Three-dimensional printing technologies exhibit tremendous potential in the advancing fields of tissue engineering and regenerative medicine due to the precise spatial control over depositing the biomaterial.Despite t...Three-dimensional printing technologies exhibit tremendous potential in the advancing fields of tissue engineering and regenerative medicine due to the precise spatial control over depositing the biomaterial.Despite their widespread utilization and numerous advantages,the development of suitable novel biomaterials for extrusion-based 3D printing of scaffolds that support cell attachment,proliferation,and vascularization remains a challenge.Multi-material composite hydrogels present incredible potential in this field.Thus,in this work,a multi-material composite hydrogel with a promising formulation of chitosan/gelatin functionalized with egg white was developed,which provides good printability and shape fidelity.In addition,a series of comparative analyses of different crosslinking agents and processes based on tripolyphosphate(TPP),genipin(GP),and glutaraldehyde(GTA)were investigated and compared to select the ideal crosslinking strategy to enhance the physicochemical and biological properties of the fabricated scaffolds.All of the results indicate that the composite hydrogel and the resulting scaffolds utilizing TPP crosslinking have great potential in tissue engineering,especially for supporting neo-vessel growth into the scaffold and promoting angiogenesis within engineered tissues.展开更多
To meet the requirements of spacecraft for the thermal conductivity of resins and solve the problem of low thermal conduction efficiency when 3D printing complex parts,we propose a new type of continuous mesophase-pit...To meet the requirements of spacecraft for the thermal conductivity of resins and solve the problem of low thermal conduction efficiency when 3D printing complex parts,we propose a new type of continuous mesophase-pitch-based carbon fiber/thermoplastic polyurethane/epoxy(CMPCF/TPU/epoxy)composite filament and its preparation process in this study.The composite filament is based on the high thermal conductivity of CMPCF,the high elasticity of TPU,and the high-temperature resistance of epoxy.The tensile strength and thermal conductivity of the CMPCF/TPU/epoxy composite filament were tested.The CMPCF/TPU/epoxy composites are formed by 3D printing technology,and the composite filament is laid according to the direction of heat conduction so that the printed part can meet the needs of directional heat conduction.The experimental results show that the thermal conductivity of the printed sample is 40.549 W/(m·K),which is 160 times that of pure epoxy resin(0.254 W/(m·K)).It is also approximately 13 times better than that of polyacrylonitrile carbon fiber/epoxy(PAN-CF/epoxy)composites.This study breaks through the technical bottleneck of poor printability of CMPCF.It provides a new method for achieving directional thermal conductivity printing,which is important for the development of complex high-performance thermal conductivity products.展开更多
Recently in the area of biological manufacturing and rapid prototyping manufacturing, the bone scaffolds based on the additive manufacturing in repairing bone defects have been paid more and more attention. In the pro...Recently in the area of biological manufacturing and rapid prototyping manufacturing, the bone scaffolds based on the additive manufacturing in repairing bone defects have been paid more and more attention. In the process of preparation, path planning directly affects the structure, performance as well as the final bone cell culture conditions. Due to the special natural bone scaffold structural characteristic, the traditional rapid prototyping(RP) path planning is not fully suitable for the preparation of bone scaffolds. In this paper, based on the 3D printing extrusion forming technology, a method of path planning for osteochondral integrated scaffolds with gradient structure is put forward, which provides a theoretical basis for bone-scaffold modeling and practical preparation. The implementation of the path planning processing system makes it possible to process data automatically from the initial stereo lithography(STL) model of the actual bone defect part by computer X-ray tomography technique(CT) scan or modeling,to generate the path code and to generate the final machining information after post-processing. This work provides some guidelines for independent research and development of automation equipment for biological manufacturing preparation and software technology.The experiment and test results have verified the validity of the path planning method and the good properties of the bone scaffolds with gradient structures.展开更多
