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    08 December 2018, Volume 22 Issue 34 Previous Issue    Next Issue
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    Percutaneous osteoplasty combined with multiholed catheter bone cement injection for metastatic tumor-induced impending fracture of the long bone
    Ye Yong, Liu Xunwei, Wang Zhiguo, Li Zunyong, Xie Zhiyong, Sun Gang
    2018, 22 (34):  5413-5418.  doi: 10.3969/j.issn.2095-4344.0948
    Abstract ( 382 )   PDF (764KB) ( 129 )   Save

    BACKGROUND: The long bone is the recurrent site of metastatic tumors. Broken sclerotin weakens the support strength of long bone, which leads to fracture under external force. Percutaneous osteoplasty can reinforce local bone strength and kill tumor cells. But it cannot fortify the whole long bone enough to avoid fracture occurrence.

    OBJECTIVE: To compare the efficacy of percutaneous long bone cementoloplasty with and without embedding a cement-filled catheter in the medullary canal for painful long bone metastases with impending fracture.
    METHODS: Forty-two patients were divided into two groups according to the treatment schedule. Patients in control group were treated with percutaneous osteoplasty combined with bone cement injection and the other patients in experimental group were treated with percutaneous osteoplasty combined with multiholed catheter bone cement injection. Rate of bone cement leakage was statistically analyzed. Visual analogue scale score, Karnofsky function score and number of cases of long bone fracture were detected and compared between the two groups.

    RESULTS AND CONCLUSION: (1) All the patients completed puncture and bone cement injection. There were seven cases of bone cement leakage in the control group and eight cases of bone cement leakage in the experimental group, and no difference existed in two groups (P > 0.05). (2) The visual analogue scale score and Karnofsky function score in each patient were both improved after treatment (P < 0.05), but there was no difference between the two groups (P > 0.05). (3) Five cases of bone re-fracture were found in the control group, but no case in the experimental group. To conclude, the use of percutaneous osteoplasty combined with multiholed catheter bone cement injection for metastatic tumor-induced impending fracture of the long bone can prevent bone fracture at the lesion site.

     

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    Development and physicochemical characterization of a porous calcium phosphate/bone matrix gelatin composite cement
    Wang Song, Yang Han, Yang Jian, Zhang Kaiquan, Kang Jianping, Wang Qing
    2018, 22 (34):  5419-5425.  doi: 10.3969/j.issn.2095-4344.0640
    Abstract ( 370 )   PDF (785KB) ( 158 )   Save

    BACKGROUND: Calcium phosphate cement has good biocompatibility, osteoinductive activity and biodegradability, which meets some of the needs for repairing bone defects. However, single calcium phosphate cement is brittle and has poor biological activity without osteoinductive activity.

    OBJECTIVE: To develop porous calcium phosphate/bone matrix gelatin composite cements and to explore the physicochemical characterization.
    METHODS: Bone matrix gelatin was extracted from rabbits and poly(lactic-co-glycolic) acid (PLGA) microspheres were prepared. The new porous cement was developed using calcium phosphate cement composited with bone matrix gelatin and PLGA microspheres. The composited cement was then divided into three groups including blank group, 5% microsphere group and 10% microsphere group. Then, the physicochemical characterizations of the new porous composite bone cement in different groups were assessed by microstructure, setting time, injectability, resistance to collapsibility, in vitro degradation and porosity. Bone marrow mesenchymal stem cells were co-cultured with the extracts of these three kinds of composite cements, and cell proliferation rate was detected within 14 days of co-culture. The three kinds of composite cements were implanted into the lumbar vertebral bone defects in the rabbit model, and bone defect repair was analyzed by Micro-CT at 12 weeks after implantation.

    RESULTS AND CONCLUSION: With the increasing ratio of the microsphere, the setting time was shortened (P < 0.05), the porosity was increased (P < 0.05), the compressive strength and elastic modulus were reduced (P < 0.05), the injectability and anti-diffusivity were weakened, and the in vitro degradation was fastened. Compared with the blank group, the cell proliferation was significantly increased in the 5% and 10% microsphere groups (P < 0.05). At 12 weeks after implantation, Micro-CT findings revealed new bone tissues formed at the bone defect site. Compared with the blank group, significantly increased bone mineral density, bone volume fraction, trabecular thickness, and trabecular number were observed in the 5% and 10% microsphere groups (P < 0.05), but the trabecular spacing was significantly lower than that in the blank group (P < 0.05). To conclude, the calcium phosphate/bone matrix gelatin composite cement with 5% PLGA microsphere has proper maneuverability, mechanical strength and cytocompatibility, degradability and osteoinductive activity.

    中国组织工程研究杂志出版内容重点:生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程

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    Relationship between bone cement leakage and vascular anatomy of the thoracolumbar vertebral body:  a retrospective analysis of 105 cases
    Zhang Yang, Gong Weiming, Song Hongliang, Zhong Jiangbo, Jia Tanghong
    2018, 22 (34):  5426-5432.  doi: 10.3969/j.issn.2095-4344.0652
    Abstract ( 326 )   PDF (822KB) ( 102 )   Save

    BACKGROUND: Previous studies have shown that bone cement leakage rate is mainly associated with surgical procedure of kyphoplasty and vertebral venous reflux.

    OBJECTIVE: To analyze the relationship between bone cement leakage rate and surgical procedure of vertebral kyphoplasty based on the distribution rule of thoracolumbar vessels.
    METHODS: Clinical data of 105 patients treated with vertebral kyphoplasty for osteoporotic vertebral compression fractures (OVCFs) were retrospectively reviewed. All patients were divided into three groups according to the puncture angle: oblique downward position (group A), horizontal position (group B) and oblique upward position (group C). Then, the patients were divide into three groups according to the injection site of bone cement: the left side of safety zone (group 1), safety zone (group 2) and the right side of safety zone (group 3). Bone cement leakage rate, the amount of bone cement injected, the recovery rate of vertebral height and the recovery of Cobb angle and the improvement of pain were observed in each group.
    RESULTS AND CONCLUSION: (1) The total rate of bone cement leakage and the rate of leakage via the vertebral vein in the group A were lower than those in the groups B and C (P < 0.05), and the amount of bone cement injected was higher than that in the groups B and C (P < 0.05). On the second day after surgery, there was no significant difference between the three groups in the recovery rate of vertebral height, the recovery of Cobb angle and visual analogue scale score. (2) The total rate of bone cement leakage and the rate of leakage via the vertebral vein in the group 2 were lower than those in the groups 1 and 3 (P < 0.05), and the amount of bone cement injected was higher than that in the groups B and C (P < 0.05). On the second day after surgery, there was no significant difference between the three groups in the recovery rate of vertebral height, the recovery of Cobb angle and visual analogue scale score. Overall, the results from this study confirm the existence of “safety zone” in the vertebra and indicate that management of puncture angel and injection site of bone cement can potentially reduce the cement leakage rate. 
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    Kyphoplasty with polyethylene terephthalate treats Kummell disease
    Li Zhijun, Ci Yuan, Zheng Yupeng, Zhang Guangyu
    2018, 22 (34):  5433-5438.  doi: 10.3969/j.issn.2095-4344.0637
    Abstract ( 320 )   PDF (779KB) ( 152 )   Save

    BACKGROUND: Kyphoplasty with polyethylene terephthalate can relieve pain quickly, restore the vertebral height and correct kyphosis. However, there are less reports on percutaneous kyphoplasty to deal with the Kummell's disease.

