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    08 December 2021, Volume 25 Issue 34 Previous Issue    Next Issue
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    Preparation and degradation properties of concentrated growth factor fibrin membrane
    Xiao Deli, Sun Yinzhe, Cui Cheng, Liu Bo
    2021, 25 (34):  5413-5419.  doi: 10.12307/2021.232
    Abstract ( 209 )   PDF (1410KB) ( 28 )   Save
    BACKGROUND: The degradation time of biomaterials is crucial in the clinical application of guided bone regeneration surgery.

    OBJECTIVE: To systematically compare the difference in degradation performance of platelet-rich fibrin membrane and concentrated growth factor membrane in vitro, and analyze the effects of different machines of the same type and different blood collection tubes on the degradation performance of concentrated growth factor membrane.

    METHODS: Platelet-rich fibrin membranes and concentrated growth factor membranes were prepared with a Multi-CGF-3 centrifuge, and soaked in saliva to observe the changes in membrane quality and area. Two centrifuges of the same type were used to prepare concentrated growth factor membranes, which were then soaked in saliva to observe changes in membrane quality and area. Two types of vacuum blood collection tubes (BD tube and Kangjie tube) were used to prepare concentrated growth factor membranes, and the membranes were soaked in saliva to observe changes in membrane quality and area.
    RESULTS AND CONCLUSION: (1) The in vitro degradation performance of the platelet-rich fibrin membrane and concentrated growth factor membrane was different. The initial mass of the concentrated growth factor membrane was larger and its degradation time in vitro was longer. (2) The initial mass of the concentrated growth factor membranes prepared by different machines of the same type had no significant difference. The smaller the initial area-to-mass ratio, the slower the degradation rate of the concentrated growth factor membrane. (3) Compared with the Kangjie tube, the BD tube had a better layering effect on blood samples after centrifugation; however, the degradation time and overall degradation performance of concentrated growth factor membranes prepared by the two test tubes were similar. (4) The results show that, as the latest generation of autologous platelet-concentrated products, the concentrated growth factor membrane exhibits better degradation performance than the platelet-rich fibrin membrane. 


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    Osteogenesis using bone marrow mesenchymal stem cell sheets combined with three-dimensional printed Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol scaffold in vivo
    Liu Xiaoyuan, Li Lei, Zhang Kai, Li Jun, Han Xiangzhen He Huiyu
    2021, 25 (34):  5420-5426.  doi: 10.12307/2021.233
    Abstract ( 195 )   PDF (1345KB) ( 33 )   Save
    BACKGROUND: Cervus elaphus antler powder is a bone tissue engineering material with good biocompatibility and mechanical properties. The use of cell patch technology and three-dimensional (3D) printing technology to build tissue engineered bone can accomplish individualized treatment of limit bone defects.
    OBJECTIVE: To explore the ability and osteogenesis effect of bone marrow mesenchymal stem cell sheet combined with 3D printed Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol bone scaffold to repair the limit defect of sheep mandible.
    METHODS: The whole bone marrow method was used to cultivate sheep bone marrow mesenchymal stem cells, and the cell sheets technology and 3D printing technology were used to construct the bone marrow mesenchymal stem cell sheets combined with 3D printed Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol scaffold tissue engineered bone. Totally 12 Xinjiang Altay big-tail sheep were randomly divided into 1-, 2-, and 3-month groups (n=4 per group). An experimental bone defect area of 20 mm×3 mm×5 mm was prepared in the bilateral mandible edentulous area. Two sheep in each group were implanted with cell membrane combined with 3D printed Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol scaffold. Cell sheets combined with gelatin sponge was implanted on the other side. The other two sheep was composited with nano-hydroxyapatite/silk fibroin/polyvinyl alcohol scaffold, and the other side was implanted with cell sheets combined with gelatin sponge. The experimental animals were sacrificed at the end of 1, 2, and 3 months after implantation, and the mandible specimens were taken for gross observation, cone beam CT, histological observation, and RT-PCR to detect related osteogenic indicators. 
    RESULTS AND CONCLUSION: (1) Cone beam CT: At the end of the 1st and 2nd months, the bone defect area in the cell sheets compounded with Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol group was thin and cloudy; the scaffold absorbed more. The absorption of the cell sheets compounded with nano-hydroxyapatite/silk fibroin/polyvinyl alcohol group was relatively low. At the end of the 3rd month, a large amount of new bone was formed in the cell sheets composite Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol group, and the density was close to the surrounding bone; however, the bone defect area in the composite nano-hydroxyapatite/silk fibroin/polyvinyl alcohol group was not overgrown and the bone density was lower. The cell sheets composite gelatin sponge group did not change significantly within 3 months, and there was no new bone formation. (2) Histological observation: At the end of the 3rd month, compared with the other two groups, the scaffold material of the cell sheets composite Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol group was more absorbed, showing the regular arrangement of bone trabeculae and mature plate-like bone. There was also a small amount of new bone formation in the composite nano-hydroxyapatite/silk fibroin/polyvinyl alcohol group, and the cell sheets composite gelatin sponge group did not change significantly within 3 months. (3) RT-PCR: The mRNA expression levels of osteopontin, osteocalcin and type I collagen were higher than those of the other two groups in the cell sheets composite Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol group, and the expression of osteogenic genes reached the highest level at the third month. (4) The results show that the bone marrow mesenchymal stem cell sheets combined with 3D printed Cervus elaphus antler powder/silk fibroin/polyvinyl alcohol scaffold tissue engineered bone can repair the limit bone defect of the sheep mandible, and can meet the repair and reconstruction of the experimental sheep jaw defect.

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    Microstructure and mechanical properties of the new dental glass ceramics with different formulations
    Ren Shipeng, Chen Xinmin, Qing Song, Yu Jie, Yang Ting, Tang Wanrong
    2021, 25 (34):  5427-5431.  doi: 10.12307/2021.234
    Abstract ( 213 )   PDF (1816KB) ( 119 )   Save
    BACKGROUND: Through adjusting the base glass elements and process system, glass-ceramic with specific features can be expected to obtain. 
    OBJECTIVE: To prepare a self-formulated lithium disilicate glass-ceramic, and determine their mechanical properties and microstructures after crystallization. 
    METHODS: Using lithium disilicate as the basic composition of glass, G1, G2, and G3 glass base bodies were fabricated with different formulations by melting method. After burnishing and polishing, relative surface was kept parallel. The glass base bodies of No. G1, G2, and G3 were prepared by crystallization heat treatment (increase the temperature to 606 °C for 30 minutes, then 880 °C in speed of 10 °C/min as keeping the temperature for 30 minutes). The glass was burnished, polished, and dried. The glass base body of No. G1 without crystallization heat treatment was set as blank control. The bending strength, elastic modulus, Knoop hardness and microstructure of each group of glass-ceramic were measured in each group. 
    RESULTS AND CONCLUSION: (1) The bending strength and elastic modulus of G1, G2, and G3 glass ceramics were significantly higher than those of blank control group (P < 0.05), and there was no significant difference in bending strength and elastic modulus of G1, G2, and G3 glass ceramics (P > 0.05). (2) The Knoop hardness of G1, G2, and G3 glass ceramics was significantly higher than that of blank control group (P < 0.05), and there was no significant difference in Knoop hardness of G1, G2, and G3 glass ceramics (P > 0.05). (3) The results of scanning electron microscopy showed that the main crystal phase of G1, G2, and G3 glass ceramics was lithium disilicate, but the microstructures of those glass ceramics were changed by adjusting the processing formula. G1 and G3 glass ceramics have similar microstructure. The crystalline forms of the samples were rodlike crystals with uniform size and high crystal content. The crystalline form of G2 was flakes, inhomogeneous in size, and high in crystal content. (4) The results showed that the mechanic performance of this new type of glass-ceramic is close to IPS e.max Press, and it is a repair material with promising future.
