A multi-layer sheet of collagen membrane material includes a barrier layer including an outer smooth barrier face and further including a fibrous face opposite the smooth barrier face, and a matrix layer of collagen material adhered to the fibrous face, the matrix layer including collagen I, collagen III, or a combination thereof, the matrix layer carrying cultivated bone-forming cells including osteocytes, osteoblasts, stromal cells and/or stem cells committed to differentiation into bone-forming osteoblasts.