    OBJECTIVE: To evaluate the efficacy and safety of percutaneous kyphoplasty with polyethylene terephthalate in treating Kummell disease.
    METHODS: Seventeen patients with Kummell disease (5 males and 12 females) aged 67 to 72 years old were included in this study. Affected vertebral segments included T11 in two cases, T12 in seven cases, L1 in five cases, L2 in two cases, and L3 in one case. All the patients were treated by percutaneous kyphoplasty with polyethylene terephthalate. Pain relief, living ability and imaging evaluations were performed before and after the surgery.
    RESULTS AND CONCLUSION: (1) Pain relief: The Visual Analogue Scale scores in the 17 patients were significantly lowered at 3 days, 3 months and 6 months after the surgery than the preoperative scores (P < 0.05). (2) Living ability: The mean Oswestry disability index scores in 17 patients at 3 days, 3 months and 6 months after the surgery were lowered compared to the preoperative scores (P < 0.05). (3) Imaging evaluation: The height of the anterior and middle line vertebral body in 17 patients at 3 days, 3 months and 6 months after the surgery were higher than the preoperative (P < 0.05), and the Cobb angle was significantly lowered compared to the preoperative (P < 0.05). (4) Adverse reaction: There was no leakage of bone cement in the vertebral canal and vessels, and no adverse reactions related to bone cement occurred. These results suggest that the percutaneous kyphoplasty with polyethylene terephthalate is safe in treating elderly Kummell disease, which can relieve pain quickly, improve patients’ quality of life, and rebuild the spinal stability. 
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    Structural allogeneic freeze-dried bone bone for treatment of lumbar tuberculosis
    Wang Pengbo, Sheng Weibin, Wang Bingchao, Cao Rui, Xu Tao, Pulati Maimaiti
    2018, 22 (34):  5439-5444.  doi: 10.3969/j.issn.2095-4344.0678
    Abstract ( 369 )   PDF (690KB) ( 122 )   Save

    BACKGROUND: Increasing attentions have been paid to allogeneic freeze-dried bone, but it is uncertain whether it can substitute the autologous bone in the treatment of lumbar tuberculosis.

    OBJECTIVE: To retrospectively analyze the therapeutic efficacy of structural allogeneic freeze-dried bone in the treatment of lumbar tuberculosis.
    METHODS: 198 patients with lumbar tuberculosis scheduled for surgical treatment were selected, including 105 males and 93 females, 16-80 years of age. There were 168 cases of single-segment infection, 30 cases involving 2 segments and more than 2 infections, and 24 cases of obvious lumbar deformity. 129 of the 198 patients underwent anterior lumbar interbody fusion and internal fixation, 52 cases underwent simple posterior lumbar interbody fusion and internal fixation, and 17 cases underwent anterior and posterior lumbar interbody fusion and internal fixation. Structural allogeneic freeze-dried bone was used as the graft material. The postoperative neurological function, pain score, deformity correction, degree of bone fusion, fusion rate and complications were analyzed.

    RESULTS AND CONCLUSION: All the patients were followed up for (30±11) years. At the final follow-up, C-reactive protein expression (P < 0.05), Japanese Orthopaedic Association score, Cobb angle (P < 0.05) and neurologic function were significantly improved compared with the preoperative data. The time for bone fusion was (9.3±2.2) months as assessed by X-ray and (12.7±3.1) months as assessed by CT. Bridwell grade I patients underwent postoperative CT examination, and trabecular bone formation was implemented in 141 cases, with the positive rate of 76%. Two patients had fractures of the bone graft within 6 postoperative months and six patients had recurrent tuberculosis, two of whom had sinus formation. All these findings indicate that on the basis of systemic anti-tuberculosis drugs, it is safe and feasible to treat lumbar tuberculosis with allogeneic freeze-dried bone.

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    Influence of additives on the tetragonal phase purity and grain size of zirconia
    Zang Sitian, Yang Qian, He Ningxiang, Ji Yang, Yang Huazhe
    2018, 22 (34):  5445-5451.  doi: 10.3969/j.issn.2095-4344.0679
    Abstract ( 390 )   PDF (951KB) ( 134 )   Save

    BACKGROUND: Numerous studies have been made on the experimental parameters that influence the grain size of zirconia crystal and purity of tetragonal phase of zirconia. Until now, however, there is no unified conclusion on the influence of additives (ethylenediaminetetraacetic acid or glycerol) on the grain size of zirconia

    crystal and purity of tetragonal phase of zirconia.
    OBJECTIVE: To investigate the influence of additives (ethylenediaminetetraacetic acid or glycerol) on the grain size of zirconia crystal and purity of tetragonal phase of zirconia.
    METHODS: Nitrates were adopted as raw materials, ethylenediaminetetraacetic acid or glycerol was adopted as additives, and ammonium hydroxide was chosen to adjust the pH of the solution. Then six kinds of zirconia were synthesized using hydrothermal method. The mole ratio of Zr4+:ethylenediaminetetraacetic acid:glycerol were 1:0:0, 1:1:0, 1:0:1, 1:0.5:0.5, 1:0.25:0.75, 1:0.75:0.25, and the samples were numbered 1-6 and characterized by X-ray diffraction. Afterwards, the influence of additives (ethylenediaminetetraacetic acid or glycerol) on the grain size and purity of tetragonal phase of zirconia was analyzed.
    RESULTS AND CONCLUSION: Sample No. 3 was pure tetragonal zirconia and had the largest grain size. The other five samples contained two kinds of crystalline phases: tetragonal and monoclinic phases. Meanwhile, the content of tetragonal phase was higher than that of monoclinic phase. The grain size of samples No. 3-6 was larger than that of samples No. 1 and 2. The content of tetragonal phase of samples No. 1 and 3 was higher than that of samples No. 2, 4, 5, and 6. Our experimental data indicate that ethylenediaminetetraacetic acid could decrease the grain size and proportion of tetragonal phase of zirconia, while glycerol could increase the proportion and grain size of tetragonal phase of zirconia.  
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    Repair of mandibular defects with polyetheretherketone/biphase bioceramic composites
    Yu Hedong, Leng Weidong, Chen Yongji, Ni Xiaobing, Ai Jun, Tan Yaqin, Luo Jie
    2018, 22 (34):  5452-5457.  doi: 10.3969/j.issn.2095-4344.0680
    Abstract ( 374 )   PDF (1724KB) ( 147 )   Save

    BACKGROUND: Polyetheretherketone has good affinity and corrosion resistance, and its biocompatibility is stable. Bioceramic materials also have good mechanical properties and bio-affinity. Therefore, polyetherketone can be combined with biphase bioceramics to prepare composite scaffolds that may promote the repair of bone defects. 

