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Chee Kai Chua - One of the best experts on this subject based on the ideXlab platform.
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improved biocomposite development of poly vinyl alcohol and hydroxyapatite for tissue engineering Scaffold Fabrication using selective laser sintering
Journal of Materials Science: Materials in Medicine, 2008Co-Authors: Florencia Edith Wiria, Chee Kai Chua, Kahfai Leong, Margam Chandrasekaran, Zai Yan Quah, Munwai LeeAbstract:In Scaffold guided tissue engineering (TE), temporary three-dimensional Scaffolds are essential to guide and support cell proliferation. Selective Laser Sintering (SLS) is studied for the development of such Scaffolds by eliminating pore spatial control problems faced in conventional Scaffolds Fabrication methods. SLS offers good user control over the Scaffold’s microstructures by adjusting its main processing parameters, namely the laser power, scan speed and part bed temperature.
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poly e caprolactone hydroxyapatite for tissue engineering Scaffold Fabrication via selective laser sintering
Acta Biomaterialia, 2007Co-Authors: Florencia Edith Wiria, K F Leong, Chee Kai ChuaAbstract:Abstract Rapid prototyping (RP) techniques are becoming more popular for fabricating tissue engineering (TE) Scaffolds owing to their advantages over conventional methods, such as the ability to fabricate Scaffolds with predetermined interconnected networks without the use of organic solvents. A versatile RP technique, selective laser sintering (SLS), offers good user control of Scaffold microstructure by adjusting the process parameters. This research focuses on a the use of biocomposite material, consisting of poly- e -caprolactone (PCL) and hydroxyapatite (HA), to fabricate TE Scaffolds using SLS. Biocomposite blends with different percentage weights of HA were physically blended and sintered to assess their suitability for Fabrication via SLS. Optimal sintering conditions for the powders were achieved by varying parameters such as laser power and scan speed. Studies of the sintered specimen morphology were performed by scanning electron microscopy. Thermogravimetric analysis confirmed the homogeneity of the biocomposite blend. Simulated body fluid (SBF) samples show the formation of hydroxy carbonate apatite, as a result of soaking HA in a SBF environment. Cell culture experiment showed that Saos-2 cells were able to live and replicate on the fabricated Scaffolds. The results show the favorable potential of PCL/HA biocomposite as TE Scaffolds that are fabricated via SLS.
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indirect Fabrication of collagen Scaffold based on inkjet printing technique
Rapid Prototyping Journal, 2006Co-Authors: Wai Yee Yeong, Chee Kai Chua, Kahfai Leong, Margam Chandrasekaran, Munwai LeeAbstract:Purpose – This paper presents a new indirect Scaffold Fabrication method for soft tissue based on rapid prototyping (RP) technique and preliminary characterization for collagen Scaffolds.Design/methodology/approach – This paper introduces the processing steps for indirect Scaffold Fabrication based on the inkjet printing technology. The Scaffold morphology was characterized by scanning electron microscopy. The designs of the Scaffolds are presented and discussed.Findings – Theoretical studies on the inkjet printing process are presented. Previous research showed that the availability of biomaterial that can be processed on a commercial RP system is very limited. This is due mainly to the unfavorable machine processing parameters such as high working temperature and restrictions on the form of raw material input. The process described in this paper overcomes these problems while retaining the strength of RP techniques. Technical challenges of the process are presented as well.Research limitations/implicati...
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investigation of the mechanical properties and porosity relationships in fused deposition modelling fabricated porous structures
Rapid Prototyping Journal, 2006Co-Authors: Ker Chin Ang, Chee Kai Chua, Kahfai Leong, Margam ChandrasekaranAbstract:Purpose – The purpose of this paper is to investigate the mechanical properties and porosity relationships in fused deposition modelling (FDM) fabricated porous structures.Design/methodology/approach – Porous structures of numerous build architectures aimed at tissue engineering (TE) application were fabricated using the FDM. The employment of FDM to fabricate these non‐random constructs offers many advantages over conventional Scaffold Fabrication techniques as patient specific Scaffolds with well‐defined architectures and controllable pore sizes can be fabricated accurately and rapidly. There exist several FDM parameters that one needs to specify during the Scaffold Fabrication process. These parameters, which can be interdependent and exhibit varying effects on Scaffold properties, were identified and examined using the design of experiment (DOE) approach. Essentially, the effects of five FDM process parameters, namely air gap, raster width, build orientation, build layer and build profile, on the poro...
