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    16 September 2016, Volume 20 Issue 38 Previous Issue    Next Issue
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    Poly(hydroxybutyrate-co-hydroxyoctanoate/collagen) osteochondral tissue-engineered scaffold used for repair of knee cartilage injury
    Duan Xin-hu
    2016, 20 (38):  5629-5635.  doi: 10.3969/j.issn.2095-4344.2016.38.001
    Abstract ( 329 )   PDF (16390KB) ( 379 )   Save

    BACKGROUND: Due to the complex physiological characteristics of the osteochondral tissue, the clinical repair of knee cartilage injury often has dissatisfied outcomes. Tissue engineering methods and tools provide a new idea for osteochondral repair.
    OBJECTIVE: To observe the effect of poly(hydroxybutyrate-co-hydroxyoctanoate/collagen) osteochondral tissue-engineered scaffold on the repair of articular cartilage injury in a rabbit.
    METHODS: The poly(hydroxybutyrate-co-hydroxyoctanoate/collagen) osteochondral tissue-engineered scaffold was prepared by solvent casting/particle leaching method. Then, seed cells were isolated and cultured on the scaffold. Twenty-four healthy New Zealand white rabbits, 4 weeks of age, were used for the study. Under balanced anesthesia, an articular cartilage defect (4.5 mm in diameter, 5 mm in depth) was created on the rabbit’s femoral condyle using a bone drill. After modeling, rabbits were randomized into three groups and given direct suture in blank group, pure scaffold implantation in control group and implantation of the scaffold-cell complex in experimental group. Femoral condyle of each rabbit was taken out for gross and histological observations at 8, 20 weeks after surgery.
    RESULTS AND CONCLUSION: At 8 weeks after surgery, transparent film-covered defects and small/irregular cells were found in the experimental group; the defects were filled with fibrous tissues in the control group; while there was no repair in the blank group. Until the 20th week, the defects were covered with hyaline cartilage-like tissues, accompanied by regular cell arrangement in the experimental group; in the control group, the defects were covered with white membranous tissues, and many chondrocytes were found at the basement and edge; in the blank group, some newborn tissues were visible at the defect region. These findings suggest that the poly (hydroxybutyrate-co- hydroxyoctanoate/collagen) osteochondral tissue-engineered scaffold carrying seed cells contributes to articular cartilage repair.

     

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    Graphene oxide loaded with doxorubicin: a killer for multiple myeloma cells
    Xing Li-na, Zhang Xue-jun, Wang Ying, Niu Zhi-yun, Wang Fu-xu, Wen Shu-peng
    2016, 20 (38):  5636-5641.  doi: 10.3969/j.issn.2095-4344.2016.38.002
    Abstract ( 274 )   PDF (951KB) ( 185 )   Save

    BACKGROUND: Cytotoxicity of graphene oxide to normal cells is relatively low, but whether graphene oxide loaded with doxorubicin has some effects on malignant cells is rarely reported.
    OBJECTIVE: To explore the cytotoxicity of graphene oxide loaded with doxorubicin on multiple myeloma cells.
    METHODS: Multiple myeloma cell line RPMI8226 in logarithmic phase was selected, cultured and divided into four groups, including graphene oxide loaded with doxorubicin, doxorubicin and graphene oxide groups as well as control group with no intervention. After 24 hours of culture, the cell activity was detected by cell counting kit-8 method, and the cell cycle and apoptosis were detected using flow cytometry.
    RESULTS AND CONCLUSION: Plump-shaped cells with translucent and clear cytoplasm were found in the control group; cells with relatively translucent cytoplasm, and even a few shrunken cells appeared in the graphene oxide group; cellular morphology was in a heterogeneity, apoptotic bodies appeared in the doxorubicin group; the cells was significantly reduced in size, presenting more obvious shrinkage and apoptotic bodies in the group of graphene oxide loaded with doxorubicin. The cell survival rate in the graphene oxide loaded with doxorubicin, doxorubicin and graphene oxide groups was significantly lower than that in the control group (P < 0.05), and this indicator was significantly lower in the group of graphene oxide loaded with doxorubicin than the graphene oxide group (P < 0.05). The apoptotic rate in the group of graphene oxide loaded with doxorubicin and doxorubicin group was significantly higher than those in the graphene oxide and control groups (P < 0.05), respectively. Additionally, there were no significant differences in the cell cycle among groups. These results show that graphene oxide loaded with doxorubicin has a stronger cytotoxicity, and can induce apoptosis in human multiple myeloma cells.

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    Hydroxyapatite biocoating improves bone-implant interface and promotes osseointegration
    Qin Jie1, Zhao Bo, Wang Dong, Dong Jun, Li Hao-peng, Guo Lei, Wang Shuang, He Xi-jing
    2016, 20 (38):  5642-5649.  doi: 10.3969/j.issn.2095-4344.2016.38.003
    Abstract ( 329 )   PDF (5481KB) ( 567 )   Save