    OBJECTIVE: To investigate the effect of polyetheretherketone/biphasic bioceramic composites in the repair of rabbit mandibular defects.
    METHODS: Twenty New Zealand white rabbits (purchased from the Animal Experimental Center, Hubei University of Medicine, China) were divided into four groups. In the control group, no treatment was given. In the operation group, a mandibular defect model was made in the rabbit. In the composite scaffold group, polyetheretherketone/biphasic bioceramic composite scaffold was implanted into the mandibular defect. In the sham group, the incision was directly sutured after exposing the gingival groove. Mandibular specimens in each group were taken at 4, 8, and 16 weeks after surgery, and hematoxylin-eosin staining, Goldner’s trichrome staining, and bone morphogenetic protein-2 expression were detected.
    RESULTS AND CONCLUSION: (1) Results from the hematoxylin-eosin staining and Goldner’s trichrome staining revealed that: in the composite scaffold group, osteoblasts actively grew into the pores at 4 weeks after surgery, and peaked at 16 weeks, while in the operation group, granulation tissues and a small amount of osteoblasts were visible, but the number of osteoblasts was lower relative to the composite scaffold group. (2) PCR results showed that the mRNA expression of bone morphogenetic protein 2 was significantly higher in the composite scaffold group than the control and operation groups at 8 and 16 weeks after surgery (P < 0.05 or P < 0.01). (3) Western blot results indicated that the protein expression of bone morphogenetic protein 2 was significantly higher in the composite scaffold group than the control and operation groups at 4, 8, 16 weeks after surgery (P < 0.05 or P < 0.01). To conclude, the polyetheretherketone/biphasic bioceramic composite scaffold can effectively promote the expression of bone morphogenetic protein 2 in the cells, and then promote the growth and differentiation of osteoblasts, while effectively repairing bone defects.  
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    Perforation of the pulp chamber floor: repair with mineral trioxide aggregate, light-cured glass ionomer cement and light-cured calcium hydroxide
    Wang Jing, Wang Mengyang, Feng Qiaoqiao, Sun Jijun, Ci Haosu
    2018, 22 (34):  5458-5463.  doi: 10.3969/j.issn.2095-4344.0654
    Abstract ( 266 )   PDF (703KB) ( 129 )   Save

    BACKGROUND: Mineral trioxide aggregate (MTA), a new biomaterial, has significant advantages in sealing, biocompatibility, antibacterial activity, which can be used as the first choice for the repair of perforated pulp chamber floor. However, the clinical efficacy of MTA has not been widely verified.

    OBJECTIVE: To compare the therapeutic effects of light-cured glass ionomer cement (LGIC), light-cured calcium hydroxide (LCH) and MTA in the repair of perforation of the pulp chamber floor.
    METHODS: One hundred and fifty-three patients with perforation of the pulp chamber floor who were treated at the Department of Dentistry, Binzhou Medical University Hospital from May 2013 to May 2015 were selected as the research objects. According to the simple random sampling method, these patients were randomized into MTA group, LGIC group and LCH group, with 51 cases in each group. The MTA, LGIC and LCH were used to repair the affected teeth in corresponding groups. One-year post-treatment therapeutic effect, the repair time of periodontal hard tissue, the incidence of adverse reactions and the satisfaction of the patients were compared among the three groups. Meanwhile, the clinical efficacy on the affected teeth with different characteristics (including different position, perforation diameter and perforation reason) in the MTA group was compared.

    RESULTS AND CONCLUSION: The total effective rate and overall satisfaction rate of MTA group were significantly higher than those in the other two groups (P < 0.05), while the incidence of adverse reactions was significantly lower in the MTA group than the other two groups (P < 0.05). When the perforation diameter was < 2 mm, the percentage of patients who underwent the repair of periodontal hard tissue within 3 months was significantly higher in the MTA group than the LGIC group and LCH group (P < 0.05). Moreover, in the MTA group, the total effective rate with the perforation diameter < 2 mm was significantly higher than with the perforation diameter ≥ 2 mm (P < 0.05), and the total effective rate of the iatrogenic group was significantly higher than that of the carious group (P < 0.05). Logistic regression results showed that the diameter of perforation and the cause of perforation were both significant factors influencing the clinical efficacy of MTA (P < 0.05). These results confirm that MTA has a significant effect on the repair of the perforation of the pulp chamber floor, characterized by relatively short repair time and few adverse reactions. Therefore, MTA can be used as the first choice for the restoration of the affected teeth, and its clinical efficacy is related to the size and the cause of the affected teeth.

    中国组织工程研究杂志出版内容重点:生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程

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    Periodontal tissue changes in a Beagle dog model of peri-implantitis under orthodontic force
    Chang Lijun, Tang Tian, Zhang Xiaoge
    2018, 22 (34):  5464-5468.  doi: 10.3969/j.issn.2095-4344.0681
    Abstract ( 370 )   PDF (630KB) ( 142 )   Save

    BACKGROUND: The early-stage progression of peri-implantitis is an important factor affecting the stability of micro-implants.

    OBJECTIVE: To establish an animal model of peri-implantitis under orthodontic force, and to evaluate periodontal indexes in different stages of the development of peri-implantitis.
    METHODS: Eight adult male Beagle dogs were provided by the Experimental Animal Center of Sichuan University in China. Forty-eight micro-implants were randomly implanted into the maxillary interradicular region at the center of the mesial and distal roots of bilateral second, third, and fourth premolars of Beagle dogs. One side served as experimental group with three loaded micro-implants under 100 g of orthodontic force at 1, 2, 3, 4 weeks of peri-implantitis, and the force lasted for 1 month. The contralateral side acted as control group with no orthodontic force. Two dogs were selected at each visit time. Incidence and development of peri-implantitis were evaluated based on the periodontal indexes such as modified plaque index, modified sulcus bleeding index, periodontal probe depth, and micro-implant looseness.
    RESULTS AND CONCLUSION: (1) In the experimental group, plaque or soft scale accumulation on the micro-implant surface formed, with soft tissue congestion and swelling. Sometimes hyperplasia and even mucosal erosion, ulceration developed as well as bleeding occurred during the probing. With the increase of probe depth, a few of micro-implants were loosened. All of these indicated the occurrence of peri-implantitis. In the control group, no color change, no edema or swelling, and no bleeding after probing appeared, and the gingiva was in health status. (2) In the experimental group, there were significant differences in the modified plaque index and periodontal probe depth at different visit time (P < 0.05), while no significant difference was visible in the modified sulcus bleeding index (P > 0.05). (3) Only 3 of 48 micro-implants were loosened, which belonged to the experimental group, including one of degree I and two of degree II. To conclude, with the stimulation of orthodontic stress, the modified plaque index and periodontal probe depth values around the micro-implant are positively related to the different stages of the development of the peri-implantitis. This indicates that early intervention under the orthodontic force is an important measure to prevent peri-implantitis during the development of peri-implantitis.  
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    Evaluation of osseointegration of plasma electrolytic oxidation coated titanium implants in vivo
    He Tao, Zhang Yunhui, Zhang Chao, Xu Zhiguo, Dong Yuqi
    2018, 22 (34):  5469-5476.  doi: 10.3969/j.issn.2095-4344.0682
    Abstract ( 416 )   PDF (936KB) ( 187 )   Save

    BACKGROUND: A number of in vitro cytological experiments have shown that titanium oxide surfaces with oxidized coatings exhibit better biocompatibility and biological activity than conventional titanium metal surfaces.

