The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two ...The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting (SLM) technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.展开更多
Peripheral nerve injury is a common clinical problem and affects the quality of life of patients. Traditional restoration methods are not satisfactory. Researchers increasingly focus on the field of tissue engineering...Peripheral nerve injury is a common clinical problem and affects the quality of life of patients. Traditional restoration methods are not satisfactory. Researchers increasingly focus on the field of tissue engineering. The three key points in establishing a tissue engineering material are the biological scaffold material, the seed cells and various growth factors. Understanding the type of nerve injury, the construction of scaffold and the process of repair are necessary to solve peripheral nerve injury and promote its regeneration. This review describes the categories of peripheral nerve injury, fundamental research of peripheral nervous tissue engineering and clinical research on peripheral nerve scaffold material, and paves a way for related research and the use of conduits in clinical practice.展开更多
This paper presents a life cycle assessment(LCA) based biofuel supply chain(SC) analysis framework which enables the study of economic, energy and environmental(3E) performances by using multi-objective optimization. ...This paper presents a life cycle assessment(LCA) based biofuel supply chain(SC) analysis framework which enables the study of economic, energy and environmental(3E) performances by using multi-objective optimization. The economic objective is measured by the total annual profit, the energy objective is measured by the average fossil energy(FE) inputs per MJ biofuel and the environmental objective is measured by greenhouse gas(GHG) emissions per MJ biofuel. A multi-objective linear fractional programming(MOLFP) model with multi-conversion pathways is formulated based on the framework and is solved by using the ε-constraint method. The MOLFP problem is turned into a mixed integer linear programming(MILP) problem by setting up the total annual profit as the optimization objective and the average FE inputs per MJ biofuel and GHG emissions per MJ biofuel as constraints. In the case study, this model is used to design an experimental biofuel supply chain in China. A set of the weekly Pareto optimal solutions is obtained. Each non-inferior solution indicates the optimal locations and the amount of biomass produced, locations and capacities of conversion factories, locations and amount of biofuel being supplied in final markets and the flow of mass through the supply chain network(SCN). As the model reveals trade-offs among 3E criteria, we think the framework can be a good support tool of decision for the design of biofuel SC.展开更多
An environmentally friendly Mn‐oxide‐supported metal‐organic framework(MOF),Mn3O4/ZIF‐8,was successfully prepared using a facile solvothermal method,with a formation mechanism proposed.The composite was characteri...An environmentally friendly Mn‐oxide‐supported metal‐organic framework(MOF),Mn3O4/ZIF‐8,was successfully prepared using a facile solvothermal method,with a formation mechanism proposed.The composite was characterized using X‐ray diffraction,scanning electron microscopy,transmission electron microscopy,X‐ray photoelectron microscopy,and Fourier‐transform infrared spectroscopy.After characterization,the MOF was used to activate peroxymonosulfate(PMS)for degradation of the refractory pollutant rhodamine B(RhB)in water.The composite prepared at a0.5:1mass ratio of Mn3O4to ZIF‐8possessed the highest catalytic activity with negligible Mn leaching.The maximum RhB degradation of approximately98%was achieved at0.4g/L0.5‐Mn/ZIF‐120,0.3g/L PMS,and10mg/L initial RhB concentration at a reaction temperature of23°C.The RhB degradation followed first‐order kinetics and was accelerated with increased0.5‐Mn/ZIF‐120and PMS dosages,decreased initial RhB concentration,and increased reaction temperature.Moreover,quenching tests indicated that?OH was the predominant radical involved in the RhB degradation;the?OH mainly originated from SO4??and,hence,PMS.Mn3O4/ZIF‐8also displayed good reusability for RhB degradation in the presence of PMS over five runs,with a RhB degradation efficiency of more than96%and Mn leaching of less than5%for each run.Based on these findings,a RhB degradation mechanism was proposed.展开更多
Bioactive scaffolds with interconnected porous structures are essential for guiding cell growth and new bone formation. In this work, we successfully fabricated three-dimensional (3D) porous β-tricalcium phosphate...Bioactive scaffolds with interconnected porous structures are essential for guiding cell growth and new bone formation. In this work, we successfully fabricated three-dimensional (3D) porous β-tricalcium phosphate (β-TCP)/calcium silicate (CS) composite scaffolds with different ratios by 3D printing technique and further investigated the physiochemical properties, in vitro apatite mineralization properties and degradability of porous β-TCP/CS scaffolds. Moreover, a series of in vitro cell experiments including the attachment, proliferation and osteogenic differentiation of mouse bone marrow stromal cells