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    Heat production and bacteriostatic effect of neodymium laser and semiconductor laser on cavity disinfection: in-vitro study
    Liang Xiaoyue, Zou Zhaohui, Dong Xiaoxi, Zhang Yu
    2021, 25 (34):  5432-5438.  doi: 10.12307/2021.235
    Abstract ( 204 )   PDF (877KB) ( 38 )   Save
    BACKGROUND: Local effective disinfection method can kill the bacteria to the maximum extent, so as to prevent the recurrence and development of caries. As a new technology, laser destroys the cell membrane of bacteria through its thermal and biological stimulation effects. 
    OBJECTIVE: To evaluate the safety and effectiveness of cavity disinfection with neodymium laser (Nd:YAP, Nd:YAG) and semiconductor laser (Diode). 
    METHODS: The intact premolars were collected and the isolated alveolar cavity model was prepared. Samples should be processed with Nd:YAP laser, 810 nm semiconductor (Diode), and Nd:YAG laser, separately. The pulp temperature was monitored by thermocouple temperature measuring instrument. The growth of Streptococcus mutans and Lactobacillus was observed by colony counting. 
    RESULTS AND CONCLUSION: (1) The pulp temperature increased with the increase of irradiation power. (2) At the same power, different laser disinfection, the temperature was increased and less than the pulp necrosis 5.5 °C, when the power was 1.8 and 4.0 W. Nd:YAP laser temperature was higher than Nd:YAG laser and semiconductor laser group (P < 0.05). (3) Colony count showed that with the same laser, the number of colonies decreased significantly with the increase of laser power; compared with the negative control group (normal saline group), the difference was statistically significant (P < 0.05). (4) There was no statistical difference between 1.8 W, 3.0 W, and 4.0 W groups and positive control group (5.25% NaClO solution) (P > 0.05). (5) The results show that, based on the principles of safety, effectiveness and minimum power, the optimal power that can be selected for the three kinds of lasers in the disinfection of cavities is 1.8 W.
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    Acellular bone matrix/chitosan scaffold combined with basic fibroblast growth factor for repairing bone defects
    Zhang Zhiwen, Huang Yuliang, Zhang Lixuan, Wang Xiaofeng, Chen Ruixiong
    2021, 25 (34):  5439-5444.  doi: 10.12307/2021.236
    Abstract ( 168 )   PDF (1124KB) ( 22 )   Save
    BACKGROUND: Some studies have shown that basic fibroblast growth factor can promote the proliferation and osteogenic differentiation of mesenchymal stem cells. 
    OBJECTIVE: To compare the ability of acellular bone matrix/chitosan scaffold combined with basic fibroblast growth factor in repairing rabbit femoral defect.
    METHODS: The acellular bone matrix/chitosan scaffolds were prepared by fusion blending and freeze-drying method, and the acellular bone matrix/chitosan scaffold loaded with basic fibroblast growth factor was prepared by immersion method. Mouse embryonic osteoblasts MC3T3-E1 were seeded on the surface of the two scaffolds for cell proliferation, cell adhesion and osteogenic gene detection. Cells cultured alone served as control. Bone defect models with a diameter of 5 mm were made in bilateral distal femurs using thirty-six 6-month-old New Zealand white rabbits and randomly divided into three groups by drawing lots. The blank group was not intervened. The simple composite scaffold and growth factor + composite scaffold groups were implanted with acellular bone matrix/chitosan scaffold and acellular bone matrix/chitosan scaffold loaded with basic fibroblast growth factor for X-ray and histological examination.
    RESULTS AND CONCLUSION: (1) Within 1-11 days of culture, the cell proliferation of basic fibroblast growth factor/acellular bone matrix/chitosan scaffold group was faster than that of the acellular bone matrix/chitosan scaffold group (P < 0.05), and that of the acellular bone matrix/chitosan scaffold group was faster than that of the control group (P < 0.05). (2) After 4 days of co-culture with the scaffold, the mRNA expressions of type I collagen, osteocalcin, osteopontin and Runx2 were higher in the cells in basic fibroblast growth factor/acellular bone matrix/chitosan scaffold group cultured for 4 and 7 days than those of acellular bone matrix/chitosan scaffold group (P < 0.05), and the mRNA expression of alkaline phosphatase was higher than that of acellular bone matrix/chitosan scaffold group after 7 days of culture (P < 0.05). (3) Scanning electron microscopy showed that the scaffolds of the two groups supported the adhesion of MC3T3-E1 cells after 7 days of co-culture. (4) X-ray film of animal experiment showed that there was no obvious bone repair in the blank group at 12 weeks after operation; new bone formation could be seen at 8 weeks after operation in the simple composite scaffold group, and obvious new bone formation could be seen at 12 weeks after operation; new bone formation could be seen at 4 weeks after operation in the cytokine + composite scaffold group, and the bone defect site was almost completely repaired at 12 weeks after operation (5) Hematoxylin staining and Masson staining showed that a large amount of fibrous tissue could be seen in the blank group at 12 weeks after operation; a large amount of new bone formation could be seen in the two scaffold groups, in which the area and maturity of new bone formation in the growth factor + composite scaffold group were higher than those in the simple composite scaffold group. (6) The results showed that the acellular bone matrix/chitosan composite scaffold loaded with basic fibroblast growth factor is an ideal bone tissue repair material, which can promote bone formation.
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    Cartilage composite scaffold loaded with transforming growth factor beta 3 using three-dimensional bioprinting
    Yang Zhen, Li Hao, Fu Liwei, Gao Cangjian, Jiang Shuangpeng, Wang Fuxin, Yuan Zhiguo, Sun Zhiqiang, Zha Kangkang Tian Guangzhao, Cao Fuyang, Sui Xiang, Liu Shuyun, Guo Quanyi
    2021, 25 (34):  5445-5452.  doi: 10.12307/2021.237
    Abstract ( 248 )   PDF (1408KB) ( 47 )   Save
    BACKGROUND: The therapeutic strategy of in situ regeneration of cartilage injury by recruiting endogenous stem cells is a new research direction of cartilage tissue engineering in the future.
    OBJECTIVE: To construct a tissue engineering cartilage composite scaffold that can not only recruit stem cells, promote cell adhesion and proliferation, but also be beneficial to the maturation of neo-tissue.
    METHODS: Acellular cartilage extracellular matrix (ECM) and methacrylate gelatin (GelMA) were mixed to prepare photosensitive bio-ink, and three-dimensional bioprinting technology was used to prepare polycaprolactone (PCL) scaffolds and PCL/GelMA/ECM scaffolds. Transforming growth factor β3 (TGF-β3) was loaded into bio-ink to prepare PCL/GelMA/ECM/TGF-β3 scaffold, and its sustained release performance was tested. The physical and chemical properties of PCL/GelMA/ECM scaffolds were evaluated from the point of view of morphology, histology, biochemistry and biomechanics. CCK-8 assay was used to detect the cytotoxicity of PCL/GelMA/ECM scaffolds. After adipose-derived mesenchymal stem cells were seeded on PCL/GelMA/ECM scaffold for 1, 4 and 7 days, the cell viability was observed by confocal microscope and the cell adhesion was observed by scanning electron microscope. PCL/GelMA/ECM scaffolds were implanted subcutaneously in SD rats, and the infiltration of inflammatory cells and the degradation of scaffolds were observed histologically. The effects of PCL/GelMA/ECM scaffold and PCL/GelMA/ECM/TGF-β3 scaffold on the migration of adipose-derived mesenchymal stem cells were detected by Transwell chamber test, and the cells cultured alone were used as negative control.