    OBJECTIVE: To further observe the osseointegration ability of plasma electrolytic oxidation (PEO) coated titanium rods in vivo.
    METHODS: Thirty-six 16-week-old male Sprague-Dawley rats (purchased from Shanghai Sippr-BK Laboratory Animal Co., Ltd., China) were used to establish a bilateral distal femoral intramedullary nail implantation model. PEO coated titanium rods were implanted into the left side as the PEO group, whilst uncoated titanium rods were implanted into the right side as the control group. At 2, 4, and 6 weeks after implantation, the rats were sacrificed and bone specimens with implants at the distal femur were harvested. Van Gieson staining, double-labeled fluorescent staining, and biomechanical evaluation were then performed.
    RESULTS AND CONCLUSION: (1) Van Gieson staining results showed no fibrous tissue ingrowth at the implant-bone interface in both the experimental group and the control group. At 2 weeks of implantation, bone tissue growth was observed at the implant surface in both groups. The osseointegration around the implant was formed at 4 weeks of implantation in the PEO group, while that of control group was formed at 6 weeks after implantation. (2) Double-labeled fluorescent staining results showed that at 2 weeks after implantation, implants in both groups were closely bound to a large amount of newly formed bone tissue. When implanted for 4 weeks, the newly formed bone in PEO group was in continuous contact with the surface of the implant, while that in the control group was in contact with the surface of the implant in a discontinuous block. At 6 weeks after implantation, continuous implant-bone contact was observed in both groups, but the amount of newly formed bone was significantly lower than that at 4 weeks. (3) Biomechanical examination results showed that the maximum compression load of the PEO group at 4 weeks was higher than that of the control group (P < 0.001). There was no significant difference in the maximum compression load between the two groups at 2 and 6 weeks (P > 0.05). In the PEO group, the maximum compression load at 4 weeks after implantation was higher than that at 2 and 6 weeks after implantation (P < 0.05), while in the control group, the maximum compression load at 6 weeks after implantation was higher than that at 2 and 4 weeks after implantation (P < 0.05). Overall, our study findings indicate that the PEO coated titanium rods have better osseointegration than pure titanium rods in the early stage after implantation.  
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    Bladder acellular matrix combined with vascular endothelial growth factor repairs rabbit urethral defects
    Gu Shaodong, Zhou Yun, Xiong Qianwei, Zhang Ya, Yang Jinlong
    2018, 22 (34):  5477-5483.  doi: 10.3969/j.issn.2095-4344.0683
    Abstract ( 296 )   PDF (1255KB) ( 160 )   Save

     BACKGROUND: The use of bladder acellular matrix as a free graft to repair urethral defects and induce urinary tract regeneration has achieved certain results, but this method cannot fundamentally solve insufficient angiogenesis of the graft.

    OBJECTIVE: To observe the effect of bladder acellular matrix (BAM) combined with vascular endothelial growth factor (VEGF) in the repair of rabbit urethral defects.
    METHODS: Thirty adult New Zealand rabbits were randomly allocated into five groups (n=6 per group), including healthy control group, sham operation group, model group, BAM group, and BAM combined with VEGF group (VEGF-BAM group). Animal models of urethral defect were made in the latter three groups. The animals were sacri?ced at 4 and 12 weeks after surgery, respectively. The penis was immediately harvested for standardized passive ?owmetry, urethral radiography and subsequently ?xed for immunohistochemical staining for evaluation.
    RESULTS AND CONCLUSION: (1) The average urinary flow rate of the VEGF+BAM group was significantly higher than that of the model group and BAM group at 4 and 12 weeks after surgery (P < 0.05), while there was no difference from the healthy control group and sham operation group. (2) Urethral radiography at 12 weeks after surgery indicated that urethra continuity was repaired with no urethral fistula in the VEGF+BAM group, but not incompletely in the model and BAM groups. (3) Hematoxylin-eosin staining results indicated there were more collagen fibers and infiltrated lymphocytes in the model group, with the fiber arrangement being disordered; the collagen matrix in the VEGF+BAM group was basically degraded, new collagen fibers arranged regularly, and there were many blood vessels, but no hemangioma; and in the BAM group, massive collagen deposition and less blood vessels were observed. (4) Masson staining results indicated that less collagen deposition was observed in VEGF+BAM group compared with BAM group and model group at 12 weeks after surgery (P < 0.05), which was similar to the healthy control group and sham operation group (P > 0.05). (5) CD31 staining results indicated that the local density of new blood vessels in the VEGF+BAM group was significantly higher than that in the BAM and models groups at 12 weeks after surgery (P > 0.05), which was also close to the value in the healthy control and sham operation groups (P > 0.05). (6) Regeneration of urethral smooth muscle in the VEGF+BAM group was significantly better than that in the BAM and model groups at 12 weeks after surgery (P < 0.05), as indicated by a-SMA immunohistochemical staining. Moreover, there was no significant difference among VEGF+BAM group, sham operation group and health control group. To conclude, BAM scaffolds combined with VEGF show a totally potential capacity in inducing the urethral reconstruction. The combined use of VEGF and BAM can stimulate angiogenesis, decrease the rate of collagen deposition, promote urethral smooth muscle regeneration, and improve the urethra regeneration microenvironment in urethral reconstruction.  
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    Leukocyte- and platelet-rich fibrin promotes wound healing
    Wu Yuxiang, Si Shaoyan, Xu Zhangrong, Wang Aihong
    2018, 22 (34):  5484-5489.  doi: 10.3969/j.issn.2095-4344.0684
    Abstract ( 339 )   PDF (763KB) ( 180 )   Save

    BACKGROUND: Leukocyte- and platelet-rich plasma (L-PRP) and leukocyte- and platelet-rich fibrin (L-PRF) are two kinds of autologous platelet rich gels that can accelerate wound healing.

