The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Kerm Sin Chian - One of the best experts on this subject based on the ideXlab platform.
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fabrication and in vitro and in vivo Cell Infiltration study of a bilayered cryogenic electrospun poly d l lactide scaffold
Journal of Biomedical Materials Research Part A, 2010Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Kerm Sin Chian, Wing Yue Chan, James M AndersonAbstract:Cryogenic electrospinning has previously been demonstrated for controlling the pore sizes of electrospun scaffolds, which has been impossible with traditional electrospinning processes. This article describes the application of the cryogenic technique to fabricate a bilayered electrospun poly(D,L-lactide) scaffold (BLES) in a single uninterrupted process. The resulting BLES consisted of a traditional electrospun (ES) fibrous layer with a dense pore area of 17 ± 3 μm2 adjacent to a cryogenic electrospun layer (CES) with a pore area of 3300 ± 500 μm2. The significance of this bilayered scaffold was to mimic the anatomical structure of tissues with dense basement membrane followed by loose and highly porous connective tissue such as skin and blood vessels. Cell Infiltration in the BLES was compared in vitro and in vivo. Both studies suggested the CES supported high Cell Infiltration, whereas the ES could serve as a physical barrier to prevent Cell Infiltration across the CES-ES boundary because of its size exclusion. The bilayered structure produced by this technique suggests a great potential for engineering tissues with similar architectures. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
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in vitro Cell Infiltration and in vivo Cell Infiltration and vascularization in a fibrous highly porous poly d l lactide scaffold fabricated by cryogenic electrospinning technique
Journal of Biomedical Materials Research Part A, 2009Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Tze Chiun Lim, Kerm Sin ChianAbstract:One of the obstacles limiting the application of electrospun scaffolds for tissue engineering is the nanoscale pores that inhibit Cell Infiltration. In this article, we describe a technique that uses ice crystals as templates to fabricate cryogenic electrospun scaffolds (CES) with large three-dimensional and interconnected pores using poly(D,L-lactide) (PLA). Manipulating the humidity of the electrospinning environment the pore sizes are controlled. We are able to achieve pore sizes ranging from 900 +/- 100 microm(2) to 5000 +/- 2000 microm(2) depending on the relative humidity used. Our results show that Cells infiltrated the CES up to 50 microm in thickness in vitro under static culture conditions whereas Cells did not infiltrate the conventional electrospun scaffolds. In vivo studies demonstrated improved Cell Infiltration and vascularization in the CES compared with conventionally prepared electrospun scaffolds. In gaining control of the pore characteristics, we can then design CES that are optimized for specific tissue engineering applications.
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in vitro Cell Infiltration and in vivo Cell Infiltration and vascularization in a fibrous highly porous poly d l lactide scaffold fabricated by cryogenic electrospinning technique
Journal of Biomedical Materials Research Part A, 2009Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Kerm Sin ChianAbstract:One of the obstacles limiting the application of electrospun scaffolds for tissue engineering is the nanoscale pores that inhibit Cell Infiltration. In this article, we describe a technique that uses ice crystals as templates to fabricate cryogenic electrospun scaffolds (CES) with large three-dimensional and interconnected pores using poly(D,L-lactide) (PLA). Manipulating the humidity of the electrospinning environment the pore sizes are controlled. We are able to achieve pore sizes ranging from 900 ± 100 μm2 to 5000 ± 2000 μm2 depending on the relative humidity used. Our results show that Cells infiltrated the CES up to 50 μm in thickness in vitro under static culture conditions whereas Cells did not infiltrate the conventional electrospun scaffolds. In vivo studies demonstrated improved Cell Infiltration and vascularization in the CES compared with conventionally prepared electrospun scaffolds. In gaining control of the pore characteristics, we can then design CES that are optimized for specific tissue engineering applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Mohamed Zulfikar Rasheed - One of the best experts on this subject based on the ideXlab platform.