Cholangiocarcinoma(CCA)is characterized by heterogeneous mutations and a refractory nature.Thus,the development of a model for effective drug screening is urgently needed.As the established therapeutic testing models ...Cholangiocarcinoma(CCA)is characterized by heterogeneous mutations and a refractory nature.Thus,the development of a model for effective drug screening is urgently needed.As the established therapeutic testing models for CCA are often ineffective,we fabricated an enabling three-dimensional(3D)-bioprinted CCA-on-a-chip model that to a good extent resembled the multicellular microenvironment and the anatomical microstructure of the hepato-vascular-biliary system to perform high-content antitumor drug screening.Specifically,cholangiocytes,hepatocytes,and vascular endotheliocytes were employed for 3D bioprinting of the models,allowing for a high degree of spatial and tube-like microstructural control.Interestingly,it was possible to observe CCA cells attached to the surfaces of the gelatin methacryloyl(GelMA)hydrogelembedded microchannels and overgrown in a thickening manner,generating bile duct stenosis,which was expected to be analogous to the in vivo configuration.Over 4000 differentially expressed genes were detected in the CCA cells in our 3D coculture model compared to the traditional two-dimensional(2D)monoculture.Further screening revealed that the CCA cells grown in the 3D traditional model were more sensitive to the antitumoral prodrug than those in the 2D monoculture due to drug biotransformation by the neighboring functional hepatocytes.This study provides proof-of-concept validation of our bioprinted CCA-on-a-chip as a promising drug screening model for CCA treatment and paves the way for potential personalized medicine strategies for CCA patients in the future.展开更多
Plasma surfacing is an important enabling technology in high-performance coating applications. Recently, it is applied to rapid prototyping/tooling to reduce development time and manufacturing cost for the development...Plasma surfacing is an important enabling technology in high-performance coating applications. Recently, it is applied to rapid prototyping/tooling to reduce development time and manufacturing cost for the development of new products. However, this technology is in its infancy, it is essential to understand clearly how process variables relate to deposit microstructure and properties for plasma deposition manufacturing process control. In this paper, layer appearance of single surfacing under different parametem such as plasma current, voltage, powder feedrate and travel speed is studied. Back-propagation neural networks are used to associate the depositing process variables with the features of the deposit layer shape. These networks can be effectively implemented to estimate the layer shape. The results Indicate that neural networks can yield fairly accurate results and can be used as a practical tool in plasma deposition manufacturing process.展开更多
Acellular dermal matrix(ADM)as a biomaterial is currently believed to be promising tissue repair improvement.With the development of tissue engineering,ADM is increasingly used as biological scaffolds.We explored the ...Acellular dermal matrix(ADM)as a biomaterial is currently believed to be promising tissue repair improvement.With the development of tissue engineering,ADM is increasingly used as biological scaffolds.We explored the feasibility and performance of ADM biological scaffolds that fabricated by 3D printing.This paper presented our study on the printability of 3D printed ADM scaffolds,with a focus on identifying the influence of printing parameters/conditions on printability.To characterize the printability,we examined the fiber morphology,pore size,strand diameter,and mechanical property of the printed scaffolds.Our results revealed that the printability could be affected by a number of factors and among them,the most considerable one was related to the nozzle diameter and the composition of ADM.We then evaluated the biocompatibility in terms of cytotoxicity,cell proliferation and vivisection.In vitro evaluation of the ADM scaffolds was carried out and the experimental results indicated that cells were viable and proliferative during the period of study.In vivo results also indicated that the defect area was well repaired without any noticeable infection,hematoma and other conditions.In conclusion,ADM could be reconstructed with 3D printing technology and ADM biological scaffold has potential applications for tissue engineering.展开更多
The near-wake flow of a NACA0012 airfoils mounted above a water surface were experimentally studied in a wind/wave tunnel. The main objective of this study is to investigate the influence of the free surface on the st...The near-wake flow of a NACA0012 airfoils mounted above a water surface were experimentally studied in a wind/wave tunnel. The main objective of this study is to investigate the influence of the free surface on the structure of the airfoil trailing wake. The flow structure was measured with different ride heights between the airfoil and free surface using a Particle Image Velocimetry （PIV） system. The Reynolds number based on the chord length of the airfoil was about 3.5×10^3. For each experimental condition, large amount of instantaneous velocity fields were captured and ensemble-averaged to get the spatial distributions of mean velocity and mean vorticity, as well as turbulence statistics. The results show that the flow structures of the airfoil wake varies remarkably with the change in the ride height.展开更多
基金The authors acknowledge the funding support from the National Natural Science Foundation of China(Nos.52175474 and 51775324)the China Scholarship Council(No.202006890054).
