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15 April 2016, Volume 20 Issue 16 Previous Issue    Next Issue

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Effect of bone cement with a low elastic modulus on the fractured and adjacent vertebrae in patients with osteoporotic vertebral compression fractures: a three-dimensional finite analysis Bao Yong-zheng, Zhu Zhou-xing, Feng Yun-sheng, Wu Qiang, Hu Kong-he, He Xiao-long, Zhu Wen-gang, Xi Xin-hua, Zhong Xue-ren, Zhou Long-ze, Liao Jun-jian, Dai Xiang-heng 2016, 20 (16):  2285-2293.  doi: 10.3969/j.issn.2095-4344.2016.16.001 Abstract ( 373 )   PDF (3100KB) ( 517 )   Save BACKGROUND: Vertebroplasty and kyphoplasty can effectively repair osteoporotic vertebral compression fractures, but bone cement injection can cause the change of stress in the fractured vertebrae and adjacent vertebrae after surgery, leading to new fractures. OBJECTIVE: To analyze the stress changes of the fractured vertebrae and adjacent vertebrae after vertebroplasty with different elastic modulus bone cement by a three-dimensional finite element method. METHODS: One healthy adult male volunteer was selected for lumbar spine CT scan. The acquired images were imported for three-dimensional reconstruction using Mimics. The three-dimensional model was smoothed, polished and denoised by Geomagic software, and then the solid mode was built under Workbench Ansys. An osteoporotic vertebral compression fracture model in L2-4 segments was established after assignment. Bone cement (4 mL) with different elastic moduli (8 000, 4 000, 2 000 and 1 000 MPa) injected into the L3 segment distributed in the middle of the vertebrae as spherical shape. 500 N pre-load was applied on the L2 surface with an additional bending moment of 50 N•m. The lower surface free degree of L4 was restrained. The L2-4 forward flexion, posterior extension, right flexion and axial rotation on the right side were stimulated. The stress changes of the fractured vertebrae and the upper and lower adjacent vertebrae before and after bone cement injection with different elastic moduli were compared.  RESULTS AND CONCLUSION: The stress of the fractured vertebrae and adjacent vertebrae were significantly increased compared with that before operation. With the increase of elastic modulus, the stress of the fractured vertebrae increased, but there were no changes in the stress of adjacent vertebrae. These findings indicate that the elastic modulus of bone cement may be a method to reduce new fractures of the fractured and adjacent vertebrae after bone cement injection. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Calcium phosphate cement incorporated with N-acetylcysteine-loaded silk fibroin microspheres: preparation and characterization Jiang Lei, Pi Bin, Feng Tao, Li Bin, Lu Ying-jie, Yang Hui-lin, Zhu Xue-song 2016, 20 (16):  2294-2302.  doi: 10.3969/j.issn.2095-4344.2016.16.002 Abstract ( 269 )   PDF (3865KB) ( 269 )   Save BACKGROUND: Calcium phosphate bone cement has been applied to clinical surgery because of its good biocompatibility and osteoconduction. However poor mechanical properties and lack of osteoinductivity limit its wide application. OBJECTIVE: To develop calcium phosphate cement incorporated with N-acetylcysteine (NAC) loaded silk fibroin microspheres (SFM), which is a kind of new injectable bone graft material with slow-release function, and evaluate its physical and chemical properties and cell compatibility. METHODS: Empty SFMs were prepared with emulsion solvent evaporation to absorb NAC solution of different concentrations by NAC-SFM and the concentration of NAC at the maximum drug loading ratio was determined. Then, NAC-SFM was loaded into calcium phosphate bone cement to test the drug release properties in vitro. MC3T3-E1 osteoblasts were cultured on the surface of NAC-SFM calcium phosphate bone cement and cell attachment and growth were observed by scanning electron microscope. Additionally, MC3T3-E1 cells were cultured with three kinds of bone cement extracts (calcium phosphate cement, SFM-calcium phosphate cement, NAC-SFM-calcium phosphate cement, as well as cultured in the α-minimum essential medium containing a volume fraction of 10% fetal bovine serum and 1% penicillin-streptomycin double antibody as the control. MTS assay was used to evaluate cell proliferation. RESULTS AND CONCLUSION: Microspheres in the composite bone cement presented with smooth surface, same size, diffused distribution and no obvious destroy. Thus, the SFM could remain stable in the reaction process of the composite bone cement. The double slow release system which contained silk fibroin microspheres and calcium phosphate bone cement showed a significant decrease in the cumulative release percentage of NAC within the first 24 hours compared with the control group (P < 0.05). In the next 28 days, the release speed of NAC was significantly lower in the NAC-SFM-calcium phosphate cement group than the calcium phosphate cement group (P < 0.05). In addition, different extracts had no significant cytotoxicity to the growth of MC3TC-E1 cells. Thus, the NAC-SFM-calcium phosphate cement has good cytocompatibility, which provide a new insight into the development of bone repair biomaterials. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Degradation of AZ31 magnesium alloys in vivo: micro-CT assessment Xu Yi-chi, Yin He-yong, Sun Zhen, Meng Hao-ye, Xiao Bo, Wang Ai-yuan, Guo Quan-yi, Peng Jiang, Lu Shi-bi 2016, 20 (16):  2303-2309.  