Download or read book The Effect of Mechanical Cues on in Vitro Aging and Differentiation of Human Mesenchymal Stem Cells written by Courtney Eileen LeBlon and published by . This book was released on 2013 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tissue engineering is a field that aims to replace or repair damaged tissue through the use of stem cells, biomaterials, and biomolecules. Human mesenchymal stem cells are multipotent adult stem cells that can be autologously transplanted. This work describes the effect of mechanical cues on human mesenchymal stem cells. An analysis on the age-related stiffening of these cells, and its effect on osteogenic and myogenic differentiation, is presented. This study gives insight to those using stem cells in vitro for extended periods of time. The effect of mechanical loading on stem cell differentiation is examined. Tensile and compressive loading are used to induce myogenic and osteogenic differentiation, respectively, in the absence of chemical cues. This study demonstrates that loading alone can accelerate differentiation. A 3-D cell culture method for cardiomyocyte differentiation is also explored. Numerous cardiomyocyte markers were observed, signifying that this method may be superior to chemical induction methods. A biodegradation study of four porous polymers is also presented, as scaffold choice is of great importance in the area of tissue engineering. This research provides guidance to those using human mesenchymal stem cells for tissue engineering.

Download or read book The Effect of Mechanical Cues on the Chondrogenic Differentiation of Bone Marrow Derived Mesenchymal Stem Cells written by Stephen Thorpe and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanical and Biological Mechanisms of Regulating Human Mesenchymal Stem Cell Differentiation written by Anne Kathryn Staples and published by . This book was released on 2006 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Knowledge of how hMSCs respond to different types of mechanical loading, how this response differs from a traditional growth factor approach of inducing cellular differentiation and how their responsiveness to mechanical stimulation varies with cell differentiation stage are all critical for the successful design of tissue engineering constructs that are optimally organized for a specific mechanical function.

Download or read book In Vitro Chondrogenic Differentiation of Human Mesenchymal Stem Cells in Collagen Gels written by 許婷恩 and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "In Vitro Chondrogenic Differentiation of Human Mesenchymal Stem Cells in Collagen Gels" by 許婷恩, Ting-yan, Hui, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled In Vitro Chondrogenic Differentiation of Human Mesenchymal Stem Cells in Collagen Gels submitted by Hui Ting Yan for the Degree of Master of Philosophy at The University of Hong Kong in August, 2007 Articular cartilage, the load-bearing tissue of the joint, has limited potential for repair and regeneration. Given a lack of satisfactory surgical solutions, cartilage tissue engineering has been suggested as a promising approach for cartilage repair. The present study demonstrated the fabrication of cartilage-like tissue-engineered constructs by chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in collagen gels in vitro. Collagen-hMSC constructs were synthesized with 5 6 varying cell seeding densities (110 - 510 cells/ml) and initial collagen concentrations (0.5 - 3 mg/ml) to investigate the effects of the two parameters. The constructs were cultured in chondrogenic differentiation induction medium for 21 days and evaluated by histological, immunohistochemial, morphological, biochemical and biomechanical examinations. In addition, with inclusion of chondroitin sulfate (CS), collagen/CS-hMSC constructs were also fabricated and compared to their collagen-hMSC constructs counterparts. After 21 days of culture, chondrogenesis was evident in the collagen-hMSC constructs, as indicated by positive immunohistochemical staining for cartilage-specific extracellular matrix components (type II collagen and aggrecan). The meshwork of collagen fibers was remodeled into a highly ordered microstructure, characterized by thick and parallel collagen bundles. Higher cell seeding density and higher collagen concentration favored the chondrogenic differentiation of the cells, yielding an increased matrix production (glycosaminoglycans) and a higher mechanical strength (reduced elastic modulus) of the constructs. A biochemical analysis of matrix accumulation revealed no difference between the collagen/CS-hMSC and collagen-hMSC constructs. Further investigation showed that most of the CS added during fabrication was lost to the surrounding medium within the first 24 hours. To study the effects of inclusion of CS, further studies should be performed to develop a fabrication method which enables effective CS incorporation into the constructs. The current work presented a systematic study to understand the parameters in building a cartilage-like construct, and provided the groundwork for optimization of the biological and mechanical characteristics. The findings may contribute towards the development of tissue engineering solutions for cartilage injuries. DOI: 10.5353/th_b3955874 Subjects: Chondrogenesis Collagen Stem cells Mesenchyme Tissue engineering

Download or read book The Extracellular Environment s Effect on Cellular Processes An In Vitro Study of Mechanical and Chemical Cues on Human Mesenchymal Stem Cells and C17 2 Neural Stem Cells written by Meghan E. Casey and published by . This book was released on 2013 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stem cells are widely used in the area of tissue engineering. The ability of cells to interact with materials on the nano- and micro- level is important in the success of the biomaterial. It is well-known that cells respond to their micro- and nano-environments through a process termed chemo-mechanotransduction.

