Biometic Fabrication Of Bone Tissue Engineering Scaffolds With Controlled Architecture.

To mimic the structure and component of natural bone,a series of hydroxyapatite (HA) and chitosan(CS) composite woodpile scaffolds were designed with rapid prototyping technique(RP),freeze drying and biomineralization.These bone tissue engineering scaffolds with controlled architecture and porosity were HA/CS and HA/CS/PLLA woodpile,nano-micron HA/CS woodpile-network and biomineralized CS woodpile(BMCW).The morphology,biocompatibility and mechanical properties were characterized by SEM,FTIR,XRD,cell culture and compression test.Results showed that the scaffolds were produced with the RP technique in batch and the scaffolds had almost the same properties such as mechanical,geometry etc.The composite scaffolds possessed controlled woodpile structure,in which the dimension of one strut as well as the distance between two struts was 500μm,which will be suitable for cell seeding,attachment and rapid vascularisation.Osteoblast grew not only in the macropores but also micropores of the strut and formed thick cell multilayer after four weeks.The cells preferred to grow on the chitosan network in woodpile-network scaffold,which is similar to the real three dimensional physiological environment.Nano HA improved the compression strength and compressive modulus dramatically to 0.54±0.02 MPa and 6.13±0.60 MPa respectively.The BMCW was prepared by mineralization of CS woodpile scaffolds,and the thick nano HA crystal layer with high crystallization deposited in the scaffolds to form nanoscopic hybrid composites, which achieved the compression strength of 0.54±0.005Mpa and modulus of 5.47±0.65 MPa respectively.The rapid and efficient one-pot mineralization approach and ethanol/H₂O co-solvent system can be extended to the mineralization of other materials and will have a very broad application in the future.