306 results on '"Wen-Feng Lu"'
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302. Adding Value through Design.
- Author
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Wen Feng Lu and Ching-Chiuan Yen
- Subjects
- *
PREFACES & forewords , *DESIGNERS - Abstract
The article introduces this issue with a selection of works from exhibitions and design competitions, highlighting designers such as Toshiyuki Kita and James Dyson.
- Published
- 2007
303. 3D-printed ceramic triply periodic minimal surface structures for design of functionally graded bone implants
- Author
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Sanjairaj Vijayavenkataraman, Lai Yee Kuan, and Wen Feng Lu
- Subjects
Bone implants ,Triply periodic minimal surfaces ,Ceramics ,Stress-shielding ,Vat polymerization ,3D printing ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Stress shielding is one of the main problems that lead to bone resorption and revision surgery after implantation. Most of the commercially available metallic non-porous bone implants have a much greater stiffness than the native human bones and are prone to cause stress-shielding. With an open cell structure and intricate architecture, hyperbolic minimal surfaces offer several advantages such as less stress concentration, high permeability and high surface area to volume ratio, thus providing an ideal environment for cell adhesion, migration, and proliferation. This paper explores the use of porous bone implant design based on Triply Periodic Minimal Surfaces (TPMS) which is additively manufactured with ceramic material (Alumina) using Lithography-based Ceramics Manufacturing (LCM) technology. A total of 12 different primitive surface structure unit cells with pore size in the range of 500–1000 μm and porosity above 50% were considered. This is one of the earliest studies reporting the 3D printing of TPMS-based structures using ceramic material. Our results suggest that the choice of material and a porous TPMS-based design led to fabrication of structures with a much lesser compressive modulus comparable with the native bone and hence could potentially be adopted for bone implant design to mitigate the stress-shielding effect.
- Published
- 2020
- Full Text
- View/download PDF
304. Fabrication of dentin-like scaffolds through combined 3D printing and bio-mineralisation
- Author
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Yang Wu, Danial F.B. Azmi, Vinicius Rosa, Amr S. Fawzy, Jerry Y.H. Fuh, Yoke San Wong, and Wen Feng Lu
- Subjects
electrohydrodynamic jet printing ,polycapronolactone ,mineral trioxide aggregate ,dental pulp stem cells ,dentin tissue engineering ,innovative design and manufacturing ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In this study, polycaprolactone/mineral trioxide aggregate (PCL/MTA) scaffolds were successfully fabricated via an electrohydrodynamic jet (or E-jet) 3D printing system developed by our group. The viscosity of the composited solutions and the key process parameters (i.e. applied voltage and feed rate) were investigated to achieve an optimal process condition. To investigate the potential of PCL/MTA scaffolds to support regeneration ability for dentin related tissue, we seeded dental pulp stem cells on the scaffolds, and compared the results with cell-seeded PCL scaffolds. Assessment of cell viability and proliferation using live/dead cell staining and MTS assay showed compatibility of PCL and PCL/MTA scaffolds for cellular attachment and growth. These scaffolds could be used for fabrication of three-dimensional tissues and in future could be applied to dentin and periodontal tissue engineering applications.
