Temperature responsive hydrogel for cells encapsulation based on graphene oxide reinforced poly(N- isopropylacrylamide)/hydroxyethyl-chitosan

Temperature-responsive hydrogels exhibit great potentials to encapsulate cells for 3D bioprinting and tissue engineering applications; however, cell aggregation and the hydrogel stiffness determine cell fate and limit its application. Here, we developed a new temperature-responsive hydrogel with interpenetrating polymer networks using poly (N-isopropylacrylamide) (pNiPAM) and hydroxyethyl-chitosan (HECS) with the incorporation of dithiol-modified graphene oxide nanosheets (t-GO). The fabricated hydrogel showed excellent cytocompatibility toward human bone marrow mesenchymal stem cells (hBMSCs), and as expected, the lower critical solution temperature (LCST) could be regulated by changing the weight ratio of pNiPAM/HECS/t-GO. Finally, hBMSCs could be directly encapsulated in the hydrogel at a low temperature (around 20 °C), after then, the cell-laden hydrogel was formed above LCST and displayed high cell viability after 3D culturing. The results indicate that the new pNiPAM/HECS/t-GO hydrogel has the potential to serve as a cell carrier for drug delivery and tissue engineering applications.