    BACKGROUND: We have designed and manufactured a novel artificial cervical vertebra and intervertebral complex (ACVC) which combines the cervical titanium cage with the artificial cervical disc, and also developed the ACVC with a hydroxyapatite biocoating (ACVC-HA).
    OBJECTIVE: To evaluate biomechanical properties of the joint system, and the role of HA coating in promoting osseointegration and long-term stability.
    METHODS: Twenty-four goats were randomly divided into three groups and underwent the anterior C 2/3 and C 3/4 discectomy, and C3 subtotal corpectomy, followed by ACVC implantation (group 1) and ACVC-HA implantation (group 2), and given no intervention (black control group), respectively. group. At 12 weeks after surgery, C 1-5 samples were collected to undergo biomechanical tests and histological staining.
    RESULTS AND CONCLUSION: Prior to the fatigue test, compared with the blank control group, the range of motion and neural zone of groups 1 and 2 in the directions of flexion-extension and lateral bending showed no significant differences, but the above indicators were significantly increased in the direction of rotation (P < 0.05). Additionally, the stiffness in all three directions was significantly lower than that in the blank control group (P < 0.05). There were no significant differences in the range of motion and neural zone in all directions between groups 1 and 2. Similar results were found after the fatigue test. The histological staining showed that both two implants had good biocompatibility and abradability, but more new bone formed on the ACVC-HA. These results suggest that ACVC can effectively reconstruct the motor function of the cervical spine after decompression. Furthermore, HA coating can markedly improve bone-implant interface to promote osseointegration.

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    Biological safety of silk fibroin/nano-hydroxyapatite composites
    Fan Chun-quan, Ye Xiao-jian
    2016, 20 (38):  5650-5656.  doi: 10.3969/j.issn.2095-4344.2016.38.004
    Abstract ( 388 )   PDF (5335KB) ( 326 )   Save

    BACKGROUND: Silk fibroin has excellent biocompatibility, biodegradability and unique mechanical properties. Its composite, silk fibroin/nano-hydroxyapatite, can simulate the composition and structure of nature bone tissue, contributing to remedying the insufficient mechanical properties of nano-hydroxyapatites.
    OBJECTIVE: To observe the biological safety of silk fibroin/nano-hydroxyapatite composites.
    METHODS: Silk fibroin/nano-hydroxyapetite composite biomaterial was synthesized by the coprecipitation method using silk fibroin, calcium chloride and diammonium phosphate as raw materials. According to the demands of International Standard Organization (ISO10993) and Technical Evaluation Standards of Biomedical Materials and Medical Instruments promulgated by Chinese Board of Health (GB/T 16886), experiments of cell toxicity in vitro, acute toxicity and hemolysis were investigated to evaluate the biocompatibility of silk fibroin/nano-hydroxyapetite composite.
    RESULTS AND CONCLUSION: L929 cells co-cultured with silk fibroin/nano-hydroxyapatite composite leaching liquor had good cell morphology, metabolism and proliferation. The leaching extract of silk fibroin/nano-hydroxyapatite composite injected into mice intraperitoneally had no significant adverse reactions. And silk fibroin/nano-hydroxyapatite composite extracts caused 2.39% blood hemolysis, less than the international standards 5%. These experimental results on cell toxicity test in vitro, acute toxicity and hemolysis met the demands of ISO10993 and GB/T, which show the biological safety of the silk fibroin/nano-hydroxyapatite composite for clinical application.

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    Effects of nano porous beta-tricalcium phosphate/collagen scaffold modified with human bone morphogenetic protein 2 gene on differentiation of MC3T3-E1 cell lines
    Ruan Qiang, Zhao Gang, Guo Rui, Xiao Yue, Li Chao
    2016, 20 (38):  5657-5663.  doi: 10.3969/j.issn.2095-4344.2016.38.005
    Abstract ( 299 )   PDF (5431KB) ( 178 )   Save

    BACKGROUND: Bone tissue transplantation or osteogenic material filling is after used for bone defect repair. To remove autologous bone tissues can lead to additional damage and secondary deformity, therefore, it is extremely urgent to search for a new osteogenic material.
    OBJECTIVE: To construct the porous β-tricalcium phosphate (β-TCP)/collagen scaffold modified with human bone morphogenetic protein 2 (hBMP2) gene, and to observe its effects on differentiation of MC3T3-E1 cell lines.
    METHODS: The porous β-TCP/collagen scaffold modified with hBMP2 gene was prepared. Then in vitro culture system of MC3T3-E1 cell lines with composite scaffold was established. There were scaffold and plate groups, and each group was divided into two subgroups according to the different concentrations of plasmid. Samples were collected and observed morphologically by scanning electron microscope and light microscope after complex culture. After 1, 3, 7 and 14 days of induction, calcium nodules were observed through alizarin red staining, the cell cycle was detected by real-time PCR, and expressions of α I-chain collagen type I gene, Osterix and bone sialoprotein were observed.
    RESULTS AND CONCLUSION: The number of cells adhered, differentated and distributed on the composite scaffold was significantly higher than that of the single scaffold (P < 0.05). Alizarin red staining and real-time PCR detection showed that the osteogenesis ability of MC3T3-E1 cell lines in the scaffold group was stronger than that in the plate group. To conclude, the porous β-TCP/collagen scaffold modified with hBMP2 gene is an appropriate candidate for bone defect repair.

