The Experts below are selected from a list of 417510 Experts worldwide ranked by ideXlab platform
Robert C Chang - One of the best experts on this subject based on the ideXlab platform.
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Direct Cell writing of 3d microorgan for in vitro pharmacokinetic model
Tissue Engineering Part C-methods, 2008Co-Authors: Robert C ChangAbstract:A novel targeted application of tissue engineering is the development of an in vitro pharmacokinetic model for drug screening and toxicology. An in vitro pharmacokinetic model is needed to realistically and reliably predict in vivo human response to drug administrations and potential toxic exposures. This paper details the fabrication process development and adaptation of microfluidic devices for the creation of such a physiologically relevant pharmacokinetic model. First, an automated syringe-based, layered Direct Cell writing (DCW) bioprinting process creates a 3D microorgan that biomimics the Cell's natural microenvironment with enhanced functionality. Next, soft lithographic micropatterning techniques are used to fabricate a microscale in vitro device to house the 3D microorgan. This paper demonstrates the feasibility of the DCW process for freeform biofabrication of 3D Cell-encapsulated hydrogel-based tissue constructs with defined reproducible patterns, Direct integration of 3D constructs onto a mic...
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effects of dispensing pressure and nozzle diameter on Cell survival from solid freeform fabrication based Direct Cell writing
Tissue Engineering Part A, 2008Co-Authors: Robert C Chang, Jae Nam, Wei SunAbstract:Novel technologies are emerging that incorporate Cells as part of the building blocks for various biomanufacturing processes, such as solid freeform fabricated tissue constructs for tissue regeneration, three-dimensional pharmacokinetic models, Cell-based microelectromechanical systems, sensors, and microfluidic devices. However, the effects of these biomanufacturing processes on Cells have not been fully studied. This paper examines the effect of solid freeform fabrication-based Direct Cell writing process, focusing on dispensing pressure and nozzle size, on the viability and functional behavior of HepG2 Cells encapsulated within alginate. Our experimental results revealed a process-induced mechanical damage to Cell membrane integrity, causing a quantifiable loss in Cell viability due to incremental increases and decreases in the studied process parameters of dispensing pressure and nozzle size, respectively. The experimental results also suggested that Cells may require a recovery period following Direct Cell writing biofabrication. The general finding of this study may be applicable to freeform fabrication of Cell-based tissue constructs and three-dimensional biological models.
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effects of dispensing pressure and nozzle diameter on Cell survival from solid freeform fabrication based Direct Cell writing
Tissue Engineering Part A, 2008Co-Authors: Robert C ChangAbstract:Novel technologies are emerging that incorporate Cells as part of the building blocks for various biomanufacturing processes, such as solid freeform fabricated tissue constructs for tissue regenera...
Robert L. Mauck - One of the best experts on this subject based on the ideXlab platform.
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Programmed biomolecule delivery to enable and Direct Cell migration for connective tissue repair.
Nature Communications, 2017Co-Authors: Feini Qu, Julianne L. Holloway, John L. Esterhai, Jason A. Burdick, Robert L. MauckAbstract:Dense connective tissue injuries have limited repair, due to the paucity of Cells at the wound site. We hypothesize that decreasing the density of the local extraCellular matrix (ECM) in conjunction with releasing chemoattractive signals increases Cellularity and tissue formation after injury. Using the knee meniscus as a model system, we query interstitial Cell migration in the context of migratory barriers using a novel tissue Boyden chamber and show that a gradient of platelet-derived growth factor-AB (PDGF-AB) expedites migration through native tissue. To implement these signals in situ, we develop nanofibrous scaffolds with distinct fiber fractions that sequentially release active collagenase (to increase ECM porosity) and PDGF-AB (to attract endogenous Cells) in a localized and coordinated manner. We show that, when placed into a meniscal defect, the controlled release of collagenase and PDGF-AB increases Cellularity at the interface and within the scaffold, as well as integration with the surrounding tissue. Dense connective tissues do not easily heal, in part due to a low supply of reparative Cells. Here, the authors develop a fibrous scaffold for meniscal repair that sequentially releases collagenase and a growth factor at the injury site, breaking down the extraCellular matrix and recruiting endogenous Cells.
