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28 July 2022, Volume 26 Issue 21 Previous Issue    Next Issue

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Design and biological activity of beta-tricalcium phosphate biomimetic bone scaffold based on triply periodic minimal surfaces Wang Jinsi, Wang Shengfa, Wu Zhuguo, He Xiaoling, Wang Xinyu, Luo Xiaoyu, Zhao Yi, Zhang Jingying 2022, 26 (21):  3291-3297.  doi: 10.12307/2022.634 Abstract ( 552 )   PDF (4000KB) ( 87 )   Save BACKGROUND: The bone scaffold with complex porous structure can be customized accurately and individually by additive manufacturing technology, so as to achieve the dual bionics of the structure and function of cancellous bone at critical-sized bone defects. OBJECTIVE: To clear the mechanical properties and biological activity of β-tricalcium phosphate bioceramic bone scaffold with triply periodic minimal surface structure, and reveal the regulatory effect of triply periodic minimal surface structure on osteoblasts through material and cytological characterizations.  METHODS: Three kinds of triply periodic minimal surface G surface structure β-tricalcium phosphate bioceramic bone scaffolds with different pore sizes of 330, 420, and 510 μm were designed by Matlab R2020a software, and the design drawings were analyzed by Inspire 2018 software. The STL file exported based on the triply periodic minimal surface structure was the blueprint. β-Tricalcium phosphate scaffolds were fabricated by additive manufacturing technology based on digital laser processing. The surface morphology was observed by scanning electron microscope. The phase composition was detected by X-ray diffractometer, and the mechanical strength was detected by universal material testing machine. MC3T3-E1 cells were co-cultured with scaffolds. Cell proliferation, cell adhesion, and alkaline phosphatase activity were detected.    RESULTS AND CONCLUSION: (1) Inspire 2018 software showed that triply periodic minimal surface presented a smooth, continuous and uniform porous structure. (2) Scanning electron microscope confirmed that the additive manufacturing technology based on digital laser processing successfully realized the accurate molding of triply periodic minimal surface structure. (3) X-ray diffraction confirmed that the scaffold was composed of pure β-tricalcium phosphate crystal phase. (4) The compressive strength and elastic modulus of the three groups of scaffolds were all within or near the range of cancellous bone, and the compressive strength of the scaffolds was inversely proportional to the pore size. (5) CCK8 assay showed that MC3T3-E1 cells grew well on the scaffolds; the biological activity of the scaffolds was dose-dependent with the pore size; and the 510 μm pore diameter scaffold had the best effect on promoting proliferation. (6) Living cell imager and laser confocal microscope showed that MC3T3-E1 cells could adhere to the scaffold in the early stage, and the amount of adhesion increased with the increase of pore size. (7) Alkaline phosphatase activity analysis showed that the alkaline phosphatase activity of cells on 420 μm scaffold was the highest. (8) The results show that the mechanical properties and biological activity of the triply periodic minimal surface structure β-tricalcium phosphate bioceramic scaffold are excellent; the pore size of 420 μm is beneficial to cell differentiation and 510 μm is beneficial to cell proliferation, which has the potential to repair critical bone defects. Figures and Tables | References | Related Articles | Metrics

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Preparation and characterization of the composites of amino-modified artificial jaw nano-hydroxyapatite/polylactic acid Liu Longzhu, Long Yuanzhu, Yang Chengxue, Zhong Xinqi, Wang Yifang, Liu Jianguo 2022, 26 (21):  3319-3326.  doi: 10.12307/2022.638 Abstract ( 445 )   PDF (30310KB) ( 41 )   Save BACKGROUND: Bone graft materials and artificial bone substitutes are often selected for oral maxillofacial defects repair. Bone graft materials have their advantages, but the shortcomings exist such as immune response and insufficient sources. The application potential of artificial bone substitutes as materials for bone defects repair is huge.  OBJECTIVE: To explore the method of the preparation and characterization of the composites of amino-grafted nano-hydroxyapatite and polylactic acid as oral artificial jaw materials.  METHODS: The graft-modified nano-hydroxyapatite/polylactic acid composites were prepared based on amino-modified hydroxyapatite for making artificial jaws. The content of graft-modified nano-hydroxyapatite in the composite was 10%, 30%, and 50%, separately. Physical and chemical properties, mechanical properties, and cytocompatibility of the composite were characterized. RESULTS AND CONCLUSION: (1) The spectroscopy of 1H nuclear magnetic resonance, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis showed that the amino modifier diethylene glycol amine phosphate monoester of modified hydroxyapatite was successfully prepared. Under the transmission electron microscope, graft-modified nano-hydroxyapatite could still be dispersed in nanometer size in the organic solvent of the N,N-dimethylformamide. The stable dispersion state could be maintained for more than 180 days. (2) Scanning electron microscopy showed that when the content of the graft-modified nano-hydroxyapatite in the composite was 10% and 30%, an excellent nano-level dispersion effect exhibited. When the content was 50%, the modified nano-hydroxyapatite could not be uniformly dispersed in the poly lactic acid system. (3) With the increase of graft-modified nano-hydroxyapatite content, tensile strength decreased and elastic modulus increased. The results showed that graft-modified nano-hydroxyapatite content in the composite had better mechanical properties when the content was 10%. (4) CCK-8 assay results displayed that the composites of amino-grafted nano-hydroxyapatite (10% content) and polylactic acid have no obvious toxicity to mouse fibroblasts. (5) It is concluded that the composites of amino-grafted nano-hydroxyapatite (10% content) and polylactic acid have good mechanical properties and cytocompatibility.  Figures and Tables | References | Related Articles | Metrics

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Biomechanical properties of a novel bone cement screw and traditional methods for Kummell’s disease Zhan Yi, Kang Xin, Wang Yuhang, Zhang Haiping, He Simin, Sun Honghui, Hao Dingjun, Wang Biao 2022, 26 (21):  3381-3388.  doi: 10.12307/2022.648 Abstract ( 378 )   PDF (2960KB) ( 78 )   Save BACKGROUND: The serious complication of bone cement displacement is easy to occur when Kummell’s disease is treated with common bone cement filling method. OBJECTIVE: To analyze the biomechanical properties of the novel bone cement screw system, percutaneous vertebroplasty and percutaneous vertebroplasty combined with percutaneous pediculoplasty in treatment of Kummell’s disease with three-dimensional finite element method. METHODS: The collected CT data in Kummell’s disease patients were imported into Mimics image processing software to read the images. A three-segment three-dimensional finite element model of T12, L1, and L2 vertebrae was established (L1 was the diseased segment), and a novel cement screw model was reconstructed with Creo software. The three-dimensional finite element model of Kummell’s disease was repaired and treated with five options: novel unilateral cement screw placement, novel bilateral cement screw placement, percutaneous vertebroplasty combined with unilateral percutaneous pediculoplasty, and percutaneous vertebroplasty combined with bilateral percutaneous pediculoplasty, and pure percutaneous vertebroplasty. Maximum equivalent stress of T12 inferior endplate, maximum Von-Mises of bone cement, relative displacement of bone cement, and stability of bone cement under flexion, extension, left flexion, right flexion, and rotation conditions were analyzed. RESULTS AND CONCLUSION: (1) There was little change in the stress distribution of the inferior endplate of T12 under different schemes, and the maximum Von-Mises of inferior endplate of T12 of percutaneous vertebroplasty combined with unilateral and bilateral percutaneous pediculoplasty group was larger under different working conditions. The maximum Von-Mises of inferior endplate of T12 of other groups was smaller. (2) The maximum Von-Mises of bone cement of percutaneous vertebroplasty group was obviously larger than that of the other four schemes, and its stress distribution was not uniform. (3) The bone cement displacement of percutaneous vertebroplasty group was the largest under most working conditions, and the relative displacement of the bone cement in the other schemes was different under different working conditions. The relative displacement of the bone cement in the novel unilateral and bilateral cement screw groups was small under flexion, extension and lateral flexion. Under the rotation, there was no significant difference in the relative displacement of the bone cement between the novel unilateral and bilateral cement screw group and the percutaneous vertebroplasty combined with unilateral and bilateral percutaneous pediculoplasty group. (4) The cement displacement load ratio of novel unilateral and bilateral bone cement screw group was higher than those of other schemes. (5) Results showed that for the treatment of Kummell’s disease, the use of a novel bone cement screw treatment will have a more stable structure, can effectively avoid bone cement displacement. However, this study requires clinical confirmation of its practicability in the treatment of Kummell’s disease. Figures and Tables | References | Related Articles | Metrics

