Robust MeO2MA/vinyl-4,6-diamino-1,3,5-triazine copolymer hydrogels-mediated reverse gene transfection and thermo-induced cell detachment

We have fabricated a robust temperature sensitive hydrogel by photoinitiated copolymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MeO2MA), 2-vinyl-4,6-diamino-1,3,5-triazine (VDT) and crosslinker polyethylene glycol diacrylate (PEGDA). It was shown that self-hydrogen bondings of VDT moieties in the bulk considerably strengthened the mechanical properties of gels, which was dependent on the weight ratio of MeO2/VDT and the initial monomer concentration; the VDT motifs on the surface could efficiently bind DNA for reverse gene transfection. On this soft-wet platform, gene expression lasted 7 days and the re-treated gels could be reused for new cycle of transfection. The gene modified cells could be detached by thermo-triggered switchable surface hydrophilicity of PMEO2MA in hydrogel. MTT assay showed low cytotoxicity of hydrogels. The results suggested that this type of mechanically strong H-bonded and thermoresponsive hydrogels hold a great potential as an integrated functional soft-wet platform for the unharmful harvest of gene modified seed cells for tissue engineering or as implantable scaffold for gene therapy and regenerative medicine applications.