Study on mineralization of type-I collagen fibrils induced by carboxylated polyamide-amine/amorphous calcium phosphate

Objective:To synthesize and characterize a biomimetic mineralization complex material (ACP/CPAMAM) with both organic and inorganic properties using carboxylated polyamide-amine to stabilize the precursor of mineralized amorphous calcium phosphate, and to observe its biomimetic mineralization effect on collagen fibrils.Methods:ACP/CPAMAM nanocomplex was prepared, characterized and verified by transmission electron microscopy(TEM), electron diffraction(SAED), particle size analysis and potential analysis.Collagen fibrils of bovine tendon were applied in vitro experiment, and the crystal formation in and around collagen fibrils was observed by TEM and the energy spectrum analysis.Results:ACP/CPAMAM nanocomplex was successfully synthesized and was amorphous with an average size of 25.13 nm.TEM and SAED showed that the surface of ACP had a low-contrast coating with a thickness of 10 nm, which confirmed the successful synthesis of ACP/CPAMAM was amorphous.TEM and energy spectrum analysis showed that high density crystals were observed after the application of ACP/CPAMAMmineralized tendon type-Ⅰcollagen fibers, and dense and continuous crystal formation was observed around the collagen fibers, which confirmed the nanocomplex could continuously induce collagen fiber mineralization.Conclusion:ACP/CPAMAM, as a novel nanocomplex, has good biological activity and biomimetic mineralization characteristics.It can induce the type-I collagen fibrils to form mineralized products, suggesting that ACP/CPAMAM may become a novel nanomaterial to induce biomimetic re-mineralization of collagen fibers.