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solid freeform Fabrication of three dimensional Scaffolds for engineering replacement tissues and organs
Biomaterials, 2003Co-Authors: K F Leong, C M Cheah, Chee Kai ChuaAbstract:Abstract Most tissue engineering (TE) strategies for creating functional replacement tissues or organs rely on the application of temporary three-dimensional Scaffolds to guide the proliferation and spread of seeded cells in vitro and in vivo. The characteristics of TE Scaffolds are major concerns in the quest to fabricate ideal Scaffolds. This paper identifies essential structural characteristics and the pre-requisites for Fabrication techniques that can yield Scaffolds that are capable of directing healthy and homogeneous tissue development. Emphasis is given to solid freeform (SFF), also known as rapid prototyping, technologies which are fast becoming the techniques of choice for Scaffold Fabrication with the potential to overcome the limitations of conventional manual-based Fabrication techniques. SFF-fabricated Scaffolds have been found to be able to address most, if not all the macro- and micro-architectural requirements for TE applications. This paper reviews the application/potential application of state-of-the-art SFF Fabrication techniques in creating TE Scaffolds. The advantages and limitations of the SFF techniques are compared. Related research carried out worldwide by different institutions, including the authors’ research are discussed.
Dong-woo Cho - One of the best experts on this subject based on the ideXlab platform.
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development of an indirect stereolithography technology for Scaffold Fabrication with a wide range of biomaterial selectivity
Tissue Engineering Part C-methods, 2012Co-Authors: Hyunwook Kang, Dong-woo ChoAbstract:Tissue engineering, which is the study of generating biological substitutes to restore or replace tissues or organs, has the potential to meet current needs for organ transplantation and medical interventions. Various approaches have been attempted to apply three-dimensional (3D) solid freeform Fabrication technologies to tissue engineering for Scaffold Fabrication. Among these, the stereolithography (SL) technology not only has the highest resolution, but also offers quick Fabrication. However, a lack of suitable biomaterials is a barrier to applying the SL technology to tissue engineering. In this study, an indirect SL method that combines the SL technology and a sacrificial molding process was developed to address this challenge. A sacrificial mold with an inverse porous shape was fabricated from an alkali-soluble photopolymer by the SL technology. A sacrificial molding process was then developed for Scaffold construction using a variety of biomaterials. The results indicated a wide range of biomateria...
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blended pcl plga Scaffold Fabrication using multi head deposition system
Microelectronic Engineering, 2009Co-Authors: Jong Young Kim, Dong-woo ChoAbstract:Solid free-form Fabrication (SFF) technologies can endow a great chance for regeneration of damaged tissues or organs in Scaffold-based tissue engineering. In this study, a novel blended Scaffold Fabrication through multi-head deposition system (MHDS) for tissue engineering is introduced. Fabrication of 3D tissue Scaffolds using MHDS required the combination of several technologies, including motion control, thermal control, pneumatic control, and CAD/CAM software. Blended 3D poly-caprolactone (PCL)/poly-lactic-co-glycolic acid (PLGA) Scaffolds with a uniform pore size of [email protected] and a line width and height of [email protected] were well fabricated having a fully interconnected architecture and calculated porosity of about 69.6%. The compressive strength and modulus of the Scaffold is each about 0.8 and 12.9MPa, which is enough to maintain its architecture during in vitro cell experiments. Finally, the biocompatibility of fabricated 3D Scaffold was demonstrated through the cell proliferation experiment. In the near future, blended PCL/PLGA Scaffold will be a good option of Scaffold for tissue engineering.
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Fabrication and characteristic analysis of a poly(propylene fumarate) Scaffold using micro-stereolithography technology.
