14 research outputs found

    Debiased ambient vibrations optical coherence elastography to profile cell, organoid and tissue mechanical properties

    Get PDF
    The role of the mechanical environment in defining tissue function, development and growth has been shown to be fundamental. Assessment of the changes in stiffness of tissue matrices at multiple scales has relied mostly on invasive and often specialist equipment such as AFM or mechanical testing devices poorly suited to the cell culture workflow.In this paper, we have developed a unbiased passive optical coherence elastography method, exploiting ambient vibrations in the sample that enables real-time noninvasive quantitative profiling of cells and tissues. We demonstrate a robust method that decouples optical scattering and mechanical properties by actively compensating for scattering associated noise bias and reducing variance. The efficiency for the method to retrieve ground truth is validated in silico and in vitro, and exemplified for key applications such as time course mechanical profiling of bone and cartilage spheroids, tissue engineering cancer models, tissue repair models and single cell. Our method is readily implementable with any commercial optical coherence tomography system without any hardware modifications, and thus offers a breakthrough in on-line tissue mechanical assessment of spatial mechanical properties for organoids, soft tissues and tissue engineering

    Comparability: manufacturing, characterization and controls, report of a UK Regenerative Medicine Platform Pluripotent Stem Cell Platform Workshop, Trinity Hall, Cambridge, 14–15 September 2015

    Get PDF
    This paper summarizes the proceedings of a workshop held at Trinity Hall, Cambridge to discuss comparability and includes additional information and references to related information added subsequently to the workshop. Comparability is the need to demonstrate equivalence of product after a process change; a recent publication states that this ‘may be difficult for cell-based medicinal products’. Therefore a well-managed change process is required which needs access to good science and regulatory advice and developers are encouraged to seek help early. The workshop shared current thinking and best practice and allowed the definition of key research questions. The intent of this report is to summarize the key issues and the consensus reached on each of these by the expert delegates

    The genetic architecture of the human cerebral cortex

    Get PDF
    The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

    Investigation of interconnectivity and permeability in correlation with scaffold structural properties

    No full text
    It is widely accepted that pore interconnectivity and permeability are important characteristics effecting cell migration and cell response as well as the transport of nutrients, oxygen and cellular waste products throughout porous tissue engineering scaffolds. Furthermore, it was hypothesized that limited mass transport throughout three-dimensional structures resulted in diminished cell survival and cell distribution being restricted to the scaffold periphery. Several approaches were described for the quantification of scaffold permeability for liquid systems. Up to date, there are only a limited number of quantitative approaches to determine three-dimensional scaffold interconnectivity. This study aims to investigate interconnectivity and permeability in correlation with pore size and porosity. Therefore, tissue engineering scaffolds were fabricated by solvent casting/particulate leaching, supercritical fluid technology and particle sintering. In order to obtain different scaffold architectures, processing conditions were modified. Pore size, pore size distribution and porosity were quantified by MicroCT, and pore windows were analyzed using SEM. A novel interconnectivity algorithm was developed, which allowed the quantification of interconnectivity in 3D throughout the entire scaffold. Permeability of pre-wet scaffolds was determined. Results suggested that scaffolds with larger pore sizes and porosities also exhibited highest interconnectivities and permeabilities. However, these scaffolds showed a heterogeneous pore structure and pore distribution. The distribution of 3T3 fibroblasts through scC02-foamed scaffolds and particulate scaffolds was investigated by MicroCT and MTT staining. Homogenous cell distributions and largest cell volumes were observed on scaffolds with homogenous pore structure and hence smallest pore sizes, porosities, interconnectivities and permeabilities. This study might enable the tailoring of scaffold interconnectivity and permeability by altering scaffold processing conditions. Further, this study might allow the investigation of a minimum interconnectivity that is required for cell migration and proliferation in to order to generate tissues such as bone and cartilage; as well as to promote vascularization.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Donor variability of ovine bone marrow derived mesenchymal stem cell - implications for cell therapy

    No full text
    ABSTRACTIt is assumed that all species, including sheep, demonstrate significant variation between individuals including the characteristics of their bone marrow-derived mesenchymal stem cells (BM-MSCs). These differences may account for limited success in pre-clinical animal studies and may also impact on treatment strategies that are used within regenerative medicine. This study investigates variations between ovine MSCs (oMSCs) isolated from 13 English Mule sheep donors by studying cell viability, expansion, the cells’ trilineage differentiation potential and the expression of cell surface markers. In addition to the primary objective, this article also compares various differentiation media used for the trilineage differentiation of oMSCs. In this study, a clear individual variation between the sheep donors regarding oMSCs characterization, tri-lineage differentiation potential and marker expression was effectively demonstrated. The results set out to systematically explore the ovine mesenchymal stem cell population derived from multiple donors. With this information, it is possible to start addressing the issues of personalized approaches to regenerative therapies

    Triphasic 3D In Vitro Model of Bone-Tendon-Muscle Interfaces to Study Their Regeneration

    No full text
    The transition areas between different tissues, known as tissue interfaces, have limited ability to regenerate after damage, which can lead to incomplete healing. Previous studies focussed on single interfaces, most commonly bone-tendon and bone-cartilage interfaces. Herein, we develop a 3D in vitro model to study the regeneration of the bone-tendon-muscle interface. The 3D model was prepared from collagen and agarose, with different concentrations of hydroxyapatite to graduate the tissues from bones to muscles, resulting in a stiffness gradient. This graduated structure was fabricated using indirect 3D printing to provide biologically relevant surface topographies. MG-63, human dermal fibroblasts, and Sket.4U cells were found suitable cell models for bones, tendons, and muscles, respectively. The biphasic and triphasic hydrogels composing the 3D model were shown to be suitable for cell growth. Cells were co-cultured on the 3D model for over 21 days before assessing cell proliferation, metabolic activity, viability, cytotoxicity, tissue-specific markers, and matrix deposition to determine interface formations. The studies were conducted in a newly developed growth chamber that allowed cell communication while the cell culture media was compartmentalised. The 3D model promoted cell viability, tissue-specific marker expression, and new matrix deposition over 21 days, thereby showing promise for the development of new interfaces
    corecore