The Experts below are selected from a list of 7587 Experts worldwide ranked by ideXlab platform
Dirk W. Grijpma - One of the best experts on this subject based on the ideXlab platform.
-
Preparation of Designed Poly(trimethylene carbonate) Meniscus Implants by Stereolithography: Challenges in Stereolithography
Macromolecular Bioscience, 2016Co-Authors: Bas Van Bochove, Gerjon Hannink, Pieter Buma, Dirk W. GrijpmaAbstract:Three-armed poly(trimethylene carbonate) macromers with a relatively high molecular weight of 28.9 kg mol−1 are prepared by ring opening polymerization and subsequent functionalization with methacrylate end groups. A resin suitable for processing by Stereolithography is developed using propylene carbonate as a diluent, a photoinitiator, and a dye to control the curing char- acteristics. The difficulties in building designed structures with digital light processing stereo- lithography and the ways of optimizing the resin compositions are described in detail. Using an optimized resin composition, which contained 50 wt% macromer, 50 wt% diluent, 0.05 wt% (relative to the macromer) dye, and 5 wt% (relative to the macromer) photoinitiator, designed 3D porous structures with a gyroid pore network geometry are manufactured. By varying pore sizes and porosities between, respectively, 300 and 1000 µm and 60% and 90%, cylindrical porous poly(trimethylene carbonate) network structures with compression moduli of 85–2320 kPa are prepared. A porous poly(trimethylene carbonate) network meniscus implant is designed on the basis of computed tomography imaging data. By adjusting the characteristics of the gyroid pore architec- ture, an implant with a compression modulus close to 400 kPa, which fits the compression modulus of human meniscal tissue, is manufactured by Stereolithography
-
preparation of poly e caprolactone based tissue engineering scaffolds by Stereolithography
Acta Biomaterialia, 2011Co-Authors: Laura Elomaa, Dirk W. Grijpma, Sandra Da Silva Teixeira, Risto Hakala, Harri Korhonen, Jukka SeppäläAbstract:A photocrosslinkable poly(e-caprolactone) (PCL)-based resin was developed and applied using Stereolithography. No additional solvents were required during the structure preparation process. Three-armed PCL oligomers of varying molecular weights were synthesized, functionalized with methacrylic anhydride, and photocrosslinked, resulting in high gel content networks. Stereolithography was used to build designed porous scaffolds using the resin containing PCL macromer, Irgacure 369 photoinitiator, inhibitor and dye. A suitable resin viscosity was obtained by heating the resin during the curing process. The scaffolds precisely matched the computer-aided designs, with no observable material shrinkage. The average porosity was 70.5 ± 0.8%, and the average pore size was 465 μm. The pore network was highly interconnected. The photocrosslinkable, biodegradable PCL resin is well suited for the solvent-free fabrication of tissue engineering scaffolds by Stereolithography.
-
a review on Stereolithography and its applications in biomedical engineering
Biomaterials, 2010Co-Authors: Ferry P W Melchels, Dirk W. Grijpma, Jan FeijenAbstract:Stereolithography is a solid freeform technique (SFF) that was introduced in the late 1980s. Although many other techniques have been developed since then, Stereolithography remains one of the most powerful and versatile of all SFF techniques. It has the highest fabrication accuracy and an increasing number of materials that can be processed is becoming available. In this paper we discuss the characteristic features of the Stereolithography technique and compare it to other SFF techniques. The biomedical applications of Stereolithography are reviewed, as well as the biodegradable resin materials that have been developed for use with Stereolithography. Finally, an overview of the application of Stereolithography in preparing porous structures for tissue engineering is given.
Timothy E Long - One of the best experts on this subject based on the ideXlab platform.
-
polymer structure property requirements for stereolithographic 3d printing of soft tissue engineering scaffolds
Biomaterials, 2017Co-Authors: Ryan J Mondschein, Akanksha Kanitkar, Christopher B Williams, Scott S Verbridge, Timothy E LongAbstract:Abstract This review highlights the synthesis, properties, and advanced applications of synthetic and natural polymers 3D printed using Stereolithography for soft tissue engineering applications. Soft tissue scaffolds are of great interest due to the number of musculoskeletal, cardiovascular, and connective tissue injuries and replacements humans face each year. Accurately replacing or repairing these tissues is challenging due to the variation in size, shape, and strength of different types of soft tissue. With advancing processing techniques such as Stereolithography, control of scaffold resolution down to the μm scale is achievable along with the ability to customize each fabricated scaffold to match the targeted replacement tissue. Matching the advanced manufacturing technique to polymer properties as well as maintaining the proper chemical, biological, and mechanical properties for tissue replacement is extremely challenging. This review discusses the design of polymers with tailored structure, architecture, and functionality for Stereolithography, while maintaining chemical, biological, and mechanical properties to mimic a broad range of soft tissue types.