Journal of biomedical materials research. Part B Applied biomaterials, 2008Co-Authors: Jin Woo Lee, Phung Xuan Lan, Geunbae Lim, Byung Kim, Dong-woo ChoAbstract:Scaffold Fabrication for regenerating functional human tissues has an important role in tissue engineering, and there has been much progress in research on Scaffold Fabrication. However, current methods are limited by the mechanical properties of existing biodegradable materials and the irregular structures that they produce. Recently, several promising biodegradable materials have been introduced, including poly(propylene fumarate) (PPF). The development of micro-stereolithography allows the Fabrication of free-form 3D microstructures as designed. Since this technology requires a low-viscosity resin to fabricate fine structures, we reduced the viscosity of PPF by adding diethyl fumarate. Using our system, the curing characteristics and material properties of the resin were analyzed experimentally. Then, we fabricated waffle shape and 3D Scaffolds containing several hundred regular micro pores. This method controlled the pore size, porosity, interconnectivity, and pore distribution. The results show that micro-stereolithography has big advantages over conventional Fabrication methods. In addition, the ultimate strength and elastic modulus of the fabricated Scaffolds were measured, and cell adhesion to the fabricated Scaffold was observed by growing seeded cells on it. These results showed that the PPF/DEF Scaffold is a potential bone Scaffold for tissue engineering.
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3d Scaffold Fabrication with ppf def using micro stereolithography
Microelectronic Engineering, 2007Co-Authors: Jin Woo Lee, Phung Xuan Lan, Geunbae Lim, Byung Kim, Dong-woo ChoAbstract:Current studies on Scaffold Fabrication have focused on overcoming the limitations imposed by the mechanical properties of existing biodegradable materials and the irregular structures they produce. Recently, several promising biodegradable materials were introduced, including poly(propylene fumarate) (PPF). In addition, the development of micro-stereolithography allows the Fabrication of free-form 3D microstructures by dividing a desired shape into several slices of a given thickness. This technology, however, requires a low-viscosity resin to fabricate fine structures, which excludes the use of PPF. To fabricate precise 3D Scaffolds using micro-stereolithography, we created a system in which the viscosity of PPF was reduced by adding diethyl fumarate. The fabricated Scaffold was sterilized, and fibroblasts in cell culture medium were seeded onto the structure. Cells were fixed and freeze-dried after 4, 7, and 28 days of culture. Under scanning electron microscopy, we observed that the cells were able to attach to the Scaffold surface and grow.
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3D Scaffold Fabrication with PPF/DEF using micro-stereolithography
Microelectronic Engineering, 2007Co-Authors: Jin Woo Lee, Phung Xuan Lan, Geunbae Lim, Byung Kim, Dong-woo ChoAbstract:Current studies on Scaffold Fabrication have focused on overcoming the limitations imposed by the mechanical properties of existing biodegradable materials and the irregular structures they produce. Recently, several promising biodegradable materials were introduced, including poly(propylene fumarate) (PPF). In addition, the development of micro-stereolithography allows the Fabrication of free-form 3D microstructures by dividing a desired shape into several slices of a given thickness. This technology, however, requires a low-viscosity resin to fabricate fine structures, which excludes the use of PPF. To fabricate precise 3D Scaffolds using micro-stereolithography, we created a system in which the viscosity of PPF was reduced by adding diethyl fumarate. The fabricated Scaffold was sterilized, and fibroblasts in cell culture medium were seeded onto the structure. Cells were fixed and freeze-dried after 4, 7, and 28 days of culture. Under scanning electron microscopy, we observed that the cells were able to attach to the Scaffold surface and grow. © 2007 Elsevier B.V. All rights reserved.
Kahfai Leong - One of the best experts on this subject based on the ideXlab platform.
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improved biocomposite development of poly vinyl alcohol and hydroxyapatite for tissue engineering Scaffold Fabrication using selective laser sintering
Journal of Materials Science: Materials in Medicine, 2008Co-Authors: Florencia Edith Wiria, Chee Kai Chua, Kahfai Leong, Margam Chandrasekaran, Zai Yan Quah, Munwai LeeAbstract:In Scaffold guided tissue engineering (TE), temporary three-dimensional Scaffolds are essential to guide and support cell proliferation. Selective Laser Sintering (SLS) is studied for the development of such Scaffolds by eliminating pore spatial control problems faced in conventional Scaffolds Fabrication methods. SLS offers good user control over the Scaffold’s microstructures by adjusting its main processing parameters, namely the laser power, scan speed and part bed temperature.