    RESULTS AND CONCLUSION: (1) The PCL/GelMA/ECM scaffolds had a three-dimensional porous reticular structure, without cellular components, contained cartilage-specific components such as type II collagen and glycosaminoglycan and its elastic modulus was (14.24±2.44) MPa. (2) PCL/GelMA/ECM scaffolds showed no obvious cytotoxicity. (3) Adipose-derived mesenchymal stem cells were adhered closely to the PCL/GelMA/ECM scaffolds, had good cell activity and could secrete extracellular matrix. (4) One week after PCL/GelMA/ECM scaffolds were implanted subcutaneously in rats, there was a mild acute inflammatory reaction, and the inflammatory reaction was alleviated after 3 weeks, and the scaffolds were gradually degraded. (5) PCL/GelMA/ECM/TGF-β3 scaffold had good sustained release performance, and TGF-β3 could be released continuously for 60 days. (6) Compared with the negative control group, PCL/GelMA/ECM scaffolds and PCL/GelMA/ECM/TGF-β3 scaffolds could promote the migration of adipose-derived mesenchymal stem cells, and PCL/GelMA/ECM/TGF-β3 scaffold could promote the migration of adipose-derived mesenchymal stem cells more significantly. (7) The results showed that three-dimensional printing PCL/GelMA/ECM/TGF-β3 scaffolds could promote the proliferation, adhesion and migration of adipose-derived mesenchymal stem cells.
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    Effect of high-concentration H2O2 immersion and ultrasonic treatment with different durations on interfacial bonding strength of fiber post and resin
    Dong Yi, Deng Jiupeng, Fan Xinhao, Xi Guangwei
    2021, 25 (34):  5453-5458.  doi: 10.12307/2021.238
    Abstract ( 186 )   PDF (3208KB) ( 29 )   Save
    BACKGROUND: H2O2 treatment had been proven to be effective for enhancing the bonding strength of fiber pile-resin, with a time-consuming process.  
    OBJECTIVE: To compare the effects of pure H2O2 treatment or combined with ultrasonic cleaning of core piles with different durations on the interfacial bonding strength of fiber post-resin.
    METHODS:  Totally 65 glass fiber posts were randomly divided into five groups (n=13 per group): group A: pure silanization treatment; group B: immersed in 30% H2O2 solution for 15 minutes and then received silanization; 30% H2O2 solution immersion with ultrasonic washing for 2 minutes (group C), 5 minutes (group D) or 15 minutes (group E), respectively, then received silanization treatment. The surface roughness and fiber fracture of each specimen were observed by scanning electron microscope. The PP plastic straw was used as the external plastic support, filled with resin bonding material and inserted into the processed fiber post to make the test piece. Three slices with a thickness of 1.5 mm were cut from each fiber post specimen by diamond grinder, which was used to conduct wafer rush-out test, and the fracture of the slices was observed under anatomic microscope.  
    RESULTS AND CONCLUSION: (1) Scanning electron microscope: Resin materials on the surface of the group A were evenly distributed, with smooth surface and rare fracture. In group B, surface was rough, and a lot of broken glass fibers were observed; a large number of grooves were left after glass fiber fracture, and the inner part of the groove was relatively smooth. In group C, the surface of the fiber post was rough, with a small amount of broken glass fiber and remaining grooves, and the grooves were rough inside. The surface roughness of fiber post was greater in group D than that of group C, and a large number of broken glass fibers and remaining grooves were observed. The inner roughness of the grooves was relatively rough. The surface roughness of the fiber post in group E was similar to that in group D; and there were a large number of broken glass fibers and remaining grooves, while the interior of the grooves was smooth. (2) Push-out test results showed that the bonding strength of group C was significantly higher than that of groups A, B and E (P < 0.05), and that of group D was significantly higher than that of group E (P < 0.05), and the difference between the other groups was not significant (P > 0.05). (3) The fracture mode of the thin section in groups C and D was significantly different from that in group A (P  <  0.05). (4) The results showed that the fiber posts treated with 30% H2O2 combined with ultrasonic wash for 2 minutes could significantly improve the bonding strength of the fiber post-resin interface.
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    Three-dimensional electrohydrodynamic printing of attapulgite/polycaprolactone scaffolds and osteogenic differentiation ability in vitro
    Li Chenkai, Qin Wen, Liu Chun, Chen Wenyang, Zhao Hongbin
    2021, 25 (34):  5459-5464.  doi: 10.12307/2021.239
    Abstract ( 202 )   PDF (1254KB) ( 28 )   Save
    BACKGROUND:  The polycaprolactone nanofiber scaffolds prepared by electrostatic spinning have a structure resembling extracellular matrix, but it is not conducive to cell adhesion, migration, proliferation and differentiation due to the poor hydrophilicity.
    OBJECTIVE: To fabricate attapulgite/polycaprolactone scaffolds via three-dimensional (3D) electrohydrodynamic printing and evaluate the biological effects and osteogenic induction ability on mouse bone marrow mesenchymal stem cells. 

    METHODS: Attapulgite/polycaprolactone scaffolds with different concentration of attapulgite (0%, 0.5%, 1%, 2%) were prepared by 3D electrohydrodynamic, and the morphology and structure were observed by scanning electron microscope. The mouse bone marrow mesenchymal stem cells were co-cultured with four groups of scaffolds. The growth and morphology of bone marrow mesenchymal stem cells were observed with scanning electron microscope and Live/Dead staining at 7 and 2 days, respectively. The proliferation of bone marrow mesenchymal stem cells was detected by CCK-8 assay at 1, 3 and 5 days. The mRNA expression levels of osteogenic marker genes were detected by real-time PCR at 3, 7, and 14 days. Alkaline phosphatase activity was detected at 3, 7 and 10 days of co-culture. 

    RESULTS AND CONCLUSION: (1) Scanning electron microscopy results showed that four groups of scaffolds presented macropore morphology with the pore size of about 450 μm, and the surfaces of 0% and 0.5% attapulgite were smooth, while the scaffold surfaces in 1% and 2% attapulgite groups were rough. (2) Scanning electron microscopy showed that cells adhered and grew well on the surface of these scaffolds, and there were more cells grow in 1% attapulgite group than in other groups. (3) Live/Dead staining showed that cells adhered and grew well on the surface of four groups of scaffolds, among which 2% attapulgite group had the least cells. (4) The results of CCK-8 assay showed that the cell proliferation rate of 0.5% attapulgite group was higher than that of the other groups. (5) Real-time PCR showed that the expressions of alkaline phosphatase, osteocalcin, osteoblast-specific transcription factor and Runx-2 genes in 0.5% attapulgite group for 14 days were higher than those in the other groups. (6) The alkaline phosphatase activities of 0.5%, 1% and 2% attapulgite groups were all higher than 0% attapulgite group, in which the 0.5% attapulgite group was the highest at 3 and 7 days but 1% and 2% attapulgite groups were higher than other groups at 10 days of co-culture. (7) The 0.5% attapulgite scaffold has better biocompatibility and osteogenic induction potential.

