Objective To investigate the effect of domestic porous tantalum encapsulated with pedicled fascial flap on repairing of segmental bone defect in rabbits’ radius. Methods A total of 60 New Zealand white rabbits (aged 6- 8 months and weighing 2.5-3.0 kg) were randomly divided into the experimental group and control group (30 rabbits each group). A 1.5 cm segmental bone defect in right radius was established as the animal model. The porous tantalums encapsulated with pedicled fascial flaps (30 mm×20 mm) were implanted in the created bone defect in the experimental group, and the porous tantalums were only implanted in the control group. X-ray films were observed at the day after operation and at 4, 8, and 16 weeks after operation. Specimens were taken out at 4, 8, and 16 weeks after operation for HE staining and toluidine blue staining observation. The maximum load force and bending strength were detected by three point bending biomechanical test, and the Micro-CT analysis and quantitative analysis of the new bone volume fraction (BV/TV) were performed at 16 weeks after operation to compare the bone defect repair abilityin vivo in 2 groups. Results All incisions healed by first intention without wound infection. At 4, 8, and 16 weeks after operation, the X-ray films showed that the implants were well maintained without apparent displacement. As followed with time, the combination between the implants and host bone became more and more closely, and the fracture line gradually disappeared. HE staining and toluidine blue staining showed that new bone mass and maturity gradually increased at the interface and inside materials in 2 groups, and the new bone gradually growed from the interface to internal pore. At 16 weeks after operation, the three point bending biomechanical test showed that the maximum load force and bending strength in the experimental were (96.54±7.21) N and (91.26±1.76) MPa respectively, showing significant differences when compared with the control group [(82.65±5.65) N and (78.53±1.16) MPa respectively] (t=3.715, P=0.004; t=14.801, P=0.000). And Micro-CT analysis exhibited that there were a large amount of new bone at the interface and the surface of implant materials and inside the materials. The new bone BV/TV in the experimental group (32.63%±3.56%) was significantly higher than that in control group (25.07%±4.34%) (t=3.299, P=0.008). Conclusion Domestic porous tantalum encapsulated with pedicled fascial flap can increase local blood supply, strengthen material bone conduction ability, and promote the segmental bone defect repair.
With the in-depth research on bone repair process, and the progress in bone repair materials preparation and characterization, a variety of artificial bone substitutes have been fully developed in the treatment of bone related diseases such as bone defects. However, the current various natural or synthetic biomaterials are still unable to achieve the structure and properties of natural bone. Carbon nanotubes (CNTs) have provided a new direction for the development of new materials in the field of bone repair due to their excellent structural stability, mechanical properties, and functional group modifiability. Moreover, CNTs and their composites have broad prospects in the design of bone repair materials and as drug delivery carriers. This paper describes the advantages of CNTs related to bone tissue regeneration from the aspects of morphology, chemistry, mechanics, electromagnetism, and biosafety, as well as the application of CNTs in drug delivery carriers and reinforcement components of scaffold materials. In addition, the potential problems and prospects of CNTs in bone regenerative medicine are discussed.
ObjectiveTo evaluate the bone repair efficacy of the new nano-hydroxyapatite (n-HA)/polyurethane (PU) composite scaffold in the treatment of chronic osteomyelitis in tibia.MethodsA novel levofloxacin@mesoporous silica microspheres (Lev@MSNs)/n-HA/PU was successfully synthesized. Its surface structure was observed by scanning electron microscopy (SEM). Fifty adult female New Zealand rabbits were randomly selected, and osteomyelitis was induced in the right tibia of the rabbit by injecting bacterial suspension (Staphylococcus aureus; 3×107 CFU/mL), which of the method was described by Norden. A total of 45 animals with the evidence of osteomyelitis were randomly divided into 4 groups, and the right medullary cavity of each animal was exposed. Animals in the blank control group (group A, n=9) were treated with exhaustive debridement only. The remaining animals were first treated by exhaustive debridement, and received implantations of 5 mg Lev@PMMA (group B, n=12), 1 mg Lev@MSNs/n-HA/PU (group C, n=12), and 5 mg Lev@MSNs/n-HA/PU (group D, n=12), respectively. At 12 weeks postoperatively, the right tibia of rabbits were observed by X-ray film, and then gross observation, methylene blue/acid fuchsin staining, and SEM observation of implant-bone interface, as well as biomechanical test (measuring the maximal compression force) were performed.ResultsX-ray films showed that the infection were severer than those of preoperation in group A, while the control of inflammation and bone healing of rabbits in group D were obviously better than those at preoperation. The gross observation showed extensive bone destruction in group A, a significant gap between bone tissue and the material in groups B and C, and close combination between bone tissue and the material in group D. The histology of the resected specimens showed that there was no obvious new bone formation around the materials in groups B and C, and there was abundant new bone formation around the periphery and along the voids of the materials and active bone remodeling in group D. The SEM observation of the bone-implant interface demonstrated that no new bone formation was observed at the bone-implant interface in groups B and C. However, bony connections and blurred boundaries were observed between the material and host bone tissue in group D. The biomechanical test showed the maximal compression force of groups B and D were significantly higher than that of groups A and C (P<0.05), but there was no significant difference between groups B and D (P>0.05).ConclusionThe novel synthetic composite Lev@MSNs/n-HA/PU exhibit good antibacterial activities, osteoconductivity, and biomechanical properties, and show great potential in the treatment of chronic osteomyelitis of rabbits.
