||Islet cell transplantation is considered as a promising treatment for type 1 diabetes. To avoid immune response after transplantation, we decided to use hydrogel system because hydrogels are expected to be the most excellent cell carriers. Hydrogel contains a lot of water in its structure, so it can prevent bioactive agents such as drugs, proteins and cells from denaturation. In this study, we designed injectable hydrogel by mixing oppositely charged nanoparticles together. Among many biopolymers, we decided to make gelatin nanoparticles because it has a lot of RGD sequences in its content, so it is expected that the gelatin containing hydrogel can enhance cell adhesion. By blending oppositely charged gelatin nanoparticles, we confirmed the gelatin behavior and also found that the hydrogel using this system is injectable by shear thinning property. Finally, we applied this hydrogel into islet cell carrier to control the high glucose level by in vivo experiment.