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    Effect of modified citrus pectin on chondrocytes
    Zhang Yiyun, Wang Ziqiang, Ren Ying, Du Fuchong, Du Bo, Li Xuemin
    2021, 25 (34):  5465-5472.  doi: 10.12307/2021.240
    Abstract ( 289 )   PDF (1492KB) ( 26 )   Save
    BACKGROUND: Galectin-3 is an important proinflammatory factor during articular cartilage injury and the development of osteoarthritis. Therefore, it could be a potential target for the treatment of osteoarthritis. Modified citrus pectin is a competitive inhibitor of galectin-3. However, the effect of modified citrus pectin on cartilage is not unclear.
    OBJECTIVE: To investigate the effect of modified citrus pectin on the metabolic activity and genes expression of in vitro cultured chondrocytes and interleukin-1β induced osteoarthritis chondrocytes. 
    METHODS: (1) Chondrocytes from rabbit knee were collected and subjected to the treatment of modified citrus pectin of 0 (normal control), 250, 500 or 750 mg/L respectively for 1, 3, and 5 days. (2) Posttreatment experiment of modified citrus pectin: Chondrocytes of rabbit knee were collected. Chondrocytes were pretreated by interleukin-1β for 24 hours, then posttreated with modified citrus pectin of 0 (control), 250, 500 or 750 mg/L respectively for 1, 3, and 5 days. At the same time, a normal control group was set up. (3) Pretreatment experiment of modified citrus pectin: Chondrocytes of rabbit knee were collected. Chondrocytes were pretreating with modified citrus pectin of 0 (control), 250, 500 or 750 mg/L respectively for 6 hours and following by posttreating by interleukin-1β for 1, 3, and 5 days. At the same time, a normal control group was set up. At the corresponding time point, the mRNA levels of type II collagen, aggrecan, SOX9, type I collagen, matrix metalloproteinase 13 and galectin-3 were determined via RT-qPCR. Furthermore, immunofluorescence staining was conducted to examine the synthesis of type II collagen of chondrocytes.
    RESULTS AND CONCLUSION: (1) Compared with normal control group, modified citrus pectin treatment with different mass concentrations significantly enhanced chondrocyte viability, upregulated mRNA of SOX9 and type II collagen, and downregulated mRNA of type I collagen, matrix metalloproteinase 13 and galectin-3. (2) Compared with normal control group, interleukin-1β treatment induced downregulation of expression levels of aggrecan, SOX9, and type II collagen, and upregulation of expression levels of galectin-3 and matrix metalloproteinase 13. (3) Compared with interleukin-1β treated groups, interleukin 1β pretreatment + modified citrus pectin treatment up-regulated the expression levels of type II collagen, aggrecan and SOX9, and decreased the expression levels of galectin-3, matrix metalloproteinase 13 and type I collagen. Modified citrus pectin + interleukin 1β posttreatment up-regulated the expression of type II collagen, aggrecan and SOX9, and decreased the expression of type I collagen, galectin-3 and matrix metalloproteinase 13, but up-regulated type II collagen and aggrecan expression levels failed to reach normal cartilage levels. (4) In summary, under the experimental conditions, modified citrus pectin could enhance the proliferation activity of chondrocytes and maintain their phenotype. At the same time, the intervention of modified citrus pectin can change the gene expression of interleukin 1β-induced chondrocytes, and up-regulate the expression of cartilage cell extracellular matrix synthesis and cartilage formation transcription factor-related genes, and down-regulate the expression levels of catabolism, inflammatory factors and dedifferentiation related genes.
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    Effect of Kartogenin/Pluronic F127 micelles on osteogenic differentiation of bone marrow mesenchymal stem cells
    Chen Dong, Jiang Xin
    2021, 25 (34):  5473-5477.  doi: 10.12307/2021.241
    Abstract ( 220 )   PDF (834KB) ( 19 )   Save
    BACKGROUND: The small molecule drug Kartogenin is an activator of the Smad4/Smad5 pathway. It has a strong ability to promote bone differentiation and can promote the directional differentiation of bone marrow mesenchymal stem cells into osteoblasts, but its drug effect is relatively limited.
    OBJECTIVE: We designed and developed Kartogenin/Pluronic F127 micelles to observe its effect on the directional osteogenic differentiation of bone marrow mesenchymal stem cells.
    METHODS: Kartogenin was dissolved in dimethyl sulfoxide and mixed with Pluronic F127 solution. The organic solvent was removed by vacuum rotary evaporator to form a dry drug lipid membrane. PBS was added to prepare Kartogenin/Pluronic F127 micelles. The bone marrow mesenchymal stem cells of rats in the logarithmic growth phase were divided into four groups, which were treated with conventional cell culture medium (blank group), cell culture medium containing Pluronic F127 micelle solution (Pluronic F127 group), cell culture medium containing Kartogenin (drug group), and cell culture medium containing Kartogenin/Pluronic F127 micelle solution (experimental group). Among them, the drug concentration in the drug group and the experimental group was          1 μmol/L, and the micelle concentration in Pluronic F127 group was the same as that in the experimental group. Cell proliferation, apoptosis and expression of osteogenic related proteins were detected.
    RESULTS AND CONCLUSION: (1) Transmission electron microscope revealed that Kartogenin/Pluronic F127 micelles had irregular spherical shape and uniform particle size distribution. The particle size ranged from 32.6 nm to 118.9 nm, most of which were concentrated at 77.3 nm. (2) MTT assay showed that with the extension of culture time, the cell survival rate of the four groups decreased, but remained above 90%, and there was no significant difference in the cell survival rate among the four groups (P > 0.05). (3) Flow cytometry after 24 hours of treatment showed that there was no significant difference in the cell apoptosis rate among the four groups (P > 0.05). (4) After 24 hours of treatment, western blot assay showed that the expression levels of osteopontin, alkaline phosphatase, bone morphogenetic protein-2 and matrix metalloproteinase-2 in drug group and experimental group were higher than those in Pluronic F127 micelle group and blank group (P < 0.05). The expression levels of alkaline phosphatase, bone morphogenetic protein-2 and matrix metalloproteinase-2 in experimental group were higher than those in drug group (P < 0.05). (5) The results showed that Kartogenin/Pluronic F127 micelles could promote the osteogenic differentiation of bone marrow mesenchymal stem cells.
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    Correlation between puncture-side bone cement/vertebral body volume ratio and bone cement paravertebral vein leakage in vertebroplasty
    Gao Tao, Li Tao, Hu Haigang, Yuan Dechao, Wu Fan, Zeng Jun, Wu Chao, Lin Xu
    2021, 25 (34):  5478-5483.  doi: 10.12307/2021.242
    Abstract ( 156 )   PDF (784KB) ( 16 )   Save
    BACKGROUND: The current research on bone cement leakage in the paravertebral vein mainly focuses on the puncture site, vertebral body blood vessel distribution and bone cement/vertebral body volume ratio. However, there have been no relevant reports about the effect of puncture-side bone cement/vertebral body volume ratio on cement leakage in the paravertebral vein in and outside China. 
    OBJECTIVE: To explore the influencing factors of bone cement paravertebral vein leakage in the treatment of osteoporotic compression fractures by vertebroplasty, and to verify the correlation between puncture-side bone cement/vertebral body volume ratio and bone cement paravertebral vein leakage. 
