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Patrick Hansheinrich Warnke - One of the best experts on this subject based on the ideXlab platform.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
Mohammad A Alamein - One of the best experts on this subject based on the ideXlab platform.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
Sebastien Robert Stephens - One of the best experts on this subject based on the ideXlab platform.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
Ravi Kumar - One of the best experts on this subject based on the ideXlab platform.
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multi level cascaded electromagnetically induced transparency in cold atoms using an optical nanofibre interface
New Journal of Physics, 2015Co-Authors: Ravi Kumar, Vandna Gokhroo, Sile Nic ChormaicAbstract:Ultrathin optical fibres integrated into cold atom setups are proving to be ideal building blocks for atom-photon hybrid quantum networks. Such optical Nanofibres (ONFs) can be used for the demonstration of nonlinear optics and quantum interference phenomena in atomic media. Here, we report on the observation of multilevel cascaded electromagnetically induced transparency (EIT) using an optical nanofibre to interface cold 87Rb atoms. Intense evanescent fields can be achieved at ultralow probe (780 nm) and coupling (776 nm) powers when the beams propagate through the nanofibre. The observed multipeak transparency spectra of the probe beam could offer a method for simultaneously slowing down multiple wavelengths in an optical nanofibre or for generating ONF-guided entangled beams, showing the potential of such an atom-nanofibre system for quantum information. We also demonstrate all-optical-switching in the all-fibred system using the obtained EIT effect.
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interaction of laser cooled 87 rb atoms with higher order modes of an optical nanofibre
New Journal of Physics, 2015Co-Authors: Ravi Kumar, Vandna Gokhroo, Aili Maimaiti, Kieran Deasy, Mary C Frawley, C F Phelan, Sile Nic ChormaicAbstract:Optical Nanofibres are used to confine light to sub-wavelength regions and are very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near Nanofibres have focussed on fundamental fibre mode interactions. In this work, we demonstrate the integration of a few-mode optical nanofibre into a magneto-optical trap for 87Rb atoms. The nanofibre, with a waist diameter of ∼700 nm, supports both the fundamental and first group of higher order modes (HOMs) and is used for atomic fluorescence and absorption studies. In general, light propagating in higher order fibre modes has a greater evanescent field extension around the waist in comparison with the fundamental mode. By exploiting this behaviour, we demonstrate that the detected signal of fluorescent photons emitted from a cloud of cold atoms centred at the nanofibre waist is larger if HOMs are also included. In particular, the signal from HOMs appears to be about six times larger than that obtained for the fundamental mode. Absorption of on-resonance, HOM probe light by the laser-cooled atoms is also observed. These advances should facilitate the realization of atom trapping schemes based on HOM interference.
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interaction of laser cooled 87 rb atoms with higher order modes of an optical nanofiber
arXiv: Atomic Physics, 2013Co-Authors: Ravi Kumar, Vandna Gokhroo, Aili Maimaiti, Kieran Deasy, Mary C Frawley, C F Phelan, Sile Nic ChormaicAbstract:Optical Nanofibres are used to confine light to subwavelength regions and are very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near Nanofibres have focussed on fundamental fibre mode interactions. In this work, we demonstrate the integration of a few-mode optical nanofibre into a magneto-optical trap for $^{87}$Rb atoms. The nanofibre, with a waist diameter of $\sim$700 nm, supports both the fundamental and first group of higher order modes and is used for atomic fluorescence and absorption studies. In general, light propagating in higher order fibre modes has a greater evanescent field extension around the waist in comparison with the fundamental mode. By exploiting this behaviour, we demonstrate that the detected signal of fluorescent photons emitted from a cloud of cold atoms centred at the nanofibre waist is larger ($\sim$6 times) when higher order guided modes are considered as compared to the fundamental mode. Absorption of on-resonance, higher order mode probe light by the laser-cooled atoms is also observed. These advances should facilitate the realisation of atom trapping schemes based on higher order mode interference.
Renato Comotto - One of the best experts on this subject based on the ideXlab platform.
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multi jet nozzle electrospinning on textile substrates observations on process and nanofibre mat deposition
Polymer International, 2010Co-Authors: Alessio Varesano, F Rombaldoni, Giorgio Mazzuchetti, C Tonin, Renato ComottoAbstract:Electrospinning is a simple and versatile process for producing small-diameter fibres (Nanofibres). However, in spite of the many potential applications of electrospun Nanofibres, further process developments are still necessary to achieve a decisive productivity breakthrough for electrospinning plants. Increasing knowledge of multi-jet electrospinning is crucial for developing industrial devices for large-scale nanofibre production. This paper reports on the effect of a non-conducting textile substrate placed between a jet-emitting source (nine-nozzle arrangement) and collector. Shielding the electric field changes the electrospinning conditions, nanofibre morphology, stability of jets and fibre deposition on the collecting surface. Various perturbation phenomena of the electrically driven jets were recorded and are described. The intensity of the perturbations increases as the weight of the non-woven substrate increases resulting in defects in the nanofibrous mat (i.e. beaded Nanofibres), production of tick fibres or failure to produce fibrous materials (e.g. films, droplets). The paper also reports an objective image-processing procedure to enhance the evaluation of the collector after nanofibre deposition. Copyright © 2010 Society of Chemical Industry
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Multi-jet nozzle electrospinning on textile substrates: observations on process and nanofibre mat deposition
Polymer International, 2010Co-Authors: Alessio Varesano, F Rombaldoni, Giorgio Mazzuchetti, C Tonin, Renato ComottoAbstract:Electrospinning is a simple and versatile process for producing small-diameter fibres (Nanofibres). However, in spite of the many potential applications of electrospun Nanofibres, further process developments are still necessary to achieve a decisive productivity breakthrough for electrospinning plants. Increasing knowledge of multi-jet electrospinning is crucial for developing industrial devices for large-scale nanofibre production. This paper reports on the effect of a non-conducting textile substrate placed between a jet-emitting source (nine-nozzle arrangement) and collector. Shielding the electric field changes the electrospinning conditions, nanofibre morphology, stability of jets and fibre deposition on the collecting surface. Various perturbation phenomena of the electrically driven jets were recorded and are described. The intensity of the perturbations increases as the weight of the non-woven substrate increases resulting in defects in the nanofibrous mat (i.e. beaded Nanofibres), production of tick fibres or failure to produce fibrous materials (e.g. films, droplets). The paper also reports an objective image-processing procedure to enhance the evaluation of the collector after nanofibre deposition. Copyright © 2010 Society of Chemical Industry