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    Preparation and properties of recombinant human bone morphogenetic protein-2/ bone repair material
    Liu Qi-sheng, Zhang Dong-gang
    2016, 20 (38):  5664-5671.  doi: 10.3969/j.issn.2095-4344.2016.38.006
    Abstract ( 344 )   PDF (4610KB) ( 250 )   Save

    BACKGROUND: It has become a hotspot to prepare the bone repair material that exhibits natural bone structure and is used in combination with biological factors.
    OBJECTIVE: To prepare the recombinant human bone morphogenetic protein-2 (rhBMP-2)/bone repair material, and to evaluate its capacities of release, activity and ectopic osteoinduction.
    METHODS: A collagen-binding domain was added to the N-terminal of native rhBMP-2 that allowed bind to collagens in the bone repair material. Then, rhBMP-2/bone repair material was obtained through freeze-dried method. The releasing ability of rhBMP-2 in vitro was assayed by ELISA. C2C12 cell lines were loaded to the composite material with 0.25, 0.5 and 1 µg rhBMP-2, respectively. Afterwards, alkaline phosphatase activity was detected at 72 hours. The composite materials with 0, 2, 5 and 10 µg rhBMP-2 were implanted into the quadriceps of Sprague-Dawley rats, respectively. Alkaline phosphatase activity and the newly formed bone were detected at 2 and 4 weeks after implantation. The CY-7-labeled composite material was implanted into the quadriceps of Sprague-Dawley rats to observe its stability.
    RESULTS AND CONCLUSION: Substantially no rhBMP-2 from the rhBMP-2/bone repair material was released within 45 days. The alkaline phosphatase activity of C2C12 was in a rise with the increased concentration of rhBMP-2. The stability of the composite material in vivo was better, the alkaline phosphatase activity and ectopic bone formation increased as the concentration of rhBMP-2 rose. To conclude, the rhBMP-2/bone repair material preserves the stability of rhBMP-2, and improves ectopic osteoinduction ability.

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    Type II collagen hydrogel-cell complexes for cartilage injury
    Shi Xiang
    2016, 20 (38):  5672-5677.  doi: 10.3969/j.issn.2095-4344.2016.38.007
    Abstract ( 448 )   PDF (4083KB) ( 264 )   Save

    BACKGROUND: As the main component of articular cartilage, type II collagen can induce bone marrow mesenchymal stem cells to differentiate into the cartilage. However, there is no uniform standard for the preparation of type II collagen hydrogel and its usage in the repair of sports-induced cartilage injury.
    OBJECTIVE: To investigate the effect of type II collagen hydrogel-cell complexes in the repair of cartilage injury.
    METHODS: After modeling, 30 New Zealand rabbits with cartilage injury were randomized into two groups (n=15 per group): type II collagen hydrogel-bone marrow mesenchymal stem cell complexes were implanted into the injured site of rabbits in experimental group, while only type II collagen hydrogel implanted in control group. Histomorphology observation was performed by hematoxylin-eosin and toluidine blue staining after 4 and 8 weeks after implantation.
    RESULTS AND CONCLUSION: In the experimental group, there were inflammatory cells infiltrated at the injured site, most of which were macrophages and only a small amount of which were neutrophils under hematoxylin-eosin staining, at 4 weeks after implantation, while toluidine blue staining showed no positive. At 8 weeks after implantation, a large amount of chondrocytes proliferated at the injured site that was repaired by chondroblasts and myotubes as well as new vessels under hematoxylin-eosin staining, and toluidine blue staining showed the injured tissues were similar to normal tissues. In the control group, at 4 weeks after implantation, obvious interstitial edema existed, whereas skeletal muscle cells disappeared around the injured site, and a lot of inflammatory cells infiltrated. Several chondroblasts formed at 8 weeks, accompanied by increased fibrous tissues. Moreover, toluidine blue staining always showed no positive in the control group. To conclude, the type II collagen hydrogel-cell complex has better chondrogenic ability that can be used for cartilage repair.

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    Micron traditional Chinese medicine functional lining material: activating blood circulation and promoting fracture healing
    Zeng Qing, Huang Guo-zhi, Liang Dong-hui, Deng Hong-zhu, Yi Yan-kui
    2016, 20 (38):  5678-5683.  doi: 10.3969/j.issn.2095-4344.2016.38.008
    Abstract ( 296 )   PDF (4997KB) ( 200 )   Save

    BACKGROUND: As a new self-synthetized medical orthopedic fixation material, micron traditional Chinese medicine functional lining material can promote the secretion of alkaline phosphatase and callus formation, decrease serum calcium level, as well as increase serum phosphorus level and calcium-phosphorus product.
    OBJECTIVE: To further verify the therapeutic effect of micron traditional Chinese medicine functional lining material on fracture healing.
    METHODS: Twenty-four New Zealand rabbits were selected to prepare models of right radial fracture, and then were randomly allocated into four groups: rabbits in micron group were treated with micron traditional Chinese medicine functional lining material (micron Panax notoginseng powder mixed with active ingredients of Davallia divaricata and Carthamus tinctoriousplus) plus plaster external fixation; those in traditional Chinese medicine control group treated with ordinary Chinese medicine functional material plus plaster external fixation; those in lining material control group treated with ordinary lining material (sterile degreasing cotton) plus plaster external fixation; those in model control group received no treatment. The whole blood viscosity at high/middle/low shear rates and plasma viscosity were detected at 2, 4 and 6 weeks before and after modeling. Additionally, rabbits in each group were killed at 6 weeks after modeling, and radial samples were removed for histological observation.
    RESULTS AND CONCLUSION: The whole blood viscosity at high/middle/low shear rates and plasma viscosity in the micron group were all lower than those in the other three groups in the same period, and had significant differences from those in the model control group at 4 and 6 weeks after modeling (P < 0.05 or 0.01). A large number of osteoblasts could be found, woven bone began to form and the bone marrow cavity was recanalized in the micron group; in the traditional Chinese medicine group, woven bone, chondrocytes and endochondral ossification coexisted and there was a connection between calluses inside and outside of the broken end, but the bone marrow cavity was not recanalized. In contrast, neither connection between calluses inside and outside of the broken end, nor recanalized bone marrow cavity appeared in the lining material and model control groups. In conclusion, micron traditional Chinese medicine functional lining material can promote fracture healing by improving microcirculation and accelerating osteoblast proliferation.

