The aim of this study was to evaluate the role of demineralized and particulate autogenous tooth, and interleukin-6 in bone regeneration. A demineralized and particulate autogenous tooth was prepared and human osteoblast-like cells (MG63) and human osteosarcoma cells were inoculated into the culture. The rate of cell adhesion, proliferation and mineralization were examined, and the appearance of cellular attachment was observed. An 8 mm critical size defect was created in the cranium of rabbits. Nine rabbits were divided into three groups including: An experimental group A (3 rabbits), in which a demineralised and particulate autogenous tooth was grafted; an experimental group B (3 rabbits), in which a demineralized, particulate autogenous tooth was grafted in addition to interleukin-6 (20 ng/mL); and a control group. The rabbits were sacrificed at 1, 2, 4 and 6 weeks for histopathological examination with H-E and Masson’s Trichrome, and immunohistochemistry with osteocalcin. The cell-based assay showed a higher rate of cell adhesion, mineralization and cellular attachment in the experimental group A compared with the control group. The animal study revealed an increased number of osteoclasts, newly formed and mature bones in the experimental group A compared with the control group. Eventually, a higher number of osteoclasts were observed in the experimental group B. However, the emergence of newly formed and mature bone was lower than in the experimental group A. The current results suggest that treatment with demineralized and particulate autogenous tooth and interleukin-6 is not effective in stimulating bone regeneration during the bone grafting procedure.

This study was performed to improve the efficiency of guided bone regeneration by adapting the tissue-engineered bone regeneration approach. The PHBV-collagen nonofibrous membranes cultured with rat calvarial periosteum derived cells in osteogenic culture medium for 7 days were applied to 5 x 2mm size artificial rat tibial defects for 3weeks and evaluated its efficiency as an alternative cell engineered membrane for effective guided bone regeneration by routine histological observation. The defects covered with cell attached PHBV-collagen nanofibrous membrane complexes showed favorable bone repair compared to both membrane non-covered control and membrane only covered group without specific side effects. These findings suggest that the favorable guided bone generation can be achieved by adapting the tissue engineered bone regeneration approach using PHBV-Collagen nanofibrous membrane scaffold.

Natural biopolymers such as collagen and fibrin have been widely used in bone regenerative applications. Despite the frequent use, their comparative biological propertiesis are largely unknown. In a previous study, we found the superiority of fibrin to collagen in the adsorption of serum proteins and the proliferation and differentiation of cultured osteoblasts. In this study, we used an in vivo model to evaluate how effectively fibrin supports bone regeneration, as compared with collagen. Collagen and fibrin were placed in critical size defects made on rat calvarial bones. Compared with collagen, fibrin supported substantially more new bone tissue formation, which was confirmed by micro-CT measurement and histological analyses. The cells in the regenerative tissues of the fibrin-filled defects were immunostained strongly for Runx2, while collagen-placed defects were stained weakly. These in vivo results demonstrate that fibrin is superior to collagen in supporting bone regeneration

This study evaluated the possibility of clinical application using matrigel-based bioceramic/polymer scaffolds treated with bone morphogenetic protein, angiogenic factor, and mesenchymal stem cells (MSCs) for new bone formation. In the in vitro study, bone morphogenetic protein (BMP-2) and vascular endothelial growth factor (VEGF) containing matrigel, which is a basement membrane gel, was injected into HA/PCL scaffolds to estimate the release rates of growth factors. In the in vivo study, BMP-2, VEGF, and MSCs with matrigel-based scaffolds were implanted into rat femoral segmental defects, and new bone formation was evaluated at 4 and 8 weeks. In the results, the release rates of BMP-2 and VEGF explosively increased by day 5. For the in vivo study results, radiological evaluation revealed that the matrigel-based HA/PCL scaffolds with BMP-2 and VEGF grafted (M+B+V) and matrigel-based HA/PCL scaffolds with BMP-2, VEGF, and MSC grafted (MSC) groups showed increased bone volume and bone mineral density. Moreover, in the histological evaluation, large new bone formation was observed in the M+B+V group, and high cellularity in the scaffold was observed in the MSC group. In conclusion, grafted matrigel-based HA/PCL scaffolds with BMP-2, angiogenic factor, and MSCs increased new bone formation, and in clinical cases, it may be effective and useful to enhance healing of delayed fractures.

Silk fibroin has been widely tested as a candidate biomaterial applicable to various attempts of tissue engineering. In order to examine bone forming ability of silk 3-D scaffold, we have developed a tibial interlocking intramedullary nailing model. A tibial intramedullary nail in the weight bearing hind limb of a rat was interlocked with a pin through a pin hole at the proximal end of the intramedullary nail. Interlocking of the intramedullary nail prevented total collapse of proximal region of a bone defect and helped maintain the critical gap that was filled with silk 3-D scaffold, though minor shinkage about 1 mm at distal region was unavoidable. Bone forming ability of an implanted silk scaffold was monitored weekly for 8~10 wks by X-ray radiography of live animals and bone formation in the scaffold was examined by H & E staining and Masson’s trichrome staining of the bone tissue recovered from the animals. Although scattered islets of bone tissue was observed in the implanted silk scaffold, bone tissue was not widely developed and implanted scaffolds of silk nanofiber and salt-leached sponge were X-ray transparent, suggesting inefficient bone formation. By contrast, X-ray image of implanted silk nanofibrous scaffold coated with hydroxyapatite was getting darkened with time, which suggests bone tissue formation in the scaffold, while untreated silk 3-D scaffold remained undisturbed. Although existence of bone tissue in the scaffold should be confirmed by histological criteria, hydroxyapatite-coated silk scaffold appeared competent to support regeneration of the long bone defects In addition, the interlocking intramedullary nailing in tibia of rat hind limb could be applicable in assessing long bone regenerative capacity of various biocompatible materials.