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Complication comparison and application improvement of 3D-printed plastic polyetherketone and titanium mesh cranioplasty Hu Junxian, Zhao Deying, Wang Lei, Huang Minghuo, Wu Yalan, Chen Jincao, Liu Zheng 2022, 26 (21):  3327-3331.  doi: 10.12307/2022.639 Abstract ( 464 )   PDF (2219KB) ( 47 )   Save BACKGROUND: There are many kinds of skull repair materials, but there is still no one material in high biocompatibility, high cost-effective and low incidence of complications in all aspects of clinical needs.  OBJECTIVE: To analyze the difference in postoperative complications of 3D printed plastic polyetherketone and titanium mesh cranioplasty, and point out the improvement directions. METHODS: Data of 207 patients undergoing cranioplasty in Huanggang Central Hospital of Yangtze University from June 2014 to June 2021 were retrospectively analyzed, including 157 males and 50 females, at the age of 16-68 years old. Among them, 42 patients were treated with polyetheretherketone and 165 patients were treated with titanium mesh. The satisfaction survey of the reconstruction of the frontotemporal parietal defect area was carried out at 3 weeks after the operation. Complications were analyzed during postoperative follow-up.   RESULTS AND CONCLUSION: (1) There were 32 cases of skull defect repaired with polyetheretherketone, with shaping satisfaction of 56.3%, and 117 cases of skull defect repaired with titanium mesh, with shaping satisfaction of 75.2%. Significant differences in shaping satisfaction were found between the two groups (P < 0.05). (2) Complications occurred in 14 of 42 cases in the polyetheretherketone group, including 12 cases of subcutaneous hydrops (28.6%), 1 case of epilepsy, and 1 case of forehead screw fixation swelling pain; with a complication rate of 33.3%. Among the 165 cases in the titanium mesh group, 28 cases had complications, including 15 cases of subcutaneous hydrops (9.1%), 7 cases of epilepsy, 2 cases of intracranial infection, 2 cases of material exposure, 1 case of intracranial hematoma, 1 case of material loosening, with a complications rate of 17.0%. There was a significant difference in the incidence of subcutaneous hydrops and total complication rate between the two groups (P < 0.05). (3) It is concluded that titanium mesh was better than polyetherketone mesh in repairing bone defect of frontotemporal parietal region, with a high satisfaction. The main improvement direction of polyetheretherketone in cranioplasty is to reduce the incidence of postoperative subcutaneous hydrops.  Figures and Tables | References | Related Articles | Metrics

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Genipin crosslinked sonic hedgehog composite fibrin scaffolds for the repair of spinal cord injury in rats Chen Pingbo, Wang Jing, Sun Yong, Xu Xiaofeng, Chen Qian, Zhang Zhijian 2022, 26 (21):  3345-3350.  doi: 10.12307/2022.642 Abstract ( 475 )   PDF (3584KB) ( 50 )   Save BACKGROUND: Tissue engineering scaffold transplantation is one of the most promising therapeutic methods for repairing spinal cord injury. Endogenous neural stem cells are recruited through tissue engineering scaffolds and promoted to differentiate into nerve cells to repair spinal cord injury. OBJECTIVE: To observe the effect of transplantation of genipin crosslinked sonic hedgehog (Shh) composite fibrin scaffolds into the injured spinal cord of rats on the repair of spinal cord injury and to explore the underlying mechanism.  METHODS: Fibrin glue, Shh composite fibrin scaffold, and genipin crosslinked Shh composite fibrin scaffold were prepared separately. In vitro degradation rate and sustained release performance of genipin crosslinked Shh composite fibrin scaffold were detected. Totally 120 female Sprague-Dawley rats were randomly divided into four groups (n=30). No material was implanted at the T10-T11 spinal cord injury site in group A. Fibrin glue was implanted in the T10-T11 spinal cord injury site of group B. T10-T11 spinal cord injury site was implanted with Shh composite fibrin scaffold in group C. Genipin crosslinked Shh composite fibrin scaffold was implanted at the T10-T11 spinal cord injury site in group D. After surgery, the rats were scored with BBB motor function every week. At 12 weeks after surgery, spinal cord tissue at and around the injury site was harvested and used for morphological observation and western blot assay.  RESULTS AND CONCLUSION: (1) Shh composite fibrin scaffold was basically completely degraded at 14 days. The degradation rate of the genipin crosslinked fibrin scaffold at 14 days did not exceed 20%. The Shh composite fibrin scaffold basically released the Shh at 7 days. Genipin crosslinked Shh composite fibrin scaffold released Shh explosively in 1-3 days, and slowly released Shh within 4-14 days, which had a good slow-release property. (2) As time went by, the BBB scores of motor function of rats increased in each group. The BBB scores of groups B and C were higher than those of group A at 12 weeks after surgery (P < 0.05). The BBB score of group D was higher than those in groups B and C at 12 weeks after surgery (P < 0.05). (3) Hematoxylin-eosin staining showed that the recovery from spinal cord injury site in group A was the worst, and the recovery in group D was the best. (4) Immunohistochemical staining and western blot assay showed that the expression of nestin, nerve growth-associated protein 43, neurofilament protein 200, and myelin basic protein was the lowest, and the expression of glial fibrillary acidic protein was the highest in group A. The expression of nestin, nerve growth-associated protein 43, neurofilament protein 200, and myelin basic protein was the highest, and glial fibrillary acidic protein expression was the lowest in group D. (5) It is concluded that genipin crosslinked Shh composite fibrin scaffold had a good slow-release effect and could promote the repair of rat spinal cord. Figures and Tables | References | Related Articles | Metrics

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Epigallocatechin gallate/hexanediamine coating grafted chlorhexidine improves the antibacterial properties of implants Yan Kaiquan, Liu Huishan, Wang Xiaowei, Wu Xiaoqin, Zhang Weibo, Li Xiangyang, Wang Yinlong, Chen Jialong 2022, 26 (21):  3332-3337.  doi: 10.12307/2022.640 Abstract ( 424 )   PDF (24219KB) ( 41 )   Save BACKGROUND: The complications caused by bacterial infection seriously affect the long-term efficacy of implants, so the antibacterial performance is of great significance in the design of implant surface.  OBJECTIVE: To construct chlorhexidine-loaded phenolic amine cross-linked coating on the surface of porous titanium, and to evaluate the antibacterial properties and osteoblast compatibility of the coating. METHODS: The titanium sheet was polished, cleaned, dried, and soaked in NaOH solution, placed in a 60℃ drying box for 24 hours, washed and dried in boiling water, and then recorded as the control group. The titanium sheet of the control group was immersed in the Tris solution containing epigallocatechin gallate and hexanediamine for 24 hours, washed and dried, and recorded as the phenolamine group. The titanium sheet of the phenolamine group was soaked in the chlorhexidine solution for 24 hours, washed and dried, and recorded as the chlorhexidine group. The samples were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle meter, and NH group quantification. The antibacterial ability of each group was evaluated by live/dead bacteria staining, bacteriostatic ring method, and turbidity method. The biocompatibility of each group was evaluated by methyl thiazolyl tetrazolium method and fluorescent staining. The cell adhesion ability of each group in the bacterial environment was evaluated by bacterial-cell coculture.  RESULTS AND CONCLUSION: (1) The surface of titanium sheet in the chlorhexidine group was covered by a large number of spherical particles, and the Cl2p peak appeared. The water contact angle rose to (24.6±3.3)°, and the NH content was (46.14±7.63) nmol/cm2, which proved that the coating was successfully constructed. (2) The antibacterial results showed that the bacterial adhesion on the surface of chlorhexidine group was the lowest and all of them were dead bacteria. There was a transparent bacteriostatic ring around the coating, and the bacteria did not proliferate in the culture system. It is proved that the coating can inhibit bacteria on and around the material. There were more bacteria on the surface of titanium sheets in the control group and the phenolamine group, and live bacteria were more common. There was no obvious antibacterial ring around, and the bacterial proliferation in the culture system was obvious. (3) Cell results showed that the titanium sheet in the chlorhexidine group slightly inhibited cell adhesion but did not affect cell proliferation. (4) Bacterial-cell coculture results showed that only chlorhexidine group adhered to a large number of cells, and the cell morphology was good. (5) The results confirmed that chlorhexidine grafted surface was successfully constructed and had good antibacterial ability, which was beneficial to the adhesion and proliferation of osteoblasts in the bacterial environment.  Figures and Tables | Related Articles | Metrics

