Density gradient biopolymeric matrix implants

A method for preparing a density gradient biopolymeric matrix implant, the method comprising:

• obtaining a first homogeneous biopolymeric matrix layer having a first density and having a first surface and a second surface opposed to the first surface, the first homogeneous biopolymeric matrix layer being formed of first biopolymeric fibers;
• obtaining a second homogeneous biopolymeric matrix layer having a second density lower than the first density and having a first surface and a second surface opposed to the first surface, the second homogeneous biopolymeric matrix layer being formed of second biopolymeric fibers;
• hydrating the first homogeneous biopolymeric matrix layer,
• placing in contact the first surface of the hydrated first homogeneous biopolymeric matrix layer with the first surface of the second homogeneous biopolymeric matrix layer such that the first biopolymeric fibers at the first surface of the first homogeneous biopolymeric matrix layer are entangled and physically trapped with the second biopolymeric fibers at the first surface of the second homogeneous biopolymeric matrix layer, thereby forming a two-layer matrix,
• freezing the two-layer matrix,
• drying the frozen two-layer matrix, and
• cross-linking the dried frozen two-layer matrix,
• wherein the hydrating step is carried out by coating the first surface of the first homogeneous biopolymeric matrix layer with an aqueous dispersion of biopolymeric fibers, whereby the dispersed biopolymeric fibers are cross-linked to both the first surface of the hydrated first homogeneous biopolymeric matrix layer and the first surface of the second homogeneous biopolymeric matrix layer.