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fabrication and in vitro and in vivo Cell Infiltration study of a bilayered cryogenic electrospun poly d l lactide scaffold
Journal of Biomedical Materials Research Part A, 2010Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Kerm Sin Chian, Wing Yue Chan, James M AndersonAbstract:Cryogenic electrospinning has previously been demonstrated for controlling the pore sizes of electrospun scaffolds, which has been impossible with traditional electrospinning processes. This article describes the application of the cryogenic technique to fabricate a bilayered electrospun poly(D,L-lactide) scaffold (BLES) in a single uninterrupted process. The resulting BLES consisted of a traditional electrospun (ES) fibrous layer with a dense pore area of 17 ± 3 μm2 adjacent to a cryogenic electrospun layer (CES) with a pore area of 3300 ± 500 μm2. The significance of this bilayered scaffold was to mimic the anatomical structure of tissues with dense basement membrane followed by loose and highly porous connective tissue such as skin and blood vessels. Cell Infiltration in the BLES was compared in vitro and in vivo. Both studies suggested the CES supported high Cell Infiltration, whereas the ES could serve as a physical barrier to prevent Cell Infiltration across the CES-ES boundary because of its size exclusion. The bilayered structure produced by this technique suggests a great potential for engineering tissues with similar architectures. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
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in vitro Cell Infiltration and in vivo Cell Infiltration and vascularization in a fibrous highly porous poly d l lactide scaffold fabricated by cryogenic electrospinning technique
Journal of Biomedical Materials Research Part A, 2009Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Tze Chiun Lim, Kerm Sin ChianAbstract:One of the obstacles limiting the application of electrospun scaffolds for tissue engineering is the nanoscale pores that inhibit Cell Infiltration. In this article, we describe a technique that uses ice crystals as templates to fabricate cryogenic electrospun scaffolds (CES) with large three-dimensional and interconnected pores using poly(D,L-lactide) (PLA). Manipulating the humidity of the electrospinning environment the pore sizes are controlled. We are able to achieve pore sizes ranging from 900 +/- 100 microm(2) to 5000 +/- 2000 microm(2) depending on the relative humidity used. Our results show that Cells infiltrated the CES up to 50 microm in thickness in vitro under static culture conditions whereas Cells did not infiltrate the conventional electrospun scaffolds. In vivo studies demonstrated improved Cell Infiltration and vascularization in the CES compared with conventionally prepared electrospun scaffolds. In gaining control of the pore characteristics, we can then design CES that are optimized for specific tissue engineering applications.
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in vitro Cell Infiltration and in vivo Cell Infiltration and vascularization in a fibrous highly porous poly d l lactide scaffold fabricated by cryogenic electrospinning technique
Journal of Biomedical Materials Research Part A, 2009Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Kerm Sin ChianAbstract:One of the obstacles limiting the application of electrospun scaffolds for tissue engineering is the nanoscale pores that inhibit Cell Infiltration. In this article, we describe a technique that uses ice crystals as templates to fabricate cryogenic electrospun scaffolds (CES) with large three-dimensional and interconnected pores using poly(D,L-lactide) (PLA). Manipulating the humidity of the electrospinning environment the pore sizes are controlled. We are able to achieve pore sizes ranging from 900 ± 100 μm2 to 5000 ± 2000 μm2 depending on the relative humidity used. Our results show that Cells infiltrated the CES up to 50 μm in thickness in vitro under static culture conditions whereas Cells did not infiltrate the conventional electrospun scaffolds. In vivo studies demonstrated improved Cell Infiltration and vascularization in the CES compared with conventionally prepared electrospun scaffolds. In gaining control of the pore characteristics, we can then design CES that are optimized for specific tissue engineering applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Meng Fatt Leong - One of the best experts on this subject based on the ideXlab platform.
