Cyclodextrin-cross-linked diaminotriazine-based hydrogen bonding strengthened hydrogels for drug and reverse gene delivery

A hydrogen bonding strengthened hydrogel was prepared by radical copolymerization of poly(ethylene glycol) methacrylated -cyclodextrin (PEG--CD) and 2-vinyl-4,6-diamino-1,3,5-triazine (VDT) monomer. PEG--CD served not only as a cross-linker, but also as a built-in solubilizing agent of the hydrophobic drug in the gel. Increasing VDT content resulted in a notable enhancement in the mechanical strengths of hydrogels whose equilibrium water contents could be modulated from 75% to 85% by varying the ratio of PEG--CD cross-linker. It was shown that copolymerizing more PEG--CDs could load higher amount of ibuprofen (IBU) in the gels and contribute to a slower release rate of IBU. Plasmid DNA could be anchored onto the surface of hydrogels due to the hydrogen bonding between the base pairs and diaminotriazine, thereby mediating efficient reverse gene transfection of luciferase gene in COS-7 cells cultured on the gel surface. The cytocompatible PEG--CD-cross-linked PVDT hydrogels with multifunction of drug and gene delivery hold a potential as tissue engineering scaffold.