Download or read book The Effect of Mechanical Strain on the Differentiation of Mesenchymal Stem Cells Into a Cardiac Phenotype in Vitro written by Yasmeen Adia Midgette and published by . This book was released on 2008 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book In Vitro Chondrogenic Differentiation of Human Mesenchymal Stem Cells in Collagen Gels written by Ting-yan Hui and published by . This book was released on 2007 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Novel Design of a Bioreactor for in Vitro Proliferation and Differentiation of Human Mesenchymal Stem Cells written by Joshua D. Salvi and published by . This book was released on 2009 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of the Effect of Physical Cues on Stem Cell Fate Determination written by and published by . This book was released on 2007 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stem cell research has been fueled by increasing evidence of their great promise in clinical regenerative therapy. Conventionally, stem cell fate determination can be attributed to genetic and biochemical factors. However, the field has started to recognize the importance of the stem cell microenvironments that provide physical cues to influence cell fate decision. From a tissue engineer's point of view, introducing physical factors to the differentiation process could be an approach to direct stem cell fate. This concept is supported by a growing body of evidence showing the responsiveness of stem cells to physical stimuli. I thus develop two platforms to study the effect of (a) static environmental cues and (b) dynamic mechanical loading on stem cell fate decisions. Carbon nanotubes (CNTs), which possess relevant features such as (1) dimension analogous to that of natural extracellular matrix (ECM) molecules, (2) large surface area, and (3) ability to serve as nano-heaters to convert absorbed near-infrared (NIR) radiation into heat, were used to fabricate artificial stem cell niches. I exploit properties (1) and (2) of CNTs to make a biocompatible thin film with large surface area, to promote growth factor adsorption and preferential stem cell differentiation. Enhanced neuron differentiation from human embryonic stem cells (hESCs) was observed in poly(methacrylic acid) (PMAA)-functionalized CNT (PMAA-g-CNT) thin films. Polarized expression of motor neuron-specific marker, synapsin 1, was also detected in cells differentiatedon PMAA-g-CNT surfaces. Cells survive in this platform, with no detrimental effects observed. The improved differentiation can be attributed to the increased surface area created by the nanofibrillar structure, leading to enhanced growth factor adsorption. This is the first study to indicate that increasing surface area by use of CNT substrates leads to enhanced growth factor adsorption and stem cell differentiation. To shed light on how mechanical stimulation instructs cell fate decision, preliminary work has also been done to develop a remote-controlled nanohybrid actuator system to apply dynamic mechanical stimulation to stem cells. This is achieved by employing the thermal responsive nature of poly(N-isopropylacrylamide) (PNIPAM), and the unique ability of CNTs to absorb NIR. The actuation of PNIPAM hydrogel can be triggered by temperature change, while the cells on the PNIPAM actuator change in cell shape and size upon sensing the mechanical stimulation. CNTs embedded in the polymer matrix convert photon energy into heat and initiate the contraction of PNIPAM gel. The novel device can sense NIR inputs and showed noticeable shrinkage after NIR stimulation. It can therefore be used to apply remotely controlled mechanical loads to stem cells for cell behavior study. Cytosolic calcium fluctuations, which play an important role in cell differentiation and are sensitive to mechanical stimulation, may thus be tuned by using the novel actuator to achieve controlled cell differentiation. My work described above paves a way for further studies to investigate the effect of mechanical inputs on stem cell fate decision.