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fabrication and in vitro and in vivo Cell Infiltration study of a bilayered cryogenic electrospun poly d l lactide scaffold
Journal of Biomedical Materials Research Part A, 2010Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Kerm Sin Chian, Wing Yue Chan, James M AndersonAbstract:Cryogenic electrospinning has previously been demonstrated for controlling the pore sizes of electrospun scaffolds, which has been impossible with traditional electrospinning processes. This article describes the application of the cryogenic technique to fabricate a bilayered electrospun poly(D,L-lactide) scaffold (BLES) in a single uninterrupted process. The resulting BLES consisted of a traditional electrospun (ES) fibrous layer with a dense pore area of 17 ± 3 μm2 adjacent to a cryogenic electrospun layer (CES) with a pore area of 3300 ± 500 μm2. The significance of this bilayered scaffold was to mimic the anatomical structure of tissues with dense basement membrane followed by loose and highly porous connective tissue such as skin and blood vessels. Cell Infiltration in the BLES was compared in vitro and in vivo. Both studies suggested the CES supported high Cell Infiltration, whereas the ES could serve as a physical barrier to prevent Cell Infiltration across the CES-ES boundary because of its size exclusion. The bilayered structure produced by this technique suggests a great potential for engineering tissues with similar architectures. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
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in vitro Cell Infiltration and in vivo Cell Infiltration and vascularization in a fibrous highly porous poly d l lactide scaffold fabricated by cryogenic electrospinning technique
Journal of Biomedical Materials Research Part A, 2009Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Tze Chiun Lim, Kerm Sin ChianAbstract:One of the obstacles limiting the application of electrospun scaffolds for tissue engineering is the nanoscale pores that inhibit Cell Infiltration. In this article, we describe a technique that uses ice crystals as templates to fabricate cryogenic electrospun scaffolds (CES) with large three-dimensional and interconnected pores using poly(D,L-lactide) (PLA). Manipulating the humidity of the electrospinning environment the pore sizes are controlled. We are able to achieve pore sizes ranging from 900 +/- 100 microm(2) to 5000 +/- 2000 microm(2) depending on the relative humidity used. Our results show that Cells infiltrated the CES up to 50 microm in thickness in vitro under static culture conditions whereas Cells did not infiltrate the conventional electrospun scaffolds. In vivo studies demonstrated improved Cell Infiltration and vascularization in the CES compared with conventionally prepared electrospun scaffolds. In gaining control of the pore characteristics, we can then design CES that are optimized for specific tissue engineering applications.
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in vitro Cell Infiltration and in vivo Cell Infiltration and vascularization in a fibrous highly porous poly d l lactide scaffold fabricated by cryogenic electrospinning technique
Journal of Biomedical Materials Research Part A, 2009Co-Authors: Meng Fatt Leong, Mohamed Zulfikar Rasheed, Kerm Sin ChianAbstract:One of the obstacles limiting the application of electrospun scaffolds for tissue engineering is the nanoscale pores that inhibit Cell Infiltration. In this article, we describe a technique that uses ice crystals as templates to fabricate cryogenic electrospun scaffolds (CES) with large three-dimensional and interconnected pores using poly(D,L-lactide) (PLA). Manipulating the humidity of the electrospinning environment the pore sizes are controlled. We are able to achieve pore sizes ranging from 900 ± 100 μm2 to 5000 ± 2000 μm2 depending on the relative humidity used. Our results show that Cells infiltrated the CES up to 50 μm in thickness in vitro under static culture conditions whereas Cells did not infiltrate the conventional electrospun scaffolds. In vivo studies demonstrated improved Cell Infiltration and vascularization in the CES compared with conventionally prepared electrospun scaffolds. In gaining control of the pore characteristics, we can then design CES that are optimized for specific tissue engineering applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Simon Arnett Jones - One of the best experts on this subject based on the ideXlab platform.