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Effect of concentrated growth factor and bioceramic material iRoot BP on survival, proliferation and mineralization of human dental pulp cells in vitro Yan Qifang, Xie Cuiliu, Yan Guowei 2022, 26 (21):  3363-3368.  doi: 10.12307/2022.645 Abstract ( 408 )   PDF (3206KB) ( 60 )   Save BACKGROUND: Concentrated growth factors are rich in a variety of high-concentration growth factors, which can induce the proliferation of dental pulp cells and promote the repair of local dentin. OBJECTIVE: To compare the effects of concentrated growth factor and bioceramic material iRoot BP on the survival, proliferation and mineralization of human dental pulp cells in vitro, and then evaluate the feasibility of concentrated growth factor as a direct pulp capping material.  METHODS: The peripheral blood of healthy adults was collected and centrifuged to extract and concentrate growth factors. The modified tissue mass enzymatic digestion method was used to isolate and culture human dental pulp cells. The cells were treated with concentrated growth factor membrane extract and iRoot BP material extract. Cell proliferation was detected by the CCK8 assay. Human dental pulp cells were separately inoculated on the surface of the concentrated growth factor membrane and iRoot BP material to detect the alkaline phosphatase activity, cell cycle distribution, apoptosis and gene expression related to odontogenesis.  RESULTS AND CONCLUSION: (1) CCK8 assay showed that cell proliferation of the concentrated growth factor patch extract group was faster than that of the iRoot BP material extract group for 1, 3, and 7 days (P < 0.05). (2) The alkaline phosphatase activity of the cells of the concentrated growth factor group treated for 3 days was higher than that of the iRoot BP group (P < 0.05), and there was no significant difference in alkaline phosphatase activity between the two treatments for 1 and 7 days (P > 0.05). (3) The percentage of S-phase cells in the concentrated growth factor group treated for 1, 3, and 7 days was higher than that in the iRoot BP group (P < 0.05), and the apoptosis rate of cells on days 1, 3, and 7 was lower than that in iRoot BP group (P < 0.05). (4) The qRT-PCR test on the 7th day of treatment showed that the mRNA levels of Runx2, alkaline phosphatase, dentin sialophosphoprotein and osteocalcin in the concentrated growth factor group were higher than those in the iRoot BP group (P < 0.05). (5) The results show that concentrated growth factors can promote the survival, proliferation and mineralization of human dental pulp cells, and it is expected to be used as a direct pulp capping material. Figures and Tables | References | Related Articles | Metrics

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Apical sealing of GuttaFlow Bioseal in oval-root canals Shi Jinghua, Kang Wenyan, Man Dula, Liang Zhonghua, Wang Xiaoguang, Yin Yin, Zhang Lei 2022, 26 (21):  3389-3393.  doi: 10.12307/2022.649 Abstract ( 523 )   PDF (5930KB) ( 68 )   Save BACKGROUND: Tight obturation of oval root canals has become a major problem for clinicians. GuttaFlow Bioseal has good physical and chemical characteristics and biological properties, and its obturation of oval root canals has not been reported.  OBJECTIVE: To evaluate the apical sealing ability of GuttaFlow Bioseal root canal sealer in oval root canals.  METHODS: Ninety mandibular premolars with single oval-root canal were decoronated to obtain 14 mm root segments. The root canals were instrumented using Protaper files to F3. Roots were randomly divided into four groups. The root canals of group A (n=20) were obturated with AH-plus and the continuous wave of condensation technique. The root canals of group B (n=20) were obturated with iRoot SP and single gutta-percha cone. The root canals of group C (n=20) were obturated with GuttaFlow 2 and single gutta-percha cone. The root canals of group D (n=20) were obturated with GuttaFlow Bioseal and single gutta-percha cone. The group E (n=5) and group F (n=5) were served as the positive and negative control groups, respectively. The apical leakage and the filling of the lateral accessory canals were evaluated by dye penetration method and transparent teeth technique in each group.  RESULTS AND CONCLUSION: (1) There were significant differences in the length of leakage among groups A-D. The dye penetrated the entire length of the root canal in the positive control group. The dye did not penetrate into the root canal in the negative control group. The dye penetration length of group B was longer than that of groups A, C, and D (P < 0.05). The length of dye penetration among groups A, C, and D was not significantly different (P > 0.05). (2) The filling rate of lateral accessory root canals was not statistically significant among the group A (60%), group B (30%), group C (40%), and group D (50%) (P > 0.05). The overfilling rate in group A was significantly lower than that in groups B, C, and D (P < 0.05). There was no significant difference in the overfilling rate among groups B, C, and D (P > 0.05). (3) These results demonstrate that GuttaFlow Bioseal has good apical sealing ability and lateral accessory canal filling effect on oval root canals, with high filling efficiency, but with the disadvantage of high overfilling rate. Figures and Tables | References | Related Articles | Metrics

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Preparation and performance evaluation of composite tissue-engineered material hydrogel with sustained-release antibacterial microspheres Le Guoping, Xi Licheng 2022, 26 (21):  3298-3305.  doi: 10.12307/2022.635 Abstract ( 488 )   PDF (6616KB) ( 304 )   Save BACKGROUND: Oxidized hydroxypropyl methylcellulose-sodium hyaluronate hydrogel system exerts perfect mechanical properties, biocompatibility, and degradability, can be employed as a tissue engineered scaffold to protect and support injured tissues, and can also be applied as a drug carrier to achieve a regional sustained-release effect. OBJECTIVE: To prepare sustained-release antibacterial microsphere composite tissue-engineered material hydrogel, and investigate its physical and chemical, biological, osteoinductive, and antibacterial properties. METHODS: Using poly(lactic-co-glycolicacid), chitosan, and sodium hyaluronate as materials, a porous microsphere carrier with a multilayer structure was prepared by the emulsion method. Vancomycin hydrochloride was loaded to prepare sustained-release antibacterial microspheres. Oxidized hydroxypropyl methylcellulose-hydrazide-modified sodium hyaluronate was utilized as the matrix to prepare an injectable hydrogel. Different mass concentrations of antibacterial sustained-release microspheres (0.1, 0.2, and 0.3 g/mL) were added to the hydrogel to prepare an injectable hydrogel containing sustained-release antibacterial microspheres. The physical and chemical properties (determination of gel-forming time, swelling performance, degradation performance), biological properties (cytotoxicity, cell hemolysis), and osteogenic properties (alkaline phosphatase activity and osteogenic genes RUN-x2, bone morphogenetic protein 2, osteocalcin, type I collagen expression levels), and antibacterial properties were tested and evaluated.   RESULTS AND CONCLUSION: (1) The three kinds of sustained-release antibacterial microsphere hydrogels had good gel-forming properties and a small swelling ratio. The in vitro degradation scanning electron microscope results exhibited that the hydrogels had stable self-degradation properties. (2) The cytotoxicity experiment displayed that when the added number of sustained-release antibacterial microspheres was less than or equal to 0.2 g/mL, the hydrogel did not have remarkable cytotoxicity (the relative growth rate of cells within 7 days was all greater than 80%). The hemolysis experiment demonstrated that cell hemolysis rate of three kinds of the sustained-release antibacterial microsphere hydrogel was less than 2%, without obvious cell hemolysis. (3) Three kinds of sustained-release antibacterial microsphere hydrogels could increase the osteogenic gene RUN-x2, bone morphogenetic protein 2, type I collagen, osteocalcin contents, and alkaline phosphatase production in MG-63 cells. (4) These hydrogels could suppress the growth of Staphylococcus aureus continuously and for a long time, and the antibacterial ability of the hydrogels increased with the increased amount of sustained-release antibacterial microspheres. (5) These results show that the prepared injectable antibacterial microsphere hydrogel has perfect sustained-release antibacterial, osteogenic, and osteoinductive capabilities, as well as good biohistocompatibility and degradability.  Figures and Tables | References | Related Articles | Metrics