Download or read book The Effect of Mechanical Stimulation on PEG encapsulated Mesenchymal Stem Cells written by Brooke McClarren and published by . This book was released on 2017 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Effect of Mechanical Stimulation on PEG-Encapsulated Mesenchymal Stem Cells By: BROOKE MCCLARREN Thesis Advisor: Dr. Ronke Olabisi Human mesenchymal stem cells (hMSCs) are multipotent cells capable of differentiating into any mesenchymal tissue, including bone, cartilage, muscle, and fat. hMSC differentiation can be influenced by a variety of stimuli, including environmental and mechanical stimulation, including scaffold physical properties or applied loads. Numerous studies have evaluated the effects of vibration or tensile strain on MSCs but these studies generally use MSCs on tissue culture plastic or scaffolds derived from natural sources. Tissue culture plastic forces cells into a 2D monolayer in which they behave differently than in their native tissues and naturally sourced scaffolds have inherent biochemical and microarchitectural cues that also influence MSC fate. To isolate the effects of vibration and strain on hMSCs, polyethylene glycol diacrylate (PEGDA), a bioinert synthetic polymer hydrogel, was used to 3D encapsulate cells in hydrogel sheets. This Masters' thesis expands on previous results where microencapsulated hMSCs were subjected to vibrations. Microencapsulated cells are subjected to vortexing and the surface tension caused by forming emulsion-based microdroplets. Hydrogel sheets were selected to eliminate the confounding factors introduced by the fabrication method, to standardize the encapsulation efficiency, and to enable the performance of tensile tests. hMSCs were entrapped in 10 kDa PEGDA hydrogel sheets, then subjected to 10% cyclic tensile strain, or 100 Hz vibrations at accelerations of 0.3, 3.0, or 6.0 g, for 24 hours. Following testing, entrapped cells were evaluated for viability and markers of differentiation at 1, 4, 7, 14, and 21 Days. Cells subjected to cyclic strain and cells subjected to accelerations of 0.3 g showed greater viability than control cells. hMSCs vibrated with accelerations of 3.0 g showed no change in viability compared to control while accelerations of 6.0 g were lethal to cells. Accelerations of 0.3 g also appeared to induce differentiation of encapsulated hMSCs along the osteogenic pathway. For vibration studies, these findings differed from previous findings with microspheres in that on day 4, 0.3 g microencapsulated cells exhibited alkaline phosphatase activity but cells in sheets did not. Additionally, 0.3 g cells encapsulated in hydrogel sheets exhibited mineral formation as early as day 7, while microencapsulated cells did not until day 14. These findings show the feasibility of using PEGDA as a scaffold for probing cell response to mechanical stimuli, and further demonstrate that the geometry of the scaffold selected can also influence hMSC fate.

Download or read book In Vitro Evaluation of Human Mesenchymal Stem Cell Neural Differentiation on Tyrsine derived Polyarylates and Polycarbonates written by Yee-Shuan Lee and published by . This book was released on 2005 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Present spinal cord injury treatments cannot restore motor and sensory functions caused by the injury. These functions can return in the hopes of repairing the neural cells with a tissue engineered designed scaffold complex. The scaffold complex will include cells to repair and replace the damaged cells. Mesenchymal stem cells (MSC) are multipotent adult stem ells that are capable of differentiating along several lineage pathways. Neural stem cell and MSC differentiating along the neural lineage bave been investigated both in vivo and in vitro depicting its feasibility. MSC for neural differentiation can be achieved by microenvironmental signaling. Substrate surface characteristics may influence both neuron and stem cell behavior and differentiation. The effects of the polymer surface of tyrosine-derived polycarbonates and polyarylates on MSC differentiation along the neural lineage were investigated in this research. These polymers were developed by Dr. Joachim Kohn, where by altering the length of the alkyl ester pendent chain and the backbone composition, these polymers can have a gradual change in physicomechanical, chemical, and biological properties. The MSC differentiated into neuron-like cell at 24 hours after induction. These cells express the presence of NSE which is a neuron marker. No systematic variation on cell proliferation among the polyarylate polymers was observed. The oxygen-contained diacid backbone stimulated cell growth on all the polyarylate polymers in this study. Cell proliferation increased as the substrate surface became less hydrophobic for all polymer surfaces. Wettability of polycarbonate polymers depicts high linear correlation with cell number and percentage of neural differentiation. The copolymer of tyrosine-derived poly DTE carbonate and 5% PEG was hydrophobic and did not stimulate cell growth and cells tend to aggregate on this substrate surface.

Download or read book Multiplex Biomaterial Matrix Cues Regulate Redox Status and Stemness in Human Mesenchymal Stem Cells written by Spencer William Crowder and published by . This book was released on 2014 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Mechanical Load on Human Mesenchymal Stem Cell Differentiation written by Siân Marie Parker and published by . This book was released on 2008 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Tensile Loading and Extracellular Environmental Cues on Fibroblastic Differntiation and Extracellular Matrix Production by Mesenchymal Stem Cells written by Derek M. Doroski and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ligament/tendon tissue engineering has the potential to provide therapies that overcome the limitations of incomplete natural healing responses and inadequate graft materials. While ligament/tendon fibroblasts are an obvious choice of cell type for these applications, difficulties associated with finding a suitable cell source have limited their utility. Mesenchymal stem cells/marrow stromal cells (MSCs) are seen as a viable alternative since they can be harvested through routine medical procedures and can be differentiated toward a ligament/tendon fibroblast lineage. Further study is needed to create an optimal biomaterial/biomechanical environment for ligament/tendon fibroblastic differentiation of MSCs. The overall goal of this dissertation was to improve the understanding of the role that biomechanical stimulation and the biomaterial environment play, both independently and combined, on human MSC (hMSC) differentiation toward a ligament/tendon fibroblast phenotype. Specifically, the effects of cyclic tensile stimuli were studied in a biomaterial environment that provided controlled presentation of biological moieties. The influence of an enzymatically-degradable biomaterial environment on hMSC differentiation was investigated by creating biomaterials containing enzymatically-cleavable moieties. The role that preculture may play in tensile responses of hMSCs was also explored. Together, these studies provided insights into the contributions of the biomaterial and biomechanical environment to hMSC differentiation toward a ligament/tendon fibroblast phenotype.