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programmed biomolecule delivery to enable and Direct Cell migration for connective tissue repair
Nature Communications, 2017Co-Authors: Julianne L. Holloway, John L. Esterhai, Jason A. Burdick, Robert L. MauckAbstract:Dense connective tissue injuries have limited repair, due to the paucity of Cells at the wound site. We hypothesize that decreasing the density of the local extraCellular matrix (ECM) in conjunction with releasing chemoattractive signals increases Cellularity and tissue formation after injury. Using the knee meniscus as a model system, we query interstitial Cell migration in the context of migratory barriers using a novel tissue Boyden chamber and show that a gradient of platelet-derived growth factor-AB (PDGF-AB) expedites migration through native tissue. To implement these signals in situ, we develop nanofibrous scaffolds with distinct fiber fractions that sequentially release active collagenase (to increase ECM porosity) and PDGF-AB (to attract endogenous Cells) in a localized and coordinated manner. We show that, when placed into a meniscal defect, the controlled release of collagenase and PDGF-AB increases Cellularity at the interface and within the scaffold, as well as integration with the surrounding tissue.
Joji Mochida - One of the best experts on this subject based on the ideXlab platform.
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human nucleus pulposus Cells significantly enhanced biological properties in a coculture system with Direct Cell to Cell contact with autologous mesenchymal stem Cells
Journal of Orthopaedic Research, 2010Co-Authors: Takuya Watanabe, Yukihiro Yamamoto, Daisuke Sakai, Toru Iwashina, Kenji Serigano, Futoshi Tamura, Joji MochidaAbstract:Activated nucleus pulposus (NP) Cells can be reinserted into the disc to inhibit intervertebral disc degeneration. Experimental studies in animals showed that using a coculture system with Direct Cell-to-Cell contact with mesenchymal stem Cells (MSCs) significantly upregulated the biological activity of NP Cells. The purpose of this study is to determine whether this activation of NP Cells by autologous MSCs is applicable to human Cells in vitro. Human NP tissue was obtained from surgical specimens and MSCs from bone marrow of 10 subjects. Six-well culture plates and inserts were used for culture; 1.0 × 104 NP Cells were seeded onto each insert and incubated alone, in standard coculture with 1.0 × 104 MSCs, or cocultured with Direct Cell-to-Cell contact. NP Cell proliferation, DNA synthesis, and proteoglycan (PG) synthesis were evaluated. Chromosome abnormalities in the activated NP Cells and tumorigenesis of the Cells were evaluated in an additional 10 patients by microscopic examination for segmented Cells and histological assessment of activated Cells transplanted into nude mice. Cell proliferation, DNA synthesis, and PG synthesis were significantly upregulated. The positive effects of the coculture system with Direct Cell-to-Cell contact seen in animal studies were also confirmed in human Cells. Chromosome abnormalities and tumorigenesis were not observed in the activated NP Cells. In conclusion, a coculture system with Direct Cell-to-Cell contact demonstrated a significant positive effect, enhancing the biological properties of human NP Cells, as it did in animal models. These results should prove useful for conducting trials leading to the clinical use of activated NP Cell transplantation. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:623–630, 2010
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upregulation of the viability of nucleus pulposus Cells by bone marrow derived stromal Cells significance of Direct Cell to Cell contact in coculture system
Spine, 2004Co-Authors: Yukihiro Yamamoto, Tomoko Nakai, Hiroshi Kawada, Joji Mochida, Daisuke Sakai, Kazuhiro Nishimura, Tomomitsu HottaAbstract:Study design Upregulation of the viability of nucleus pulposus Cells by coculture with bone marrow-derived stromal Cells using a novel culture system. Objectives The objective was to apply a novel coculture system having Direct Cell-to-Cell contact between nucleus pulposus Cells and bone marrow-derived stromal Cells for stimulation of nucleus pulposus Cells. Summary of background data Reinsertion of nucleus pulposus Cells was effective for treatment of intervertebral disc degeneration. However, obtaining highly viable nucleus pulposus Cells was necessary to achieve successful results. Thus, an alternative method to upregulate the biologic and metabolic viabilities of nucleus pulposus Cells was desired. Methods Nucleus pulposus Cells and bone marrow-derived stromal Cells were isolated from New Zealand white rabbits. A 6-well culture plate and insert with track-etched membrane having 0.4 microm pores at the bottom were used for coculture. Nucleus pulposus Cells were monocultured, cocultured conventionally (having no Direct Cell-to-Cell contact) with bone marrow-derived stromal Cells, or cocultured having Direct Cell-to-Cell contact with bone marrow-derived stromal Cells. On day 4 of coculture, nucleus pulposus Cells were evaluated for proliferation using WST-8 assay, deoxyribonucleic acid synthesis by measuring [H]-thymidine uptake, and proteoglycan synthesis by measuring [S]-sulfate uptake. We also quantified cytokines in supernatants from the culture system. Results Cell proliferation, deoxyribonucleic acid synthesis, and proteoglycan synthesis of nucleus pulposus Cells were significantly upregulated in samples cocultured having Direct Cell-to-Cell contact. Moreover, evaluations of supernatants revealed that growth factors associated with proliferation and Cellular metabolism of nucleus pulposus Cells were increased. Conclusions Direct Cell-to-Cell contact in coculture system between nucleus pulposus Cells and bone marrow-derived stromal Cells accomplished significant upregulation in viability of nucleus pulposus Cells.