Poly-L-lactic acid (PLLA), PLLA/hydroxyapatite (HA), PLLA/multiwalled carbon nanotubes (MWNTs)/HA, PLLA/trifluoroethanol (TFE), PLLA/gelatin, and carbon nanofibers (CNFs)/β-tricalcium phosphate (β-TCP) composite membranes (scaffolds) were fabricated by electrospinning and their morphologies, and mechanical properties were characterized for use in bone tissue regeneration/guided tissue regeneration. MWNTs and HA nanoparticles were well distributed in the membranes and the degradation characteristics were improved. PLLA/MWNTs/HA membranes enhanced the adhesion and proliferation of periodontal ligament cells (PDLCs) by 30% and inhibited the adhesion of gingival epithelial cells by 30%. Osteoblast-like MG-63 cells on the randomly fiber oriented PLLA/TEF membrane showed irregular forms, while the cells exhibited shuttle-like shapes on the parallel fiber oriented membrane. Classical supersaturated simulated body fluids were modified by CO2 bubbling and applied to promote the biomineralization of the PLLA/gelatin membrane; this resulted in predictions of bone bonding bioactivity of the substrates. The β-TCP membranes exhibit good biocompatibility, have an effect on PDLC growth comparable to that of pure CNF membrane, and can be applied as scaffolds for bone tissue regeneration.

1'0 develop an effi cient scaffold fo1' t issue-engineered bone 1'egene1'ation, we evaluated fully in terconnected globular porous bisphasic calcium-phosphate ceramics. Materials and Methods: Biphasic HA/TCP cera mic scaffolds having f띠 l y interconnected globular structure with small fenestrations adopting foaming method were p1'epared. They were evaluated by cytotoxici ty‘ cellular attachment. and theil‘ differentiation in vitro and the hi s tocompatibili ty, osteoconductivity. and ectopic os teoinductive capacity in 띠 vo ， respectively. They have average 400um s ized spherical pores and ave1'age 100um s ized inter connecting interpores with average 85% porosity. They r evealed comparable compression strength with cancellous bone. They were nontoxic and revealed no noxious effect on cellular proliferation and osteoblastic diffe re ntiation. The cul tured cells on scaffolds were well attacbed and proliferated in multi-layers. The increased surface in fully interconnected globular porous scaffold facilitated osteogenic repair by favored cell ular attachment and osteogenic differentia tion with good osteoconductivity. 1n addition. the scaffold-cell constructs induced favorable ectopic bone formati on These findings suggest that the fully interconnected globular porous biphas ic HA/ß -TCP ceramic scaffold formed by foaming method can be a promising bone substitute and a scaffold fo 1' tissue-engineered bone 1'egeneration

We evaluated the influence of internal macro- porous structure on tissue-engineered bone regeneration by cOll1paring the effi cien cy of scaffold-cell construct forll1ation and its bone induction activity. T매o types of macro-porous CMP cera rnic blocks having 400 um average pore s ize in an interconnected trabecular framework and interconnected globular structu1'e with small fenestrations were prepa1'ed, adopting sponge method and foaming method. respectively. They ware evaluated by cytotoxicity. cell ular attachment. and t heir differenti ation in vitro and the histocompatibility, osteoconductivity, and ectopic osteoinductive potenetial in vivo, respecti vely. Both scaffolds having either interconnected trabecu lar pOI‘es formed by sponge ll1ethod 0 1' fully interconnected globu lar pores formed by foam-based technology were no cyt otoxic and induced neither an immune nor an infl ammatory response regardless 0 1' geometry and manufacturing methods. The fu lly interconnected globul 81 porous scaffold showed more favora ble compression strength compared to the interconnected trabecualr porous scaffold (8.7 :tO. 5 MPa va 5. 5:t0. 5 MPa) . The increased surface in fully interconnected globular po1'ous scaffold facilitated osteogenic repall‘ by favored cellular attachment and osteogenic differentiation with good osteoconductivity. These results suggest that the fully interconnected globular porous structure be more sui table for both bone s ubstit ute and scaffold for t issue-engineered bone regeneration‘

As a pa rt 0 1' the effort to develop a suitable scaffold for tissue-engineered bone regene ration, we modified calcium metaphosphate(CMP) ce ramic with 5 mol% Na20 or K20 to improve t he biodegradability and evaluated their effi ciency as a biodegr adable scaffold for ti ssue-engineered bone regeneration. The macroporous αiIP ceramic blocks incor porated with 5 mol% Na20 or K20 were prepa recl to have average pore size of 250 um in an inte rconnectecl framework structure The influ e nce of inco r pora tecl 5 mol% Na20 or K20 on cytotoxicity‘ cellular attachmont and t heir clifferentiation was evaluated by in vit ro analyzing sys tern. res pectively. The bioclegradability, histocompatibility, and osteogenic effect by cell-scaffolcl co nstruc ts were evalua ted by im plantation of them into subcutaneous pouches of SD-rats 0 1' SCID ITllce The incorporation of 5 mol% Na20 or K20 causecl clecrease of compressive strength without improving of biodegr adabili ty . The moclifi ed scaffolcls revea led no cy totoxic and excell ent biocompatability but osteogneic effect was recluced compa red to pure CMP ce ramic porous blocks . These res ul Ls s ugge::;t tha t the incorporation of 5 mol% Na20 0 1' K20 into pure CMP is not effective for improv ing effï ciency 0 1' scaffolcls fo1' tissue-engineered bone regeneration in terms of bioclegradabi li ty‘ physical s trength . a ncl osteogenic rege ne ra tive effect