doi: 10.3969/j.issn.2095-4344.2016.16.003 Abstract ( 368 )   PDF (512KB) ( 257 )   Save BACKGROUND: Magnesium can be degraded voluntarily in vivo, so a second surgery is avoided. However, its alloys have not been widely used in the clinical orthopedics because there is a lack of accurate and reliable methods to assess its degradation in vivo. OBJECTIVE: To explore the degradation of micro-arc-oxidized AZ31 magnesium alloy in the femoral condyle of rabbits based on micro-CT images and relative data. METHODS: Forty micro-arc-oxidized AZ31 magnesium alloys were implanted into the right femoral condyle of 40 New Zealand rabbits. Then 10 right femoral condyles were removed at 5, 10, 15 and 20 weeks after surgery, respectively, to quantitatively analyze and evaluate the degradation of AZ31 magnesium alloys by micro-CT images and relative data. RESULTS AND CONCLUSION: The surface of AZ31 alloys was corroded progressively with dark color and distorted appearance at 5-20 weeks post implantation. Micro-CT images showed that in the first 5 weeks, the degradation was inactive, and at the 10th week, it turned active; at the 15th week, the corrosion pits were obviously increased in number, and the corrosion area and corrosion speed were enlarged and fastened, respectively. Up to the 20th week, the alloy surfaces were full of corrosion pits besides roughness and discontinuity. Relevant data analysis showed that the volume fraction of magnesium alloy was 98.6%, 97.1% and 86.4% at the 5th, 10th and 20th weeks after implantation, respectively, and it had a significant decrease from the 10th to 15th week and from the 15th to 20th week (P < 0.05). Within 15-20 weeks, the volume fraction of magnesium alloy was decreased by 6.5% that was the maximum volume reduction per unit cycle. With the progress of corrosion, the surface continuously became rough and vague, and its surface area was enlarged; the ratio of surface area to volume continuously increased, and there was a significant difference at 15 and 20 weeks (P < 0.05). Because of the increasing number of corrosion pits, the cross-sectional radius decreased, which was reflected by the trabecular thickness decreasing from 1.00 to 0.87 mm. From the view of the slope of curve, the trabecular thickness decreased most rapidly at 10-15 weeks. The mineral density of magnesium alloy continuously decreased from 649.302 to 356.445 mg/cm3 during the whole experiment period (P < 0.05). In addition, the micro-CT image density decreased from 679.710 to 644.947 mg/cm3, but there was no significant difference. To conclude, the degradation speed is peaked at 10-20 weeks after implantation, and the content of magnesium alloys decrease with degradation, but the magnesium density has no significant change. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Absorbable bio-glass injection in osteoporosis mice: a support for the osteoporotic vertebral body and mechanism of osteogenic induction Bian Jing, Gong Tai-fang, Chen Wen, Zheng Hong-mei 2016, 20 (16):  2310-2316.  doi: 10.3969/j.issn.2095-4344.2016.16.004 Abstract ( 275 )   PDF (1284KB) ( 299 )   Save BACKGROUND: Absorbable bio-glass injection composed by bio-glass and calcium phosphate bone cement can be tightly combined with bone tissue by a strong chemical bond to improve the stability of the bone-implant interface. OBJECTIVE: To investigate the effect of absorbable bio-glass injection to support the vertebral body of osteoporosis mice and its mechanism of osteogenic induction. METHODS: Osteoporosis models were prepared in 30 female Sprague-Dawley rats undergoing bilateral ovariectomy. After modeling, model rats were randomly divided into three groups, and given polymethylmethacrylate, injectable calcium phosphate bone cement and absorbable bio-glass injection into L3-5 vertebral bone defects, respectively. L3-5 segments were removed at 12 weeks after implantation to detect the biomechanical and degradation properties, levels of calcium and phosphate, alkaline phosphatase activity, bone mineral density, levels of bone morphogenetic protein 2 and transforming growth factor β, as well as histological observation.  RESULTS AND CONCLUSION: In the absorbable bio-glass injection group, the degradation properties, compressive strength, surface hydroxyapatite deposition amount and bone mineral density were significantly higher than those in the other two groups(P < 0.05); trabecular bone relative volume, thickness and number were significant higher than those in the other two groups (P < 0.05); serum levels of calcium, alkaline phosphatase, bone morphogenetic protein 2 and transforming growth factor β were significantly higher than those in the other two groups(P < 0.05); but the level of serum phosphate was lower than that in the other two groups(P < 0.05). These results show that the absorbable bio-glass injection can enhance the support for the osteoporotic vertebral body and induce osteogenesis, probably by increasing bone morphogenetic protein 2 and transforming growth factor β levels. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Biocompatibility and security of calcium sulfate bone substitutes Qiu Yi-yan, Chen Yang, Zhou Wen-yu, Xia Xiao-long, Yang Xin-jian 2016, 20 (16):  2317-2323.  