The Experts below are selected from a list of 594 Experts worldwide ranked by ideXlab platform
Sunghoon Kwon - One of the best experts on this subject based on the ideXlab platform.
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fine tuned grayscale optofluidic maskless lithography for three dimensional freeform shape microstructure fabrication
Optics Letters, 2014Co-Authors: Sukheung Song, Sunghoon Kwon, Kibeom Kim, Sungeun Choi, Sangkwon Han, Hosuk Lee, Wook ParkAbstract:This article presents free-floating three-dimensional (3D) microstructure fabrication in a microfluidic channel using direct fine-tuned grayscale image lithography. The image is designed as a freeform shape and is composed of gray shades as light-absorbing features. Gray shade levels are modulated through multiple reflections of light in a digital micromirror device (DMD) to produce different height formations. Whereas conventional photolithography has several limitations in producing grayscale colors on photomask features, our method focuses on a maskless, single-shot process for fabrication of freeform 3D micro-scale shapes. The fine-tuned gray image is designed using an 8-bit grayscale color; thus, each pixel is capable of displaying 256 gray shades. The pattern of the UV light reflecting on the DMD is transferred to a Photocurable Resin flowing through a microfluidic channel. Here, we demonstrate diverse free-floating 3D microstructure fabrication using fine-tuned grayscale image lithography. Additionally, we produce polymeric microstructures with locally embedded gray encoding patterns, such as grayscale-encoded microtags. This functional microstructure can be applied to a biophysical detection system combined with 3D microstructures. This method would be suitable for fabricating 3D microstructures that have a specific morphology to be used for particular biological or medical applications.
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Three-dimensional fabrication of heterogeneous microstructures using soft membrane deformation and optofluidic maskless lithography.
Lab on a chip, 2009Co-Authors: Seung Ah Lee, Sung Hoon Lee, Su Eun Chung, Wook Park, Sunghoon KwonAbstract:We propose a method for high-throughput generation of 3D microstructures using a membrane-mounted microfluidic channel. Utilizing an optofluidic maskless lithography system, photopolymerized 3D microstructures are fabricated in a layer-by-layer fashion with the thickness of each layer controlled by the deformation of the membrane. The combination of low numerical aperture optical systems for photopolymerization and a soft membrane for height control allows large area projection lithography with high vertical resolution, overcoming the trade-off between vertical resolution and the field-of-view. The material composition of each layer is varied using microfluidic control of Photocurable Resin and composite microstructures with heterogeneity in both lateral and vertical directions are generated. Using this technique, we demonstrate three-dimensional patterning of different types of cells in a hydrogel for a microfluidic platform to study co-culture and cell-to-cell interactions. The proposed technique is fast and simple, allowing parallel synthesis of complex heterogeneous 3D microstructures and in situ biomaterial patterning for microfluidic bioassays.
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optofluidic maskless lithography system for real time synthesis of photopolymerized microstructures in microfluidic channels
Applied Physics Letters, 2007Co-Authors: Su Eun Chung, Hyunsung Park, Kyoungsik Yu, Namkyoo Park, Wook Park, Sunghoon KwonAbstract:The authors propose an optofluidic maskless lithography technique that can dynamically synthesize free-floating polymeric microstructures inside microfluidic channels by selectively polymerizing Photocurable Resin with high-speed two-dimensional spatial light modulators. The combination of programable optical projection and microfluidic devices allows one to precisely control the timing and location of the photopolymerization process for microstructure fabrication. Real-time generation of microparticles with various shapes, sizes, ordering, and material contents are experimentally demonstrated. Long polymeric structures of which size is not limited by the exposure field of view can also be fabricated.
Wook Park - One of the best experts on this subject based on the ideXlab platform.
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fine tuned grayscale optofluidic maskless lithography for three dimensional freeform shape microstructure fabrication
Optics Letters, 2014Co-Authors: Sukheung Song, Sunghoon Kwon, Kibeom Kim, Sungeun Choi, Sangkwon Han, Hosuk Lee, Wook ParkAbstract:This article presents free-floating three-dimensional (3D) microstructure fabrication in a microfluidic channel using direct fine-tuned grayscale image lithography. The image is designed as a freeform shape and is composed of gray shades as light-absorbing features. Gray shade levels are modulated through multiple reflections of light in a digital micromirror device (DMD) to produce different height formations. Whereas conventional photolithography has several limitations in producing grayscale colors on photomask features, our method focuses on a maskless, single-shot process for fabrication of freeform 3D micro-scale shapes. The fine-tuned gray image is designed using an 8-bit grayscale color; thus, each pixel is capable of displaying 256 gray shades. The pattern of the UV light reflecting on the DMD is transferred to a Photocurable Resin flowing through a microfluidic channel. Here, we demonstrate diverse free-floating 3D microstructure fabrication using fine-tuned grayscale image lithography. Additionally, we produce polymeric microstructures with locally embedded gray encoding patterns, such as grayscale-encoded microtags. This functional microstructure can be applied to a biophysical detection system combined with 3D microstructures. This method would be suitable for fabricating 3D microstructures that have a specific morphology to be used for particular biological or medical applications.