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    Biocompatibility of magnetic ferrosoferric oxide nanoparticles in preosteoblasts
    Guan Chen-yu, Hou Shi-da, Zhou Yang，Zeng Rong-sheng
    2016, 20 (38):  5684-5690.  doi: 10.3969/j.issn.2095-4344.2016.38.009
    Abstract ( 438 )   PDF (4820KB) ( 283 )   Save

    BACKGROUND: Investigations on toxic mechanism and safety of magnetic ferrosoferric oxide (Fe3O4) nanoparticles are extremely necessary when these nanoparticles as an emerging material for bone tissue engineering are implanted into the living body.
    OBJECTIVE: To investigate the biocompatibility of magnetic Fe3O4 nanoparticles with preosteoblasts.
    METHODS: Mouse preosteoblasts were cultured in 0, 200, 400, 800 mg/L magnetic Fe3O4 nanoparticles. After 24 hours, alkaline phosphatase activity, osteocalcin level, cell proliferation rate, cellular morphology, cytoskeleton variation, cell apoptosis and autophagy-related genes, such as Caspase-3, LC3A, LC3B, were detected by alkaline phosphatase assay kit, ELISA kit, cell counting kit-8 kit, inverted microscope, laser confocal microscopy and real-time PCR, respectively.
    RESULTS AND CONCLUSION: After 24 hours of culture, there ware no significant differences between 200 mg/L group and control group. However, in the groups of 400 and 800 mg/L, the ratio of alkaline phosphatase activity to total protein and osteocalcin level increased, the cell proliferation rate decreased, cellular morphology and cytoskeleton changed remarkably, LC3B expression was up-regulated compared with the control group. Additionally, there were also no significant differences in the expression of Caspase-3 and LC3A between 400 and 800 mg/L groups and control group. Therefore, magnetic Fe3O4 nanoparticles at high level contributes to cytotoxicity and up-regulation of LC3B expression, and affects cellular morphology, cytoskeleton and cell proliferation rate, although these nanoparticles can increase the osteoblastic differentiation.   

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    Release and distribution of anti-tuberculosis drug delivery materials locally oriented in the rabbit radius
    Miao Rui-rui, Zhang Wen-long, Bao Yu-cheng, Li Mei
    2016, 20 (38):  5691-5696.  doi: 10.3969/j.issn.2095-4344.2016.38.010
    Abstract ( 310 )   PDF (1189KB) ( 274 )   Save

    BACKGROUND: Polylactic acid-glycolic acid polymer is a sustained-release material with relatively large drug loading and long-term release abilities that can degrade with cell growth in the body. However, its poor hydrophily easily leads to aseptic inflammation that is detrimental to the body’s recovery.
    OBJECTIVE: To study the release and distribution of anti-tuberculosis drug delivery materials locally oriented within the rabbit radius.
    METHODS: After modeling, 20 New Zealand white rabbits with distal radius bone defect were randomly divided into a control group and an experimental group, which were respectively given implantation of isoniazid-rifampicin polylactic acid-glycolic acid polymer/β-tricalcium phosphate material and isoniazid-rifampicin polylactic acid-glycolic acid polymer into the defect. Then, X-ray examination of the defect region was conducted at weeks 4, 8, 12 post implantation. Histological observation and detection of peripheral blood or local blood concentration were performed at week 12.
    RESULTS AND CONCLUSION: After implantation, Lane-Sandhu X-ray scores were significantly higher in the experimental group than the control group (P < 0.05). The defect in the experimental group was healed completely with less release residual among newborn bone trabeculae and osteocytes were markedly visible on the material surface, while in the control group, new bone tissues were interconnected with the surrounding bone tissues at the defect site, and less release residual was found. Both peripheral blood and local blood concentrations in the experimental group were significantly higher than those in the control group after implantation (P < 0.05). To conclude, the anti-tuberculosis drug delivery material, isoniazid-rifampicin polylactic acid-glycolic acid polymer/β-tricalcium phosphate, has ideal release effect that can stably deliver anti-tuberculosis drugs for a long term at a high bactericidal concentration.  