文摘Three-dimensional printing technologies exhibit tremendous potential in the advancing fields of tissue engineering and regenerative medicine due to the precise spatial control over depositing the biomaterial.Despite their widespread utilization and numerous advantages,the development of suitable novel biomaterials for extrusion-based 3D printing of scaffolds that support cell attachment,proliferation,and vascularization remains a challenge.Multi-material composite hydrogels present incredible potential in this field.Thus,in this work,a multi-material composite hydrogel with a promising formulation of chitosan/gelatin functionalized with egg white was developed,which provides good printability and shape fidelity.In addition,a series of comparative analyses of different crosslinking agents and processes based on tripolyphosphate(TPP),genipin(GP),and glutaraldehyde(GTA)were investigated and compared to select the ideal crosslinking strategy to enhance the physicochemical and biological properties of the fabricated scaffolds.All of the results indicate that the composite hydrogel and the resulting scaffolds utilizing TPP crosslinking have great potential in tissue engineering,especially for supporting neo-vessel growth into the scaffold and promoting angiogenesis within engineered tissues.
基金supported by the National Natural Science Foundation of China(Nos.52175474 and 52275498)。
文摘To meet the requirements of spacecraft for the thermal conductivity of resins and solve the problem of low thermal conduction efficiency when 3D printing complex parts,we propose a new type of continuous mesophase-pitch-based carbon fiber/thermoplastic polyurethane/epoxy(CMPCF/TPU/epoxy)composite filament and its preparation process in this study.The composite filament is based on the high thermal conductivity of CMPCF,the high elasticity of TPU,and the high-temperature resistance of epoxy.The tensile strength and thermal conductivity of the CMPCF/TPU/epoxy composite filament were tested.The CMPCF/TPU/epoxy composites are formed by 3D printing technology,and the composite filament is laid according to the direction of heat conduction so that the printed part can meet the needs of directional heat conduction.The experimental results show that the thermal conductivity of the printed sample is 40.549 W/(m·K),which is 160 times that of pure epoxy resin(0.254 W/(m·K)).It is also approximately 13 times better than that of polyacrylonitrile carbon fiber/epoxy(PAN-CF/epoxy)composites.This study breaks through the technical bottleneck of poor printability of CMPCF.It provides a new method for achieving directional thermal conductivity printing,which is important for the development of complex high-performance thermal conductivity products.
基金supported by National Natural Science Foundation of China(Nos.51475281 and 51375292)National Youth Foundation of China(No.51105239)
文摘Recently in the area of biological manufacturing and rapid prototyping manufacturing, the bone scaffolds based on the additive manufacturing in repairing bone defects have been paid more and more attention. In the process of preparation, path planning directly affects the structure, performance as well as the final bone cell culture conditions. Due to the special natural bone scaffold structural characteristic, the traditional rapid prototyping(RP) path planning is not fully suitable for the preparation of bone scaffolds. In this paper, based on the 3D printing extrusion forming technology, a method of path planning for osteochondral integrated scaffolds with gradient structure is put forward, which provides a theoretical basis for bone-scaffold modeling and practical preparation. The implementation of the path planning processing system makes it possible to process data automatically from the initial stereo lithography(STL) model of the actual bone defect part by computer X-ray tomography technique(CT) scan or modeling,to generate the path code and to generate the final machining information after post-processing. This work provides some guidelines for independent research and development of automation equipment for biological manufacturing preparation and software technology.The experiment and test results have verified the validity of the path planning method and the good properties of the bone scaffolds with gradient structures.