    OBJECTIVE: To compare the differences in the composition, structure and release of growth factors between L-PRP and L-PRF.
    METHODS: Fasting blood samples were collected from healthy volunteers to prepare L-PRP and L-PRF gels. The microstructure of the gels was observed by light microscope and scanning electron microscope, and the concentration times and recovery rates of leukocytes and platelets were calculated. The two gels were stored in DMEM medium. After 1, 3, 7, 14 and 21 days, the culture fluid containing exudate was collected. The platelet-derived growth factor, transforming growth factor β1, and vascular endothelial growth factor were detected by ELISA.
    RESULTS AND CONCLUSION: (1) Under the light microscope, platelet, leukocytes and erythrocytes were clearly demarcated, and leukocytes and fibrin aggregated in cluster. The platelets and leukocytes in the L-PRP gel were less in number and dispersed among erythrocytes. (2) Under the electron microscope, a large amount of fibrins were in the L-PRF gel, to form a dense special 3D structure, and the platelet superposition structure at the junction was clear. There were less fibers and a large number of platelets at the junction of L-PRP gel, and some of the platelets were cleaved. (3) Compared with the L-PRP gel, the L-PRF had a higher platelet recovery rate (P=0), leukocyte recovery rate (P=0) and lymphocyte recovery rate (P=0). (4) In addition to the vascular endothelial cell growth factor, the levels of transforming growth factor β1 and platelet-derived growth factor in the L-PRF gel stored for 3, 7, 14 and 21 days were higher than those in the L-PRP gel. These findings indicate that compared with the L-PRP gel, the L-PRF gel is easier to prepare, has better structure and slower release of growth factors, which have more advantages in the treatment of wounds. 
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    Effects of two toothpastes used at different time on enamel remineralization and acid resistance
    Zhao Yulong, Yang Desheng, Xu Fan, Li Yanfeng
    2018, 22 (34):  5490-5495.  doi: 10.3969/j.issn.2095-4344.0685
    Abstract ( 429 )   PDF (750KB) ( 260 )   Save

    BACKGROUND: Tooth brushing to reduce tooth wear is mostly recommended at 30 minutes after eating acidic food. However, little is reported on the effect of toothpastes used at different time on enamel remineralization.

    OBJECTIVE: To evaluate the effect of bioactive glass toothpaste or fluoride toothpaste on enamel remineralization and acid resistance after remineralization when used instantly after being eroded or 30 minutes after being eroded.
    METHODS: Fifty bovine enamel samples were randomly divided into five groups after the acid etching of carbonated beverage. The blank control group was placed in the natural saliva for 30 minutes. Instant fluoride group and instant bioactive glass group were immediately smeared with fluoride toothpaste and bioactive glass toothpaste, respectively, and then the samples in these two groups were placed in the natural saliva for 30 minutes. Groups of fluoride toothpaste or bioactive glass used at 30 minutes after acid etching were placed in the natural saliva for 30 minutes, and then the fluoride toothpaste or the bioactive glass toothpaste paste was applied respectively. After remineralization, all the samples were re-etched by carbonated beverages. After remineralization and re-etching, the surface microhardness of each sample was detected and observed by scanning electron microscope.

    RESULTS AND CONCLUSION: (1) After remineralization, the surface microhardness of each group was higher than that in the blank control group (P < 0.05). The surface microhardness of the bioactive glass groups was higher than that in the fluoride groups (P < 0.05). The surface microhardness of the group with fluoride toothpaste used at 30 minutes after acid etching was higher than that in the instant fluorine group (P < 0.05). (2) After re-etching, the decrease in the surface microhardness was lower in the treatment groups than the blank control group (P < 0.05), and the decrease in the surface microhardness in the bioactive glass groups was lower than that in the fluoride groups (P < 0.05). (3) After remineralization and re-etching, most serious damage to the interprismatic substance was found in the blank control group, and the surface of the interprismatic substance was obviously lower than that of the enamel prisms. The flattest surface of the interprismatic substance in the bioactive glass groups was observed, and there was a minimal damage to the interprismatic substance and the enamel prisms. Moreover, a large number of spherical particles were attached to the surface of the interprismatic substance in the bioactive glass groups. To conclude, these results show that the bioactive glass can effectively enhance the remineralization and anti-corrosion ability of the etched enamel. The use of fluoride toothpaste instantly after acid etching can reduce the enamel remineralization. Moreover, there is no difference in enamel remineralization and acid resistance using bioactive glass instantly or 30 minutes after immersion in the natural saliva.

      中国组织工程研究杂志出版内容重点:生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程

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    Purification process of non-denatured type II collagen
    Li Jie, Wang Yumei
    2018, 22 (34):  5496-5500.  doi: 10.3969/j.issn.2095-4344.0641
    Abstract ( 505 )   PDF (1418KB) ( 128 )   Save

    BACKGROUND: Increasing studies have been concentrated on the purification of non-denatured collagen at the laboratory level, but there are fewer reports on the extraction and purification of pilot scale and production scale. After all, this technology has to be out of the laboratory to make sense. At the trial and production stages, more is faced with the measurement of cost, yield, and ease of operation.

    OBJECTIVE: To explore the methods and conditions for the desalination and deacidification purification of non-denatured type II collagen in the pilot test and production.
    METHODS: The commonly used desalination and deacidification methods for non-denatured type II collagen extracted included dialysis bag method, water washing method, rejection filtration method, and hollow fiber membrane method. The denatured type II collagen was purified according to these four methods. Disadvantages and advantages of the dialysis bag method, water washing method, rejection filtration method, and hollow fiber membrane method in the collagen purification process were compared using three indexes: yield, collagen content, and purity.

    RESULTS AND CONCLUSION: For the yield, the ranking order was as follows: dialysis bag method > hollow fiber membrane method > rejection filtration method > water washing method; for the collagen content, dialysis bag method > hollow fiber membrane method > water washing method > rejection filtration method; for the purity of collagen, there was no significant difference among the four methods. Moreover, pressure was positively but insignificantly correlated with the membrane flux. By comparing the yield, collagen content, collagen purity, pressure difference, and membrane flux numerical value, it is considered that the hollow fiber membrane method has a comparative advantage in the purification of non-denatured type II collagen. This concludes that the hollow fiber membrane method is more suitable for industrial production, which has been patented on May 1, 2013 with national patent No. ZL 2011 10065733.X, and the authors are the first inventors of the patent.

     

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    Preparation of silk fibroin/polycaprolactone temporary rotator cuff patch by electrospinning technique
    Guo Ganggang, Pang Yabo, Yang Jianhua, Liu Shichen, Gao Shuang, Xiao Tongguang, Zhang Weixiang, Zhai Raosheng, Guo Quanyi
    2018, 22 (34):  5501-5509.  doi: 10.3969/j.issn.2095-4344.0686
    Abstract ( 339 )   PDF (1208KB) ( 170 )   Save

    BACKGROUND: As the rate of re-fracture of the rotator is very high, the rotator cuff patch is designed to enhance the healing of the injured rotator cuff. Therefore, the preparation of temporary rotator cuff patch with good biocompatibility, biodegradability and biomechanical properties has become a committed step.