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Three-dimensional fabrication of heterogeneous microstructures using soft membrane deformation and optofluidic maskless lithography.
Lab on a chip, 2009Co-Authors: Seung Ah Lee, Sung Hoon Lee, Su Eun Chung, Wook Park, Sunghoon KwonAbstract:We propose a method for high-throughput generation of 3D microstructures using a membrane-mounted microfluidic channel. Utilizing an optofluidic maskless lithography system, photopolymerized 3D microstructures are fabricated in a layer-by-layer fashion with the thickness of each layer controlled by the deformation of the membrane. The combination of low numerical aperture optical systems for photopolymerization and a soft membrane for height control allows large area projection lithography with high vertical resolution, overcoming the trade-off between vertical resolution and the field-of-view. The material composition of each layer is varied using microfluidic control of Photocurable Resin and composite microstructures with heterogeneity in both lateral and vertical directions are generated. Using this technique, we demonstrate three-dimensional patterning of different types of cells in a hydrogel for a microfluidic platform to study co-culture and cell-to-cell interactions. The proposed technique is fast and simple, allowing parallel synthesis of complex heterogeneous 3D microstructures and in situ biomaterial patterning for microfluidic bioassays.
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optofluidic maskless lithography system for real time synthesis of photopolymerized microstructures in microfluidic channels
Applied Physics Letters, 2007Co-Authors: Su Eun Chung, Hyunsung Park, Kyoungsik Yu, Namkyoo Park, Wook Park, Sunghoon KwonAbstract:The authors propose an optofluidic maskless lithography technique that can dynamically synthesize free-floating polymeric microstructures inside microfluidic channels by selectively polymerizing Photocurable Resin with high-speed two-dimensional spatial light modulators. The combination of programable optical projection and microfluidic devices allows one to precisely control the timing and location of the photopolymerization process for microstructure fabrication. Real-time generation of microparticles with various shapes, sizes, ordering, and material contents are experimentally demonstrated. Long polymeric structures of which size is not limited by the exposure field of view can also be fabricated.
Dana M Spence - One of the best experts on this subject based on the ideXlab platform.
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polyjet 3d printed enclosed microfluidic channels without Photocurable supports
Analytical Chemistry, 2019Co-Authors: Andre D Castiaux, Cody Pinger, Elizabeth A Hayter, Marcus E Bunn, Scott R Martin, Dana M SpenceAbstract:Microfluidic devices have historically been prepared using fabrication techniques that often include photolithography and/or etching. Recently, additive manufacturing technologies, commonly known as 3D-printing, have emerged as fabrication tools for microfluidic devices. Unfortunately, PolyJet 3D-printing, which utilizes a Photocurable Resin that can be accurately printed, requires the use of support material for any designed void space internal to the model. Removing the support material from the printed channels is difficult in small channels with single dimensions of less than ∼200 μm and nearly impossible to remove from designs that contain turns or serpentines. Here, we describe techniques for printing channels ranging in cross sections from 0.6 cm × 1.5 cm to 125 μm × 54 μm utilizing commercially available PolyJet printers that require minimal to no postprocessing to form sealed channels. Specifically, printer software manipulation allows printing of one model with an open channel or void that is sealed with either a viscous liquid or a polycarbonate membrane (no commercially available support material). The printer stage is then adjusted and a second model is printed directly on top of the first model with the selected support system. Both the liquid-fill and the membrane method have enough structural integrity to support the printing Resin while it is being cured. Importantly, such complex channel geometries as serpentine and Y-mixers can be designed, printed, and in use in under 2 h. We demonstrate device utility by measuring ATP release from flowing red blood cells using a luciferin/luciferase chemiluminescent assay that involves on-chip mixing and optical detection.