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Characterization of chitosan-modified polyetheretherketone and its effect on MC3T3-E1 cell adhesion and proliferation Feng Le, Qiu Peng, Liu Min, Zhou Hui 2022, 26 (21):  3351-3356.  doi: 10.12307/2022.643 Abstract ( 361 )   PDF (8238KB) ( 66 )   Save BACKGROUND: The biological inert surface of polyetheretherketone limits its medical application, so how to improve the biological activity of polyetheretherketone needs to be solved urgently.  OBJECTIVE: To analyze the surface characteristics of polyetheretherketone modified by chitosan bioactive coating and its effect on the adhesion and proliferation of MC3T3-E1 cells.  METHODS: Disc-shaped polyetheretherketone material was obtained and treated with NaBH4, 3-aminopropyltriethoxysilane, glutaraldehyde aqueous solution, and chitosan solution to form polyetheretherketone modified with chitosan bioactive coating. X-ray photoelectron spectroscopy, scanning electron microscope, atomic force microscope, and automatic contact angle measurement instrument were used to observe the surface characteristics of chemically treated polyetheretherketone. MC3T3-E1 cells were seeded on the surface of polyetheretherketone and chitosan-modified polyetheretherketone separately, and the proliferation and adhesion of the cells were observed.  RESULTS AND CONCLUSION: (1) X-ray photoelectron spectroscopy showed that the polyetheretherketone material only contained C and O elements. The chitosan modified polyetheretherketone material contained C, O, N, and Si elements. The contact angle on the surface of chitosan modified polyetheretherketone material was smaller than that of the polyetheretherketone material (P < 0.05). (2) Under the scanning electron microscope, the surface of the polyetheretherketone material had obvious groove-like undulations, and the surface of the chitosan-modified polyetheretherketone material had chitosan molecule. The size was 1.0-2.0 μm. Atomic force microscope exhibited that there were many tiny pits on the surface of the polyetheretherketone material, and the size was about 0.1 μm. The pits on the surface of the chitosan-modified polyetheretherketone material increased; the size was 0.2-0.5 μm, and the surface roughness was greater than that of the polyetheretherketone material. (3) Under an inverted microscope, the number of cells on the surface of the chitosan-modified polyetheretherketone material was more than that of the polyetheretherketone material (P < 0.05 ). Under a laser confocal microscope, the cells adhered to the surface of the polyetheretherketone material had poor stretchability, fewer pseudopods, and inconspicuous actin microfilaments. The extensibility of cells adhered to the surface of the chitosan-modified polyetheretherketone material was better; the pseudopodia were more; the actin microfilament was more and obvious. (4) CCK-8 experiment showed that the cell proliferation on the surface of the chitosan-modified polyetheretherketone material was faster than that of the polyetheretherketone material (P < 0.05). (5) These results confirm that chitosan surface modification increases surface roughness and wettability of polyetheretherketone, promotes adhesion and proliferation of MC3T3-E1 cells on the surface of the material.  Figures and Tables | References | Related Articles | Metrics

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Autologous, mixed and ligament advanced reinforcement system ligaments reconstruction of anterior cruciate ligament: evaluation of bone tunnel enlargement value, ligament growth factor and knee function Cao Fuyang, Xu Jianzhong, Lu Shitao, Tan Jun, Jiang Xu, Yang Meng, Shi Jianming, Chang Yingjian 2022, 26 (21):  3281-3290.  doi: 10.12307/2022.633 Abstract ( 725 )   PDF (1861KB) ( 41 )   Save BACKGROUND:  Anterior cruciate ligament knee reconstruction under arthroscopy is the most effective treatment for anterior cruciate ligament injury. However, the choice of graft in anterior cruciate ligament reconstruction is still controversial, which is the key problem to be solved facing clinicians.  OBJECTIVE: To explore the clinical efficacy of autologous, mixed, and simple ligament advanced reinforcement system ligaments in anterior cruciate ligament reconstruction.   METHODS: Totally 132 patients who were admitted to First Affiliated Hospital of Zhengzhou University from January 2016 to January 2019 and underwent anterior cruciate ligament reconstruction were enrolled in this study. These patients were divided into autologous group, mixed group, and artificial group (n=44) according to the different graft selections. Among them, the autologous group took the medial half tendon and femoral tendon of the calf tibial nodules and woven into autologous ligament for treatment. Patients in the mixed group were treated with semi-tendon, femoral tendon and ligament advanced reinforcement system artificial ligament graft. Patients with the artificial group were treated with ligament advanced reinforcement system artificial ligament. Before and 2 years after operation, Lysholm score, International Knee Documentation Committee (IKDC) score, Lachman test, Tegner score, and HSS score were used to evaluate the recovery of the knee. At the same time, the bone tunnel enlargement value, ligament growth factors, quality of life, and recovery time were observed.  RESULTS AND CONCLUSION: (1) The time for patients in the mixed group to resume daily activities and exercise after surgery was earlier than that of the autologous group and the artificial group (P < 0.05). The SF-36 score of the quality of life 2 years after surgery was higher in the mixed group than that of the autologous group and the artificial group (P < 0.05). The complication rates of the mixed group and the artificial group were lower than that of the autologous group (P < 0.05). (2) The knee joint function of the three groups of patients recovered to varying degrees. The Lysholm score, IKDC score, and Tegner score of the mixed group were higher than those of the autologous group and the artificial group at 0.5, 1, and 2 years after operation (P < 0.05). The KT1000 knee range of motion of the mixed group was less than that of the autologous group and the artificial group (P < 0.05) at 1 and 2 years after operation. The bone tunnel enlargement value at 1 year after operation was lower in the mixed group than that of autologous group and artificial group (P < 0.05). The HSS scores at 0.5, 1, and 2 years after operation were higher in the mixed group than those of the autologous group and the artificial group (P < 0.05). The number of normal people in Lachman test at 2 years after operation was more in the mixed group than that of autologous group and artificial group (P < 0.05). (3) The levels of ligament growth factor transforming growth factor β1 and basic fibroblast growth factor in the mixed group were higher than those in the autologous group and the artificial group at 0.5, 1, and 2 years after surgery (P < 0.05). (4) It is concluded that the mixed ligament can be used as the primary graft for clinic, and is more helpful in helping patients return to normal work and life as soon as possible. However, the use of mixed ligaments still has practical problems, such as the need to extract autologous tendons and high medical costs. Figures and Tables | References | Related Articles | Metrics