Download or read book Oscillating Hydrogel Based Bioreactors for Chondrogenic Differentiation of Mesenchymal Stem Cells written by Veronica Juliet Neiman and published by . This book was released on 2010 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Harnessing the differentiative potential of stem cells for use in tissue repair could be a powerful therapy for debilitating diseases. However, one of the bottlenecks of stem cell based therapeutics and tissue engineering is inefficient and homogeneous stem cell differentiation. Various physico-chemical cues such as mechanical strain, chemical components, and soluble factors have been shown to direct stem cell differentiation. This study developed a multifunctional polymer-based artificial ECM replicating the multifunctional characteristics of native ECM to understand the physico-chemical cues present in a 3D environment. Specifically, we have developed a synthetic hydrogel that acts as a scaffold and bioreactor providing dynamic mechanical cues and structural support to cells. A heating device was used to induce ~5% volume strain by applying temperature oscillations to thermoresponsive hydrogels. Human mesenchymal stem cells (hMSCs) were encapsulated in P[MEO2MA-OEGMA-EGDA] (MO) (10 and 20% Mw PEG: 3400) and PEGDA(15% Mw PEG: 10000) hydrogels and cultured with and without TGF[Beta]-1. Fluorescent particle tracking was used to measure realtime volume strains of acellular and cellular hydrogels under temperature oscillations and verified with swelling ratios. hMSCs produced cartilaginous ECM as evidenced from histological and biochemical analysis. Realtime PCR was used to characterize the expression of various chondrogenic markers, indicating optimal chondrogenic differentiation with 1 hour stimulated PEGDA (15% PEG) hydrogels and TGF[Beta]-1. Due to static mechanical strains induced by high crosslinking density and confined heating chambers, enhanced chondrogenic differentiation was limited for all gels. Overall, this study demonstrated the potential use of polymer-based synthetic bioactuators for stem cell differentiation.

Download or read book Modulation of Osteogenic Differentiation in Human Mesenchymal Stem Cells by Submicron Topographically patterned Ridges and Grooves written by Shinya Watari and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies have shown that nanoscale and submicron topographic cues modulate a menu of fundamental cell behaviors, and the use of topographic cues is an emerging area of tissue engineering. We used topographically-patterned substrates containing anisotropically-ordered ridges and grooves to mimic one feature of the biophysical environment of type I collagen, which consists of aligned nano- to submicron-scale fibrils. We investigated the effects of topographic cues on mesenchymal stem cell morphology, proliferation, and osteogenic differentiation. Cells cultured on 1400 or 4000 nm pitches showed greater elongation and alignment relative to 400 nm pitch or planar control. Cells cultured on 400 nm pitch demonstrated significant increases in RUNX2 and BGLAP expression relative to cells cultured on 1400 or 4000 nm pitch or planar control. 400 nm pitch enhanced extracellular calcium deposition. Cells cultured in osteoinductive medium revealed combinatory effects of topography and chemical cues on 400 nm pitch as well as up-regulation of expression of ID1, a target of the BMP pathway. Our data demonstrate that a specific size scale of topographic cue promotes osteogenic differentiation with or without osteogenic agents. These data demonstrate that the integration of topographic cues may be useful for the fabrication of orthopedic implants.

Download or read book In Situ Tissue Regeneration written by Sang Jin Lee and published by Academic Press. This book was released on 2016-07-17 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Situ Tissue Regeneration: Host Cell Recruitment and Biomaterial Design explores the body’s ability to mobilize endogenous stem cells to the site of injury and details the latest strategies developed for inducing and supporting the body’s own regenerating capacity. From the perspective of regenerative medicine and tissue engineering, this book describes the mechanism of host cell recruitment, cell sourcing, cellular and molecular roles in cell differentiation, navigational cues and niche signals, and a tissue-specific smart biomaterial system that can be applied to a wide range of therapies. The work is divided into four sections to provide a thorough overview and helpful hints for future discoveries: endogenous cell sources; biochemical and physical cues; smart biomaterial development; and applications. Explores the body’s ability to mobilize endogenous stem cells to the site of injury Details the latest strategies developed for inducing and supporting the body’s own regenerating capacity Presents smart biomaterials in cell-based tissue engineering applications—from the cell level to applications—in the first unified volume Features chapter authors and editors who are authorities in this emerging field Prioritizes a discussion of the future direction of smart biomaterials for in situ tissue regeneration, which will affect an emerging and lucrative industry