were conducted to testify their biological performances. The results showed that 3D printed β-TCP/CS scaffolds possessed of controllable internal porous structures and external shape. Furthermore, the introduction of CS decreased the shrinkage of scaffolds and improved the in vitro apatite formation activity and degradation rate. Meanwhile, compared with pure β- TCP scaffold, the β-TCP/CS composite scaffolds were more conducive to promote cell adhesion, spread and osteogenesis differentiation. However, when the content of CS was increased to 45%, the ions dissolution rate of the composite scaffolds was so high that leaded to the increase in pH value, which inhibited the proliferation of cells. Our results suggested that the introduction of appropriate CS into β-TCP bioceramic is an effective strategy to prepare bioactive 3D printed bioceramic scaffolds for hard tissue regeneration.展开更多
Objective Study of bupropion hydrochloride gel matrix sustained release tablet and the preparation method, test the skeleton material of hydroxypropyl methyl cellulose influencing drug release for evaluation, explore ...Objective Study of bupropion hydrochloride gel matrix sustained release tablet and the preparation method, test the skeleton material of hydroxypropyl methyl cellulose influencing drug release for evaluation, explore the preparation of sustained release tablets of optimization method. Method With hydroxypropyl methyl cellulose as skeleton material, according to the different prescription preparation of bupmpion hydrochloride sustained release tablets. Different HPMC viscosity, Consumption, particle size, compression pressure and slurry rotational speed and other factors, analysis the influence on drug release rate.Through the release of test evaluation of sustained release effect, and the preliminary study on the drug release characteristic. With hydroxypropyl methyl cellulose ( HPMC ) as skeleton material, with citric acid citrate as a porogenic agent, direct powder tabletting method of bupropion hydrochloride sustained release tablets; by using single factor and orthogonal experiment method to investigate HPMC different viscosity, different Consumption, different particle size, different compression pressure, different pulp rotational speed and other factors on the release of delivery rate. Result Select HPMC-K100M for bupropion hydrochloride sustained release tablets of the skeleton materials; reinforcing materials of high viscosity HPMC K100M and main drug quality ratio of 1: 1; HPMC particle diameter of 125p m, make use of these conditions to preparation of bupropion hydrochloride sustained release tablets for optimal prescription conditions. Conclusion bupropion hydroehloride sustained release tablets on the drug release rate is mainly affected by HPMC viscosity and dosage effect. Along with the tablet of HPMC viscosity increased, the drug is released slowly. HPMC viscosity, dosage on the drug release rate has significant influence.展开更多
To evaluate the biological safety of manufactured heterologous deproteinized bone and to provide an experimental basis for clinical applications. Methods : Deproteinized bone ( 10 mm) and leaching liquor were made...To evaluate the biological safety of manufactured heterologous deproteinized bone and to provide an experimental basis for clinical applications. Methods : Deproteinized bone ( 10 mm) and leaching liquor were made from pig ribs with a series of physical and chemical methods, then were evaluated through acute and subacute toxicity test, hemolysis test, pyrogen test, intracutaneous test, intramuscular implantation test and cytotoxity test. Results : No obvious toxicity, hemolysis, pyrogenic characteristics, skin irritation, inflammatory reaction after intramusclar implantation and cytotoxity were observed. Conclusions: The heterologous deproteinized bone has good biological safety and meets all the demands of scaffold material for tissue engineering.展开更多
Biomimetic scaffolds are appealing products for the repair of bone defects using tissue engineering strategies.In the present study,novel biomimetic composite scaffolds,with similar properties to natural bone,were pre...Biomimetic scaffolds are appealing products for the repair of bone defects using tissue engineering strategies.In the present study,novel biomimetic composite scaffolds,with similar properties to natural bone,were prepared,blended and cross-linked with bioactive glass,type I collagen and phosphatidylserine.When exposed to cell culture solution in the absence of a cellular source,the composite scaffolds form crystals with octahedral structure.These crystals are similar to the products derived from MC3T3-E1 cell mineralization within the composite scaffolds,with respect to both composition and morphology.Furthermore,crystals with octahedral structure were observed to develop into plate-like hydroxyapatite.The bio-mineralization behavior of the composite scaffolds is likely influenced by inorganic components.Finally,a rabbit tibia defect model shows that the highly bioactive properties of the investigated composites result in excellent bone repair.展开更多
