Temperature-sensitive biocompatible IPN hydrogels based on poly(NIPA-PEGdma) and photocrosslinkable gelatin methacrylate

The future of tissue engineering and regenerative medicine relies on the development of biomimetic extracellular matrices (ECM). Hydrogels based on biological and synthetic macromolecules could mimic native ECM which is an interpenetrating network (IPN) of proteins and other biomacromolecules. In this study, gelatin and N-isopropylacrylamide-based IPN hydrogels, named as NPxG, were developed to fabricate 3D matrix systems. A series of IPN hydrogels with different contents in poly(NIPA-PEGdma) (NPx) and gelatin methacrylate (GelMA) were synthesized. NPx and GelMA were characterized by Habeeb’s assay, FTIR, and 1H-NMR. IPN hydrogels were fully characterized by ATR-FTIR, swelling measurements, optical microscopy, SEM, DSC, and rheology. Optical microscopy images and rheology demonstrated that hydrogel properties change around 37°C. Above LCST, the translucent colorless hydrogel shifted to an opaque white hydrogel and the storage modulus increased. A wide range of IPN gels with different swelling properties and potential applications in different fields can be produced by controlling experimental parameters.