文摘Cholangiocarcinoma(CCA)is characterized by heterogeneous mutations and a refractory nature.Thus,the development of a model for effective drug screening is urgently needed.As the established therapeutic testing models for CCA are often ineffective,we fabricated an enabling three-dimensional(3D)-bioprinted CCA-on-a-chip model that to a good extent resembled the multicellular microenvironment and the anatomical microstructure of the hepato-vascular-biliary system to perform high-content antitumor drug screening.Specifically,cholangiocytes,hepatocytes,and vascular endotheliocytes were employed for 3D bioprinting of the models,allowing for a high degree of spatial and tube-like microstructural control.Interestingly,it was possible to observe CCA cells attached to the surfaces of the gelatin methacryloyl(GelMA)hydrogelembedded microchannels and overgrown in a thickening manner,generating bile duct stenosis,which was expected to be analogous to the in vivo configuration.Over 4000 differentially expressed genes were detected in the CCA cells in our 3D coculture model compared to the traditional two-dimensional(2D)monoculture.Further screening revealed that the CCA cells grown in the 3D traditional model were more sensitive to the antitumoral prodrug than those in the 2D monoculture due to drug biotransformation by the neighboring functional hepatocytes.This study provides proof-of-concept validation of our bioprinted CCA-on-a-chip as a promising drug screening model for CCA treatment and paves the way for potential personalized medicine strategies for CCA patients in the future.
基金Project supported by National Natural Science Foundation of China ( Grant No .50075032) , and National High-Technology Research and Development Program of China ( Grant No .2001AA421150)
文摘Plasma surfacing is an important enabling technology in high-performance coating applications. Recently, it is applied to rapid prototyping/tooling to reduce development time and manufacturing cost for the development of new products. However, this technology is in its infancy, it is essential to understand clearly how process variables relate to deposit microstructure and properties for plasma deposition manufacturing process control. In this paper, layer appearance of single surfacing under different parametem such as plasma current, voltage, powder feedrate and travel speed is studied. Back-propagation neural networks are used to associate the depositing process variables with the features of the deposit layer shape. These networks can be effectively implemented to estimate the layer shape. The results Indicate that neural networks can yield fairly accurate results and can be used as a practical tool in plasma deposition manufacturing process.
基金This research was funded by National Natural Science Foundation of China,Grant Nos.51775324 and 81970455.
文摘Acellular dermal matrix(ADM)as a biomaterial is currently believed to be promising tissue repair improvement.With the development of tissue engineering,ADM is increasingly used as biological scaffolds.We explored the feasibility and performance of ADM biological scaffolds that fabricated by 3D printing.This paper presented our study on the printability of 3D printed ADM scaffolds,with a focus on identifying the influence of printing parameters/conditions on printability.To characterize the printability,we examined the fiber morphology,pore size,strand diameter,and mechanical property of the printed scaffolds.Our results revealed that the printability could be affected by a number of factors and among them,the most considerable one was related to the nozzle diameter and the composition of ADM.We then evaluated the biocompatibility in terms of cytotoxicity,cell proliferation and vivisection.In vitro evaluation of the ADM scaffolds was carried out and the experimental results indicated that cells were viable and proliferative during the period of study.In vivo results also indicated that the defect area was well repaired without any noticeable infection,hematoma and other conditions.In conclusion,ADM could be reconstructed with 3D printing technology and ADM biological scaffold has potential applications for tissue engineering.
基金the National Natural Science Foundation of China (Grant No.10572082)the Shanghai Leading Academic Discipline Project (Grant No.Y0103).
文摘The near-wake flow of a NACA0012 airfoils mounted above a water surface were experimentally studied in a wind/wave tunnel. The main objective of this study is to investigate the influence of the free surface on the structure of the airfoil trailing wake. The flow structure was measured with different ride heights between the airfoil and free surface using a Particle Image Velocimetry （PIV） system. The Reynolds number based on the chord length of the airfoil was about 3.5×10^3. For each experimental condition, large amount of instantaneous velocity fields were captured and ensemble-averaged to get the spatial distributions of mean velocity and mean vorticity, as well as turbulence statistics. The results show that the flow structures of the airfoil wake varies remarkably with the change in the ride height.