- Published
- 2016
- Full Text
- View/download PDF
305. Design of Three-Dimensional Scaffolds with Tunable Matrix Stiffness for Directing Stem Cell Lineage Specification: An In Silico Study
- Author
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Sanjairaj Vijayavenkataraman, Zhang Shuo, Jerry Y. H. Fuh, and Wen Feng Lu
- Subjects
3D scaffolds ,scaffold design ,tissue engineering ,regenerative medicine ,stem cells ,Technology ,Biology (General) ,QH301-705.5 - Abstract
Tissue engineering is a multi-disciplinary area of research bringing together the fields of engineering and life sciences with the aim of fabricating tissue constructs aiding in the regeneration of damaged tissues and organs. Scaffolds play a key role in tissue engineering, acting as the templates for tissue regeneration and guiding the growth of new tissue. The use of stem cells in tissue engineering and regenerative medicine becomes indispensable, especially for applications involving successful long-term restoration of continuously self-renewing tissues, such as skin. The differentiation of stem cells is controlled by a number of cues, of which the nature of the substrate and its innate stiffness plays a vital role in stem cell fate determination. By tuning the substrate stiffness, the differentiation of stem cells can be directed to the desired lineage. Many studies on the effect of substrate stiffness on stem cell differentiation has been reported, but most of those studies are conducted with two-dimensional (2D) substrates. However, the native in vivo tissue microenvironment is three-dimensional (3D) and life science researchers are moving towards 3D cell cultures. Porous 3D scaffolds are widely used by the researchers for 3D cell culture and the properties of such scaffolds affects the cell attachment, proliferation, and differentiation. To this end, the design of porous scaffolds directly influences the stem cell fate determination. There exists a need to have 3D scaffolds with tunable stiffness for directing the differentiation of stem cells into the desired lineage. Given the limited number of biomaterials with all the desired properties, the design of the scaffolds themselves could be used to tune the matrix stiffness. This paper is an in silico study, investigating the effect of various scaffold parameter, namely fiber width, porosity, number of unit cells per layer, number of layers, and material selection, on the matrix stiffness, thereby offering a guideline for design of porous tissue engineering scaffolds with tunable matrix stiffness for directing stem cell lineage specification.
- Published
- 2017
- Full Text
- View/download PDF
306. Taguchi's methods to optimize the properties and bioactivity of 3D printed polycaprolactone/mineral trioxide aggregate scaffold: Theoretical predictions and experimental validation.
- Author
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Bhargav A, Min KS, Wen Feng L, Fuh JYH, and Rosa V
- Subjects
- Aluminum Compounds metabolism, Apoptosis, Biocompatible Materials metabolism, Calcium Compounds metabolism, Cell Proliferation drug effects, Drug Combinations, Gene Expression Regulation drug effects, Humans, Hydrogen-Ion Concentration, MSX1 Transcription Factor genetics, Matrix Metalloproteinase 2 genetics, Models, Chemical, Osteocalcin genetics, Oxides metabolism, Peptide Fragments genetics, Porosity, Printing, Three-Dimensional, Silicates metabolism, Time Factors, Tissue Engineering, Aluminum Compounds chemistry, Biocompatible Materials chemistry, Calcium Compounds chemistry, Oxides chemistry, Polyesters chemistry, Silicates chemistry, Tissue Scaffolds chemistry
- Abstract
Mineral trioxide aggregate (MTA) can provide bioactivity to poly-caprolactone (PCL), which is an inert polymer used to print scaffolds. However, testing all combinations of scaffold characteristics (e.g., composition, pore size, and distribution) to optimize properties of scaffolds is time-consuming and costly. The Taguchi's methods can identify characteristics that have major influences on the properties of complex designs, hence decreasing the number of combinations to be tested. The objective was to assess the potential of Taguchi's methods as a predictive tool for the optimization of bioactive scaffold printed using electro-hydro dynamic jetting. A three-level approach assessed the influence of PCL/MTA proportion, pore size, fiber dimension and number of layers in pH, degradation rate, porosity, yield strength, and Young's modulus. Data were analyzed using Tukey's honest significant difference test, analysis of mean and signal-to-noise ratio (S/N) test. Cytocompatibility and differentiation potential were assessed for 5 and 30 days using dental pulp stem cells and analyzed with one-way analysis of variance (proliferation) or Mann-Whitney (qPCR). The S/N ratio and analysis of mean showed that fiber diameter and composition were the most influential characteristics in all properties. The experimental data confirmed that the addition of MTA to PCL increased the pH and scaffold degradation. Only PCL and PCL with 4% MTA allowed cell proliferation. The latter increased the genetic expression of ALP, COL-1, OCN, and MSX-1. The theoretical predictions were confirmed by the experiments. The Taguchi's identified the inputs that can be disregarded to optimize 3D printed meshed bioactive scaffolds., (© 2019 Wiley Periodicals, Inc.)
- Published
- 2020
- Full Text
- View/download PDF
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