Biomaterial scaffolds play an important role in maintaining the viability and biological functions of highly metabolic hepatocytes in liver tissue engineering. One of the major challenges involves building a complex m...Biomaterial scaffolds play an important role in maintaining the viability and biological functions of highly metabolic hepatocytes in liver tissue engineering. One of the major challenges involves building a complex microchannel network inside three-dimensional (3D) scaffolds for efficient mass transportation. Here we presented a biomimetic strategy to generate a mi- crochannel network within porous biomaterial scaffolds by mimicking the vascular tree of rat liver. The typical parameters of the blood vessels were incorporated into the biomimetic design of the microchannel network such as branching angle and diameter. Silk fibroin-gelatin scaffolds with biomimetic vascular tree were fabricated by combining micromolding, freeze drying and 3D rolling techniques. The relationship between the micro-channeled design and flow pattern was revealed by a flow experiment, which indicated that the scaffolds with biomimetic vascular tree exhibited unique capability in improving mass transportation inside the 3D scaffold. The 3D scaffolds, preseeded with primary hepatocytes, were dynamically cultured in a bioreactor system. The results confirmed that the pre-designed biomimetic microchannel network facilitated the generation and expansion of hepatocytes.展开更多
Metal-organic frameworks (MOFs) have been emerging as important multifunctional hybrid materials, not only due to the diversify framework architectures, but also contribute to the rich interactions among metals, lig...Metal-organic frameworks (MOFs) have been emerging as important multifunctional hybrid materials, not only due to the diversify framework architectures, but also contribute to the rich interactions among metals, ligands and guests. Nitro explosives have important influences tbr environmental protection and national homeland security, in this review, a brief description of luminescent MOFs is presented, accompanied by a short comment on the four types of metal-based luminescent MOFs as sensing materials for nitro explosives detection. Then the trends and challenges of luminescent MOFs as sensing materials ibr nitro explosives are also prospected.展开更多
Relapse and metastasis of tumor may occur for osteosarcoma(OS)patients after clinical resection.Conventional metallic scaffolds provide sufficient mechanical support to the defected bone but fail to eradicate recurrin...Relapse and metastasis of tumor may occur for osteosarcoma(OS)patients after clinical resection.Conventional metallic scaffolds provide sufficient mechanical support to the defected bone but fail to eradicate recurring tumors.Here we report that biodegradable magnesium(Mg)wirebased implant can inhibit OS growth.In brief,the Mg wires release Mg ions to activate the transport of zinc finger protein Snail1 from cytoplasm to cell nucleus,which induces apoptosis and inhibits proliferation of OS cells through a parallel antitumor signaling pathway of miRNA-181d-5p/TIMP3 and miRNA-181c-5p/NLK downstream.Simultaneously,the hydrogen gas evolution from Mg wires eliminates intracellular excessive reactive oxygen species,by which the growth of bone tumor cells is suppressed.The subcutaneous tumor-bearing experiment of OS cells in nude mice further confirms that Mg wires can effectively inhibit the growth of tumors and prolong the survival of tumor-bearing mice.In addition,Mg wires have no toxicity to normal cells and tissues.These results suggest that Mg implant is a potential anti-tumor scaffold for OS patients.展开更多
Different cell types make up tissues and organs hierarchically and communicate within a complex, three-dimensional (3D) en- vironment. The in vitro recapitulation of tissue-like structures is meaningful, not only for ...Different cell types make up tissues and organs hierarchically and communicate within a complex, three-dimensional (3D) en- vironment. The in vitro recapitulation of tissue-like structures is meaningful, not only for fundamental cell biology research, but also for tissue engineering (TE). Currently, TE research adopts either the top-down or bottom-up approach. The top-down approach involves defining the macroscopic tissue features using biomaterial scaffolds and seeding cells into these scaffolds. Conversely, the bottom-up approach aims at crafting small tissue building blocks with precision-engineered structural and functional microscale features, using physical and/or chemical approaches. The bottom-up strategy takes advantage of the repeating structural and functional units that facilitate cell-cell interactions and cultures multiple cells together as a functional unit of tissue. In this review, we focus on currently available microscale methods that can control mammalian cells to assemble into 3D tissue-like structures.展开更多
基金Project (51275179) supported by the National Natural Science Foundation of ChinaProject (2010A090200072) supported by Industry,University and Research Institute Combination of Ministry of Education, Ministry of Science and Technology and Guangdong Province,China+1 种基金Project (2012M511797) supported by China Postdoctoral Science FoundationProject (2012ZB0014) supported by FundamentalResearch Funds for the Central Universities of China
文摘The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting (SLM) technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.
