Growth factor controllable slow-releasing system composite multilayer membrane promoting ossification and preparation method thereof

The invention discloses a surface modification method of a bio-material promoting ossification and a growth factor controllable slow-releasing system composite multilayer membrane promoting the ossification. In particular, the invention relates to a biological multilayer membrane which is constructed on the surface of the bio-material in a layer-by-layer electrostatic self-assembly manner through a layer-by-layer self-assembly technology and a growth factor slow-controllable-releasing technology with casein and heparin as a negative electric macro-molecular layer and collagen and a growth factor as a positive electric macro-molecular layer, wherein the obtain the multilayer membrane is in a structure of a circulation of a casein layer/heparin layer and a collagen/growth factor layer. In the invention, the four biological macro-molecules having excellent physico-chemical properties are deposited onto a same substrate material alternatingly, so that not only is the biological activity of the growth factor protected, but also the load amount and slow releasing of the growth factor can be controlled and adjusted. In addition, the multilayer membrane is excellent in biological mineralization promoting and ossification promoting capabilities and meanwhile can improve adhesion, growth and proliferation of mesenchymal stem cells. The multilayer membrane can be widely used in tissue repair engineering of cartilage, bone, blood vessel, nerve, cardiac valve and the like.