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    Nano-hydroxyapatite/composite resin: cytototoxicity and application in dental restoration
    Wang Pu, Wei Li-bin
    2016, 20 (38):  5697-5702.  doi: 10.3969/j.issn.2095-4344.2016.38.011
    Abstract ( 338 )   PDF (1004KB) ( 258 )   Save

    BACKGROUND: It has been found that the compressive strength and flexural strength of nano- hydroxyapatite combined with light-cured resin matrix can neet the requirements of dental restorative materials.
    OBJECTIVE: To detect the cytotoxicity of nano-hydroxyapatite/composite resin, and to analyze its effects on the dental restoration.
    METHODS: In vitro test: passage 5 periodontal ligament fibroblast-like cells and L-929 cells suspensions were cultured in the 10%, 50%, 100% of nano-hydroxyapatite/composite resin extracts, respectively, and fresh maintenance medium functioned as negative control group. Absorbance values were detected within 7-day culture. In vivo repair test: 57 cases with tooth defect were enrolled containing 37 males and 20 females aged from 15 to 31 years old, and all were subjected to nano-hydroxyapatite/composite resin treatment. A 3-year follow-up was undergone to detect the completeness, marginal adaptation and color matching of the restoration, as well as the periodontal probing depth, sulcus bleeding index, tooth mobility, dental plaque index, gingival crevicular fluid and aspartate aminotransferase level.
    RESULTS AND CONCLUSION: In vitro test results showed that the different concentrations of nano- hydroxyapatite/composite resin extracts had no effects on both periodontal ligament fibroblast-like cells and L-929 cells. In vivo repair test results found that after 3 years of follow-up, the periodontal probing depth, sulcus bleeding index, tooth mobility, dental plaque index, gingival crevicular fluid and aspartate aminotransferase level of patients were significantly decreased than those before repair (P < 0.05), but the alkaline phosphatase level revealed no significant change (P > 0.05). Unfortunately, three cases with incomplete restoration, four cases with color mismatching, and three cases with the inadaptable edge occurred. To conclude, the nano-hydroxyapatite/composite resin holds good biocompatibility and no cytotoxicity, which can maintain a good periodontal health condition in the dental restoration.

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    Gingival changes in patients with single molar loss undergoing fixed implant restoration: a 1-year follow-up
    Zhang Ning, Wang Xiao-lan, Li Xiao-lu, Wang Xiao-xin, Li Hong-mei, Li Yun-sheng
    2016, 20 (38):  5703-5708.  doi: 10.3969/j.issn.2095-4344.2016.38.012
    Abstract ( 297 )   PDF (987KB) ( 205 )   Save

    BACKGROUND: Submerged dental implants that are completely embedded into soft tissues and isolated from the oral environment reduce the potential for infection factors, and are not influenced by the bite force, to ensure the implant osseointegration.
    OBJECTIVE: To compare the effects of submerged and non-submerged dental implants on the recovery of oral soft tissues.
    METHODS: Twenty-four patients who had no contraindication of dental implants and missed one molar with the gingival thickness of more than 1.5 mm were enrolled and divided into two groups. Patients were implanted with non-submerged SS implants of OSSTEM in one group (non-submerged group) and implanted with submerged TS implants of OSSTEM in the other group (submerged group). Variation of gingival thickness, Jemt index and alveolar bone resorption were detected after 2 weeks of one- and two-stage surgery and 1 year after surgery.
    RESULTS AND CONCLUSION: There were no statistical differences in gingival thickness, Jemt index and alveolar bone resorption between two groups. As these two surgical methods have no difference, we would like to use submerged or non-submerged implants in the patients with corresponding indications.

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    Porous titanium-niobium alloys with different porosities: biomechanical strength and cytocompatibility
    Wang Lei, Li Qiang
    2016, 20 (38):  5709-5715.  doi: 10.3969/j.issn.2095-4344.2016.38.013
    Abstract ( 292 )   PDF (1249KB) ( 219 )   Save

    BACKGROUND: Titanium-niobium alloy holds high biomechanical strength and low elastic modulus that is close to the human cortical bone, so it has been extensively used as implant materials of dental, orthopedics and artificial hip joints.
    OBJECTIVE: To observe the biomechanical strength and cytocompatibility of porous titanium-niobium alloys with different porosities.
    METHODS: Porous titanium-niobium alloys with the porosity of 40% and 70% were prepared using powder metallurgy technology. Afterwards, the pore size, elasticity modulus and compressive strength of the two alloys were detected. Then the rabbit bone marrow mesenchymal stem cells were seeded onto the 40% and 70% porous titanium-niobium alloys, and cell adhesion and proliferation were observed at 3, 24 and 72 hours after inoculation, respectively.
    RESULTS AND CONCLUSION: Pore size of porous titanium-niobium alloys with rough surface was 200-500 μm, and both main pore size was 350 and 400 μm, and there was three-dimensional connectivity between the pores; in the 70% group, honeycombed pores were partly fractured, and connected mutually; pores distributed unevenly and there was little communication between the pores in the 40% group. In addition, both groups had high compressive strength and low elastic modulus, but there was no difference between the two groups. Furthermore, both two alloys promoted cell adhesion, and the number of cell adhesion in the 70% group was significantly higher than that in the 40% group (P < 0.05), and extracellular matrix could be found in the 70% group. These results show that porous titanium-niobium alloy with the porosity of 70% is significantly conducive to cell adhesion.