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PolyJet 3D-Printed Enclosed Microfluidic Channels without Photocurable Supports
2019Co-Authors: Andre D Castiaux, Cody Pinger, Elizabeth A Hayter, Marcus E Bunn, Scott R Martin, Dana M SpenceAbstract:Microfluidic devices have historically been prepared using fabrication techniques that often include photolithography and/or etching. Recently, additive manufacturing technologies, commonly known as 3D-printing, have emerged as fabrication tools for microfluidic devices. Unfortunately, PolyJet 3D-printing, which utilizes a Photocurable Resin that can be accurately printed, requires the use of support material for any designed void space internal to the model. Removing the support material from the printed channels is difficult in small channels with single dimensions of less than ∼200 μm and nearly impossible to remove from designs that contain turns or serpentines. Here, we describe techniques for printing channels ranging in cross sections from 0.6 cm × 1.5 cm to 125 μm × 54 μm utilizing commercially available PolyJet printers that require minimal to no postprocessing to form sealed channels. Specifically, printer software manipulation allows printing of one model with an open channel or void that is sealed with either a viscous liquid or a polycarbonate membrane (no commercially available support material). The printer stage is then adjusted and a second model is printed directly on top of the first model with the selected support system. Both the liquid-fill and the membrane method have enough structural integrity to support the printing Resin while it is being cured. Importantly, such complex channel geometries as serpentine and Y-mixers can be designed, printed, and in use in under 2 h. We demonstrate device utility by measuring ATP release from flowing red blood cells using a luciferin/luciferase chemiluminescent assay that involves on-chip mixing and optical detection
Su Eun Chung - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional fabrication of heterogeneous microstructures using soft membrane deformation and optofluidic maskless lithography.
Lab on a chip, 2009Co-Authors: Seung Ah Lee, Sung Hoon Lee, Su Eun Chung, Wook Park, Sunghoon KwonAbstract:We propose a method for high-throughput generation of 3D microstructures using a membrane-mounted microfluidic channel. Utilizing an optofluidic maskless lithography system, photopolymerized 3D microstructures are fabricated in a layer-by-layer fashion with the thickness of each layer controlled by the deformation of the membrane. The combination of low numerical aperture optical systems for photopolymerization and a soft membrane for height control allows large area projection lithography with high vertical resolution, overcoming the trade-off between vertical resolution and the field-of-view. The material composition of each layer is varied using microfluidic control of Photocurable Resin and composite microstructures with heterogeneity in both lateral and vertical directions are generated. Using this technique, we demonstrate three-dimensional patterning of different types of cells in a hydrogel for a microfluidic platform to study co-culture and cell-to-cell interactions. The proposed technique is fast and simple, allowing parallel synthesis of complex heterogeneous 3D microstructures and in situ biomaterial patterning for microfluidic bioassays.
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optofluidic maskless lithography system for real time synthesis of photopolymerized microstructures in microfluidic channels
Applied Physics Letters, 2007Co-Authors: Su Eun Chung, Hyunsung Park, Kyoungsik Yu, Namkyoo Park, Wook Park, Sunghoon KwonAbstract:The authors propose an optofluidic maskless lithography technique that can dynamically synthesize free-floating polymeric microstructures inside microfluidic channels by selectively polymerizing Photocurable Resin with high-speed two-dimensional spatial light modulators. The combination of programable optical projection and microfluidic devices allows one to precisely control the timing and location of the photopolymerization process for microstructure fabrication. Real-time generation of microparticles with various shapes, sizes, ordering, and material contents are experimentally demonstrated. Long polymeric structures of which size is not limited by the exposure field of view can also be fabricated.
Gianmarco Griffini - One of the best experts on this subject based on the ideXlab platform.
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UV-assisted 3D printing of glass and carbon fiber-reinforced dual-cure polymer composites
Materials, 2016Co-Authors: Marta Invernizzi, Gabriele Natale, Giuseppe De Natale, Marinella Levi, Stefano Turri, Gianmarco GriffiniAbstract:Glass (GFR) and carbon fiber-reinforced (CFR) dual-cure polymer composites fabricated by UV-assisted three-dimensional (UV-3D) printing are presented. The Resin material combines an acrylic-based Photocurable Resin with a low temperature (140 C) thermally-curable Resin system based on bisphenol A diglycidyl ether as base component, an aliphatic anhydride (hexahydro-4-methylphthalic anhydride) as hardener and (2,4,6,-tris(dimethylaminomethyl)phenol) as catalyst. A thorough rheological characterization of these formulations allowed us to define their 3D printability window. UV-3D printed macrostructures were successfully demonstrated, giving a clear indication of their potential use in real-life structural applications. Differential scanning calorimetry and dynamic mechanical analysis highlighted the good thermal stability and mechanical properties of the printed parts. In addition, uniaxial tensile tests were used to assess the fiber reinforcing effect on the UV-3D printed objects. Finally, an initial study was conducted on the use of a sizing treatment on carbon fibers to improve the fiber/matrix interfacial adhesion, giving preliminary indications on the potential of this approach to improve the mechanical properties of the 3D printed CFR components.