ObjectiveTo observe and compare the effects of peptides on the repair of rabbit skull defects through two different binding modes of non-covalent and covalent, and the combination of carboxyl (-COOH) and amino (-NH2) groups with materials.MethodsTwenty-one 3-month-old male ordinary New Zealand white rabbits were numbered 1 to 42 on the left and right parietal bones. They were divided into 5 groups using a random number table, the control group (group A, 6 sides) and the material group 1, 2, 3, 4 (respectively group B, C, D, E, 9 sides in each group). All animals were prepared with 12-mm-diameter skull defect models, and bone morphogenetic protein 2 (BMP-2) non-covalently bound multiwalled carbon nanotubes (MWCNT)-COOH+poly (L-lactide) (PLLA), BMP-2 non-covalently bound MWCNT-NH2+PLLA, BMP-2 covalently bound MWCNT-COOH+PLLA, and BMP-2 covalently bound MWCNT-NH2+PLLA were implanted into the defects of groups B, C, D, and E, respectively. At 4, 8, and 12 weeks after operation, the samples were taken for CT scanning and three-dimensional reconstruction, the ratio of bone tissue regeneration volume to total volume and bone mineral density were measured, and the histological observation of HE staining and Masson trichrome staining were performed to quantitatively analyze the volume ratio of new bone tissue.ResultsCT scanning and three-dimensional reconstruction showed that with the extension of time, the defects in groups A-E were filled gradually, and the defect in group E was completely filled at 12 weeks after operation. HE staining and Masson trichrome staining showed that the volume of new bone tissue in each group gradually increased with time, and regenerated mature bone tissue appeared in groups D and E at 12 weeks after operation. Quantitative analysis showed that at 4, 8, and 12 weeks after operation, the ratio of bone tissue regeneration volume to total volume, bone mineral density, and the volume ratio of new bone tissue increased gradually over time; and at each time point, the above indexes increased gradually from group A to group E, and the differences between groups were significant (P<0.05).ConclusionThrough covalent binding and using -NH2 to bound peptides with materials, the best bone repair effect can be achieved.
Objective To introduce the basic research and cl inical appl ication of the injectable bone repair biomaterials. Methods The recent original articles about the injectable bone repair biomaterials were extensively reviewed. Results The injectable bone repair biomaterials could fill irregularly shaped defects and might allow bone augmentation, both with minimal surgical intervention, and the injectable bone repair material had a good prospect by the medical profession and attach great importance to the academic material, but there were some deficiencies and shortcomings. Conclusion The injectable bone repair biomaterials may be a future approach to repair bone defect．
Objective To review the application and research progress of in-situ tissue engineering technology in bone and cartilage repair. Methods The original articles about in-situ tissue engineering technology in bone and cartilage repair were extensively reviewed and analyzed. Results In-situ tissue engineering have been shown to be effective in repairing bone defects and cartilage defects, but biological mechanisms are inadequate. At present, most of researches are mainly focused on animal experiments, and the effect of clinical repair need to be further studied. Conclusion In-situ tissue engineering technology has wide application prospects in bone and cartilage tissue engineering. However, further study on the mechanism of related cytokines need to be conducted.
ObjectiveTo summarize the latest research progress of graphene and its derivatives (GDs) in bone repair. MethodsThe relevant research literature at home and abroad in recent years was extensively accessed. The properties of GDs in bone repair materials, including mechanical properties, electrical conductivity, and antibacterial properties, were systematically summarized, and the unique advantages of GDs in material preparation, functionalization, and application, as well as the contributions and challenges to bone tissue engineering, were discussed. ResultsThe application of GDs in bone repair materials has broad prospects, and the functionalization and modification technology effectively improve the osteogenic activity and material properties of GDs. GDs can induce osteogenic differentiation of stem cells through specific signaling pathways and promote osteogenic activity through immunomodulatory mechanisms. In addition, the parameters of GDs have significant effects on the cytotoxicity and degradation behavior.ConclusionGDs has great potential in the field of bone repair because of its excellent physical and chemical properties and biological properties. However, the cytotoxicity, biodegradability, and functionalization strategies of GDs still need to be further studied in order to achieve a wider application in the field of bone tissue engineering.
Bone tissue regeneration and blood vessel formation are inseparable. How to realize the vascularization of bone repair scaffolds is an urgent problem in bone tissue engineering. The growth and development, mineralization maturity, reconstruction and remodeling, and tissue regeneration of bone are all based on forming an excellent vascularization network. In recent years, more and more researchers have used hydrogels to carry different cells, cytokines, metal ions and small molecules for in vitro vascularization and application in bone regeneration. Based on this background, this article reviews the hydrogel-based vascularization strategies in bone tissue engineering.
Objective To review the research and application progress of bioactive glass in bone repair. Methods The recently published literature concerning bioactive glass in bone repair was reviewed and summarized. Results Bioactive glass can classified different types, such as bioactive glass particulate, bioactive glass scaffold, bioactive glass coating, injectable bioactive glass cement, and bioactive glass delivery system. Bioactive glass has been well studied in the field of bone repair due to its excellent biological properties. Also, the remarkable progress has been made in various aspects. Conclusion Bioactive glass is a reliable material of bone repair and will play an even more important role in the future.
Objective To review the osteoimmunomodulatory effects and related mechanisms of inorganic biomaterials in the process of bone repair. Methods A wide range of relevant domestic and foreign literature was reviewed, the characteristics of various inorganic biomaterials in the process of bone repair were summarized, and the osteoimmunomodulatory mechanism in the process of bone repair was discussed. Results Immune cells play a very important role in the dynamic balance of bone tissue. Inorganic biomaterials can directly regulate the immune cells in the body by changing their surface roughness, surface wettability, and other physical and chemical properties, constructing a suitable immune microenvironment, and then realizing dynamic regulation of bone repair. Conclusion Inorganic biomaterials are a class of biomaterials that are widely used in bone repair. Fully understanding the role of inorganic biomaterials in immunomodulation during bone repair will help to design novel bone immunomodulatory scaffolds for bone repair.