-
3D Printing All-Aromatic Polyimides using Mask-Projection Stereolithography: Processing the Nonprocessable
Advanced Materials, 2017Co-Authors: Maruti Hegde, Danesh Tafti, Susheel Sekhar, V. Meenakshisundaram, Nicholas Chartrain, Timothy E LongAbstract:High-performance, all-aromatic, insoluble, engineering thermoplastic polyimides, such as pyromellitic dianhydride and 4,4′-oxydianiline (PMDA–ODA) (Kapton), exhibit exceptional thermal stability (up to ≈600 °C) and mechanical properties (Young’s modulus exceeding 2 GPa). However, their thermal resistance, which is a consequence of the all-aromatic molecular structure, prohibits processing using conventional techniques. Previous reports describe an energy-intensive sintering technique as an alternative technique for processing polyimides with limited resolution and part fidelity. This study demonstrates the unprecedented 3D printing of PMDA–ODA using maskprojection Stereolithography, and the preparation of high-resolution 3D structures without sacrificing bulk material properties. Synthesis of a soluble precursor polymer containing photo-crosslinkable acrylate groups enables light-induced, chemical crosslinking for spatial control in the gel state. Postprinting thermal treatment transforms the crosslinked precursor polymer to PMDA–ODA. The dimensional shrinkage is isotropic, and postprocessing preserves geometric integrity. Furthermore, large-area mask-projection scanning Stereolithography demonstrates the scalability of 3D structures. These unique high-performance 3D structures offer potential in fields ranging from water filtration and gas separation to automotive and aerospace technologies.
Jukka Seppälä - One of the best experts on this subject based on the ideXlab platform.
-
biodegradable photocrosslinkable poly depsipeptide co e caprolactone for tissue engineering synthesis characterization and in vitro evaluation
Journal of Polymer Science Part A, 2014Co-Authors: Yunqing Kang, Laura Elomaa, Jukka Seppälä, Yunzhi YangAbstract:Stereolithography has become increasingly popular in scaffold fabrication due to automation and well-controlled geometry complexity, and consequently, there is a great need for new suitable biodegradable photocrosslinkable polymers. In this study, a new type of photocrosslinkable poly(ester amide) was synthesized based on e-caprolactone and L-alanine- derived depsipeptide and was applied to fabrication of three- dimensional (3D) scaffolds by Stereolithography. 1 H nuclear magnetic resonance and Fourier transform infra-red analysis confirmed the formation of new bonds during the polymer synthesis. Incorporation of depsipeptide increased the glass transition temperature and hydrophilicity of the polymer and accelerated hydrolytic degradation compared with the poly(e- caprolactone) homopolymer. The compressive strength of the 3D scaffolds increased with the increasing depsipeptide con- tent. This work demonstrated that incorporation of depsipep- tide into photocrosslinkable polyesters resulted in excellent cytocompatibility and tunable degradation rates and mechani- cal properties and thus expanded the repertoire of biomaterials suitable for 3D photofabrication of high-resolution tissue engi- neering scaffolds. V C 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3307-3315
-
preparation of poly e caprolactone based tissue engineering scaffolds by Stereolithography
Acta Biomaterialia, 2011Co-Authors: Laura Elomaa, Dirk W. Grijpma, Sandra Da Silva Teixeira, Risto Hakala, Harri Korhonen, Jukka SeppäläAbstract:A photocrosslinkable poly(e-caprolactone) (PCL)-based resin was developed and applied using Stereolithography. No additional solvents were required during the structure preparation process. Three-armed PCL oligomers of varying molecular weights were synthesized, functionalized with methacrylic anhydride, and photocrosslinked, resulting in high gel content networks. Stereolithography was used to build designed porous scaffolds using the resin containing PCL macromer, Irgacure 369 photoinitiator, inhibitor and dye. A suitable resin viscosity was obtained by heating the resin during the curing process. The scaffolds precisely matched the computer-aided designs, with no observable material shrinkage. The average porosity was 70.5 ± 0.8%, and the average pore size was 465 μm. The pore network was highly interconnected. The photocrosslinkable, biodegradable PCL resin is well suited for the solvent-free fabrication of tissue engineering scaffolds by Stereolithography.
Keekyoung Kim - One of the best experts on this subject based on the ideXlab platform.