doi: 10.3969/j.issn.2095-4344.2016.16.005 Abstract ( 318 )   PDF (4184KB) ( 326 )   Save BACKGROUND: It is a great potential study that calcium sulfate product loaded with antibiotics is developed, but this product is not systematically studied and its biocompatibility and security need to be further studied. OBJECTIVE: To evaluate the biocompatibility and safety of vancomycin- or gentamicin-loaded calcium sulfate bone. METHODS: (1) Hemolysis test: vancomycin-loaded, gentamicin-loaded calcium sulfate extracts, double distilled water and saline were added into rabbit anticoagulant blood samples. (2) Micronucleus test: vancomycin-loaded and gentamicin-loaded calcium sulfate extracts, cyclophosphamide and normal saline solution were intraperitoneally injected to mice, respectively. (3) Acute toxicity test: vancomycin-loaded and gentamicin-loaded calcium sulfate extracts, and normal saline solution were intraperitoneally injected to mice, respectively. (4) Pyrogen test: the mice were injected vancomycin-loaded and gentamicin-loaded calcium sulfate extracts via the ear vein. (5) Intradermal stimulation test: vancomycin-loaded and gentamicin-loaded calcium sulfate extracts were respectively injected into the unilateral spine of rabbits, respectively. (6) Intramuscular implantation test: vancomycin-loaded and gentamicin-loaded calcium sulfate extracts were respectively injected to the dorsal muscle of rabbits. (7) Intraosseous implantation test: vancomycin-loaded and gentamicin-loaded calcium sulfate were implanted into the necrotic femoral bone of rabbits. RESULTS AND CONCLUSION: Both vancomycin-loaded and gentamicin-loaded calcium sulfate products, which have no hemolytic reaction, genetic toxicity, acute toxicity, pyrogen reaction and skin irritation, are considered to have good biocompatibility and safety. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Surgical biomaterials to repair the ruptured annulus fibrosus due to intervertebral disc degeneration Zhu Xu, Ma Yuan, Meng Xiang-yu, Tian Hui-zhong 2016, 20 (16):  2324-2332.  doi: 10.3969/j.issn.2095-4344.2016.16.006 Abstract ( 474 )   PDF (7332KB) ( 341 )   Save BACKGROUND: In recent years, animal models of lumbar disc degeneration have been popularized to explore the effect of tissue engineering, cell engineering and genetic engineering technologies on intervertebral disc degeneration. OBJECTIVE: To investigate the influence of biological patches on rabbit anulus fibrosus repair. METHODS: L3-4, L4-5, L5-6 segments from rabbits were randomly divided into normal control group (the intervertebral disc was exposed correspondingly), control group (the annulus fibrosus was only cut with a surgical scalpel) and experimental group (the annulus fibrosus was cut and sutured with the surgical biomaterial). Six rabbits were selected randomly to take the lumbar X-ray and MRI preoperatively and 1, 2, 4, 8, 12 weeks postoperatively; one rabbit was chosen preoperatively and three rabbits selected respectively at 1, 2, 4, 8, 12 weeks postoperatively to execute hematoxylin-eosin and type II collagen immunohistochemistry. RESULTS AND CONCLUSION:At postoperative 1, 2 and 4 weeks, the disc height index decreased significantly in the control and experimental groups. MRI and histopathological examination showed that the T2WI signal intensity and hematoxylin-eosin grading were both increased significantly in the control and experimental groups at 2 weeks after surgery (P < 0.05). With time, the number of nucleus pulposus cells gradually reduced in the control and experimental groups. Annulus fibrosus defects were filled with granulation and fibrous tissues, and the biofilm was tightly fused with the annulus fibrosus. Findings from the type II collagen immunohistochemical staining showed that the histological staining of the nucleus pulposus was gradually changed from positive to negative in the experimental and control groups. Therefore, cutting the annulus fibrosus can lead to severe disc degeneration at early period, and surgical biomaterials can be integrated with the annulus fibrosus well to seal annulus fibrosus defects and further prevent nucleus pulposus protrusion. However, this approach cannot restrain the continuous process of disc degeneration. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Silicon carbide-carbon composites for small joint prosthesis: a three-dimensional finite element model for biomechanical study Yang Yong-chao, Tan Qing, Yang Cui, Lu Yun 2016, 20 (16):  2333-2339.  doi: 10.3969/j.issn.2095-4344.2016.16.007 Abstract ( 333 )   PDF (1766KB) ( 265 )   Save BACKGROUND: Silicon carbide-carbon (C/C-SiC) composite materials are widely used, but no relevant experimental studies on medical prosthesis materials have been reported. OBJECTIVE: To demonstrate the feasibility of C/C-SiC composite materials as a substitute for facet joint prosthesis based on the biomechanical research and three-dimensional finite element analysis. METHODS: The predetermined size C/C-SiC composites and traditional carbon/carbon(C/C) composite materials were placed in an electronic universal testing machine, to measure and calculate material compressive elastic modulus, compressive strength, maximal anticompression force, flexural modulus, bending strength and maximal antibending force. Afterwards friction coefficient, wear volume and weight wear rate were measured. Using three-dimensional finite element analysis, finite element models of the third metacarpal bone were defined as C/C and C/C-SiC composite element types, respectively. 200 N axial force was applied to analyze the total displacement and node stress. RESULTS AND CONCLUSION: Compressive elastic modulus, compressive strength，maximal anticompression force, flexural modulus, bending strength and maximal antibending force of C/C-SiC composites were significantly higher than those of the C/C materials (P < 0.05); friction coefficient, wear volume, weight wear rate, total displacement as well as node stress of C/C-SiC composites were significantly lower than those of C/C materials (P < 0.05). These results prove that C/C-SiC composite has favorable mechanical properties, antiwear ability, compression resistance and stress resistance. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Platelet-rich fibrin versus collagen membrane in the repair of gingival defects Dong Lu, Xiao Qiong, Yang Qin-qiu, Sun Yong, Chen Hong-liang 2016, 20 (16):  2340-2346.  doi: 10.3969/j.issn.2095-4344.2016.16.008 Abstract ( 377 )   PDF (4835KB) ( 289 )   Save BACKGROUND: Previous studies have found that platelet-rich fibrin has a good ability to induce gingival soft tissue repair and regeneration. OBJECTIVE: To observe the effects of platelet-rich fibrin versus collagen membrane on gingival soft tissue healing, and to evaluate the ability of platelet-rich fibrin to repair gingival defects. METHODS: Twenty-two patients (2 premolar teeth and 20 molars) scheduled for premolar or molar removal or ridge preservation due to various reasons were selected and randomized into two groups. Bio-Oss was implanted into the extraction socket followed by covering with platelet-rich fibrin or collagen membrane. Healing time and healing rate of gingival defects were detected to evaluate the ability of platelet-rich fibrin to promote gingival tissue healing at 1-2 weeks after Bio-Oss implantation. RESULTS AND CONCLUSION: The healing time was (12.17±2.25) days in the platelet-rich fibrin group and (17.30±2.58) days in the collagen group. The healing rate of the platelet-rich fibrin group was notably higher than that in the collagen membrane group at 1 and 2 weeks after Bio-Oss implantation. These findings indicate that platelet-rich fibrin is better than collagen membrane to improve the healing of gingival soft tissues with a shorter healing time. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Effect of Cu2+ and Fe3+ on osteoblast growth and differentiation in hydrogel RADA16-NBD Shi Jin-ming, Zhao Gang, Ruan Qiang 2016, 20 (16):  2347-2353.  doi: 10.3969/j.issn.2095-4344.2016.16.009 Abstract ( 430 )   PDF (4445KB) ( 469 )   Save BACKGROUND: It is a mature technology to culture MC3T3-E1 cells in the self-assembling peptide hydrogel, RADA16-NBD. Moreover, it is confirmed that a variety of metal ions, such as Fe, Cu, Zn, Mn, are involved in normal bone metabolism. OBJECTIVE: To observe the effect of Cu2+ and Fe3+ on the proliferation and differentiation of MC3T3-E1 cells cultured in the self-assembling peptide hydrogel, RADA16-NBD. METHODS: Osteoblasts cultured with RADA16-NBD were divided into three groups and respectively cultured in culture medium containing Cu2+, Fe3+ or serum-free medium (control group), respectively. After 24, 48 and 72 hours, cell proliferation was detected by cell counting kit-8. After 1, 3, 5 days, alkaline phosphatase activity was detected. At 21 days, formation of calcified nodules was observed. Cell migration ability of cells was observed at 24 hours of Transwill chamber culture. RESULTS AND CONCLUSION: Compared with the control group, the proliferative ability of cells cultured in the Cu2+, Fe3+ groups was significantly higher (P < 0.05, P < 0.01). At 72 hours of culture, there was no difference in the cell proliferation among the three groups. At 1, 3, 5 days of culture, the alkaline phosphatase activity in the Cu2+, Fe3+ groups was significantly higher than that in the control group (P < 0.05); while at 3 and 5 days of culture, the alkaline phosphatase activity in the Cu2+ group was significantly higher than that in the Fe3+ group (P < 0.05). In addition, the number of migrated cells was higher in the Cu2+ group than the Fe3+ group (P < 0.05). These findings indicate that both Cu2+ and Fe3+, especially the former one, can promote MC3T3-E1 cell proliferation, differentiation and migration. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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A novel amorphous calcium phosphate drug-eluting stent: its biocompatibility after implantation into mini-swine coronary artery Tan Zheng, Li Li, Ma Yi 2016, 20 (16):  2354-2359.  doi: 10.3969/j.issn.2095-4344.2016.16.010 Abstract ( 243 )   PDF (4318KB) ( 417 )   Save BACKGROUND: As previously reported, poly-L-lactic acid stents have been mostly used as coronary artery stents, but this stent has a lack of early support force and produces some acidic products that will induce local vascular inflammatory reactions. OBJECTIVE: To explore the biocompatibility of a novel amorphous calcium phosphate drug-eluting stent, after implantation into mini-swine coronary artery. METHODS: Twenty mini-swine were randomly equivalently divided into observation group and control group. The right femoral arteries of animals were separated layer by layer and the new type of biodegradable stent and poly-L-lactic acid stent were implanted, respectively. RESULTS AND CONCLUSION: The vessel lumes in the two groups were smooth and unobstructed showed by coronary artery angiography immediately after implantation. At 4 weeks after implantation, the coronary angiography showed the patency of vessel lumens with no stent thrombosis and stenosis in both two groups. The C-reactive protein levels in the two groups had no significant differences before and 4 weeks after stent implantation. At 4 weeks after implantation, the number of lymphocytes and inflammatory score in the observation group were significantly higher than those in the control group, but the neointimal area and percentage of stenosis area had no significant difference between the two groups. These results indicate that the novel amorphous calcium phosphate drug-eluting stent after implantation into mini-swine coronary artery has good biocompatibility. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | Related Articles | Metrics