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Preparation of protein chips for screening matrix for Muse cell culture based on fibrinogen and gelatin Li Xiuya, Sheng Yang, Wang Shengyi, Li Yue, Zhang Ruzhi, Pan Yan, Sun Yixin, Deng Linhong, Mark Bradley, Zhang Rong 2022, 26 (21):  3312-3318.  doi: 10.12307/2022.637 Abstract ( 415 )   PDF (4019KB) ( 71 )   Save BACKGROUND: Stress-tolerant multilineage differentiated (Muse) cells have excellent medical potential for regenerative medicine. However, at present, Muse cells need to be cultured and proliferated in vitro by suspension of cell aggregation, which is not conducive to large-scale expansion and application. Protein is one of the important components of extracellular matrix. Different proteins play different roles in cell growth. Therefore, the high-throughput method can be used to rapidly screen protein matrix that is conducive to the adhesion and proliferation of Muse cells on a two-dimensional surface.  OBJECTIVE: To identify suitable protein substrates for surface adhesion and passaging of Muse cells. METHODS: Bovine serum albumin, bovine blood fibrin, and gelatin were used as raw materials, and their solutions were printed on glass slides by an ink jet printer and mixed on site to prepare protein microarray chips. The optimal protein combination for the adhesion of Muse cells was identified by using high-throughput screening approach. The Muse cells were cultured and passaged on the identified protein substrates for characterization.  RESULTS AND CONCLUSION: (1) Two protein combinations were obtained by high-throughput screening, which were beneficial to the adhesion of primary Muse cells. They were bovine serum albumin/gelatin and bovine blood fibrinogen/gelatin, with combination ratios of 7/17 for both. (2) CCK-8 assay showed that Muse cells proliferated well in all groups. Among them, cells cultured on plates coated with bovine blood fibrinogen/gelatin proliferated well in 6 days. (3) By analyzing the immunofluorescence staining results of passages 1 and 3 of Muse cells cultured on the protein-coated plate, it was found that the combination of bovine blood fibrinogen and gelatin with a ratio of 7/17 in weight supported the adhesion and proliferation of Muse cells for at least 3 passages, maintaining good stem cell characteristics.  Figures and Tables | References | Related Articles | Metrics

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Effect of hydroxyapatite three-dimensional scaffolds with different apertures on the biological properties of MC3T3-E1 cells Yang Jiaojiao, Hu Ming, Li Yan, Xia Delin 2022, 26 (21):  3338-3344.  doi: 10.12307/2022.641 Abstract ( 474 )   PDF (5967KB) ( 75 )   Save BACKGROUND: The aperture of bone tissue engineering scaffold is one of the important indexes to evaluate its biological performance, and seeking the best combination of aperture and mechanical properties has always been an urgent problem to be solved in bone tissue engineering.  OBJECTIVE: To prepare three-dimensional scaffolds with different aperture gradients and to study their effects on the biological behavior of MC3T3-E1 cells.  METHODS: The three-dimensional nano-hydroxyapatite scaffolds with uniform pore size were prepared by mixing wax spheres of specific diameter (300, 500, 800 μm) with hydroxyapatite as pore-forming agent using the modified particle leaching method, which were recorded as the D300, D500, and D800 scaffolds, respectively. The wax spheres of three diameters were piled up in order from small to large. The pore gradient nano-hydroxyapatite three-dimensional scaffold was prepared by the modified particle leaching method, which was recorded as the D-Gradient scaffold. The porosity of scaffolds of the four groups was measured. MC3T3-E1 cells were inoculated on scaffolds of the four groups. The cells cultured separately were used as the blank control group. Cell proliferation activity, alkaline phosphatase activity, cell adhesion, cytoskeleton rearrangement and the transcription level of osteogenic differentiation marker factors were detected.  RESULTS AND CONCLUSION: (1) The porosity of scaffolds of the four groups was 60%-80%. (2) After 24 hours of inoculation, the scaffolds in each group could promote the proliferation of MC3T3-E1 cells. The proliferation index was: D-Gradient group > D500 group > D800 group > D300 group > blank control group. The scaffolds in the D300 group, D500 group, and D-Gradient group promoted the secretion of alkaline phosphatase in MC3T3-E1 cells. The amount of alkaline phosphatase secretion was: D300 group > D500 group > D-Gradient group > D800 group ≈ blank control group. The scaffolds in the D300 group, D500 group, and D-Gradient group promoted the expression of osteopontin and osteocalcin mRNA in MC3T3-E1 cells. The expression levels of the two genes from high to low were: D300 group > D500 group > D-Gradient group > D800 group ≈ blank control group. (3) Immunofluorescence staining after 48 hours of inoculation showed that compared with the blank control group, MC3T3-E1 cells on the four scaffolds showed better adhesion and locomotor activity. The fluorescence intensity of focal adhesion actin from high to low was: D-Gradient group > D500 group > D800C group > D300 group > blank control group. (4) It is concluded that the aperture gradient scaffolds promote the growth, proliferation, adhesion, and osteogenic differentiation of MC3T3-E1 cells. Figures and Tables | References | Related Articles | Metrics

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Preparation of a polydopamine modified hemerythrin-based nano-oxygen carrier and performance testing Yang Kang, Zhao Huimin, Fan Haojun, Su Xie, Wu Guojun 2022, 26 (21):  3369-3374.  doi: 10.12307/2022.646 Abstract ( 514 )   PDF (3532KB) ( 75 )   Save BACKGROUND: Hemerythrin may be superior to mammalian hemoglobin in terms of molecular stability and low toxicity. Polydopamine modification may further exert its advantages as a hemoglobin oxygen carrier; however, it has not been reported yet.  OBJECTIVE: To prepare a polydopamine modified hemerythrin-based nano-oxygen carrier and examine its performance.  METHODS: The sample of hemerythrin was purified from Eisenia foetida, and bovine hemoglobin was used as a control. The chemical modification reaction was completed with dopamine hydrochloride in a 1:2 mass ratio under pH=8.5-8.8 condition to construct polydopamine modified hemerythrin nanoparticles (PDA-HrNPs) and polydopamine modified bovine hemoglobin nanoparticles (PDA-BHbNPs). The diameter, polymer dispersity index, Z potential, functional molecular group, P50, and Hill coefficient were measured. Two groups of nanoparticles with different mass concentrations [0 (normal control), 1.0, 2.5, 4.0, 5.5 g/L] were co-cultured with vascular endothelial cells or macrophages, respectively. The survival rate of macrophages was measured at 6, 12, and 24 hours after culture. The survival rate of vascular endothelial cells and the concentration of NO in the culture medium were measured at 24 hours after culture.  RESULTS AND CONCLUSION: (1) Infrared spectroscopy of PDA-HrNPs showed that the amide bond bands I and II continued to exist, and a new group band formed by the cross-linking of polydopamine and hemerythrin molecules appeared between 800 and 1000 cm-1. PDA-HrNPs particle size: (202.2±13.64) nm, polymer dispersity index: 0.22±0.05, Z potential: (1.28±0.87) mV, P50: (1.44±0.02) kPa, Hill coefficient: 1.58±0.02. (2) The survival rate of macrophages cultured with two kinds of nanoparticles was lower than that of the normal control group (P < 0.05). The survival rate of macrophages decreased with the increase in time. The survival rate of macrophages at 6 hours in the PDA-HrNPs group was significantly better than that in the PDA-BHbNPs group at the same concentration (2.5, 4.0, and 5.5 g/L) (P < 0.05). (3) After 24 hours of culture, with the increase in the mass concentration of nanoparticles, the survival rate of vascular endothelial cells cultured with two kinds of nanoparticles and the NO concentration in the culture medium decreased. There was no significant difference in the survival rate of cultured cells and the NO concentration in the culture medium between the two kinds of nanoparticles at the same mass concentration (P > 0.05). (4) It is shown that the PDA-HrNPs have good oxygen-carrying activity and safety. The antiphagocytic performance of PDA-HrNPs is better than that of PDA-BHbNPs.  Figures and Tables | References | Related Articles | Metrics

