Apparatus is provided that contains cells for implantation into a human subject. The apparatus includes a substantially non-degradable three-dimensional scaffold having surfaces to which the cells are attached, and a hydrogel, which is attached to the cells. The scaffold, the cells, and the hydrogel are arranged such that the cells are sandwiched in spaces between the hydrogel and the surfaces of the scaffold, thereby allowing mobility and proliferation of the cells in the spaces between the hydrogel and the surfaces of the scaffold, and preventing the mobility and the proliferation of the cells to locations outside of the spaces between the hydrogel and the surfaces of the scaffold.
