubular scaffold where the cells maintained good viability. The strategy reported herewill open up a promising avenue to engineering self-structured tissue engineeringscaffolds.