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il 6 trans signaling via stat3 directs t Cell Infiltration in acute inflammation
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Rachel M Mcloughlin, Brendan J Jenkins, Dianne Grail, Anwen Sian Williams, Ceri Alan Fielding, Clare R Parker, Matthias Ernst, Nicholas Topley, Simon Arnett JonesAbstract:Interleukin (IL)-6 signaling through its soluble receptor (IL-6 transsignaling) directs transition between innate and acquired immune responses by orchestrating the chemokine-directed attraction and apoptotic clearance of leukocytes. Through analysis of mononuclear Cell Infiltration in WT and IL-6-deficient mice during peritoneal inflammation, we now report that IL-6 selectively governs T Cell Infiltration by regulating chemokine secretion (CXCL10, CCL4, CCL5, CCL11, and CCL17) and chemokine receptor (CCR3, CCR4, CCR5, and CXCR3) expression on the CD3+ infiltrate. Although blockade of IL-6 trans-signaling prevented chemokine release, chemokine receptor expression remained unaltered suggesting that this response is regulated by IL-6 itself. To dissect the signaling events promoting T Cell migration, inflammation was established in knock-in mice expressing mutated forms of the universal signal-transducing element for IL-6-related cytokines gp130. In mice (gp130Y757F/Y757F) deficient in SHP2 and SOCS3 binding, but presenting hyperactivation of STAT1/3, T Cell recruitment and CCL5 expression was enhanced. Conversely, both of these parameters were suppressed in mice with ablated gp130-mediated STAT1/3 activation (gp130ΔSTAT/ΔSTAT). T Cell migration was related to STAT3 activity, because monoallelic deletion of Stat3 in gp130Y757F/Y757F mice (gp130Y757F/Y757F:Stat3+/-) corrected the exaggerated responses observed in gp130Y757F/Y757F mice. Consequently, STAT3 plays a defining role in IL-6-mediated T Cell migration.
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il 6 trans signaling via stat3 directs t Cell Infiltration in acute inflammation
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Rachel M Mcloughlin, Brendan J Jenkins, Dianne Grail, Anwen Sian Williams, Ceri Alan Fielding, Clare R Parker, Matthias Ernst, Nicholas Topley, Simon Arnett JonesAbstract:Interleukin (IL)-6 signaling through its soluble receptor (IL-6 transsignaling) directs transition between innate and acquired immune responses by orchestrating the chemokine-directed attraction and apoptotic clearance of leukocytes. Through analysis of mononuclear Cell Infiltration in WT and IL-6-deficient mice during peritoneal inflammation, we now report that IL-6 selectively governs T Cell Infiltration by regulating chemokine secretion (CXCL10, CCL4, CCL5, CCL11, and CCL17) and chemokine receptor (CCR3, CCR4, CCR5, and CXCR3) expression on the CD3+ infiltrate. Although blockade of IL-6 trans-signaling prevented chemokine release, chemokine receptor expression remained unaltered suggesting that this response is regulated by IL-6 itself. To dissect the signaling events promoting T Cell migration, inflammation was established in knock-in mice expressing mutated forms of the universal signal-transducing element for IL-6-related cytokines gp130. In mice (gp130Y757F/Y757F) deficient in SHP2 and SOCS3 binding, but presenting hyperactivation of STAT1/3, T Cell recruitment and CCL5 expression was enhanced. Conversely, both of these parameters were suppressed in mice with ablated gp130-mediated STAT1/3 activation (gp130DeltaSTAT/DeltaSTAT). T Cell migration was related to STAT3 activity, because monoallelic deletion of Stat3 in gp130(Y757F/Y757F) mice (gp130Y757F/Y757F:Stat3+/-) corrected the exaggerated responses observed in gp130Y757F/Y757F mice. Consequently, STAT3 plays a defining role in IL-6-mediated T Cell migration.
Robert L Mauck - One of the best experts on this subject based on the ideXlab platform.
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dynamic culture enhances stem Cell Infiltration and modulates extraCellular matrix production on aligned electrospun nanofibrous scaffolds
Acta Biomaterialia, 2011Co-Authors: Nandan L Nerurkar, Brendon M Baker, Dawn M Elliott, Robert L MauckAbstract:Abstract Electrospun nanofibrous scaffolds have become widely investigated for tissue engineering applications, owing to their ability to replicate the scale and organization of many fiber-reinforced soft tissues such as the knee meniscus, the annulus fibrosus of the intervertebral disc, tendon, and cartilage. However, due to their small pore size and dense packing of fibers, Cellular ingress into electrospun scaffolds is limited. Progress in the application of electrospun scaffolds has therefore been hampered, as limited Cell Infiltration results in heterogeneous deposition of extraCellular matrix and mechanical properties that remain below native benchmarks. In the present study, dynamic culture conditions dramatically improved the Infiltration of mesenchymal stem Cells into aligned nanofibrous scaffolds. While dynamic culture resulted in a reduction of glycosaminoglycan content, removal from dynamic culture to free-swelling conditions after 6 weeks resulted recovery of glycosaminoglycan content. Dynamic culture significantly increased collagen content, and collagen was more uniformly distributed throughout the scaffold thickness. While mechanical function was assessed and tensile modulus increased with culture duration, dynamic culture did not result in any additional improvement beyond free-swelling culture. Transient dynamic (6 weeks dynamic followed by 6 weeks free-swelling) culture significantly enhanced Cell Infiltration while permitting GAG accumulation. In this study, we demonstrated that a simple modification to standard in vitro culture conditions effectively improves Cellular ingress into electrospun scaffolds, resolving a challenge which has until now limited the utility of these materials for various tissue engineering applications.