    METHODS: Data of 357 patients (425 vertebral bodies) with osteoporotic vertebral compression fractures treated from August 2018 to April 2020 in Zigong Fourth People’s Hospital were retrospectively analyzed. Postoperative X-ray and CT data were observed to determine whether the vertebral body has paravertebral vein leakage. Mimics software was used to import the patient’s postoperative CT data into the software. The 3D reconstruction function was applied to calculate the bone cement/vertebral body volume ratio, puncture-side bone cement/vertebral body volume ratio. The sex, age, body mass index, bone density, bone cement volume, bone cement volume of the puncture side, vertebral volume, bone cement/vertebral volume ratio, puncture-side bone cement/vertebral volume ratio were compared between the leaked group and the non-leaked group. Logistic regression analysis was used to compare the correlation between the factors with statistical significance between the two groups and the leakage of paravertebral veins. A ROC curve was drawn for the diagnosis of paravertebral vein leakage with statistically significant factors. 
    RESULTS AND CONCLUSION: (1) There were 42 cases of paravertebral vein leakage (43 vertebral bodies). There were 315 patients (382 vertebral bodies) without paravertebral vein leakage. (2) Univariate analysis showed that the differences in sex, bone density, bone cement volume of the puncture side, and puncture-side bone cement/vertebral volume ratio of the leaked and non-leaked groups were statistically significant (P < 0.05). (3) Logistic regression analysis showed that there was a correlation between sex, puncture-side bone cement volume, puncture-side bone cement/vertebral body volume ratio and paravertebral vein leakage (P < 0.05). (4) The ROC curve showed that the area of the punctured bone cement/vertebral body volume ratio for the diagnosis of paravertebral vein leakage was greater than 0.6, and P < 0.05, which had certain diagnostic value. The best cut-off point for the diagnosis of paravertebral vein leakage with puncture side bone cement/vertebral volume ratio was 13.33%, sensitivity was 81.4%, and specificity was 26.2%. (5) The sex, bone density, puncture-side bone cement volume, puncture-side bone cement/vertebral body volume ratio are risk factors for vertebroplasty treatment of paravertebral vein leakage in osteoporotic vertebral compression fractures, of which puncture-side bone cement/vertebral body volume ratio with paravertebral venous leakage is closely related, and the optimal puncture-side bone cement/vertebral body volume ratio is 13.33%. When the puncture-side bone cement/vertebral body volume ratio exceeds the optimal value, the risk of paravertebral vein leakage is significantly increased.
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    Poly(lactide-co-glycolide) scaffold combined with adipose derived stem cells in tissue-engineered urethral reconstruction
    Li Zuowei, Fu Qiang, Song Lujie, Li Yonghui, Tian Binqiang
    2021, 25 (34):  5484-5489.  doi: 10.12307/2021.243
    Abstract ( 169 )   PDF (829KB) ( 16 )   Save
    BACKGROUND: The combination of bioelectrospray and electrospinning can promote the direct integration of living cells and scaffold materials, and can distribute the cells evenly among scaffold fibers, which is a promising alternative to the preparation of scaffold containing cells.
    OBJECTIVE: To investigate the feasibility using multiple methods to prepare poly(lactide-co-glycolide) (PLGA) three-dimensional scaffolds rich in adipose derived stem cells (ASCs) as urethral tissue reconstruction materials.
    METHODS: The ASCs were integrated into PLGA by electrospinning and cell bio-electrospray method. The cell scaffold PLGA-ASCs was obtained. The pure PLGA scaffold was prepared by electrospinning. The microstructure, in vitro degradation, mechanical properties and residual solvent content of the two scaffolds were detected. The cell viability of PLGA-ASCs was detected by MTT assay. PLGA-ASCs were cultured in 37°C cell incubator for 1, 7 and 15 days. MTT assay was used to detect cell viability. Scanning electron microscopy and confocal microscopy were used to observe the growth and diffusion of ASCs on the scaffolds.
    RESULTS AND CONCLUSION: (1) Scanning electron microscopy showed that the fiber surface of PLGA-ASCs and PLGA scaffolds was smooth, and ASCs were randomly distributed on PLGA-ASCs scaffolds. The average fiber diameter and thickness of PLGA-ASCs scaffolds were larger than those of PLGA scaffolds. The cell survival rate in PLGA-ASCs scaffolds was (87.0±4.4)%, and the cell integration efficiency in PLGA-ASCs scaffolds was 28%. (2) In vitro degradation experiment showed that weight average molecular weight of PLGA scaffolds decreased rapidly in the first 15 days. The weight average molecular weight of PLGA-ASCs scaffolds decreased rapidly on 15-45 days. There was no difference in weight average molecular weight between the two groups at 45 days. (3) Young’s modulus, maximum load, and maximum elongation of PLGA-ASCs scaffolds were lower than those of PLGA scaffolds. (4) During 1-7 days of culture, the number of cells in PLGA-ASCs scaffolds gradually increased, and the number of cells in PLGA-ASCs scaffolds increased gradually from 7 to 15 days. (5) The results of scanning electron microscope observation and confocal microscope showed that the number of cells in PLGA-ASCs scaffolds increased gradually and integrated with the scaffolds with the extension of culture time. (6) The results showed that PLGA-ASCs had good physical and chemical properties and biological activity, and could be used as urethral tissue reconstruction materials.
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    Percutaneous vertebroplasty with mesh-hold in the treatment of spinal metastases with extensive destruction of cortical bone
    Li Yuwei, Wang Haijiao, Cui Wei, Zhou Peng, Li Cheng, Xiao Wei, Hu Bingtao, Li Fan
    2021, 25 (34):  5490-5494.  doi: 10.12307/2021.244
    Abstract ( 185 )   PDF (1027KB) ( 11 )   Save
    BACKGROUND:  Percutaneous vertebroplasty is a palliative treatment for spinal metastases. However, cement leakage is common in patients with extensive destruction of cortical bone (≥ 1/3). Therefore, it is a relative contraindication that the posterior margin of cortical bone of vertebral body is incomplete in the metastases of thoracolumbar spine.
    OBJECTIVE:  To observe the safety and efficacy of percutaneous vertebroplasty with mesh-hold in the treatment of spinal metastases with extensive destruction of cortical bone.
    METHODS:  Twenty-one patients suffered from spinal metastases with destruction of cortical bone of vertebral body were treated with percutaneous vertebroplasty with mesh-hold in the Luohe Central Hospital from January 2013 to January 2018 and radiotherapy of the involved vertebrae after operation, including 10 males and 11 females at the age of 42-87 years. Before operation, 3 days and 6 months after operation, X-ray films were taken to measure the height of anterior edge of diseased vertebrae. Visual analogue scale was used to evaluate the pain. Abilities of daily life scale was used to evaluate the quality of life. Oswestry disability index was used to evaluate the changes of neurological function. This study was approved by the Ethics Committee of Luohe Central Hospital (approval No. LH-KY-2013-002-117).
    RESULTS AND CONCLUSION:  (1) All the 21 patients completed the operation successfully. During bone cement injection into the mesh-hold, the bone cement oozed out into the bone trabecula through the mesh hole in a linear fashion when the mesh-hold expanded to a certain extent, and the vertebral body was elevated to a certain degree simultaneously. (2) The follow-up period ranged from 6 to 21 months. No leakage of bone cement to the front of vertebra, intervertebral disc or spinal canal, no vascular embolism, pulmonary embolism or wound infection occurred. (3) The height of anterior edge of vertebra was higher at 3 days and 6 months after operation than that before operation in 21 patients (P < 0.05). Visual analogue scale scores were lower at 3 days and 6 months after operation than that before operation (P < 0.05). Abilities of daily life scale and Oswestry disability index were lower at 6 months after operation than that before operation (P < 0.05). (4) These findings suggested that for the patients suffered from spinal metastases who have lost the chance of complete resection, even if there is extensive destruction of vertebral cortical bone (accounting for more than 1/3 of the whole vertebral cortical bone), percutaneous vertebroplasty with mesh-hold can still be performed. Its safty is high, and it can not only effectively reduce local pain, maintain the height of the vertebral body, delay the collapse of the vertebral body, but avoid the leakage of bone cement.