基金supported by the National Natural Science Foundation of China,No.31040043,31671248(to NH),No.81171146,81372044,30971526(to BGJ)the Chinese National Ministry of Science and Technology(973 Project),No.2014CB542201(to PXZ)+4 种基金the Ministry of Education Innovation Team,China,No.IRT1201(to PXZ)the Fostering Young Scholars of Peking University Health Science Center,China,No.BMU2017PY013(to PXZ)the Chinese National General Program of National Natural Science Fund,China(to PXZ)the Beijing City Science&Technology New Star Cross Project,China,No.2018019(to PXZ)the National Natural Science Foundation of China,No.31771322,31571235,51373023,21171019,31640045,31571236,31471144,31100860,31371210(to PXZ)
文摘Peripheral nerve injury is a common clinical problem and affects the quality of life of patients. Traditional restoration methods are not satisfactory. Researchers increasingly focus on the field of tissue engineering. The three key points in establishing a tissue engineering material are the biological scaffold material, the seed cells and various growth factors. Understanding the type of nerve injury, the construction of scaffold and the process of repair are necessary to solve peripheral nerve injury and promote its regeneration. This review describes the categories of peripheral nerve injury, fundamental research of peripheral nervous tissue engineering and clinical research on peripheral nerve scaffold material, and paves a way for related research and the use of conduits in clinical practice.
基金Supported by the Chinese Academy of Engineering(20121667845)
文摘This paper presents a life cycle assessment(LCA) based biofuel supply chain(SC) analysis framework which enables the study of economic, energy and environmental(3E) performances by using multi-objective optimization. The economic objective is measured by the total annual profit, the energy objective is measured by the average fossil energy(FE) inputs per MJ biofuel and the environmental objective is measured by greenhouse gas(GHG) emissions per MJ biofuel. A multi-objective linear fractional programming(MOLFP) model with multi-conversion pathways is formulated based on the framework and is solved by using the ε-constraint method. The MOLFP problem is turned into a mixed integer linear programming(MILP) problem by setting up the total annual profit as the optimization objective and the average FE inputs per MJ biofuel and GHG emissions per MJ biofuel as constraints. In the case study, this model is used to design an experimental biofuel supply chain in China. A set of the weekly Pareto optimal solutions is obtained. Each non-inferior solution indicates the optimal locations and the amount of biomass produced, locations and capacities of conversion factories, locations and amount of biofuel being supplied in final markets and the flow of mass through the supply chain network(SCN). As the model reveals trade-offs among 3E criteria, we think the framework can be a good support tool of decision for the design of biofuel SC.
基金supported by the National Key Research and Development Program of China (2016YFB0700504)~~
文摘An environmentally friendly Mn‐oxide‐supported metal‐organic framework(MOF),Mn3O4/ZIF‐8,was successfully prepared using a facile solvothermal method,with a formation mechanism proposed.The composite was characterized using X‐ray diffraction,scanning electron microscopy,transmission electron microscopy,X‐ray photoelectron microscopy,and Fourier‐transform infrared spectroscopy.After characterization,the MOF was used to activate peroxymonosulfate(PMS)for degradation of the refractory pollutant rhodamine B(RhB)in water.The composite prepared at a0.5:1mass ratio of Mn3O4to ZIF‐8possessed the highest catalytic activity with negligible Mn leaching.The maximum RhB degradation of approximately98%was achieved at0.4g/L0.5‐Mn/ZIF‐120,0.3g/L PMS,and10mg/L initial RhB concentration at a reaction temperature of23°C.The RhB degradation followed first‐order kinetics and was accelerated with increased0.5‐Mn/ZIF‐120and PMS dosages,decreased initial RhB concentration,and increased reaction temperature.Moreover,quenching tests indicated that?OH was the predominant radical involved in the RhB degradation;the?OH mainly originated from SO4??and,hence,PMS.Mn3O4/ZIF‐8also displayed good reusability for RhB degradation in the presence of PMS over five runs,with a RhB degradation efficiency of more than96%and Mn leaching of less than5%for each run.Based on these findings,a RhB degradation mechanism was proposed.
