In this study, mechanically strong hydrogels are synthesized by photopolymerization of 2-vinyl-4,6-diamino-1,3,5-triazine, poly(ethylene glycol) methacrylate, and disulfide-containing cross-linker, NN-bis(acryloyl)cystamine. The bilayer hydrogel with distinct cross-linking density is shown to self-roll into a 3D tube, which could still be well reinforced by hydrogen bondings, upon exposing reductants such as 1,4-dithio-DL-threitol (DTT) or L-glutathione (GSH), because the redox-induced cleavage of disulfide bonds results in the imbalanced internal shrinking stress between two layers. At an intracellular level of GSH, model L929 cells-seeded bilayer gel sheet could curl up into a 3D tubular scaffold where the cells maintained good viability.