    OBJECTIVE: To prepare a temporary rotator cuff patch with different ratio of silk fibroin (SF)/polycaprolactone (PCL) using electrospinning technique, and to evaluate its physiochemical properties and biocompatibility.
    METHODS: Temporary rotator cuff patches with SF/PCL at different mass ratios of 4:0, 3:1, 1:1, 1:3, 0:4 were prepared using the electrospinning technique. Microstructure, contact angle, degradation properties and composition of the patches were characterized. Temporary rotator cuff patches with the mass ratios of 3:1, 1:1, 1:3, and 0:4 were implanted subcutaneously into the back of Sprague-Dawely rats. After 2 and 4 weeks of implantation, the patch material was taken for hematoxylin-eosin staining.
    RESULTS AND CONCLUSION: (1) The temporary rotator cuff patches prepared from the mixed material improved the diameter, aperture number, and pore diameter of the pure PCL patch as well as the surface droplets caused by the high brittleness of the pure SF patch. (2) The temporary rotator cuff patches prepared by mixed materials improved hydrophilicity as compared with the SF patch and improved hydrophobicity as compared with the simple PCL patch. (3) In the temporary rotator cuff patch prepared by mixed materials, no chemical reaction occurred between the two materials. (4) With the exception of the temporary rotator cuff patch with a mass ratio of 0:4, the rest patches showed an increase in quality after immersed in PBS for 4 weeks. (5) Two weeks after subcutaneous implantation, a large number of cells were attached to the rotator cuff patch in each group, and capillaries formed in the neonatal tissues. The outer middle layer of the rotator cuff patch had a microstructure similar to the normal tendon tissue, while the middle layer of the pure PCL patch was the worst in microstructure. (6) Four weeks after subcutaneous implantation, the number of cells in the neonatal tissue of the patch significantly decreased, and the thickness of the outer neonatal tissue similar to the normal tendon tissue increased, while the pure PCL patch showed the worst function in the middle layer of the new tissue. To conclude, the results show that SF improves the potential of PCL patch to induce the cell differentiation into tendon cells.  
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    Ultra-small superparamagnetic iron oxide particles enhance MRI diagnosis of lymph node metastasis of the head and neck
    Li Wenjin, Niu Jinliang, Zhu Li, Wang Tao, Wang Yu
    2018, 22 (34):  5518-5525.  doi: 10.3969/j.issn.2095-4344.0993
    Abstract ( 398 )   PDF (1615KB) ( 207 )   Save

    BACKGROUND: Studies have shown that ultra-small superparamagnetic iron oxide particles (USPIO) enhanced scanning improves the specificity and sensitivity of malignant lymph node detection in pelvic, breast, and chest malignancies. However, USPIO is rarely reported in the literature addressing lymph node metastasis of the head and neck.

    OBJECTIVE: To establish an animal model of lymph node metastasis of the head and neck, to analyze USPIO enhanced MRI performance of the lymph metastasis, and to explore the clinical value of USPIO in the lymph node metastasis of the head and neck.
    METHODS: Animal models of lymph node metastasis of the head and neck were made in 20 healthy New Zealand rabbits. At 4 weeks after modeling, a plain MRI scan was performed. A novel MR contrast agent, USPIO, was injected into the rabbit ear vein at 90 μmol Fe/kg (about  4 mg/kg). MRI scan was performed before and 24 hours after injection. After scanning, the head and neck lymph nodes were taken out, and hematoxylin-eosin staining and Prussian blue staining were performed to determine the nature of lymph nodes. The characteristics of head and neck metastatic lymph nodes in different MRI examinations were qualitatively and quantitatively analyzed. MRI plain scan and USPIO enhanced scan were used to identify the ability of rabbit VX2 tumor metastasis and non-metastatic lymph nodes in the head and neck.

    RESULTS AND CONCLUSION: (1) Fifty-seven lymph nodes were isolated from 20 rabbits, 25 of which were confirmed to be metastatic by pathological examination (19 parotid lymph nodes and 6 submandibular lymph nodes). Pathological findings confirmed cortex invasion in 4 metastatic lymph nodes, medullary infiltration in 3 metastatic lymph nodes, and cortex and medulla infiltration in 10 metastatic lymph nodes. (2) The plain MRI scan detected 13 metastatic lymph nodes were true positive and the positive rate was 52% (13/25);10 lymph nodes were false positive and the false-positive rate was 40% (10/25). MRI scans showed 34 lymph nodes without metastasis, and 32 pathology-negative lymph nodes. The true negative rate was 69% (22/32), and the false negative rate was 38% (12/32). (3) USPIO enhanced scan detected 21 metastatic lymph nodes that were confirmed pathologically. The true positive rate was 84% (21/25), and the false positive rate was 8% (2/25). MRI scans showed 34 lymph nodes without metastasis, and the true negative rate was 94% (30/32) and the false negative rate was 13% (4/32). (4) Quantitative analysis of lymph nodes without metastasis was as follows: △SNR=-57.20±16.03, and that of metastatic lymph nodes was as follows: △SNR=-16.20±5.03. △SNR values showed statistically significant differences before and after enhanced (P < 0.05). To conclude, USPIO enhanced MRI is a new method for the diagnosis of lymph node metastasis, and has high diagnostic accuracy compared with conventional MRI scan.

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    Influence of needle puncture versus abnormal mechanical compression on the biological properties of annulus fibrosus: a preliminary study at nano-scale
    Li Haitao, Liang Ting, Shao Yijie, Chen Xi, Yang Huilin, Luo Zongping
    2018, 22 (34):  5526-5517.  doi: 10.3969/j.issn.2095-4344.0649
    Abstract ( 487 )   PDF (897KB) ( 142 )   Save

    BACKGROUND: Currently, the specific pathological mechanism of intervertebral disk degeneration, especially the tissue alteration at nano-scale, is still unknown.

    OBJECTIVE: To establish a rat model of intervertebral disk degeneration in the caudal vertebrae and to explore the biomechanical alteration of collagen fibrils of annulus fibrosus at nano-scale induced by needle puncture and abnormal mechanical loading.
    METHODS: Eight adult Sprague-Dawley male rats were chosen and the coccygeal vertebral discs from C5-11 were located under anesthesia. The Co5-Co6 segments were set as normal group. The Co6-Co7 segments were subjected to needle puncture (needle-puncture group). The Co7-Co10 segments were drilled percutaneously by four parallel K-wires and the wires were fixed with self-made braces to make the Co8-Co9 segments under a constant compression environment. The Co8-Co9 segments were set as abnormal compression group. The Co10-Co11 segments were set as adjacent group. Sagittal T2-weighted MRI scanning of the rat caudal vertebrae was performed at 4 weeks after treatment. Hematoxylin-eosin and safranin O/Fast green staining of the intervertebral disc was also performed, and the inner and outer layers of the annulus fibrosus were observed using atomic force microscope.

    RESULTS AND CONCLUSION: (1) The MRI signals in the abnormal compression group and needle-puncture group were significantly lower than those in the normal and adjacent groups (P < 0.05), while the MRI signals in normal and adjacent groups showed no significant difference. (2) Histological analysis revealed similarity in the normal and adjacent groups. In the needle-puncture group, the annulus fibrosus on the puncture site arranged disorderly, thickened and bulged inward into the nucleus pulposus, resulting in an unclear boundary between the annulus fibrosus and nucleus pulposus. The number of nucleus pulposus cells on the puncture side was dramatically reduced and vacuole-like structure disappeared. In the abnormal compression group, nucleus pulposus area remarkably decreased, the number of nucleus pulposus cells reduced and vacuole-like structure in the nucleus pulposus disappeared. Boundaries between the nucleus pulposus and annulus fibrosus remained clear. (3) Under the atomic force microscope, the elastic modulus of collagen fibrils in the outer layer was higher than that in the inner layer (P < 0.05). The elastic modulus of collagen fibrils in the adjacent and abnormal compression groups was similar to that in the normal group, while the elastic modulus of collagen fibrils in the needle-puncture group was higher than that in the normal and abnormal compression groups (P < 0.01). To conclude, these results reveal that the needle-puncture can induce remarkable stiffening of collagen fibrils which differs from the abnormal compression.