文摘Bioactive scaffolds with interconnected porous structures are essential for guiding cell growth and new bone formation. In this work, we successfully fabricated three-dimensional (3D) porous β-tricalcium phosphate (β-TCP)/calcium silicate (CS) composite scaffolds with different ratios by 3D printing technique and further investigated the physiochemical properties, in vitro apatite mineralization properties and degradability of porous β-TCP/CS scaffolds. Moreover, a series of in vitro cell experiments including the attachment, proliferation and osteogenic differentiation of mouse bone marrow stromal cells were conducted to testify their biological performances. The results showed that 3D printed β-TCP/CS scaffolds possessed of controllable internal porous structures and external shape. Furthermore, the introduction of CS decreased the shrinkage of scaffolds and improved the in vitro apatite formation activity and degradation rate. Meanwhile, compared with pure β- TCP scaffold, the β-TCP/CS composite scaffolds were more conducive to promote cell adhesion, spread and osteogenesis differentiation. However, when the content of CS was increased to 45%, the ions dissolution rate of the composite scaffolds was so high that leaded to the increase in pH value, which inhibited the proliferation of cells. Our results suggested that the introduction of appropriate CS into β-TCP bioceramic is an effective strategy to prepare bioactive 3D printed bioceramic scaffolds for hard tissue regeneration.
文摘Objective Study of bupropion hydrochloride gel matrix sustained release tablet and the preparation method, test the skeleton material of hydroxypropyl methyl cellulose influencing drug release for evaluation, explore the preparation of sustained release tablets of optimization method. Method With hydroxypropyl methyl cellulose as skeleton material, according to the different prescription preparation of bupmpion hydrochloride sustained release tablets. Different HPMC viscosity, Consumption, particle size, compression pressure and slurry rotational speed and other factors, analysis the influence on drug release rate.Through the release of test evaluation of sustained release effect, and the preliminary study on the drug release characteristic. With hydroxypropyl methyl cellulose ( HPMC ) as skeleton material, with citric acid citrate as a porogenic agent, direct powder tabletting method of bupropion hydrochloride sustained release tablets; by using single factor and orthogonal experiment method to investigate HPMC different viscosity, different Consumption, different particle size, different compression pressure, different pulp rotational speed and other factors on the release of delivery rate. Result Select HPMC-K100M for bupropion hydrochloride sustained release tablets of the skeleton materials; reinforcing materials of high viscosity HPMC K100M and main drug quality ratio of 1: 1; HPMC particle diameter of 125p m, make use of these conditions to preparation of bupropion hydrochloride sustained release tablets for optimal prescription conditions. Conclusion bupropion hydroehloride sustained release tablets on the drug release rate is mainly affected by HPMC viscosity and dosage effect. Along with the tablet of HPMC viscosity increased, the drug is released slowly. HPMC viscosity, dosage on the drug release rate has significant influence.
文摘To evaluate the biological safety of manufactured heterologous deproteinized bone and to provide an experimental basis for clinical applications. Methods : Deproteinized bone ( 10 mm) and leaching liquor were made from pig ribs with a series of physical and chemical methods, then were evaluated through acute and subacute toxicity test, hemolysis test, pyrogen test, intracutaneous test, intramuscular implantation test and cytotoxity test. Results : No obvious toxicity, hemolysis, pyrogenic characteristics, skin irritation, inflammatory reaction after intramusclar implantation and cytotoxity were observed. Conclusions: The heterologous deproteinized bone has good biological safety and meets all the demands of scaffold material for tissue engineering.
基金supported by the Science and Technology Plan Project of Fujian Department of Education,China (Grant No. JK2009021)
文摘Biomimetic scaffolds are appealing products for the repair of bone defects using tissue engineering strategies.In the present study,novel biomimetic composite scaffolds,with similar properties to natural bone,were prepared,blended and cross-linked with bioactive glass,type I collagen and phosphatidylserine.When exposed to cell culture solution in the absence of a cellular source,the composite scaffolds form crystals with octahedral structure.These crystals are similar to the products derived from MC3T3-E1 cell mineralization within the composite scaffolds,with respect to both composition and morphology.Furthermore,crystals with octahedral structure were observed to develop into plate-like hydroxyapatite.The bio-mineralization behavior of the composite scaffolds is likely influenced by inorganic components.Finally,a rabbit tibia defect model shows that the highly bioactive properties of the investigated composites result in excellent bone repair.