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Effect and histocompatibility of expended polytetrafluoroethylene in modified Blalock-Taussig shunt Zhou Shicheng, Han Hongguang, Ji Fang, Xu Liying, Zhang Xiaohui, Sun Chang 2022, 26 (21):  3394-3400.  doi: 10.12307/2022.650 Abstract ( 463 )   PDF (1750KB) ( 93 )   Save BACKGROUND: Modified Blalock-Taussig shunt surgery is commonly used in severe cyanotic congenital heart disease. This surgery requires the establishment of new internal and external blood circulation pathways based on the anatomy and the development of the heart and lungs. At this time, a suitable blood vessel replacement is indispensable.  OBJECTIVE: To evaluate the effect and histocompatibility of expended polytetrafluoroethylene in modified Blalock-Taussig shunt. METHODS: Totally 62 patients who were diagnosed with congenital heart disease and underwent a modified Blalock-Taussig shunt with expended polytetrafluoroethylene vessels at the age of 3 months-15 years were admitted from June 2009 to December 2019 in the General Hospital of Northern Theater Command. According to whether death occurred during hospitalization and follow-up, 57 cases were in the survival group and 5 cases were in the death group. The occurrence of complications was compared between the two groups. Binary logistic regression was used to analyze the risk factors of death. For the survivors, follow-up was performed to observe the histocompatibility of the expended polytetrafluoroethylene artificial vessel.  RESULTS AND CONCLUSION: (1) Postoperative SaO2 in patients increased immediately to above 80% with cyanosis alleviated significantly. Severe hypotension and arrhythmias occurred during the surgery in 8 patients (12.9%), 5 of which died in the perioperative phase in the death group. All the remaining 57 patients were followed up for one year. There were significant differences in the early postoperative bedside dialysis, hemoglobinuria, and perfusion lung between the two groups (P < 0.05). (2) Binary logistic regression analysis showed that low weight and severe low cardiac output during the surgery were risk factors for postoperative death after modified Blalock-Taussig shunt (P < 0.05). (3) During follow-up, the modified Blalock-Taussig shunt improved the development of the left ventricle and pulmonary artery. There was no occurrence of biological and anatomical adverse consequences like artificial conduit rupture or avulsion, hemolysis, rejection, nonstructural dysfunction, or structural injury. (4) The results show that Blalock-Taussing shunt for complex congenital heart disease can significantly relieve symptoms and promote the development of the left ventricle and pulmonary artery. The expended polytetrafluoroethylene has good short-term histocompatibility.  Figures and Tables | References | Related Articles | Metrics

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Design of an automatic measurement system for the micro-mechanical properties of three-dimensional printing biomaterials Feng Chen, Zhou Jiping, Xu Xiaodong, Jiang Yani, Shi Hongcan, Zhao Guoqi 2022, 26 (21):  3306-3311.  doi: 10.12307/2022.636 Abstract ( 353 )   PDF (6465KB) ( 74 )   Save BACKGROUND:  In the existing evaluation system of tissue engineering scaffolds, it is usually necessary to test the mechanical strength of scaffolds in many aspects to ensure that they can meet the requirements of clinical application. However, because the measurement of mechanical properties of biological composite materials is a small deformation measurement, it is difficult to have professional measuring instruments on the market to meet the accuracy requirements. The commonly used hardness tester or tensile tester is difficult to meet the requirements of the mechanical properties of the scaffold.   OBJECTIVE: To develop a device with the function of automatic detection of hardness and toughness to detect the mechanical properties of the biological scaffold. METHODS: This test system used two sets of differential bridges to realize the output of stress and strain respectively, and mechanical tests were conducted in different ways under constant temperature, humidity and strain rate to obtain various mechanical properties of the material. Aiming at the particularity of composite biomaterials, the equipment testing of biocomposite materials composed of nanocellulose and polycaprolactone was conducted to verify whether this test system can meet the requirements. RESULTS AND CONCLUSION: Through experiments, the test system could accurately reflect the mechanical properties of biomaterial scaffolds. Taking the slope of the “force displacement” loading curve of the tested scaffolds as the characterization of the toughness/hardness of the scaffolds, the mechanical properties of the scaffolds could be visualized, and the accuracy of the test system could reach 0.1 μm. It has theoretical basis and application value for the establishment of three-dimensional bioprinting in tissue damage repair. Figures and Tables | References | Related Articles | Metrics

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Different material attributes are assigned to the vertebral body for statics analysis Guan Tianmin, Chen Xiangyu, Zhu Ye, Ren Dong 2022, 26 (21):  3357-3362.  doi: 10.12307/2022.644 Abstract ( 350 )   PDF (5296KB) ( 44 )   Save BACKGROUND: Human bones are characterized by strong nonlinearity and uneven bone distribution. Different elastic modulus assignments lead to great differences in static results.  OBJECTIVE: To analyze differences of the three material attribute assigning methods in the numerical simulation analysis of vertebral body. METHODS: Based on the principle of reverse engineering, lumbar L4, L5 and intervertebral disc models were established through image segmentation, and three material attributes were assigned to the vertebral body models: (1) Gray value assignment: Gradient value was assigned by using gray value through Mimics. (2) Homogeneous and gray value mixed assignment: A single elastic modulus was given to the anterior cortical bone of the vertebral body, and gray values were used to give to the cancellous bone of the front end and the pedicle, transverse process and spinous process of the posterior end. (3) Cortical bone and cancellous bone assignment: Two elastic moduli of cortical bone and cancellous bone were used. The finite element model under the three assignment methods was loaded with an axial load of 100-500 N. The bending moments of 2, 4, 6, 8, and 10 N·m were applied to simulate the vertebral body to perform forward flexion, backward extension, left and right lateral bending and left and right rotation. RESULTS AND CONCLUSION: Vertebral body under different loading conditions had obvious differences in axial displacement and deflection angle. Root mean square error analysis showed that compared with the other two methods, data obtained by grey value assignment method were more close to the real experimental data. It did not produce obvious stress step phenomenon in material assignment junction, and could not produce obvious stress concentration phenomenon, was more in line with the mechanical properties of vertebral body. Thus, more accurate statics analysis of the spine can be carried out. Figures and Tables | References | Related Articles | Metrics

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Effects of three kinds of mattresses on early sacrococcygeal compression injury in human body Yang Yalan, Zhong Shuxian, Shi Jiahui, Zhou Junli, Wang Xiaojun 2022, 26 (21):  3375-3380.  doi: 10.12307/2022.647 Abstract ( 398 )   PDF (32761KB) ( 43 )   Save BACKGROUND: Reduction of sacrococcygeal pressure is the most direct and effective method to prevent the early sacrococcygeal pressure injury. Currently, there are a variety of materials in the market, but there is still insufficient evidence for the correct selection of pressure-relieving mattress in clinical practice. OBJECTIVE: To measure the sacrococcygeal pressure value, sacrococcygeal skin temperature value and observe the change of skin color of healthy people lying supine on three kinds of mattresses at different periods, in order to explore a medical mattress with better decompression effect. METHODS: Totally 33 healthy subjects were selected from First Affiliated Hospital of Guangzhou University of Chinese Medicine aged 18 to 35 years old, body mass index of 18.5-23.9 kg/m2. At 1, 2, and 3 days of the experiment, subjects were recumbent in latex mattresses, static pressure ulcers prevention mattresses, and ordinary mattress. At set time points (0, 0.5, 1.0, 1.5, 2.0 hours), the sacral pressure value, the tail in the cauda equina compression of color, and skin temperature were detected.  RESULTS AND CONCLUSION: (1) After 0.5-2 hours of test, the sacrotail pressure of latex mattress group was lower than that of static pressure ulcers prevention mattresses group and ordinary mattress group (P < 0.05). (2) There was no significant difference in the temperature values of the compression parts of the three mattress groups during 0-0.5 hours (P=0.587). During 0.5-2.0 hours of the test, the temperature of pressure position in latex mattress group was lower than that in static pressure ulcers prevention mattresses group and ordinary mattress group (P < 0.05). (3) During 0.5-1.5 hours of the test, the color of the sacrococcygeal compression parts of the subjects in the three mattress groups did not change. During the experiment of 1.5-2.0 hours, the color of the sacrococcygeal compression site of the subjects in the latex mattress group did not change, while that of the static pressure ulcers prevention mattresses group altered in one case, and that of the ordinary mattress group altered in two cases. (4) The results showed that, compared with the other two mattresses, the latex mattress can effectively reduce the sacrococcygeal pressure, and has good heat dissipation and air permeability, and plays an effective role in preventing the early pressure injury.  Figures and Tables | References | Related Articles | Metrics

