A bilayered bone graft device includes a core portion comprising deminernalized gelatin and a shell portion surrounding the core portion. The shell portion includes a calcium silicate and the deminernalized gelatin in a range of 1 to 30 weight percent, and the calcium silicate has a molar ratio of calcium to silicon ranging from 10 to 0.1. The core portion and the shell portion are bound by the deminernalized gelatin without using a binder. In one embodiment of the present invention, the core portion is configured to provide buffering for receiving an insertion, and the shell portion is configured to provide a load-bearing structure.