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indirect Fabrication of collagen Scaffold based on inkjet printing technique
Rapid Prototyping Journal, 2006Co-Authors: Wai Yee Yeong, Chee Kai Chua, Kahfai Leong, Margam Chandrasekaran, Munwai LeeAbstract:Purpose – This paper presents a new indirect Scaffold Fabrication method for soft tissue based on rapid prototyping (RP) technique and preliminary characterization for collagen Scaffolds.Design/methodology/approach – This paper introduces the processing steps for indirect Scaffold Fabrication based on the inkjet printing technology. The Scaffold morphology was characterized by scanning electron microscopy. The designs of the Scaffolds are presented and discussed.Findings – Theoretical studies on the inkjet printing process are presented. Previous research showed that the availability of biomaterial that can be processed on a commercial RP system is very limited. This is due mainly to the unfavorable machine processing parameters such as high working temperature and restrictions on the form of raw material input. The process described in this paper overcomes these problems while retaining the strength of RP techniques. Technical challenges of the process are presented as well.Research limitations/implicati...
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investigation of the mechanical properties and porosity relationships in fused deposition modelling fabricated porous structures
Rapid Prototyping Journal, 2006Co-Authors: Ker Chin Ang, Chee Kai Chua, Kahfai Leong, Margam ChandrasekaranAbstract:Purpose – The purpose of this paper is to investigate the mechanical properties and porosity relationships in fused deposition modelling (FDM) fabricated porous structures.Design/methodology/approach – Porous structures of numerous build architectures aimed at tissue engineering (TE) application were fabricated using the FDM. The employment of FDM to fabricate these non‐random constructs offers many advantages over conventional Scaffold Fabrication techniques as patient specific Scaffolds with well‐defined architectures and controllable pore sizes can be fabricated accurately and rapidly. There exist several FDM parameters that one needs to specify during the Scaffold Fabrication process. These parameters, which can be interdependent and exhibit varying effects on Scaffold properties, were identified and examined using the design of experiment (DOE) approach. Essentially, the effects of five FDM process parameters, namely air gap, raster width, build orientation, build layer and build profile, on the poro...
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the design of Scaffolds for use in tissue engineering part ii rapid prototyping techniques
Tissue Engineering, 2002Co-Authors: S Yang, Kahfai Leong, Zhaohui Du, Chee Kai ChuaAbstract:Tissue engineering (TE) is an important emerging area in biomedical engineering for creating biological alternatives for harvested tissues, implants, and prostheses. In TE, a highly porous artificial extracellular matrix or Scaffold is required to accommodate mammalian cells and guide their growth and tissue regeneration in three-dimension (3D). However, existing 3D Scaffolds for TE proved less than ideal for actual applications because they lack mechanical strength, interconnected channels, and controlled porosity or pores distribution. In this paper, the authors review the application and advancement of rapid prototyping (RP) techniques in the design and creation of synthetic Scaffolds for use in TE. We also review the advantages and benefits, and limitations and shortcomings of current RP techniques as well as the future direction of RP development in TE Scaffold Fabrication.
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the design of Scaffolds for use in tissue engineering part i traditional factors
Tissue Engineering, 2001Co-Authors: S Yang, Kahfai Leong, Zhaohui Du, Chee Kai ChuaAbstract:In tissue engineering, a highly porous artificial extracellular matrix or Scaffold is required to accommodate mammalian cells and guide their growth and tissue regeneration in three dimensions. However, existing three-dimensional Scaffolds for tissue engineering proved less than ideal for actual applications, not only because they lack mechanical strength, but they also do not guarantee interconnected channels. In this paper, the authors analyze the factors necessary to enhance the design and manufacture of Scaffolds for use in tissue engineering in terms of materials, structure, and mechanical properties and review the traditional Scaffold Fabrication methods. Advantages and limitations of these traditional methods are also discussed.
Ian Pashby - One of the best experts on this subject based on the ideXlab platform.