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    Comparison of three kinds of bone replacement materials in the treatment of bone defects around the mandibular posterior teeth with immediate implantation
    Xiao Sha, Gao Chengzhi, Zhou Dongping
    2021, 25 (34):  5495-5500.  doi: 10.12307/2021.245
    Abstract ( 210 )   PDF (663KB) ( 22 )   Save
    BACKGROUND:  Guided bone regeneration is an effective method to solve bone defects in the implant area, but the choice of bone replacement material is still controversial.
    OBJECTIVE: To investigate the treatment effect of different materials in the bone defects around the mandibular posterior teeth with immediate implantation. 
    METHODS: From May 2016 to January 2019, 138 patients with bone defects around the mandibular posterior teeth, who were admitted to the Department of Stomatology in Peking University People’s Hospital, were selected. The patients were divided into three groups by random number table method, and were respectively implanted Bio-oss, Bone Plant, and PerioGlas bone replacement materials during immediate implantation, with 46 cases in each group respectively. Postoperative regular follow-up was conducted to compare the implant success rate, marginal bone level, buccal-lingual bone plate width, vertical height, periodontal index, and patient satisfaction in the three groups. This study had been approved by the Ethics Committee of Peking University People’s Hospital, approval No. [Ethical approval(R20160412)]. 
    RESULTS AND CONCLUSION: (1) The success rate of implants in the Bone Plant group was higher than that in the PerioGlas group 12 months after PerioGlas operation (P < 0.05), but there was no significant difference between other groups (P > 0.05). (2) The edge bone levels of the Bio-OSS group and the Bone Plant group were lower than those in the PerioGlas group (P < 0.05). The width and vertical height of the buccal lingual bone plate were higher than those in the PerioGlas group (P < 0.05). The vertical height of the Bone Plant group at 6 and 12 months after operation was higher than that of the Bio-Oss group (P < 0.05), and there was no significant difference in the horizontal edge bone and the width of the buccal-lingual bone plate between the two groups (P > 0.05). (3) At 6 and 12 months after the operation, there was no significant difference in the depth of periodontal probe, the positive rate of exploratory bleeding and the gingival index between the three groups (P > 0.05). (4) There was no significant difference in patient satisfaction between the three groups (P > 0.05). (5) The results showed that the Bio-OSS, PerioGlas, and Bone Plant all had certain effects of inducing bone regeneration and osteogenesis, while the Bio-OSS absorbed slowly but maintained a certain bone plate width, and the Bone Plant maintained a good vertical height and space stability of bone defect, making it an ideal bone replacement material.
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    Long-term effects and adverse events of polyetheretherketone versus titanium mesh materials in repairing skull defects: a prospective, single-center, non-randomized controlled, 2-year follow-up clinical trial protocol
    Zhang Feng
    2021, 25 (34):  5501-5505.  doi: 10.12307/2021.246
    Abstract ( 185 )   PDF (632KB) ( 15 )   Save
    BACKGROUND: Polyetheretherketone and titanium mesh are commonly used in skull repair, but there is no clinical trial evidence of long-term (such as 2 years after operation) repair effect and safety comparison between the two materials.
    OBJECTIVE: To evaluate the long-term effect and adverse events of polyetheretherketone and titanium mesh in repairing skull defects.
    METHODS: This is a prospective, single-center, non-randomized controlled, 2-year follow-up clinical trial. Sixty inpatients scheduled for skull repair in the Fourth Affiliated Hospital of China Medical University will be enrolled and divided into two groups according to different intraoperative skull repair materials. Polyetheretherketone and titanium mesh materials will be used in the trial and control groups, respectively (n=30 per group). All patients will be followed up for 6, 12, and 24 months. This trial was approved by the Medical Ethics Committee of the Fourth Affiliated Hospital of China Medical University on February 1, 2021 (approval No. EC-2021-HS-002). This trial meets the requirements of the Declaration of Helsinki formulated by the World Medical Association. All patients are required to sign an informed consent form. The recruitment time will be from August 1, 2021 to August 1, 2022. Result analysis time will be from September 1, 2024 to September 30, 2024. Completion time will be October 31, 2024.
    RESULTS AND CONCLUSION: Primary outcome measure is rate of failure in skull repair at 24 months after surgery. Secondary outcome measures are rate of failure in skull repair at 6 and 12 months after surgery; the incidence of adverse events to assess safety of implant materials; Glasgow Outcome Scale scores to evaluate the recovery of neurological function; satisfaction score for body shaping to assess skull shaping effect; and head CT imaging to assess skull injury healing at 6, 12, and 24 months after surgery. Cost-effectiveness ratio and incremental cost-effectiveness ratio will be used to assess the difference in cost effectiveness of the two materials at 6, 12, and 24 months after surgery. The trial hopes to prove that compared with titanium mesh, the use of polyetheretherketone for skull repair has a better repair effect for 2 years, a lower incidence of adverse events, better biocompatibility, and obvious advantages in long-term efficacy and security. This study was registered with the Chinese Clinical Trial Registry on February 27, 2021 (registration number: ChiCTR2100043703). Study protocol version is 1.0.
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    Application of polycaprolactone-based biopolymer scaffolds in tissue engineering
    Wang Pei
    2021, 25 (34):  5506-5510.  doi: 10.12307/2021.247
    Abstract ( 213 )   PDF (797KB) ( 35 )   Save
    BACKGROUND: Polycaprolactone is a kind of excellent biomedical materials, which exhibits desirable biocompatibility and biodegradability.
    OBJECTIVE: To review different methods for preparing of polycaprolactone-based scaffolds for tissue engineering. 
    METHODS: “Tissue engineering, scaffold, PCL” as English and Chinese search terms were searched in American Chemical Society and CNKI for articles on the preparation technology of polycaprolactone scaffolds and their applications in tissue engineering.
    RESULTS AND CONCLUSION: Polycaprolactone is a kind of desirable materials for tissue engineering scaffolds. Scaffold with different structures can be prepared by technical means such as particulate leaching, gas foaming, freeze-drying, electrospinning, and bioprinting. Polycaprolactone-based scaffolds can be used to repair or replace skin tissue, bone tissue, heart tissue and nerve tissue, playing an important role in reducing patients’ suffering and prolonging life. However, the biological properties of this type of scaffolds, such as cell adhesion, cell proliferation, and metabolic transmission, still need to be improved. Therefore, the material structure and function of tissue engineering scaffolds have become an important research direction in the future.
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    Metagenomics and peri-implantitis
    Liu Guanjuan, Song Na, An Zheqing, Sun Jing, Liao Jian
    2021, 25 (34):  5511-5516.  doi: 10.12307/2021.248
    Abstract ( 200 )   PDF (606KB) ( 28 )   Save
    BACKGROUND: At present, the microorganisms associated with peri-implantitis are not completely clear. As a method of studying microbial diversity without culture, metagenomics is gradually applied to the study of oral microorganisms.
    OBJECTIVE: To review the application of metagenomics in peri-implantitis.
    METHODS: The first author searched PubMed, WILEY, Web of Science and CNKI databases using computer for relevant articles published from January 1998 to August 2020. The search terms were “metagenomics, high-throughput sequencing, peri-implantitis, next-generation sequencing” in English and Chinese, respectively. The articles related to metagenomics and peri-implantitis were reviewed. 