-
visible light photoinitiation of cell adhesive gelatin methacryloyl hydrogels for Stereolithography 3d bioprinting
ACS Applied Materials & Interfaces, 2018Co-Authors: Zongjie Wang, Hitendra Kumar, Zhenlin Tian, Xian Jin, Jonathan F Holzman, Frederic Menard, Keekyoung KimAbstract:We present the first cell-attachable and visible-light-crosslinkable bioinks based on gelatin methacryloyl (GelMA) with eosin Y (EY) photoinitiation for Stereolithography three-dimensional (3D) bioprinting. To develop a visible-light-crosslinkable hydrogel, we systematically studied five combinations of GelMA and EY photoinitiator with various concentrations. Their mechanical properties, microstructures, and cell viability and confluency after encapsulation were investigated rigorously to elucidate the effects of the EY and GelMA macromer concentrations on the characteristics of the hydrogel. Experimental results show that the compressive Young’s modulus and pore size are positively affected by the concentration of EY, whereas the mass swelling ratio and cell viability are negatively affected. Increasing the concentration of GelMA helps in improving the compressive Young’s modulus and cell attachment. We further employed the developed visible-light-based Stereolithography bioprinting system to print the p...
-
A simple and high-resolution Stereolithography-based 3D bioprinting system using visible light crosslinkable bioinks
Biofabrication, 2015Co-Authors: Zongjie Wang, Benjamin Parker, Raafa Abdulla, Raed Abdulla, Roya Samanipour, Sanjoy Ghosh, Keekyoung KimAbstract:Bioprinting is a rapidly developing technique for biofabrication. Because of its high resolution and the ability to print living cells, bioprinting has been widely used in artificial tissue and organ generation as well as microscale living cell deposition. In this paper, we present a low-cost Stereolithography-based bioprinting system that uses visible light crosslinkable bioinks. This low-cost Stereolithography system was built around a commercial projector with a simple water filter to prevent harmful infrared radiation from the projector. The visible light crosslinking was achieved by using a mixture of polyethylene glycol diacrylate (PEGDA) and gelatin methacrylate (GelMA) hydrogel with eosin Y based photoinitiator. Three different concentrations of hydrogel mixtures (10% PEG, 5% PEG + 5% GelMA, and 2.5% PEG + 7.5% GelMA, all w/v) were studied with the presented systems. The mechanical properties and microstructure of the developed bioink were measured and discussed in detail. Several cell-free hydrogel patterns were generated to demonstrate the resolution of the solution. Experimental results with NIH 3T3 fibroblast cells show that this system can produce a highly vertical 3D structure with 50 μm resolution and 85% cell viability for at least five days. The developed system provides a low-cost visible light Stereolithography solution and has the potential to be widely used in tissue engineering and bioengineering for microscale cell patterning.
Laura Elomaa - One of the best experts on this subject based on the ideXlab platform.
-
biodegradable photocrosslinkable poly depsipeptide co e caprolactone for tissue engineering synthesis characterization and in vitro evaluation
Journal of Polymer Science Part A, 2014Co-Authors: Yunqing Kang, Laura Elomaa, Jukka Seppälä, Yunzhi YangAbstract:Stereolithography has become increasingly popular in scaffold fabrication due to automation and well-controlled geometry complexity, and consequently, there is a great need for new suitable biodegradable photocrosslinkable polymers. In this study, a new type of photocrosslinkable poly(ester amide) was synthesized based on e-caprolactone and L-alanine- derived depsipeptide and was applied to fabrication of three- dimensional (3D) scaffolds by Stereolithography. 1 H nuclear magnetic resonance and Fourier transform infra-red analysis confirmed the formation of new bonds during the polymer synthesis. Incorporation of depsipeptide increased the glass transition temperature and hydrophilicity of the polymer and accelerated hydrolytic degradation compared with the poly(e- caprolactone) homopolymer. The compressive strength of the 3D scaffolds increased with the increasing depsipeptide con- tent. This work demonstrated that incorporation of depsipep- tide into photocrosslinkable polyesters resulted in excellent cytocompatibility and tunable degradation rates and mechani- cal properties and thus expanded the repertoire of biomaterials suitable for 3D photofabrication of high-resolution tissue engi- neering scaffolds. V C 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3307-3315
-
preparation of poly e caprolactone based tissue engineering scaffolds by Stereolithography
Acta Biomaterialia, 2011Co-Authors: Laura Elomaa, Dirk W. Grijpma, Sandra Da Silva Teixeira, Risto Hakala, Harri Korhonen, Jukka SeppäläAbstract:A photocrosslinkable poly(e-caprolactone) (PCL)-based resin was developed and applied using Stereolithography. No additional solvents were required during the structure preparation process. Three-armed PCL oligomers of varying molecular weights were synthesized, functionalized with methacrylic anhydride, and photocrosslinked, resulting in high gel content networks. Stereolithography was used to build designed porous scaffolds using the resin containing PCL macromer, Irgacure 369 photoinitiator, inhibitor and dye. A suitable resin viscosity was obtained by heating the resin during the curing process. The scaffolds precisely matched the computer-aided designs, with no observable material shrinkage. The average porosity was 70.5 ± 0.8%, and the average pore size was 465 μm. The pore network was highly interconnected. The photocrosslinkable, biodegradable PCL resin is well suited for the solvent-free fabrication of tissue engineering scaffolds by Stereolithography.