    中国组织工程研究杂志出版内容重点:生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程

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    Application of degradable implants in fracture fixation
    Li Junwei, Du Chengfei, Yuchi Chenxi, Zhang Chunqiu
    2018, 22 (34):  5526-5533.  doi: 10.3969/j.issn.2095-4344.0638
    Abstract ( 364 )   PDF (1061KB) ( 123 )   Save

    BACKGROUND: Degradable implants have good biocompatibility and bone conductivity, which have been gradually applied in surgical craniofacial reconstruction, anterior cruciate ligament reconstruction, meniscus repair, ankle joint fracture treatment, tibia and fibula fracture treatment.

    OBJECTIVE: To summarize advantages and disadvantages of degradable implants and put forward our own opinions by comparing degradable and non-degradable implants in orthopedic fractures.
    METHODS: CNKI, WanFang and Web of Science databases were retrieved for relevant articles on the application of biodegradable implants in orthopedics published from 1960 to 2017. The keywords were “biodegradable screw, biodegradable plate, orthopedics, fractures” in Chinese and English, respectively. Finally, 65 eligible articles were included in result analysis.

    RESULTS AND CONCLUSION: Both magnesium alloy and polylactic acid implants have good therapeutic effects in the treatment of orthopedic fractures. However, degradable implants have their own drawbacks. Too fast degradation of the screws will lead to the rapid loss of initial strength. How to control the degradation rate of degradable screws to match the bone growth rate is still an urgent problem to be solved. Therefore, future investigations on how to slow down the degradation rate, enhance anti-wear resistance and develop degradable implants with non-toxicity and carrying multi nutrient elements are warranted.

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    Early vascularization of scaffold materials in the repair of large bone defects
    Zhao Shengli, Shi Ben-chao, Yin Jie, Gao Junhuai, Yu Qinghe, Min Shaoxiong
    2018, 22 (34):  5534-5539.  doi: 10.3969/j.issn.2095-4344.0974
    Abstract ( 354 )   PDF (748KB) ( 202 )   Save

    BACKGROUND: Because of the lack of perfect vascular network, traditional bone filling materials yield poor outcomes in repairing large bone defects. In recent years, there is an increasing concern on tissue engineering scaffold materials in order to achieve the early vascularization of scaffold materials in the repair of large bone defects.

    OBJECTIVE: To summarize the methods and progress of tissue engineering scaffold materials in promoting early vascularization in the repair of large bone defects in recent years, and to point out the existing problems and the key points of further research.
    METHODS: Using “scaffold material, tissue engineering, bone defect repair, vascularization” as the key words in Chinese and English, respectively, we searched CNKI, WanFang, PubMed and Medline databases for articles addressing the pro-vascularization of tissue-engineered bone. The application of scaffold materials in the vascularization of tissue-engineered bone was summarized and the existing problems and prospects were analyzed.

    RESULTS AND CONCLUSION: A total of 43 articles were reviewed. A variety of scaffolds with advantages and disadvantages have been used in the vascularization of tissue-engineered bone. The internal vascularization of tissue engineering materials can be promoted by optimizing the geometric parameters of scaffolds, improving the composition of scaffolds, utilizing macrophage-mediated immune mechanism and constructing active component controlled release system. Although material science is developing rapidly at present, ideal scaffold materials for promoting vascularization of tissue-engineered bone have not emerged. The molecular mechanism of cell-scaffold interaction and macrophage angiogenesis in the modulation of grafts has not been clarified. The effectiveness and safety of controlled-release technology are still controversial in the clinical practice, which is worth further explorations.

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    Polymethylmethacrylate bone cement loaded with antituberculosis drugs: combined drug-loading program and anti-tuberculosis effects
    Yuan Hucheng, Shi Shiyuan, Ma Wenxin, Li Xusheng, Liu Zhen, Ma Xuehua
    2018, 22 (34):  5540-5546.  doi: 10.3969/j.issn.2095-4344.0972
    Abstract ( 328 )   PDF (769KB) ( 148 )   Save

    BACKGROUND: Antibiotic-loaded bone cement has become a necessary routine method to prevent infection after joint replacement and infection after open fracture as well as to treat chronic osteomyelitis.

    OBJECTIVE: To summarize the research status of polymethyl methacrylate bone cement loaded with antituberculosis drugs.
    METHODS: The author used “anti-tuberculosis drugs, polymethyl methacrylate, bone cement” as key words in English and Chinese to retrieve PubMed, Web of Science, Medline, and Springerlink for relevant articles published from 1970 to 2018 as well as to retrieve CNKI and WanFang for relevant articles published from 2010 to 2018. A total of 150 articles were initially retrieved, and 59 articles were finally analyzed according to inclusion and exclusion criteria.

    RESULTS AND CONCLUSION: The polymethyl methacrylate bone cement with antituberculosis drugs has good physical properties, strong mechanical strength, stable and sustained release characteristics. It can improve the local drug concentration and play a good antibacterial role, and it also has a good prospect in the treatment of osteoarticular tuberculosis due to low blood concentration, low toxic and side effects, and good safety. However, there are few studies on polymethyl methacrylate bone cement with antituberculosis drugs. It is necessary to comprehensively and systematically study the drug release mechanism, the combined drug loading scheme and the antituberculosis effect of polymethyl methacrylate bone cement loaded with antituberculosis drugs.

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    Application of nano-hydroxylapatite/collagen and its mineralized composites in bone tissue engineering
    Zhang Xue, Zhang Yang
    2018, 22 (34):  5547-5552.  doi: 10.3969/j.issn.2095-4344.0639
    Abstract ( 481 )   PDF (731KB) ( 119 )   Save

    BACKGROUND: A nano-hydroxylapatite/collagen (nHAC) is a scaffold material for bone tissue engineering based on the concept of bionics. As its reliable biomechanical properties and good biocompatibility, nHAC has been widely used in bone defect repair.

    OBJECTIVE: To summarize the biological effects and research progress of the nHAC and its mineralized composites in bone tissue engineering.
    METHODS: The relevant articles published from January 1997 to January 2018 were collected by a computer-based search of CNKI, SCIE, and PubMed databases using the keywords of “nano-hydroxylapatite/ collagen (nHAC), material, bone regeneration, bone tissue engineering” in English and Chinese, respectively.