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    Bio-safety of iodine-125 irradiated polyetheretherketone particle chain
    Shi Feng, Chai Wen-wen, Zeng Li, Li Jun, Wang Cheng-kai
    2016, 20 (38):  5716-5721.  doi: 10.3969/j.issn.2095-4344.2016.38.014
    Abstract ( 351 )   PDF (1131KB) ( 269 )   Save

    BACKGROUND: Polyetheretherketone (PEEK) has the potential to carry short-range radiations for cancer treatment. However, there is a lack of bio-safety assessment focusing on125I irradiated PEEK particle chain.
    OBJECTIVE: To evaluate bio-safety of the 125I brachytherapy source irradiated PEEK particle chain.
    METHODS: PEEK particle chain extracts were prepared according to GBT-16886 and applied in acute toxicity test on mice and rabbits, rabbit pyrogen test and rabbit intradermal reaction test. Animals in experimental, material and negative control groups were given irradiated PEEK particle chain extracts, non-irradiated PEEK particle chain extracts and extracts, respectively, to compare the experimental results.
    RESULTS AND CONCLUSION: In mouse and rabbit acute toxicity test: irradiated PEEK particle chain extracts made no effects on the animal general conditions like breathing, activity, hair, secretion and body weight and morphology of the heart, liver, spleen, lung and kidney and other vital organs. In pyrogen test: the maximum temperature in three rabbits reached 0.4 ℃ (< 0.6 ℃), and the sum was 0.7 ℃ (< 1.3 ℃). In intradermal reaction test: the rabbit erythema and edema reaction scores both were 0. To conclude, 125I irradiated PEEK particle chain exhibits a good bio-safety, presenting no acute toxicity, pyogen reaction and intradermal reaction. 

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    Blood flow field characteristics of cerebral aneurysm before stent implantation
    Liu Xiao-yue, Muhetaer Kelimu, Ju Gang, Wang Chen, Li Hui, Sun Hai-xia
    2016, 20 (38):  5722-5729.  doi: 10.3969/j.issn.2095-4344.2016.38.015
    Abstract ( 408 )   PDF (1594KB) ( 238 )   Save

    BACKGROUND: Cerebral aneurysm is a kind of mortal hemangioma, and its treatments such as endovascular embolization and clipping both cause high postoperative recurrence rate and mortality. So the stent implantation for cerebral aneurysm is coming into being.
    OBJECTTVE: To evaluate the hemodynamic parameters after stent implantation into cerebral aneurysm and to provide a novel feasible strategy for clinical treatment.
    METHODS: A retrospective analysis was preformed based on the CT image data of 11 patients with cerebral aneurysm from the Affiliated Hospital of Xinjiang Medical University. Firstly, the flexible and solid model of cerebral aneurysm was established by the MIMICS and reverse engineering. Secondly, the matching stent model was implanted into the cerebral aneurysm, and then the blood flow structure of cerebral aneurysm was analyzed by the fluid dynamics theory and the Fluent with the method of two-way flow solid coupling. Finally, comparative analysis of the kinetic parameters of cerebral aneurysm before and after implantation, including wall pressure, blood velocity, path line of the blood flow, wall shear stress, wall deformation was conducted, and blood flow characteristics after stent implantation were analyzed under different entrance velocity.
    RESULTS AND CONCLUSION: After implantation, the wall surface pressure was reduced about 61.1%; the blood flow velocity around the stent and the inside of the cerebral aneurysm was decelerated obviously; under setting 2 000 lines of blood flow, the number of path line of blood flow into the cerebral aneurysm reduced about 75.0%, the maximum wall shear stress decreased about 79.3%, and the maximum wall deformation reduced to a lower level. The entrance velocity was respectively v1=0.1 m/s, v2=0.2 m/s, v3=0.3 m/s and the wall pressure was in a gradient ascent; the wall shear stress increased with the velocity, meanwhile, τzou (left neck of aneurysm) <τzhong (aneurysm )< τyou (right neck of aneurysm). The path lines of blood flow mainly concentrated in the top of the aneurysm, and the blood velocity markedly affected the surface deformation. These results indicate that main hemodynamic parameters are obviously improved after stent implantation into cerebral aneurysm, and the blood velocity should never be neglectful in the treatment process.

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    Injectable small intestinal submucosa is co-cultured with adipose-derived mesenchymal stem cells in vitro
    Guo Xing, Zhou Hong, Li Dan, Gao Xiao-chun, Dai Lei, Huang Hai-jun, Tan Mei-yun
    2016, 20 (38):  5730-5736.  doi: 10.3969/j.issn.2095-4344.2016.38.016
    Abstract ( 270 )   PDF (3476KB) ( 234 )   Save

    BACKGROUND: The decellularized porcine small intestinal submucosa is a kind of bioactive extracellular matrix, which is mainly composed of collagen, glycoprotein, proteoglycan and rich in collagen, glycosaminoglycan and various growth factors, and these components play an important role in promoting the differentiation and proliferation of tissue cells.
    OBJECTIVE: To prepare the injectable small intestinal submucosa and to investigate its co-culture with rat adipose-derived mesenchymal stem cells in vitro.
    METHODS: The injectable small intestinal submucosa and rat adipose-derived stem cells were prepared. Cell counting kit-8 test for cell proliferation: Passage 3 adipose-derived stem cells were seeded onto the injectable small intestinal submucosa (experimental group) and cells cultured under normal condition as control group. The cell proliferation was observed at 1, 3, 5 and 7 days of incubation. Live/dead staining test for the survival of cells: Passage 3 adipose-derived stem cells were respectively cultured in the injectable small intestinal submucosa extracts (experimental group) and complete culture medium (control group). Cell survival was determined at 1, 3, 5 and 7 days of culture.
    RESULTS AND CONCLUSION: Scanning electron microscope oval and strip adipose- derived stem cells adhered onto the material. The absorbance values in the experimental group were higher than those in the control group at 1 and 5 days of incubation (P < 0.05). Cell survival: The number of cells appeared to be in a rising trend with time in both two groups; after 1-day co-culture, all cells in the two groups survived. Then dead cells appeared in both two groups, showing no significant difference. These results show that the injectable small intestinal submucosa exhibits a good cytocompatibility. 