基金This work was funded by the National High Technology Research and Development Program,the Natural Science Foundation of China
文摘Biomaterial scaffolds play an important role in maintaining the viability and biological functions of highly metabolic hepatocytes in liver tissue engineering. One of the major challenges involves building a complex microchannel network inside three-dimensional (3D) scaffolds for efficient mass transportation. Here we presented a biomimetic strategy to generate a mi- crochannel network within porous biomaterial scaffolds by mimicking the vascular tree of rat liver. The typical parameters of the blood vessels were incorporated into the biomimetic design of the microchannel network such as branching angle and diameter. Silk fibroin-gelatin scaffolds with biomimetic vascular tree were fabricated by combining micromolding, freeze drying and 3D rolling techniques. The relationship between the micro-channeled design and flow pattern was revealed by a flow experiment, which indicated that the scaffolds with biomimetic vascular tree exhibited unique capability in improving mass transportation inside the 3D scaffold. The 3D scaffolds, preseeded with primary hepatocytes, were dynamically cultured in a bioreactor system. The results confirmed that the pre-designed biomimetic microchannel network facilitated the generation and expansion of hepatocytes.
基金supported by the National Natural Science Foundation of China (21301005)the Natural Science Foundation of Anhui Province (1408085QB31)the open fund of Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (KFK201508)
文摘Metal-organic frameworks (MOFs) have been emerging as important multifunctional hybrid materials, not only due to the diversify framework architectures, but also contribute to the rich interactions among metals, ligands and guests. Nitro explosives have important influences tbr environmental protection and national homeland security, in this review, a brief description of luminescent MOFs is presented, accompanied by a short comment on the four types of metal-based luminescent MOFs as sensing materials for nitro explosives detection. Then the trends and challenges of luminescent MOFs as sensing materials ibr nitro explosives are also prospected.
基金the National Key Research and Development Program of China(2018YFC1106600)the Interdisciplinary Program of Shanghai Jiao Tong University(ZH2018QNB07)。
文摘Relapse and metastasis of tumor may occur for osteosarcoma(OS)patients after clinical resection.Conventional metallic scaffolds provide sufficient mechanical support to the defected bone but fail to eradicate recurring tumors.Here we report that biodegradable magnesium(Mg)wirebased implant can inhibit OS growth.In brief,the Mg wires release Mg ions to activate the transport of zinc finger protein Snail1 from cytoplasm to cell nucleus,which induces apoptosis and inhibits proliferation of OS cells through a parallel antitumor signaling pathway of miRNA-181d-5p/TIMP3 and miRNA-181c-5p/NLK downstream.Simultaneously,the hydrogen gas evolution from Mg wires eliminates intracellular excessive reactive oxygen species,by which the growth of bone tumor cells is suppressed.The subcutaneous tumor-bearing experiment of OS cells in nude mice further confirms that Mg wires can effectively inhibit the growth of tumors and prolong the survival of tumor-bearing mice.In addition,Mg wires have no toxicity to normal cells and tissues.These results suggest that Mg implant is a potential anti-tumor scaffold for OS patients.
基金supported by Ministry of Science and Technology of China(Grant Nos.2009CB930001 and 2011CB933201)Chinese Academy ofSciences(Grant No.KJCX2-YW-M15)the National Natural ScienceFoundation of China(Grant Nos.20890020,90813032,21025520 and 51073045)
文摘Different cell types make up tissues and organs hierarchically and communicate within a complex, three-dimensional (3D) en- vironment. The in vitro recapitulation of tissue-like structures is meaningful, not only for fundamental cell biology research, but also for tissue engineering (TE). Currently, TE research adopts either the top-down or bottom-up approach. The top-down approach involves defining the macroscopic tissue features using biomaterial scaffolds and seeding cells into these scaffolds. Conversely, the bottom-up approach aims at crafting small tissue building blocks with precision-engineered structural and functional microscale features, using physical and/or chemical approaches. The bottom-up strategy takes advantage of the repeating structural and functional units that facilitate cell-cell interactions and cultures multiple cells together as a functional unit of tissue. In this review, we focus on currently available microscale methods that can control mammalian cells to assemble into 3D tissue-like structures.