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Advantage of mesoporous materials in bone repair Gao Feifei, Du Bin, Liu Xin, Chen Hao, Chen Yang, Hou Wei 2022, 26 (21):  3401-3409.  doi: 10.12307/2022.651 Abstract ( 717 )   PDF (1586KB) ( 125 )   Save BACKGROUND: Mesoporous materials are characterized by high specific surface area, high entrance, and continuous aperture control, and good control-released carrier materials. Its application in the field of bone repair is various.  OBJECTIVE: To summarize the application of mesoporous materials in bone repair. METHODS: The first author searched the relevant articles in PubMed, Web of Science, CNKI, and Wanfang databases from January 1990 to April 2021 with the search terms of “mesoporous nanoparticles, biological materials, control release, bone regeneration, mesoporous materials, support material, nanomaterials, porous materials” in English and “biomaterials, mesoporous materials, bone regeneration, bone repair, drug controlled release, scaffold materials, nanomaterials, porous materials” in Chinese. A total of 72 articles were finally included for analysis and summary. RESULTS AND CONCLUSION: (1) Mesoporous materials have unique advantages for bone defect diseases. The mesoporous low nanometer pore size can effectively control the long-term and stable release of drugs (such as bone morphogenetic protein and gentamicin). Some mesoporous materials can not only be absorbed by organisms, but also have osteoinductive activity to promote bone formation. Some materials not only have high mechanical strength, but also have excellent characteristics such as light weight. (2) At present, the main types of materials that have been studied in this area are: silicon-based materials, carbon materials, hydroxyapatite, bioglass, and metal materials. These materials have stable structure, easy surface functionalization, good biocompatibility, and good mechanical properties, which make these materials become excellent materials for repairing bone defects. (3) In silicon-based materials, the hollow microsphere structure of silicon dioxide makes it carry a large amount of drug, and the silicate materials can be absorbed by organisms or integrated with bones. (4) There are two types of mesoporous carbon materials. One is mesoporous carbon microspheres, which are hollow spheres with a large drug loading capacity and can be metabolized by organisms. The other is mesoporous carbon nanotubes, which have extremely high mechanical strength, light weight and electrical conductivity. It has a certain osteoinductive ability and can be used as a bone replacement material, which makes it the most promising bone repair material, and even replaces defective limbs as a new type of biological prosthesis. (5) Hydroxyapatite presents osteoconductivity and has been widely used in the clinical treatment of bone repair (such as dental restoration materials). After its mesoporous loading of bone morphogenetic protein, it can not only promote bone regeneration and hydroxyapatite can be absorbed by organisms when it is implanted in non-weight-bearing bone defects. (6) The degradation products of mesoporous bioglass, that is, the third generation of bioglass, in the body have the properties of promoting osteogenesis. Due to the synthetic diversity of such materials, its enhanced structural functions and good biocompatibility make it the best bone repair materials. (7) Research on the use of metal materials as bone substitute materials found that after researchers mesoporated the surface of metal implants, even without drugs, the osteoblasts on the surface of the implants cling better than ordinary implants. Figures and Tables | References | Related Articles | Metrics

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Application of copper ion in bone tissue engineering: biocompatibility, antibacterial properties, angiogenic activity and osteogenic activity Guo Sutong, Guo Yu, Wang Ling, Li Yaxin, Ding Yujian, Gao Jingfeng, Xu Haitao, Ren Tianhao, Feng Dehong 2022, 26 (21):  3410-3414.  doi: 10.12307/2022.652 Abstract ( 808 )   PDF (1456KB) ( 145 )   Save BACKGROUND: Due to its good biocompatibility, antibacterial activity, angiogenic activity and osteogenic activity, copper ion has been increasingly studied and applied in the field of bone tissue engineering. OBJECTIVE: To summarize the research and application of copper ion in bone tissue engineering and its future development direction. METHODS: The relevant articles published between February 2000 and February 2021 were retrieved on PubMed, CNKI and Wanfang databases. The English and Chinese search terms were “copper, biocompatibility, antibacterial properties, angiogenesis, osteogenic differentiation, bone tissue engineering”.  RESULTS AND CONCLUSION: (1) In the field of bone tissue, copper ion has good biocompatibility, antibacterial activity, angiogenic activity and osteogenic activity. At the cellular level, copper ions can promote the differentiation of osteoblasts, inhibit osteoclast differentiation and affect bone metabolism. At the molecular biology level, copper ions can affect the hypoxia-inducible factor 1α pathway and ERK1/2 signal transduction, Integrin signaling, and TLR signaling, which affect bone metabolism. (2) There are relatively few studies on the mechanism of copper angiogenesis and osteogenesis. (3) The research on the application of copper ions in bone tissue engineering may reduce the occurrence of periprosthesis infection and prosthesis loosening to some extent. Figures and Tables | References | Related Articles | Metrics

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Application of chitosan biomaterial scaffold in the treatment of infectious bone defects Tian Yuhang, Liu Yadong, Cui Yutao, Liu He, Li Shaorong, Wang Gan, Fan Yi, Peng Chuangang, Wu Dankai 2022, 26 (21):  3415-3420.  doi: 10.12307/2022.653 Abstract ( 604 )   PDF (4690KB) ( 62 )   Save BACKGROUND:  In the process of treating bone defects, chitosan biomaterial scaffolds can be prepared to implant the defect site, which can effectively improve the biocompatibility and biodegradability, reduce the generation of side effects, and provide a new method for treating bone defects. OBJECTIVE: To introduce the latest application progress of chitosan biomaterial scaffold and its functions, describe the application in the treatment of infectious bone defects, and discuss the current research points and future trends. METHODS: Using “chitosan, scaffold, bone defect, bone tissue engineering” as keywords, articles were retrieved on PubMed, Web of Science, Springerlink, Medline, Wanfang, and CNKI databases from 2008 to 2020. A total of 198 articles were firstly examined and 51 articles were selected for further analysis. RESULTS AND CONCLUSION: Chitosan can be used as an antibacterial agent to treat drug-resistant bacteria. As an osteoconductive substance, chitosan can promote cell adhesion and proliferation. Chitosan can also be modified and combined with various biological materials to enhance its mechanical properties and functionality. Simultaneously, chitosan can also be used as an injectable hydrogel to fill bone defect sites in any shape. However, there are still deficiencies in intensity, and it is difficult to achieve better supporting effect while ensuring antibacterial activity. At present, most researches still focus on combining with other biological materials to enhance their mechanical properties. In addition, most of the application research of chitosan biomaterials is still in the experimental stage, and has not been truly applied in clinical practice. Improving the preparation process of chitosan biomaterials will contribute to the research and development of bone repair biomaterials with more functions. In the near future, chitosan can be combined with 3D printing technology, genetic engineering, and medical imaging technology to open up a new path for bone repair in the field of bone tissue engineering. Figures and Tables | References | Related Articles | Metrics

