Collagen based matrices cross-linked by a reducing sugar(s) are used for preparing composite matrices, implants and scaffolds. The composite matrices may have at least two layers including reducing sugar cross-linked collagen matrices of different densities. The composite matrices may be used in bone regeneration and/or augmentation applications. Scaffolds including glycated and/or reducing sugar cross-linked collagen exhibit improved support for cell proliferation and/or growth and/or differentiation. The denser collagen matrix of the composite matrices may have a dual effect initially functioning as a cell barrier and later functioning as an ossification supporting layer. The composite matrices, implants and scaffolds may be prepared using different collagen types and collagen mixtures and by cross-linking the collagen(s) using a reducing sugar or a mixture of reducing sugars. The composite matrices, implants and scaffolds may include additives and/or living cells.