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extrusion based rapid prototyping technique an advanced platform for tissue engineering Scaffold Fabrication
Biopolymers, 2012Co-Authors: Enamul M Hoque, Leng Y Chuan, Ian PashbyAbstract:Advances in Scaffold design and Fabrication technology have brought the tissue engineering field stepping into a new era. Conventional techniques used to develop Scaffolds inherit limitations, such as lack of control over the pore morphology and architecture as well as reproducibility. Rapid prototyping (RP) technology, a layer-by-layer additive approach offers a unique opportunity to build complex 3D architectures overcoming those limitations that could ultimately be tailored to cater for patient-specific applications. Using RP methods, researchers have been able to customize Scaffolds to mimic the biomechanical properties (in terms of structural integrity, strength, and microenvironment) of the organ or tissue to be repaired/replaced quite closely. This article provides intensive description on various extrusion based Scaffold Fabrication techniques and review their potential utility for TE applications. The extrusion-based technique extrudes the molten polymer as a thin filament through a nozzle onto a platform layer-by-layer and thus building 3D Scaffold. The technique allows full control over pore architecture and dimension in the x- and y- planes. However, the pore height in z-direction is predetermined by the extruding nozzle diameter rather than the technique itself. This review attempts to assess the current state and future prospects of this technology. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 83–93, 2012.
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extrusion based rapid prototyping technique an advanced platform for tissue engineering Scaffold Fabrication
Biopolymers, 2012Co-Authors: Enamul M Hoque, Leng Y Chuan, Ian PashbyAbstract:Advances in Scaffold design and Fabrication technology have brought the tissue engineering field stepping into a new era. Conventional techniques used to develop Scaffolds inherit limitations, such as lack of control over the pore morphology and architecture as well as reproducibility. Rapid prototyping (RP) technology, a layer-by-layer additive approach offers a unique opportunity to build complex 3D architectures overcoming those limitations that could ultimately be tailored to cater for patient-specific applications. Using RP methods, researchers have been able to customize Scaffolds to mimic the biomechanical properties (in terms of structural integrity, strength, and microenvironment) of the organ or tissue to be repaired/replaced quite closely. This article provides intensive description on various extrusion based Scaffold Fabrication techniques and review their potential utility for TE applications. The extrusion-based technique extrudes the molten polymer as a thin filament through a nozzle onto a platform layer-by-layer and thus building 3D Scaffold. The technique allows full control over pore architecture and dimension in the x- and y- planes. However, the pore height in z-direction is predetermined by the extruding nozzle diameter rather than the technique itself. This review attempts to assess the current state and future prospects of this technology. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 83–93, 2012.
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Extrusion based rapid prototyping technique: An advanced platform for tissue engineering Scaffold Fabrication
Biopolymers, 2011Co-Authors: M. Enamul Hoque, Y. Leng Chuan, Ian PashbyAbstract:Advances in Scaffold design and Fabrication technology have brought the tissue engineering field stepping into a new era. Conventional techniques used to develop Scaffolds inherit limitations, such as lack of control over the pore morphology and architecture as well as reproducibility. Rapid prototyping (RP) technology, a layer-by-layer additive approach offers a unique opportunity to build complex 3D architectures overcoming those limitations that could ultimately be tailored to cater for patient-specific applications. Using RP methods, researchers have been able to customize Scaffolds to mimic the biomechanical properties (in terms of structural integrity, strength, and microenvironment) of the organ or tissue to be repaired/replaced quite closely. This article provides intensive description on various extrusion based Scaffold Fabrication techniques and review their potential utility for TE applications. The extrusion-based technique extrudes the molten polymer as a thin filament through a nozzle onto a platform layer-by-layer and thus building 3D Scaffold. The technique allows full control over pore architecture and dimension in the x- and y- planes. However, the pore height in z-direction is predetermined by the extruding nozzle diameter rather than the technique itself. This review attempts to assess the current state and future prospects of this technology.
K F Leong - One of the best experts on this subject based on the ideXlab platform.
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rapid freeze prototyping technique in bio plotters for tissue Scaffold Fabrication
Rapid Prototyping Journal, 2008Co-Authors: Cong Bang Pham, K F Leong, Tze Chiun Lim, Kerm Sin ChianAbstract:Purpose – The purpose of this paper is to develop a new bio‐plotter using a rapid freeze prototyping (RFP) technique and to investigate its potential applications in fabricating tissue Scaffolds.Design/methodology/approach – The development of cryogenic bio‐plotters including design steps of hardware as well as software is addressed. Effects of structural parameters and process parameters on the properties of tissue Scaffolds are demonstrated through simulation and experimental results.Findings – The paper finds that the RFP method is suitable to fabricate macro‐ and micro‐porous Scaffolds, especially for temperature‐sensitive polymers. In addition, through simulation and experiment results, it also shows that macro‐ and micro‐porous properties could be manipulated by structural parameters and process parameters, respectively.Research limitations/implications – This paper shows that the chamber temperature is an important process parameter that can provide the means to control the micro‐porous structure o...