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the potential to improve Cell Infiltration in composite fiber aligned electrospun scaffolds by the selective removal of sacrificial fibers
Biomaterials, 2008Co-Authors: Brendon M Baker, Albert O Gee, Robert B Metter, Ashwin S Nathan, Ross A Marklein, Jason A Burdick, Robert L MauckAbstract:Aligned electrospun scaffolds are promising tools for engineering fibrous musculoskeletal tissues, as they reproduce the mechanical anisotropy of these tissues and can direct ordered neo-tissue formation. However, these scaffolds suffer from a slow Cellular Infiltration rate, likely due in part to their dense fiber packing. We hypothesized that Cell ingress could be expedited in scaffolds by increasing porosity, while at the same time preserving overall scaffold anisotropy. To test this hypothesis, poly(epsilon-caprolactone) (a slow-degrading polyester) and poly(ethylene oxide) (a water-soluble polymer) were co-electrospun from two separate spinnerets to form dual-polymer composite fiber-aligned scaffolds. Adjusting fabrication parameters produced aligned scaffolds with a full range of sacrificial (PEO) fiber contents. Tensile properties of scaffolds were functions of the ratio of PCL to PEO in the composite scaffolds, and were altered in a predictable fashion with removal of the PEO component. When seeded with mesenchymal stem Cells (MSCs), increases in the starting sacrificial fraction (and porosity) improved Cell Infiltration and distribution after three weeks in culture. In pure PCL scaffolds, Cells lined the scaffold periphery, while scaffolds containing >50% sacrificial PEO content had Cells present throughout the scaffold. These findings indicate that Cell Infiltration can be expedited in dense fibrous assemblies with the removal of sacrificial fibers. This strategy may enhance in vitro and in vivo formation and maturation of functional constructs for fibrous tissue engineering.
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the potential to improve Cell Infiltration in composite fiber aligned electrospun scaffolds by the selective removal of sacrificial fibers
Biomaterials, 2008Co-Authors: Brendon M Baker, Robert B Metter, Ashwin S Nathan, Ross A Marklein, Jason A Burdick, Robert L MauckAbstract:Aligned electrospun scaffolds are promising tools for engineering fibrous musculoskeletal tissues, as they reproduce the mechanical anisotropy of these tissues and can direct ordered neo-tissue formation. However, these scaffolds suffer from a slow Cellular Infiltration rate, likely due in part to their dense fiber packing. We hypothesized that Cell ingress could be expedited in scaffolds by increasing porosity, while at the same time preserving overall scaffold anisotropy. To test this hypothesis, poly(ɛ-caprolactone) (a slow-degrading polyester) and poly(ethylene oxide) (a water-soluble polymer) were co-electrospun from two separate spinnerets to form dual-polymer composite fiber-aligned scaffolds. Adjusting fabrication parameters produced aligned scaffolds with a full range of sacrificial (PEO) fiber contents. Tensile properties of scaffolds were functions of the ratio of PCL to PEO in the composite scaffolds, and were altered in a predictable fashion with removal of the PEO component. When seeded with mesenchymal stem Cells (MSCs), increases in the starting sacrificial fraction (and porosity) improved Cell Infiltration and distribution after three weeks in culture. In pure PCL scaffolds, Cells lined the scaffold periphery, while scaffolds containing >50% sacrificial PEO content had Cells present throughout the scaffold. These findings indicate that Cell Infiltration can be expedited in dense fibrous assemblies with the removal of sacrificial fibers. This strategy may enhance in vitro and in vivo formation and maturation of functional constructs for fibrous tissue engineering.