    RESULTS AND CONCLUSION: Peri-implantitis may be caused by multi-bacterial infection, and its pathogenesis is still unclear. Metagenomics, as a method of identifying microorganisms without culture, extracts DNA from all samples in a specific environment, and then compares them with the established genomic library. All the genetic materials in the samples were analyzed, and the composition and community characteristics of microorganisms were studied. Culturomics is a method that uses a variety of culture conditions to culture bacteria. It uses matrix assisted laser desorption ionization time-of-flight mass spectrometry to identify microbical species. Although metagenomics and culturomics are different analysis methods, the aim is the same; that is, to detect as many microbial species as possible in a specific ecosystem. Metagenomics, combined with molecular analysis technology and culturomics used in the study of peri-implantitis, will accelerate the process of understanding peri-implantitis, and metagenomics will be improved with the understanding process of peri-implantitis.
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    Biological advantages of biodegradable microspheres in bone regeneration
    Ma Shiqing, Wang Jie, Gao Ping, Liu Zihao
    2021, 25 (34):  5517-5522.  doi: 10.12307/2021.249
    Abstract ( 214 )   PDF (659KB) ( 26 )   Save
    BACKGROUND: Biodegradable microspheres, which release the functional modification factors encapsulated in them through self-degradation, can improve the drug solubility, half-life and other properties. They are widely used in the research of bone defect repair and regeneration.
    OBJECTIVE: To review and summarize the application of biodegradable microspheres in bone regeneration, the advantages and disadvantages of various materials used to prepare microspheres, as well as the new technology and modification methods of microspheres.
    METHODS: CNKI, Wanfang, PubMed, Elsevier, and Web of Science database were retrieved using “biodegradable microsphere, nanoparticle, bone regeneration, osteogenic” as English and Chinese keywords.
    RESULTS AND CONCLUSION: In the research of bone regeneration, the materials used to prepare biodegradable microspheres include inorganic materials, natural polymer materials and synthetic polymer materials. The preparation methods include ionic gel, solvent evaporation, spray drying, phase separation, and sol-gel method. Although the microspheres have excellent biocompatibility and bone conductivity, the osteogenic properties of most of the materials are still not ideal. Many ways are used to modify the microspheres, such as loading osteogenic factor, anti-infective factor and angiogenic factor, making it possible to functionalize the microspheres. The optimization of microsphere processing technology, the construction of composite microspheres and composite scaffolds, and the introduction of new efficient modification factors all provide new ideas for the application of microsphere in bone regeneration.
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    Bio-functionalization of medical metal materials in orthopedic application
    Li Shan, Liu Chao, Yan Yiguo
    2021, 25 (34):  5523-5529.  doi: 10.12307/2021.250
    Abstract ( 230 )   PDF (636KB) ( 26 )   Save
    BACKGROUND: There are still many problems in orthopedic medical metal materials after many years of clinical application, including autoimmune reaction, the mismatch of elastic modulus and human bone, the non-fusion of bone and interface after implantation, and the direct or indirect impact of metal corrosion and wear.
    OBJECTIVE: To summarize the bio-functionalization of medical metal materials in orthopedic applications. 
    METHODS: The first author used computer to search the relevant literature of PubMed, CNKI, and Web of Science database. The English search terms were “orthopedics, metallic material, bio-functionalization”, and the Chinese search terms were “orthopedic medical metals, 3D printing technology, bio-functionalization, surface modification, material surface coating”. Finally, 61 articles were included for review. 
    RESULTS AND CONCLUSION: Medical metal materials are the earliest materials used in orthopedics. The initial research on medical metal materials focused on the nature of metal materials. With the continuous research on bone substitute materials, the properties of materials are developing from biological inertness to biological activity and biological functionalization. Under the premise of not changing the properties of the body material, the organic coupling of the biological functions of metal materials was carried out by using surface physical modification, chemical modification and surface biological modification to further realize the bio-functionalization of medical metal materials, so that orthopedic medical metal materials not only have good mechanical properties and biocompatibility, as well as good biological activity, anti-inflammatory properties and osteoinductive properties. These multi-functional synergistic effects will become a new field of clinical application and also point out the direction for the development of new functions of biomedical metals.
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    Application of acellular tissue in ophthalmology
    Liu Jingchen, Li Mingjun, Sun Shuguang, Li Cairui
    2021, 25 (34):  5530-5536.  doi: 10.12307/2021.251
    Abstract ( 190 )   PDF (613KB) ( 51 )   Save
    BACKGROUND: Due to the lack of effective donor and tissue reconstruction materials, many diseases in the ophthalmology field have unsatisfactory therapeutic effects.
    OBJECTIVE: To summarize the sources of acellular materials by referring to the published literature, and analyze acellular material in clinical and basic research of ophthalmology so as to promote the effective application of acellular tissue materials in ophthalmology.
    METHODS: The Wanfang database, CNKI database and PubMed database were searched for relevant literature from January 2014 to August 2020 using the keywords “acellular, decellularization” combined with “cornea, conjunctiva, lacrymal gland, lacrymal drainage, trabecular meshwork, retina, sclera, orbit”, separately. A total of 56 articles were eventually included, of which 49 were in English and 7 in Chinese.
    RESULTS AND CONCLUSION: (1) There are multiple sources of decellularized tissues currently used in ophthalmology, which can be broadly categorized into three categories: human, animal and acellular matrix after in vitro cell culture. (2) The use of decellularized tissue materials in the reconstruction and repair of ophthalmic diseases can achieve better clinical results and save the vision of some blind people. (3) The acquisition of implants containing active cells through decellularized scaffolds combined with recipient cell transplantation is a new direction for future ophthalmic regenerative medicine treatment. (4) Some deficiencies were found during the application of the decellularized material, such as longer adaptation time, graft sheet dissolution and shrinkage, and incomplete cellularization.
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    Research and clinical application of calcium phosphate cement modification
    Liu Rixu, Lü Wenbo, Gao Wenshan
    2021, 25 (34):  5537-5543.  doi: 10.12307/2021.252
    Abstract ( 236 )   PDF (655KB) ( 39 )   Save
    BACKGROUND: Calcium phosphate bone cement has good self-fixation, easy formability, good biocompatibility, and bone conductivity, and is an excellent bone graft material. However, calcium phosphate cement still has the problems of poor mechanical strength, slow degradation rate, and low biocompatibility.
    OBJECTIVE: To explore the research and clinical application of calcium phosphate cement modification.
    METHODS: Web of Science, PubMed, Wanfang, and CNKI were searched using “calcium phosphate bone cement, modification” as English and Chinese keywords to search the relevant articles published from 2014 to 2020. Irrelevant and duplicate articles were excluded, and 72 articles that met the standard were finally included.
    RESULTS AND CONCLUSION: To date, calcium phosphate cement and biologically active substances, metal and non-metal elements, organic matter, and stem cells have been mixed in different ways to improve their mechanical strength, biocompatibility, and promote bone regeneration. Although some properties of bone cement can be improved by adding different materials, it is still in the experimental stage, and the calcium phosphate cement is not ideal. In the clinical application of calcium phosphate cement, it has a better effect on repairing defects of fractures, osteomyelitis, and bone tumors than traditional treatment methods. However, complications such as slow growth rate of new bone and slow degradation of bone cement, severe infection at the injection site, and collapse of the filler occurred during the application.
