Collagen-apatite (Col-Ap) scaffolds have been widely employed for bone tissue engineering. We fabricated Col-Ap with a unique multi-level lamellar structure consisting of co-aligned micro- and macro-pores. The basic building blocks of this scaffold are bone-like mineralized collagen fibers developed via a biomimetic self-assembly process in a collagen-containing modified simulated body fluid (m-SBF). This biomimetic method preserves the structural integrity and great tensile strength of collagen by reinforcing the collagen hydrogel with apatite nano-particles. Unidirectional aligned macro-pores with a size of 63.8 to 344 μm are created by controlling the freezing rate and direction. The thickness of Col-Ap lamellae can be adjusted in the range 3.6 to 23 μm depending on the self-compression time. Furthermore, the multilevel lamellar structure has led to a twelve-fold increase in Young's modulus and a two-fold increase in the compression modulus along the aligned direction compared to a scaffold of the same composition with an isotropic equiaxed pore structure. Moreover, this novel lamellar scaffold supports the attachment and spreading of MC3T3-E1 osteoblasts. Therefore,. owing to the biomimetic composition, tunable structure, improved mechanical strength and good biocompatibility of this novel scaffold, it has great potential to be used in bone tissue engineering applications.
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