    RESULTS AND CONCLUSION: nHAC has good biocompatibility and osteoinduction ability. Compared with autologous bone, nHAC has less osteogenic capacity due to the lack of osteo-inductive biological active substances, such as bone inducing factors and stem cells. Enhancement of osteogenic capacity will be achieved in the nHAC by loading with biomaterials, such as natural bone, artificial bone, cells, plasma, drugs, and bioactive substances. However, it is especially necessary to improve its osteoinduction activity in the repair of large-area bone defects as well as to keep balance between material degradation and osteogenesis needs to be further clarified.

    中国组织工程研究杂志出版内容重点:生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程

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    Chitosan coatings for titanium implants: applications and strengths
    Fan Huayang, Yin Yijia, Wang Zheng, Pei Xuan, Han Xianglong
    2018, 22 (34):  5553-5558.  doi: 10.3969/j.issn.2095-4344.0975
    Abstract ( 488 )   PDF (1415KB) ( 293 )   Save

    BACKGROUND: Titanium and its alloys as implants are extensively used in orthodontics, implant dentistry and oral and maxillofacial surgery due to their excellent physicochemical properties and biocompatibility. Titanium based implants cannot integrate with surrounding bone tissues due to their inherent surface bio-inertness. Meanwhile, bacteria tend to congregate on the implant surfaces. These two factors are mainly responsible for implant failure. To prevent such infections and increase low bone-implant contact, surface modification is feasible. Chitosan has excellent biocompatibility, antimicrobial properties and film-forming properties. It can be used as a coating to improve the biological properties of titanium.

    OBJECTIVE: To summarize the research progress of chitosan modified titanium, and to discuss the effects and advantages of chitosan modification for titanium based implants.
    METHODS: PubMed was retrieved for relevant articles published from January 2010 to May 2018. The key words were “chitosan; titanium; osseointegration; antibacterial" in English. After removal of repetitive and unrelated articles, 53 eligible articles were finally included in accordance with the inclusion criteria.

    RESULTS AND CONCLUSION: Chitosan itself has certain antimicrobial and osteogenic properties. It can be combined with a variety of organic and inorganic materials due to its film forming ability and metal binding capacity to further improve its antimicrobial and osteogenic properties. In addition, chitosan has excellent metal binding capacity, which can improve the antimicrobial ability of metal and reduce its toxicity. Chitosan also can be used as drug carrier and control drug release by reinforcing the coating stability, and thus reduce bacterial adhesion and proliferation, enhance bone binding capability, and reduce the incidence of implant failure. The combination of chitosan and biological growth factors can promote angiogenesis and bone formation abilities of the coating. And multi-layer chitosan can control growth factor release and maintain regional growth factor concentration. If the chitosan modified titanium is applied to clinics, the physical properties of the coating, such as molecular weight, composition, hydrophilicity and porosity, need to be systematically studied, and animal trials and clinical trials are needed as well.

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    Bio-safety of 3D printed titanium and titanium alloys for medical application
    Wu Liping, Zou Shanfang, Liu Ruicheng, Zeng Yiwei
    2018, 22 (34):  5559-5564.  doi: 10.3969/j.issn.2095-4344.0925
    Abstract ( 401 )   PDF (778KB) ( 166 )   Save

    BACKGROUND: Titanium and titanium alloys are widely used in the field of personalized medicine. The traditional casting technology cannot meet the demand of modern medicine. 3D printing technology can meet the increasingly high requirements for medical products in the current medicine.

    OBJECTIVE: To analyze the bio-safety of 3D printed titanium and titanium alloys, thereby providing reference for clinical application.
    METHODS: We analyzed the performance of titanium and titanium alloys produced by 3D printing in terms of corrosion resistance and biocompatibility, thereby confirming whether it could meet the bio-safety requirements of clinical applications.

    RESULTS AND CONCLUSION: 3D printed titanium and titanium alloys have good bio-safety, which can design, regulate the structure of the material itself and optimize performance. It can be used in the field of personalized medicine. Compared to the traditional casting process, 3D printing technology has obvious advantages. With continuous breakthroughs in raw materials, manufacturing equipments and key process technologies, the application of 3D printing technology will become more and more extensive in the field of medical devices.

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    Properties of bacterial cellulose in wound repair
    Zhang Weijia, Liu Ying
    2018, 22 (34):  5565-5570.  doi: 10.3969/j.issn.2095-4344.0687
    Abstract ( 379 )   PDF (719KB) ( 137 )   Save

    BACKGROUND: The ultra-fine nano-scale three-dimensional network structure formed by the natural interweaving of bacterial cellulose has become a new research direction of new biomedical materials.

    OBJECTIVE: To explore the application of bacterial cellulose in the biomedicine by summarizing the original composition and multiform of bacterial cellulose as a nanomaterial.
    METHODS: The keywords of “bacterial cellulose, tissue engineering, medical material, tensile strength” in Chinese and English were used to search CNKI, WanFang, PubMed and Medline databases for articles addressing the pro-vascularization of bacterial cellulose in wound repair. Then, the application of bacterial cellulose in wound repair was summarized, and the existing problems and prospects were also analyzed.

    RESULTS AND CONCLUSION: Bacterial cellulose secreted by the microorganism is of high purity and crystallinity. The nanofibers of bacterial cellulose form the porous network structure during static culture. It is considered as one of the ideal biomedical materials owing to its stable chemical structure, high water absorbency, good air permeability, great mechanical strength and biocompatibility. Especially in the field of wound repair, bacterial cellulose has been deeply studied and developed as the promising wound dressing, which is proven to promote tissue regeneration and accelerate wound healing.

     

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    Acellular scaffolds for tumor tissue engineering
    Ji Zhongjiao, Guo Yibing, Lu Yuhua
    2018, 22 (34):  5571-5576.  doi: 10.3969/j.issn.2095-4344.0973
    Abstract ( 283 )   PDF (673KB) ( 225 )   Save

     BACKGROUND: The development of acellular technology provides a new platform and approach for tumor tissue engineering, which can be used to fully simulate an in vivo microenvironment for tumor growth.

    OBJECTIVE: To review the application of acellular scaffolds in tumor tissue engineering.
    METHODS: PubMed database was retrieved for relevant articles published from 1995 to 2017, with the keywords of “tumor engineering; biomaterials; scaffold; 3D culture; decellularized; tumor microenvironment; ECM”.

    RESULTS AND CONCLUSION: Extracellular matrix prepared via decellularization is an ideal platform for cell culture in the terms of physiological and biochemical properties and spatial structure. It contains not only the basic components of the extracellular matrix-proteins and polysaccharides, but also specific growth factors and cytokines. In addition, a complete and specific vascular structure is also retained, which can simulate in vivo nutrient exchange via bioreactors perfusion devices. This platform for research on tumors is very close to the actual environment in the body. In recent years, with the development of tissue engineering, this three-dimensional cultivation method is becoming a hot issue in the field of tumor biology. Cell-cell and cell-extracellular matrix interactions are established in vitro, to simulate the actual tumor microenvironment, and rebuild tumor models in vitro. With the wide application and improvement of acellular technology, it will become an effective tool for the study on tumor biological behavior, drug screening and targeted therapy.

    中国组织工程研究杂志出版内容重点:生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程

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