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poly e caprolactone hydroxyapatite for tissue engineering Scaffold Fabrication via selective laser sintering
Acta Biomaterialia, 2007Co-Authors: Florencia Edith Wiria, K F Leong, Chee Kai ChuaAbstract:Abstract Rapid prototyping (RP) techniques are becoming more popular for fabricating tissue engineering (TE) Scaffolds owing to their advantages over conventional methods, such as the ability to fabricate Scaffolds with predetermined interconnected networks without the use of organic solvents. A versatile RP technique, selective laser sintering (SLS), offers good user control of Scaffold microstructure by adjusting the process parameters. This research focuses on a the use of biocomposite material, consisting of poly- e -caprolactone (PCL) and hydroxyapatite (HA), to fabricate TE Scaffolds using SLS. Biocomposite blends with different percentage weights of HA were physically blended and sintered to assess their suitability for Fabrication via SLS. Optimal sintering conditions for the powders were achieved by varying parameters such as laser power and scan speed. Studies of the sintered specimen morphology were performed by scanning electron microscopy. Thermogravimetric analysis confirmed the homogeneity of the biocomposite blend. Simulated body fluid (SBF) samples show the formation of hydroxy carbonate apatite, as a result of soaking HA in a SBF environment. Cell culture experiment showed that Saos-2 cells were able to live and replicate on the fabricated Scaffolds. The results show the favorable potential of PCL/HA biocomposite as TE Scaffolds that are fabricated via SLS.
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solid freeform Fabrication of three dimensional Scaffolds for engineering replacement tissues and organs
Biomaterials, 2003Co-Authors: K F Leong, C M Cheah, Chee Kai ChuaAbstract:Abstract Most tissue engineering (TE) strategies for creating functional replacement tissues or organs rely on the application of temporary three-dimensional Scaffolds to guide the proliferation and spread of seeded cells in vitro and in vivo. The characteristics of TE Scaffolds are major concerns in the quest to fabricate ideal Scaffolds. This paper identifies essential structural characteristics and the pre-requisites for Fabrication techniques that can yield Scaffolds that are capable of directing healthy and homogeneous tissue development. Emphasis is given to solid freeform (SFF), also known as rapid prototyping, technologies which are fast becoming the techniques of choice for Scaffold Fabrication with the potential to overcome the limitations of conventional manual-based Fabrication techniques. SFF-fabricated Scaffolds have been found to be able to address most, if not all the macro- and micro-architectural requirements for TE applications. This paper reviews the application/potential application of state-of-the-art SFF Fabrication techniques in creating TE Scaffolds. The advantages and limitations of the SFF techniques are compared. Related research carried out worldwide by different institutions, including the authors’ research are discussed.
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development of a tissue engineering Scaffold structure library for rapid prototyping part 2 parametric library and assembly program
The International Journal of Advanced Manufacturing Technology, 2003Co-Authors: C M Cheah, K F Leong, Chee Kai Chua, S W ChuaAbstract:Rapid prototyping (RP) techniques have been found to be advantageous for tissue engineering (TE) Scaffold Fabrication due to their ability to address and overcome the problems of uncontrollable microstructure and the feasibility issues of complex three-dimensional structures found in conventional processing techniques. This research proposes a novel approach for TE Scaffold manufacture using RP techniques. The approach involves the integration of medical imaging devices (CT/MRI) for the acquisition of anatomic structural data, three-dimensional CAD modelling for designing and creating the digital Scaffold models and RP for fabricating the physical Scaffolds. To aid the user in CAD modelling, a standard parametric library of Scaffold structures is designed and developed. With the library, a user can select the geometry of the Scaffold unit cell and size it to suit the end application of the TE Scaffold. A developed application program will then assemble the Scaffold structure from the selected unit cell, following the surface profile of the anatomic structure to be replicated. A physical Scaffold will then be built using an RP system.
