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RECONSTRUCTION OF BONE USING TISSUE ENGINEERING AND NANOSCALE TECHNOLOGY

Objective To explore the method of fabricating freeze-dried demineralized bone matrix with nanoscale topography (nFDBM) and to investigate the feasibility of reconstruction of tissueengineered bone with the novel scaffold. Methods Allogenic dogs’ phalangeal cortical bone was fabricatedinto freeze-dried demineralized bone (FDBM) with modified Urist’s method. FDBM was subjected toNd∶YAG laser irradiation under special conditions. The surface topography was identified by atomic force microscope(AFM) and scanning electron microscope (SEM). The osteoblasts were induced from autologous mesenchymal stem cells (MSCs) and mixed with nFDBM and FDBM in vitro.The effects of the different topography oncellbehavior was identified by SEM. The complex of nFDBM and osteoblasts wereimplanted into fascial bags on dogs’ back (experimental group A) and dogs’ phalangeal defects on right (experimental group C), while FDBMosteoblast complex (control group B) and unique FDBM (control group D) were implanted into the corresponding sites on left as control groups. The osteogenic status was assessed by X-ray, HE and SEM at 4, 8 and 12 weeks after surgery. Results The surface of FDBM subjected to Nd∶YAG laser irradiation resulted in well-defined three-dimensional nanoscale grooves (150 nm in depth and 600 to 800 nm in width). When the osteoblasts were implanted on the scaffold, the cells adhering to nFDBM were morethan those to FDBM and secreted more extracellular matrix. Either new bone-likethin layer on the nanoscale surface or a lot of new boneformation inner the experimental complex was observed by HE after 12 weeks of surgery and the experimental complexes were partially calcified at the same time, while the control groups almost had no osteogenic phenomena. Conclusion Nd∶YAG laser could produce nanoscale grooves on the FDBM surface. The nanoscale grooves are conductive to adherence, proliferation and matrix secretion of osteoblasts. Complexes by tissue engineering and nanoscale technology have some osteogenic abilities in vivoafter implanted the animal model.