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Mandibular defects repaired by coral bone with platelet rich plasma Jiang Liu-hong, Dong Ying, Yan Chun-ge, Liu Yan-hui, Jing Xiang-dong 2016, 20 (16):  2360-2368.  doi: 10.3969/j.issn.2095-4344.2016.16.011 Abstract ( 343 )   PDF (2778KB) ( 239 )   Save BACKGROUND: Platelet rich plasma contains various growth factors, such as platelet-derived growth factor, metastatic growth factor, insulin-like growth factor, epidermal growth factor as well as vascular endothelial growth factor. Therefore, it can directly or indirectly promote cell differentiation and proliferation in different stages of bone regeneration. OBJECTIVE: To study the effects of coral bone with platelet rich plasma in the repair of mandibular defects. METHODS: Totally 24 New Zealand white rabbits were randomly divided into three groups (n=8 per group) including test group, control group and blank control group. Coral bone with autologous platelet rich plasma, coral bone or nothing was implanted, respectively, after establishing unilateral mandibular defect models. The defects were evaluated by imaging observation and bone his-tomorphometric analysis at 2, 4, 8, 12 weeks after surgery. RESULTS AND CONCLUSION: At 12 weeks after surgery, by imaging observation, density of the defect increased in the blank control group, which was lower than that of the normal bone; the bone density in the test group was higher than that in the control group, both of which were similar with the normal bone. Besides, the materials were closely combined with the new tissues. By bone his-tomorphometric analysis, area of the new bone in the test group was significantly larger than that in the control and blank control group (P < 0.05). In conclusion, coral bone with platelet rich plasma has good biocompatibility and bone conductivity, which can induce bone regeneration to promote defect repair. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Effect of SonicFill ultrasonic resin on rat odontoblasts and dental pulp vessels Zhao Qian-ning, Wang Jian-ping, Tong Wei-wei, Su Dan, Yu Yan-heng 2016, 20 (16):  2369-2375.  doi: 10.3969/j.issn.2095-4344.2016.16.012 Abstract ( 610 )   PDF (2554KB) ( 483 )   Save BACKGROUND: The mechanical properties of SonicFill ultrasonic resin are better than those of the traditional light-cured composite resin, but its effect on odontoblasts and dental pulp vessels is unclear. OBJECTIVE: To study the effect of SonicFill ultrasonic resin on odontoblasts and dental pulp vessels of rats using histological methods. METHODS: Twenty-five Wistar rats are selected for experiment. Ninety-six teeth from the first and second molars were selected and randomly divided into SonicFill ultrasound resin group and Filtek Z350 nano resin group with 48 teeth in each group. Experimental teeth in each group were equally subdivided into 7 days group and 30 days group. Besides, randomly selected five teeth with no intervention served as normal control group. After anesthesia and disinfection, class I cavities on the occlusal surface of the maxillary first and second molars were prepared and filled with SonicFill ultrasound resin and Filtek Z350 nano resin group, respectively. The rats were sacrificed by ink perfusion method, and tooth specimens were taken to observe the changes of odontoblasts and pulp microvessels. RESULTS AND CONCLUSION: At 7 days after filling, two groups had similar changes in the pulp presenting with mild inflammation. Besides, there were scattered inflammatory cells distributing in the cave pulp tissue, and in most of the specimens, odontoblasts arranged disorderly with little vacuoles and microvascular dilatation in the pulp. At 30 days after filling, in the SonicFill ultrasonic resin group, odontoblasts arranged orderly, inflammatory reaction and microvascular dilatation disappeared basically. In contrast, in the Filtek Z350 nano resin group, disordered odontoblasts decreased, inflammatory reaction weakened, as well as microvascular dilatation became less. These results show that under the experimental condition, both of the SonicFill ultrasonic resin and Filtek SonicFill Z350 nano resin play certain roles in the formation of odontoblasts and dental pulp vessels, but over time all of these effects can automatically disappear.  中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Biocompatibility of domestic porous tantalum carrying bone morphogenetic protein 7 in the erector spinae muscle of rabbits Zhang Hui, Wang Qian, Tao Jian-feng, Wang Ai-jun, Shi Wei, Bian Yu-jie, Li Qi-jia, Wang Zhi-qiang 2016, 20 (16):  2376-2383.  doi: 10.3969/j.issn.2095-4344.2016.16.013 Abstract ( 267 )   PDF (2586KB) ( 473 )   Save BACKGROUND: Bone morphogenetic protein 7 (BMP-7) can induce bone and cartilage formation in vivo, and induce chondrogenic and osteogenic differentiation of mesenchymal cells in muscles and around the vessels. OBJECTIVE: To observe the structure of domestic tantalum-muscle interface fibrous capsule, growth of muscle and small blood vessels into the porous tantalum and the ability of ectopic osteogenesis after implantation of porous tantalum loaded with BMP-7 into the erector spinae of rabbits. METHODS: Porous tantalum slices loaded with BMP-7 (experimental group) and porous tantalum slices (control group) were implanted into the erector spinae muscle of New Zealand white rabbits. And the porous tantalum slices with surrounding muscle tissues about 0.5 cm thick were removed at 2, 4, 8 weeks after implantation, and observed under scanning electron microscope for hematoxylin eosin staining, Masson staining and hard tissue slice observation. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining: Fibrous capsule formation was observed around the materials in the two groups, and with the extension of time, the fibrous capsules were slightly dense, and thinned. There was no obvious inflammatory reaction in the interface between the material and the muscle. There was no significant difference between the two groups in the fibrous capsules thickness. (2) Scanning electron microscope: 2 weeks after the surgery, a small amount of collagen and muscle fibers were formed in the porous tantalum pores in the two groups, and some of collagen fibers attached to the pore walls. At 8 weeks after the surgery, all the pores of porous tantalum were full of muscle fibers that were combined with the pore wall closely. There was no significant difference between the two groups. (3) Hard tissue slices: 2 weeks after the surgery, a small amount of fibroblast cells and muscle fibers grew into the pores of porous tantalum in the two groups and new capillaries grew into the pores of porous tantalum in the experimental group. At 8 weeks after the surgery, the porous tantalum and all the pores were full of muscle fibers that were combined with the pore wall closely, the number of small blood vessels and cells decreased, and the tantalum and the muscle were fused closely. (4) Masson staining: 8 weeks after the surgery, a large number of mesenchymal cells, ossein and cartilage matrix formed in the muscle gaps and a few cartilage bone tissues were formed in the experimental group, but no cartilage was found in the control group. The study showed that porous tantalum carrying BMP-7 has good biocompatibility and osteogenic induction ability. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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A novel biomimetic nanofibrous heparin/gelatin scaffold with sustained-release recombinant human bone morphogenetic protein-2: preparation and characterization Ding Chen, Liu Hao 2016, 20 (16):  2384-2390.  doi: 10.3969/j.issn.2095-4344.2016.16.014 Abstract ( 257 )   PDF (1372KB) ( 317 )   Save BACKGROUND: Bionic structure is one of the most important goals of scaffold design in tissue engineering. However, the majority of the bionic scaffolds do not have the capacity of sustained release of growth factors. OBJECTIVE: To fabricate a novel biomimetic nanofibrous heparin/gelatin scaffold and investigate the characterization of the scaffolds including the microstructure, the mechanical strength and in vitro recombinant human bone morphogenetic protein-2 (rhBMP-2) release. METHODS: Heparin-conjugated gelatin was prepared by chemical crosslinking and mixed with gelatin at different ratios. Nanofibrous composite scaffolds with different ratios of heparin-conjugated gelatin (0, 20% and 40%) were fabricated by using a thermally induced phase separation combined with particle leaching technique. The amount of conjugated heparin in the scaffolds, scaffold microstructures and mechanical strength were detected and observed. The release kinetics of rhBMP-2 from the scaffolds with different concentrations of heparin conjugated gelatin was detected using ELISA method. RESULTS AND CONCLUSION: The composite scaffolds possessed abundant porosities, good mechanical properties, and biomimetic nano-structures. The macroporous size was 250-420 μm. When the ratio of heparin-conjugated gelatin was 0, 20% and 40%, the content of heparin in the scaffolds was 0, (12.82±2.49) and (25.08±3.69) mg/g, respectively, with significant differences; the elastic modulus of the composite scaffolds was (299±38), (286±40) and (236±33) kPa, respectively, with insignificant differences (P > 0.05). With the increase in the content of heparin-conjugated gelatin, the rhBMP-2 adsorption capacity of the nanofibrous heparin/gelatin scaffold is improved, thereby significantly reducing the burst release of rhBMP-2 and prolonging the releasing time. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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High-absorbing chitosan dressings for hemostasis and wound healing Mao Jun, Zhou Ying-shan, Wu Ting 2016, 20 (16):  2391-2396.  doi: 10.3969/j.issn.2095-4344.2016.16.015 Abstract ( 307 )   PDF (2893KB) ( 372 )   Save BACKGROUND: High liquid-absorbing property, high-capacity imbibition property and high antibacterial property of chitosan dressings can be promoted by chemical modification. OBJECTIVE: To observe the effect of high-absorbing chitosan dressings on hemostasis and wound healing. METHODS: (1) Venule bleeding experiment: symmetry oozing wounds were produced on the rabbit skin, which were respectively covered by high-absorbing chitosan dressings and sterile gauze. Then, hemostatic time and bleeding volume were recorded. (2) Deep II degree burn wound healing experiment: 40 Sprague-Dawley rats were selected to prepare deep II degree burn wounds on the back, and then model rats were randomly divided into two groups: experimental group with high-absorbing chitosan dressings and control group with vaseline gauze. After 3, 7, 14, 21 days, wound tissues were taken and analyzed histopathologically. RESULTS AND CONCLUSION: (1) Venule bleeding experiment: The bleeding amount and hemostatic time were significantly lower in the high-absorbing chitosan dressing group than the sterile gauze group (P < 0.05, P < 0.01). (2) Deep II degree burn wound healing experiment: the unhealed wound areas were significantly lower in the experimental group than the control group at days 7, 14, 21 after repair (P < 0.05). After 3 days of wound repair, necrosis of the squamous epithelial layer and the structural damage of the hair follicle in the corium layer and skin appendages were found in both two groups. Meanwhile, the infiltration caused by varying numbers of neutrophils and lymphocytes inside the damaged skin tissues was visible. After 21 days of repair, the epithelium healed well in the control group, with a little lymphocyte infiltration and formation of crust on the skin surface; while in the experimental group, the epithelium healed well, with complete squamous epithelial layer and no inflammatory cell infiltration. Thus, these experimental findings reveal that the high-absorbing chitosan dressing has an excellent effect on hemostasis and wound healing. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Biological behavior of rat bone marrow mesenchymal stem cells in oligo(poly(ethylene glycol)fumarate) hydrogel Wei Li-jun1, Cao Jun-kai1, Li Jun-jie2, Feng Lan-lan2 2016, 20 (16):  2397-2404.  doi: 10.3969/j.issn.2095-4344.2016.16.016 Abstract ( 315 )   PDF (8169KB) ( 525 )   Save BACKGROUND: Oligo(poly(ethylene glycol)fumarate) (OPF) hydrogel is a kind of biomaterial with good biocompatibility, injectability, and biodegradability. It is known that there are differences in the characteristics of hydrogels with different molecular weights. Under osteogenic induction, bone marrow mesenchymal stem cells encapsulated in the suitable molecular weight hydrogel have better proliferation and differentiation. Therefore, the use of OPF hydrogel provides new options for bone tissue-engineered scaffold. OBJECTIVE: To investigate the effect of OPF hydrogel with different molecular weights on the proliferation and differentiation of encapsulated rat bone marrow mesenchymal stem cells in vitro. METHODS: Four kinds of OPF hydrogels with molecular weights of 1 000, 3 000, 10 000 and 35 000 were developed by OPF crosslinking with a redox radical initiation system. Hydrogel swelling and degradation properties were detected. Afterwards, bone marrow mesenchymal stem cells encapsulated in different hydrogels were cultured in osteogenic medium for 1-3 weeks. The effects of hydrogels on morphplogy of bone marrow mesenchymal stem cells and osteogenic differentiation were detected via histological staining (hematoxylin-eosin staining and alizarin red staining) and immunofluorescence staining. RESULTS AND CONCLUSION: With the increase of molecular weight of hydrogels, the gelation time was shortened, the swelling ratio significantly increased, and the hydrogel degradation rate was proportional to the molecular weight. In addition, the number of mineralized nodules formed in 3 000 and 10 000 molecular weight hydrogels was more than that in the other hydrogels, indicating that hydrogels with appropriate swelling and degradation properties are beneficial to cell proliferation and differentiation. In conclusion, OPF hydrogels have good biocompatibility and hydrogels with 3 000 and 10 000 molecular weight play active regulatory roles in osteogenic differentiation of mesenchymal stem cells.  中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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3D-bioprinting manufacturing polylactic-co-glycolic acid/nano-hydroxyapatite scaffold/bone morphogenetic protein-2 sustained release composite Zang Xiao-long, Sun Jian, Li Ya-li, Chen Li-qiang, Yang Xue-cai, Liang Li-qing, Du Guo-qing 2016, 20 (16):  2405-2411.  doi: 10.3969/j.issn.2095-4344.2016.16.017 Abstract ( 519 )   PDF (4690KB) ( 793 )   Save BACKGROUND: Tissue-engineered bone scaffold fabricated by 3D-bioprinting technique has good controllability in morphology and structure. However, construction of tissue-engineered bone/cell growth factor complex and time-dose effect of sustained-release factors are needed to be further researched.  OBJECTIVE: To fabricate a sustained-release composite of polylactic-co-glycolic acid (PLGA)/nano-hydroxyapatite (n-HA) scaffold carrying bone morphogenetic protein-2 (BMP-2) using 3D-bioprinting technique, and test the biological properties of the PLGA/n-HA scaffold carrying BMP-2 and the sustained-release properties, thereby to discuss its feasibility as the tissue-engineered bone scaffold composite.  METHODS: Temperature-sensitive chitosan hydrogel was prepared using chitosan and β-glycerophosphate to construct a sustained-release composite, chitosan nanoparticles carrying BMP-2 . 3D-bioprinting technique was utilized to fabricate the PLGA/n-HA scaffold carrying BMP-2. Biological features of the scaffold composite were tested, and time-dose effect of BMP-2 sustained-release was observed.  RESULTS AND CONCLUSION: The average pore size of the scaffold-cytokine composite was (431.31±18.40) μm, and the porosity was (73.64±1.82)%. The cumulative release rate of BMP-2 from the scaffold-cytokine composite that effectively controlled the burst release during 48 hours and 30 days were suitable for the physiological needs. In conclusion, the porosity, pore size, release property, degradation rate, and mechanical strength of the scaffold-cytokine composite all meet the biological requirements of tissue-engineered bone construction. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Tissue-engineered annular fibrosus scaffold constructed by konjac glucomannan/ nano-hydroxyapatite/collagen composite material Zhuang Ying, Chen Xi-liang, Li Yong, Chen Qing-hua, Pan Xing-hua, Xu Yong-qing 2016, 20 (16):  2412-2417.  