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    Extracellular matrix-derived scaffolds for cartilage tissue engineering  
    Xiao Tong-guang, Zhang Yi-min, Guo Wei-min, Liu Shu-yun, Yang Jian-hua, Guo Quan-yi
    2016, 20 (38):  5737-5744.  doi: 10.3969/j.issn.2095-4344.2016.38.017
    Abstract ( 280 )   PDF (988KB) ( 240 )   Save

    BACKGROUND: At present, a variety of extracellular matrix-derived scaffolds have been successfully applied for cartilage tissue engineering in experiment and clinical practice.
    OBJECTIVE: To summarize the application and research status of extracellular matrix-derived scaffolds in cartilage tissue engineering.
    METHODS: A computer-based online search in PubMed, CNKI, CqVip and WanFang databases was performed using the keywords of “tissue engineering, cartilage, extracellular matrix, scaffolds” in English and Chinese, respectively. A total of 1 140 literatures were retrieved, and finally 65 eligible literatures were included.
    RESULTS AND CONCLUSION: In terms of the components, extracellular matrix-derived scaffolds are divided into monomeric natural polymers, mixed natural polymers, natural polymers compositing with synthetic polymers as well as acellular extracellular matrix-derived materials. Extracellular matrix-derived scaffolds hold good biocompatibility and degradability, and can promote proliferation and differentiation of choncrodytes; therefore, they as good bionic scaffolds have been applied for cartilage tissue engineering in clinical practice, However, poor mechanical properties and difficulty to molding should never be ignored. Further research should focus on improving the preparation technology by combining synthetic materials with extracellular matrix-derived scaffolds for cartilage tissue engineering. 

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    Collagen/silk fibroin nerve conduits used for repairing peripheral nerve defect: application and development
    Xu Yun-qiang, Liu Ying-jie, Li Rui-xin, Zhu Shuang-long, Zhang Zhen-hui
    2016, 20 (38):  5745-5751.  doi: 10.3969/j.issn.2095-4344.2016.38.018
    Abstract ( 244 )   PDF (971KB) ( 216 )   Save

    BACKGROUND: Peripheral nerve defect due to limb dysfunction has always been the difficulty faced by the medical profession. Ideal materials and processing technology for constructing a tissue engineering scaffold targeting peripheral nerve repair are still in research stage.
    OBJECTIVE: To review the research progress in peripheral nerve repair using collagen/silk fibroin nerve conduits.
    METHODS: In this paper, the first author retrieved the PubMed and CNKI from 2003 to 2016 to search articles regarding methods of constructing artificial nerve scaffolds and selection of raw materials. Data from these articles were collected, summarized and analyzed.
    RESULTS AND CONCLUSION: Forty-six articles were included for final analysis. Collagen and its degradation products trigger no inflammatory response in the host because of high biocompatibility and biodegradability. However, its use is largely limited by its rapid degradation and poor physical performance. Silk fibroin has a high flexibility and biocompatibility, and exhibits a slow degradation in vivo. As a rapid prototyping technique, three-dimensional printing can print various forms of scaffolds within a short time, characterized as high-quality pore structure and large-scale production. Given these, the collagen/silk fibroin nerve conduit prepared using the three-dimensional printing technology can maintain the biocompatibility and even improve the mechanical properties of the raw materials. Until now, more investigations on nerve repair using collagen or silk fibroin have been done, and we have never stopped improving the production process of these scaffolds. Therefore, the collagen/silk fibroin scaffold prepared using the three-dimensional printing technology is expected to become the main candidate for the repair of peripheral nerve defects. 

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    Social collaboration network analysis of animal-derived regenerative implantable medical devices: an overview based on Chinese literature from databases of CNKI, WANFANG DATA and VIP
    Yu Shu-yang, Wang Hong-man
    2016, 20 (38):  5752-5757.  doi: 10.3969/j.issn.2095-4344.2016.38.019
    Abstract ( 236 )   PDF (1548KB) ( 250 )   Save

    BACKGROUND: Tissue engineering involves many disciplines such as biology, material science, medicine and engineering, so, the collaboration among different research departments is becoming an important factor to enhancing research outputs with the rapid development of related sciences and technologies.
    OBJECTIVE: To draw the visualizing map of collaboration network of animal-derived regenerative implantable medical devices based on tissue engineering technology and describe its evolving process and current situation.
    METHODS: 2 518 Chinese literatures about the animal-derived regenerative implantable medical devices based on tissue engineering technology published before 31 December 2014 were searched in CNKI, WANFANG DATA and VIP. Subsequently, social network analysis was conducted on those literatures by utilizing UCINET software and SASI developed by Peking University.
    RESULTS AND CONCLUSION: The collaboration network of the animal-derived regenerative implantable medical devices has evolved from scattered to single-core dominated, and then to a core-edge one, characterized by increasing and extensive collaborations as well as decreasing network density and centralization. The core units from 2010 to 2014 include Tsinghua University, General Hospital of Chinese PLA and Affiliated Nanfang Hospital of South Medical University. Also, plenty of edge institutes exist. In conclusion, edge institutes should expand their scope of cooperation, while core institutes should improve their cooperation sustainability. Furthermore, cooperation among enterprises, research institutes and clinical hospitals should be strengthened to promote the industrialization of tissue engineering technology.