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    Analysis methods and transdermal absorption of collagen peptides
    Hua Jinglin, Xie Yingying, Xu Heran, Zhang Xiaona, Wang Min
    2021, 25 (34):  5544-5551.  doi: 10.12307/2021.253
    Abstract ( 352 )   PDF (792KB) ( 30 )   Save

    BACKGROUND: Collagen peptide, the peptide mixtures formed by the disassembly and breakage of molecular chains of collagen, is applied widely across domains including biomedicine, cosmetics and food thanks to its characteristics of low molecular weight, excellent biocompatibility, and good absorptivity.

    OBJECTIVE: To introduce the structural characteristics, classification and sources of collagen and collagen peptides, focus upon the preparation and bioactivity of collagen peptide and the evaluation of transdermal absorption. We prospected the future to obtain quality collagen peptide material from aquatic animal and to apply it to domains with high added value including biomedicine and cosmetics.

    METHODS: We searched the articles published from January 1997 to June 2020 in PubMed, CNKI, and Wanfang databases about the preparation and examination of collagen peptide and the methods of evaluating transdermal absorption with the keywords including “collagen, collagen peptide, transdermal absorption, preparation of collagen peptide, collagen peptide detection” in Chinese and English respectively. 
    RESULTS AND CONCLUSION: Studies into evaluation methods of the transdermal absorption of collagen peptides remain to be few in numbers, though there has been a lot about the preparation of collagen peptides. The existing studies upon the evaluation methods are majorly based upon those into the transdermal penetration of drugs. In the context where the collagen peptide industry in China remains to be immature, full attention should be paid to the actual effect and the products should be refined with the more specifically classified functions in the progress of product research and development.
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    Development prospect and research value of biodegradable poly(lactic acid) for bone repair
    Liu Zichen, Yu Baoqing
    2021, 25 (34):  5552-5560.  doi: 10.12307/2021.254
    Abstract ( 284 )   PDF (818KB) ( 233 )   Save
    BACKGROUND: As recent research hotspots, poly(lactic acid) and its composite with excellent biodegradability, biocompatibility and good mechanical properties have gradually replaced the traditional metal fixation materials.
    OBJECTIVE: To introduce typical examples of the application of poly(lactic acid) and its composite in orthopedics, and its biodegradation mechanism, and conclude some methods to regulate the degradation ability of poly(lactic acid).
    METHODS: The author retrieved PubMed, Web of Science, SpringerLink, Medline, Wanfang, and CNKI databases with “poly(lactic acid), synthesis method of poly(lactic acid), poly(lactic acid) and its composite materials, poly(lactic acid) modification, biodegradability, bone damage repair, medical implantable materials, biomedical polymer” as Chinese search terms and “poly(lactic acid), biodegradation, bone damage repair, modification of poly(lactic acid)” as English search terms for relevant articles, published from 2000 to 2020.
    RESULTS AND CONCLUSION: With the development of material science and tissue engineering, poly(lactic acid) has made remarkable achievements in orthopedics, which can be used as bone repair materials, such as bone nails, intramedullary nails, and surgical sutures, and is becoming as a substitute for traditional metals avoiding stress shielding, osteoporosis or secondary operation pains. Poly(lactic acid) possesses good biocompatibility, with gradual biodegradation into small molecules that can be easily expelled in vivo. Compared with most thermoplastic aliphatic polyesters, poly(lactic acid) has a relatively moderate degradation rate, and its degradation performance is closely related to the material’s molecular weight and molecular configuration, crystallinity, temperature, pH, enzymes, and irradiation. Various factors can be adjusted according to different application requirements, and the material can be functionalized by combining different modification methods to control the degradation rate and further enhance its mechanical properties and biocompatibility. Therefore, in the field of bioengineering that needs short-term application such as bone repair, biodegradable poly(lactic acid) is now having bright development prospects with outstanding research value.
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    Advances of endovascular stent and its treatment for aneurysms
    Li Fang, Wu Ketong, Zhao Jun, Li Gang
    2021, 25 (34):  5561-5569.  doi: 10.12307/2021.255
    Abstract ( 318 )   PDF (840KB) ( 26 )   Save
    BACKGROUND: With the increasing incidence of vascular diseases, the clinical application of vascular stents combined with minimally invasive treatment surgery is widely used.
    OBJECTIVE: To describe the research background, performance requirements, types, raw materials, production and modification techniques of endovascular stents, and analyze the complications and improvement methods after the endovascular stent implanted in the human body.
    METHODS: The databases of CNKI and Web of Science were searched, and the search time period was from 2005 to 2020. The key words were “vascular stent, aneurysm, endovascular exclusion, research status” in English and Chinese. 
    RESULTS AND CONCLUSION: The use of endovascular stents combined with minimally invasive treatment for aneurysms is very important in clinic. Traditional vascular stents cannot have good long-term patency rate, durability, anti-thrombosis and anti-tumor functions at the same time; it should be systematically designed and improved from the aspects of structural design, endothelialization, and functional modification of high effective drug release. The study of endovascular stents is a cutting-edge research involving multidisciplinary interdisciplinary research. To develop vascular stents with more biocompatible, more stable, and lower costs, the collaborative innovation of a multidisciplinary team of talents in biological materials, engineering technology and clinical medicine is important, so as to contribute to the medical cause of human beings.
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    Transalveolar sinus floor elevation with or without grafting materials: a meta-analysis
    Shi Qianhui, Wu Chao, Zhou Qian, Qi Yuhan, Huo Hua, Liao Jian
    2021, 25 (34):  5570-5576.  doi: 10.12307/2021.256
    Abstract ( 202 )   PDF (787KB) ( 25 )   Save
    OBJECTIVE: At present, there is no consensus on whether to use bone grafts while lifting the macillary sinus, and there are still controversies. This article compared and analyzed the clinical outcome after transalveolar sinus floor elevation with or without grafting materials.
    METHODS:  A computer search was conducted to search all clinical studies on transalveolar sinus floor elevation with and without grafting materials published in CNKI, Wanfang, VIP, CBM, Embase, PubMed, Web of Science and Cochrane. Finally, two reviewers independently extracted study data and conducted quality assessments according to the Cochrane manual and NOS scale, and then used RevMan 5.3 software and Stata 15.1 software to analyze the research data which finally met the inclusion criteria for meta-analysis. 
    RESULTS: (1) A total of eleven articles were included, six were randomized controlled trials and five were prospective cohort studies, including 994 implants, with 399 implants in the graft group and 595 implants in the non-graft group. (2) The results of meta-analysis showed that there was no significant difference in implant failure rate (RR=0.57, 95%CI:0.28-1.18, P=0.13), and marginal bone loss (SMD=0.03, 95%CI:-0.23-0.29, P=0.80) between implants with and without graft materials after transalveolar sinus floor elevation. The risk of membrane perforation in the non-graft group was lower than that in the graft group (RR=0.33, 95%CI:0.12-0.96, P=0.04), but the amount of endo-sinus bone gain in the non-graft group was significantly lower than that in the graft group (SMD=-0.89, 95%CI:-1.08 to -0.70, P < 0.05).
    CONCLUSION: Transalveolar sinus floor elevation simultaneously implanted with grafting and without grafting can achieve predictable results. There were no statistically significant difference between two groups in implant failure rate and marginal bone loss. There may be a trend toward more endo-sinus bone gain with grafting. However, the sinus membrane perforation rate in the graft group was higher than that in the non-graft group. Therefore, choosing transalveolar sinus floor elevation without grafting during clinical practice has more advantages than that with grafting and the security is high. However, due to the limitation of the quality and many shortcomings of the included literatures, the above conclusions need to be validated by high-quality, multi-center and large-sample randomized controlled trials.
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