▎ 摘　　要

NOVELTY - Biomimetic collagen bone repairing material with multi-layer structure comprises bone density layer (1), middle layer (2) and spongy bone layer (3). The bone spongy layer comprises 20-30 pts. wt. type-I collagen, 20-30 pts. wt. nano hydroxyapatite and 2-3 pts. wt. graphene oxide. The middle layer comprises 10-20 pts. wt. type-I collagen, 10-20 pts. wt. nano hydroxyapatite and 1-2 pts. wt. graphene oxide. The bone cancellous layer comprises 5-10 pts. wt. type-I collagen and 5-10 pts. wt. nano hydroxyapatite. USE - Biomimetic collagen bone repairing material with multi-layer structure used in injured bone with different depth. ADVANTAGE - The material has fast bone repair procedure, and can be adjusted based on depth and range of defected bone. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the biomimetic collagen bone repairing material with multi-layer structure comprising: (A) dissolving type-I collagen, graphene oxide and nano-hydroxyapatite into 0.1 mol/L acetic acid solution, stirring with ultrasonic probe for 10-30 minutes under ice bath to obtain first homogeneous solution; (B) dissolving type-I collagen, graphene oxide and nano-hydroxyapatite into 0.1 mol/L acetic acid solution, stirring with ultrasonic probe for 10-30 minutes under ice bath to obtain second homogeneous solution; (C) dissolving type-I collagen, graphene oxide and nano-hydroxyapatite into 0.1 mol/L acetic acid solution, stirring with ultrasonic probe for 10-30 minutes under ice bath to obtain third homogeneous solution; (D) slowly pouring first prepared homogeneous solution into bone repair material mold with required height of bone dense layer in biomimetic collagen bone repair material, molding at 4-6 degrees C for 1-2 hours under, removing mold and pouring into third homogeneous solution, pouring second homogeneous solution, refrigerating, removing and continuously pouring into third homogeneous solution and refrigerating again at 4-6 degrees C for 1-2 hours; (E) pouring first, second and third homogeneous solutions into 3 different molds, refrigerating at - 20 to - 40 degrees C for 24-48 hours, freezing at - 45 to - 50 degrees C for 24-48 hours, removing porous scaffolds from mold and rinsing for 2-3 times with 95% ethanol; (F) 0.5-1% 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and 0.2-0.4% N-hydroxysuccinimide (NHS) into 95% ethanol solution and stirring to obtain cross-linked solution; and (G) immersing lyophilized porous scaffold into cross-linked solution at room temperature for 24 hours, removing, rinsing, re-freezing, and sterilizing. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of biomimetic collagen bone repairing material with multi-layer structure. Bone density layer (1) Middle layer (2) Spongy bone layer (3)