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    Hot-melt adhesives for medical applications
    Zheng Meng, Luo Xin, Chen Jing-ling, Shi Shu-xian, Liu Jian-dong, Chen Xiao-nong
    2016, 20 (38):  5758-5763.  doi: 10.3969/j.issn.2095-4344.2016.38.020
    Abstract ( 623 )   PDF (836KB) ( 405 )   Save

    BACKGROUND: Hot-melt adhesive is safe and environmental friendly adhesive due to free of solvent, which is particularly suitable for medical applications.
    OBJECTIVE: To describe the types and characteristics of currently used hot-melt adhesives and to prospect the technical research and development of hot-melt adhesive for polyolefin tubes or catheters as well as to point out the corresponding key points to the hot-melt adhesion.
    METHODS: Literature search was carried out in SCI, Elsevier, and CNKI with the key words of “hot melt adhesive, medical application” in English and Chinese, respectively, for the initial retrieval of relevant articles or patents published January 1995 to December 2015.
    RESULTS AND CONCLUSION: To date, the medical hot-melt adhesives reported in the literature could be grouped as amorphous polyolefin, thermoplastic elastomer, acrylic and polyurethane types. The heat resistance of the most of the hot-melt adhesives does not meet the requirement for steam sterilizing process. In the present review, a strategy is proposed to develop a novel hot-melt adhesive which is good for binding polyolefin parts and can undergo the sterilization process. Given this, it is essential to choose a kind of polypropylene random copolymer with a suitable melting point as a substrate. With the aid of an adjuvant agent, therefore, we can develop a novel hot-melt adhesive that exhibits a lower melting point than the polyolefin tube, withstands steam sterilization temperature to ensure that the tube is not deformed during melt adhesion and is not become invalid during sterilization. 

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    Peri-implantitis and diabetes mellitus
    Liu Jing, Zhu Guo-hui, Zhang En3 Sun Ying-chun
    2016, 20 (38):  5764-5769.  doi: 10.3969/j.issn.2095-4344.2016.38.021
    Abstract ( 346 )   PDF (891KB) ( 362 )   Save

    BACKGROUND: With the development of the oral cavity planting technology, dental implants have been strongly retained and stabilized, characterized as both aesthetic appearance and functional achievements. Especially, they are accepted by more and more patients due to no damage to adjacent teeth. However, diabetes may not only lead to periodontal disease, but also result in delayed healing of the oral mucosa and alveolar bone as well as infection.
    OBJECTIVE: To summarize the relationship between diabetes and peri-implantitis, and focus on the maintenance of dental implants for diabetic patients.
    METHODS: A computer retrieval of PubMed and CNKI databases was performed for relevant articles published from January 1980 to January 2016 using the keywords of “diabetes; peri-implantitis” in English and Chinese, respectively.
    RESULTS AND CONCLUSION: We confirm that diabetes is a relative contraindication to implant restoration, but the use of a series of methods that ensure the successful osseointegration, including blood glucose control, strictly prohibiting early loading or multi-implant restoration for single alveolar bone, anti-infection, implant surface modification, can make high success rate for diabetic patients. This brings the gospel to diabetic patients who hope to solve the problem of missing teeth by implant-supported prosthesis. 

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    Screening and application of drug-eluting stents in patients with cardiovascular diseases
    Wu Jin
    2016, 20 (38):  5770-5776.  doi: 10.3969/j.issn.2095-4344.2016.38.022
    Abstract ( 404 )   PDF (1273KB) ( 281 )   Save

    BACKGROUND: Drug-eluting stents have achieved better treatment outcomes, but late stent thrombosis shakes its status. With the development of drug-eluting stents, loaded drugs are the key to reduce stent thrombosis.
    OBJECTIVE: To analyze the screening and application of drug-eluting stents.
    METHODS: A computer-based search was performed for literatures published from 2010 to 2016 in databases of PubMed and WanFang using the keywords of “drug eluting stents; rapamycin (sirolimus); paclitaxel; heparin; zotarolimus; everolimus” in English and Chinese, respectively. According to inclusion and exclusion criteria, 30 eligible literatures were included for analysis.
    RESULTS AND CONCLUISON: An ideal drug-eluting stent can selectively inhibit vascular smooth muscle and is expected to be anti-coagulated, but makes no effects on vascular endothelial cells or promoting the cell proliferation. Most of the loaded drugs are antithrombotic and anti-proliferative drugs, among which, rapamycin-eluting and paclitaxel-eluting stents are extensively used. Regardless of delaying the proliferation of vascular endothelial cells and increasing the thrombosis risk, most of drug-eluting stents are still loaded with these two drugs, and only few stents loaded with rapamycin derivatives, such as everolimus, zotarolimus, tacrolimus and pimecrolimus. Current research focuses on developing a stent with rapid drug releasing and anti-proliferative capacity. Meanwhile, the combination of drugs and biphasic releasing are another novel idea. 

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