doi: 10.3969/j.issn.2095-4344.2016.16.018 Abstract ( 340 )   PDF (1292KB) ( 347 )   Save BACKGROUND: Tissue-engineered transplantation technique has become an ideal therapeutic regimen for degenerative disc diseases through reconstituting the biological functions of the degenerated intervertebral discs. OBJECTIVE: To construct a novel tissue-engineered annular fibrosus scaffold. METHODS: Konjac glucomannan, nano-hydroxyapatite and collagen were used to fabricate a new tissue-engineered annular fibrosus scaffold by wet spinning, chemical crosslinking, and freeze drying methods. Afterwards, X-ray diffraction and Fourier transform infrared spectrometer were used to analyze the scaffold qualitative components, physico-chemical property, biomechanical performance and cytocompatibility.  RESULTS AND CONCLUSION: The bionic scaffold had a three-dimensional porous structure, with the average pore size of (425.8±47.3) μm, the average porosity of (73.4±5.6)%, and the water absorption of (718.6±24.3)%. In addition, the compressive strength of the scaffold was similar with that of the natural annular fibrosus. More importantly, the scaffold had good biocompatibility without cytotoxicity. These results show that the tissue-engineered annular fibrosus scaffold constructed by konjac glucomannan, nano-hydroxyapatite and collagen has proper three-dimensional porous structure, biocompatibility, porosity, water absorption and biomechanical strength. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Nano-hydroxyapatite/polyamide 66 as a direct pulp capping agent has effects on histological changes of odontoblasts and microvessels Tong Wei-wei, Wang Jian-ping, Zhao Qian-ning, Su Dan, Yu Yan-heng 2016, 20 (16):  2418-2424.  doi: 10.3969/j.issn.2095-4344.2016.16.019 Abstract ( 362 )   PDF (2235KB) ( 434 )   Save BACKGROUND: Previous studies have demonstrated that nano-hydroxyapatite/polyamide 66 (nHA/PA66) composites as a root canal filling material possess the basic physical and chemical properties, have antibacterial properties against the infection of medullary cavity, and have no cytotoxicity. However, it is rarely reported as a direct pulp capping agent. OBJECTIVE: To observe the histological reaction of nHA/PA66 composites as the pulp capping agent. METHODS: The first and second molars from 12 Wistar rats were selected to prepare class I cavities by exposing the dental pulp. Then, these rats were randomized into three groups and subjected to dental pulp capping using nHA/PA66 composite, nHA and calcium hydroxide, respectively, followed by filling with glass ionomer cement. At 7 and 30 days after filling, histological changes of odontoblasts and microvessels in the dental pulp were observed using ink perfusion method. RESULTS AND CONCLUSION: At 7 days after filling, significant changes in dental pulp fibroblast proliferation, predentin thickening, dilation of blood vessels were observed in the nHA/PA66 group; only dental pulp fibroblast proliferation with no predentin thickening and dilation of blood vessels was found in the nHA group; in the calcium hydroxide group, the pulp tissues in the pulp chamber were mostly damaged, and obvious hyperplasia in dental pulp fibroblasts and certain inflammatory cell infiltration with vascular necrosis were observed. At 30 days after filling, predentin thickness was increased further, dental pulp fibroblasts proliferated, the number of odontoblasts increased, and dilation of blood vessels was observed in the nHA/PA66 group; predentin thickening and dilation of blood vessels were obviously visible in the nHA group; pulp necrosis was found on the pulp surface below the pitting pore, odontoblasts grew actively at the pulp junction, with no obvious thickening of the predentin, and there were dense vessels below the necrotic area. These findings indicate that the nHA/PA66 composite can induce the regeneration of dental pulp cells. 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics

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Biomechanical properties of the lumbosacral spine and application of internal fixation materials Sun Hong-hao, Guo Qing-sheng, Zhu Zhi-yong 2016, 20 (16):  2425-2432.  doi: 10.3969/j.issn.2095-4344.2016.16.020 Abstract ( 313 )   PDF (1154KB) ( 433 )   Save BACKGROUND: In recent years, the spinal internal fixation technology has made rapid development based on biomechanics and material sciences. OBJECTIVE: To review the biomechanical characteristics of the lumbosacral spine and the application of various internal fixation materials in the reconstruction of spinal stability after lumbosacral spinal tuberculosis. METHODS: A computer-based search of Medline and Chinese Journal Full-Text Database was performed for relevant articles using the keyword of “lumbosacral spinal tuberculosis, biomaterials materials, fixation” in English and Chinese, respectively. RESULTS AND CONCLUSION: Rigid internal fixation is a conventional treatment for lumbosacral tuberculosis, which improves the spinal alignment and stability during the spinal reconstruction. Metallic materials such as stainless steel, titanium and titanium alloys have been widely used in rigid internal fixation, but metal sedimentation, non-transparency, stress shielding and osteoporosis after internal fixation impact the fusion effects and imaging observation. Absorbable materials as newly-developing materials have good biocompatibility and biodegradability in orthopedic internal fixation. To select the appropriate material for internal fixation, the biomechanical properties of internal fixation materials will be investigated according to the degree of vertebral damage and lumbosacral stability.   中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程 Figures and Tables | References | Related Articles | Metrics