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Performance optimization of a new type of calcium silicate (based) scaffold matched with bone tissue regeneration in the bone defect area Zhang Chunyu, Hu Baoyang, Feng Yao, Zhang Wanfen, Sun Leiye, Yang Yan 2022, 26 (21):  3421-3428.  doi: 10.12307/2022.654 Abstract ( 526 )   PDF (4732KB) ( 143 )   Save BACKGROUND: Calcium silicate scaffolds have attracted more and more attention, because of their high biocompatibility, osteoinduction and osteoconduction activities, and a degree of biodegradation. However, due to the unstable osteogenic effect, fast degradation rate and poor mechanical properties of calcium silicate, it has not yet been used in clinical bone defect repair.  OBJECTIVE: To review research progress in optimizing the performance of calcium silicate scaffolds, summarize the potential and insufficiency of the single-phase calcium silicate scaffolds applied in bone defect repair, and to explore the possibility of its use in clinical bone defect repair. METHODS: The search was performed on CNKI, Wanfang, PubMed, Elsevier, and Web of Science databases. With the keywords of “3D print, calcium silicate, osteogenesis, composite modification, angiogenesis, stress distribution, bone defect repairing” in Chinese and English, related articles in recent 20 years were retrieved. According to the inclusion and exclusion criteria, 83 papers were finally reviewed. Based on the final screening articles, the research progress and challenges of the performance optimization of calcium silicate based scaffolds in bone tissue engineering were systematically and comprehensively analyzed.  RESULTS AND CONCLUSION: (1) Calcium silicate materials have a certain potential to promote osteogenic and angiogenic differentiation of bone marrow mesenchymal stem cells, and have certain degradability. Free Ca2+ and Si4+ can induce hydroxyapatite deposition, promote collagen- I secretion and differentiation of osteoblasts, thereby increasing bone mineral density and promoting mineralization. Now, it has become one of the most promising frontier research direction in the field of bone repair. (2) However, single-phase calcium silicate scaffolds are not fully suitable for bone tissue regeneration in bone defect area in terms of mechanical properties, biological activity, and degradation rate, so it has not been widely used in clinical practice. (3) At present, there are abundant studies on the performance optimization of calcium silicate scaffolds, but there is a lack of systematic summary. In this study, through a large number of literature summary and data extraction, the performance optimization methods of calcium silicate scaffolds are classified into two categories, namely, the optimization of scaffold structure and the optimization of scaffold material composition. (4) 3D printing technology has a prominent effect on the structure optimization of calcium silicate scaffolds. By accurately regulating the porosity and pore size of the scaffolds, 3D printing technology can make the calcium silicate scaffolds have better stress distribution mode and osteogenic and angiogenic effect. (5) The optimization of the composition of calcium silicate scaffolds is based on the influence of composite materials (including inorganic ions, molecules, organic molecules, and high polymer) on the biochemical structure of scaffolds in many aspects, so as to improve mechanical properties of calcium silicate scaffolds as well as the bioinduction properties of osteogenesis and angiogenesis. (6) In conclusion, the comprehensive use of 3D printing technology and composite modification of materials is a new idea for the studies of calcium silicate scaffolds in the field of bone repair. Based on the disadvantages of single-phase calcium silicate scaffolds in the application of bone defect repair, by optimizing and modifying the structure, composition and surface conditions of the calcium silicate scaffolds, a new type of calcium silicate-based tissue engineered bone scaffold, which can effectively promote osteogenic differentiation and bone mineralization, and whose mechanical properties and degradation rate could match the regeneration of bone tissue in bone defect area, will be explored.  Figures and Tables | Related Articles | Metrics

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Application of polyurethane materials in the repair of osteoporotic bone defects Wang Lu, Li Limei, Li Qing, Yang Hongcai, Lan Xiaoqian, Hu Yingrui 2022, 26 (21):  3429-3434.  doi: 10.12307/2022.655 Abstract ( 413 )   PDF (1353KB) ( 78 )   Save BACKGROUND: Polyurethane scaffolds, as the basic framework of bone tissue engineering, have good biocompatibility, degradability, plasticity and bone conductivity, which is an effective method for the treatment of bone defects caused by osteoporosis. OBJECTIVE: To review the therapeutic effect of polyurethane system on bone defects, and to explore the combination of polyurethane with active components of osteogenesis so as to promote research idea of the repair of osteoporotic bone defects. METHODS: Using “osteoporosis, bone defect, polyurethane repair, polyurethane loaded drug, optimize physical structure” as English key words, PubMed was searched for articles published from 2003 to 2020. Using “osteoporosis, polyurethane repair, bone defect, loaded active factor, loaded drug” as Chinese key words, CNKI was retrieved for articles published from 2007 to 2021.  RESULTS AND CONCLUSION: At present, the traditional polyurethane materials used for bone repair are not well targeted for osteoporotic bone defects, and its structural design and biological function need to be further optimized to better meet the needs of osteoporotic bone defect treatment. On the one hand, the regulation of its mechanical strength, to ensure that the necessary bone conductibility, stable internal fixation of bone defect does not occur reset loss, and to provide three-dimensional space for bone tissue regeneration; these are mainly achieved through the design of the polyurethane monomer composition and structure of new type, to ensure that the corresponding mechanical matching, to prevent the further development of the fracture and secondary fracture risk. On the other hand, in order to accelerate bone healing, it is necessary to give polyurethane bioactive components to mediate the dynamic balance of osteogenesis and osteoclasts and accelerate bone defect regeneration. In addition, in order to improve the pathological environment of osteoporosis, targeted sustained release drugs for osteoporosis have great application prospects. However, how to combine anti-osteoporosis drugs into polyurethane materials effectively, ensure its long-term controlled release, match its release kinetics with the process of osteogenesis, and control its usage within a safe range remains to be further studied in detail. Figures and Tables | References | Related Articles | Metrics

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Relationship of the design of different bone tissue engineering scaffolds with the changes of osteoconduction, osteoinductivity and biodegradability Wang Diaodiao, Sun Yuyang, Tian Zhuang, Zhang Chu, Li Hanchen, Yao Qi 2022, 26 (21):  3435-3444.  doi: 10.12307/2022.656 Abstract ( 488 )   PDF (1659KB) ( 134 )   Save BACKGROUND:  Bone grafts are the main method for the treatment of bone defects in clinic. Due to the limitation of autografts and allografts, bone tissue-engineered materials have become particularly important as a substitute. The ideal bone tissue-engineered materials must have good biological characteristics, which depend on the microstructure and chemical properties of the scaffold material. OBJECTIVE: How do different designs of bone tissue engineering scaffolds affect the biological characteristics of bone conductivity, osteoinductivity, and biological degradability of scaffolds. METHODS: Keywords were “bone tissue engineering, osteoconduction, osteoinductivity, adhesion, diffusion, physical characteristics, chemical characteristics, structural characteristics, growth factors, ions, biological degradability, polymer, inorganic material, metal” in Chinese and English. CNKI and PubMed databases were searched for articles regarding biological characteristics of bone tissue engineering scaffolds published from January 2000 to July 2021. Finally, 91 articles were included for review. RESULTS AND CONCLUSION: (1) In the design of bone tissue engineering scaffolds, factors affecting osteoinductivity and osteoconduction contain material stiffness, wettability, biochemical factors, surface biochemical structure, structural agent, pore structure, and surface morphology. In addition, the factors affecting bone inducibility also include the delivery of differentiation inducing substances. (2) The design of bone conduction and bone induction can improve the above factors, and then promote bone regeneration by promoting the adhesion of proteins and regulating the cell-scaffold interaction. (3) The biodegradability of scaffolds is mainly related to material properties, and different kinds of materials such as polymers, inorganic materials and metals have different degradation characteristics and mechanical properties. (4) In the design of scaffolds, materials with different properties can be combined to promote the degradation of scaffolds and balance the relationship between the degradation of materials and mechanical properties. Figures and Tables | References | Related Articles | Metrics