Julianne L. Holloway - One of the best experts on this subject based on the ideXlab platform.
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Programmed biomolecule delivery to enable and Direct Cell migration for connective tissue repair.
Nature Communications, 2017Co-Authors: Feini Qu, Julianne L. Holloway, John L. Esterhai, Jason A. Burdick, Robert L. MauckAbstract:Dense connective tissue injuries have limited repair, due to the paucity of Cells at the wound site. We hypothesize that decreasing the density of the local extraCellular matrix (ECM) in conjunction with releasing chemoattractive signals increases Cellularity and tissue formation after injury. Using the knee meniscus as a model system, we query interstitial Cell migration in the context of migratory barriers using a novel tissue Boyden chamber and show that a gradient of platelet-derived growth factor-AB (PDGF-AB) expedites migration through native tissue. To implement these signals in situ, we develop nanofibrous scaffolds with distinct fiber fractions that sequentially release active collagenase (to increase ECM porosity) and PDGF-AB (to attract endogenous Cells) in a localized and coordinated manner. We show that, when placed into a meniscal defect, the controlled release of collagenase and PDGF-AB increases Cellularity at the interface and within the scaffold, as well as integration with the surrounding tissue. Dense connective tissues do not easily heal, in part due to a low supply of reparative Cells. Here, the authors develop a fibrous scaffold for meniscal repair that sequentially releases collagenase and a growth factor at the injury site, breaking down the extraCellular matrix and recruiting endogenous Cells.
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programmed biomolecule delivery to enable and Direct Cell migration for connective tissue repair
Nature Communications, 2017Co-Authors: Julianne L. Holloway, John L. Esterhai, Jason A. Burdick, Robert L. MauckAbstract:Dense connective tissue injuries have limited repair, due to the paucity of Cells at the wound site. We hypothesize that decreasing the density of the local extraCellular matrix (ECM) in conjunction with releasing chemoattractive signals increases Cellularity and tissue formation after injury. Using the knee meniscus as a model system, we query interstitial Cell migration in the context of migratory barriers using a novel tissue Boyden chamber and show that a gradient of platelet-derived growth factor-AB (PDGF-AB) expedites migration through native tissue. To implement these signals in situ, we develop nanofibrous scaffolds with distinct fiber fractions that sequentially release active collagenase (to increase ECM porosity) and PDGF-AB (to attract endogenous Cells) in a localized and coordinated manner. We show that, when placed into a meniscal defect, the controlled release of collagenase and PDGF-AB increases Cellularity at the interface and within the scaffold, as well as integration with the surrounding tissue.
Sheauling Lee - One of the best experts on this subject based on the ideXlab platform.
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physical binding of endothelial mcam and neural transmembrane protease matriptase novel Cell adhesion in neural stem Cell vascular niche
Scientific Reports, 2017Co-Authors: Hsiuhui Tung, Sheauling LeeAbstract:Brain neural stem Cells and transit amplifying Cells in the subventricular zone (SVZ) of the lateral ventricles are in Direct contact with the microvascular endothelium. The mechanisms/molecules of Direct Cell contact in the SVZ neurovascular niche are not fully understood. We previously showed that neural stem/progenitor (NS/P) Cells induce brain endothelial signaling in Direct Cell contact through matriptase (MTP) on NS/P Cell surface. In the present study, using pull-down and LC-MS/MS, we identified melanoma Cell adhesion molecule (MCAM) the brain endothelial molecule that interacts with MTP. MCAM physically binds to the CUB domains of MTP and induces a chain of brain endothelial signaling including p38MAPK activation, GSK3β inactivation and subsequently β-catenin activation; none of these signaling events occurred when either MTP or MCAM is deleted. MTP-MCAM binding and induction of endothelial signaling were all sensitive to cholera toxin. Together, we identified key molecules that may represent a mechanism in neural stem Cell vascular niche regulation.