Mechanical assessment of bovine pericardium using Mueller matrix imaging, enhanced backscattering and digital image correlation analysis.
Ontology highlight
ABSTRACT:
SUBMITTER: Cuando-Espitia N
PROVIDER: S-EPMC4541523 | biostudies-other | 2015 Aug
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Native bovine pericardium (BP) exhibits anisotropy of its surface ECM niches, with the serous surface (i.e., parietal pericardium) containing basement membrane components (e.g., Laminin, Col IV) and the fibrous surface (i.e., mediastinal side) being composed primarily of type I collagen (Col I). Native BP surface ECM niche anisotropy is preserved in antigen removed BP (AR-BP) extracellular matrix (ECM) scaffolds. By exploiting sideness (serous or fibrous surface) of AR-BP scaffolds, this study aims to determine the mechanism by which ECM niche influences human mesenchymal stem cells (hMSCs) migration. Human mesenchymal stem cells (hMSC) seeding on serous surface promoted more rapid cell migration than fibrous surface seeding. Gene analysis revealed that expression of integrin α3 and α11 were increased in cells cultured on serous surface compared to those on the fibrous side. Monoclonal antibody blockade of α3β1 (i.e., laminin binding) inhibited early (i.e. ≤ 6 h) hMSC migration following serous seeding, while having no effect on migration of cells on the fibrous side. Blockade of α3β1 resulted in decreased expression of integrin α3 by cells on serous surface. Monoclonal antibody blockade of α11β1 (i.e., Col IV binding) inhibited serous side migration at later time points (i.e., 6-24 h). These results confirmed the role of integrin α3β1 binding to laminin in mediating early rapid hMSCs migration and α11β1 binding to Col IV in mediating later hMSCs migration on the serous side of AR-BP, which has critical implications for rate of cellular monolayer formation and use of AR-BP as blood contacting material for clinical applications.
| S-EPMC7907089 | biostudies-literature
Project description:The extracellular matrix architecture of bovine pericardium (BP) has distinct biochemical and biomechanical properties that make it a useful biomaterial in the field of regenerative medicine. Collagen represents the dominant structural protein of BP and is therefore intimately associated with the properties of this biomaterial. Enzymatic degradation of collagen molecules is critical for extracellular matrix turnover, remodeling and ultimately tissue regeneration. We present a quantitative, label-free and non-destructive method for monitoring changes in biochemical and biomechanical properties of BP during tissue degradation, based on multi-spectral fluorescence lifetime imaging (ms-FLIm). Strong correlations of fluorescence intensity ratio and average fluorescence lifetime were identified with collagen content, Young's Modulus and Ultimate tensile strength during collagenase degradation, indicating the potential of optically monitoring collagen degradation using ms-FLIm. The obtained results demonstrate the value of ms-FLIm to assess the quality of biomaterials in situ for applications in regenerative medicine.
| S-EPMC7700017 | biostudies-literature
Project description:BACKGROUND: The technical advantages in utilizing human acellular dermal matrix (ADM) products as pectoral extenders in immediate breast reconstruction with tissue expanders or implants are well documented in the medical literature. In this study, the authors examine a commonly used biologic xenograft product that has not yet been described in the medical literature for use in immediate breast reconstruction to determine whether a lower overall complication rate is identified compared to published data on ADM products. METHODS: A retrospective multicenter medical record review of data on 54 subjects in 93 tissue expander/implant-based, consecutive, immediate breast reconstructions from three surgeons at different institutions was performed in which Veritas® bovine pericardium was used as the biologic graft material for the pectoral extender. RESULTS: Over a 24-month period with an average of 11-month follow-up, complication rates using Veritas® in breast reconstruction for seroma formation (7.5 %), marginal skin flap necrosis (5.4 %) infection (6.5 %), and capsular contracture (0 %) were found to compare equally or favorably with statistically significant lower overall complications relative to one comparison study and lower rates of marginal skin flap necrosis relative to two comparison studies based upon previously published data from multisurgeon studies using ADM products. CONCLUSIONS: Overall complications were found to be lower with Veritas® than ADM products in comparable multisurgeon studies, though this was found to be statistically significant in only one comparison study. Level of Evidence: Level II, theraputic study.
| S-EPMC3443340 | biostudies-literature
Project description:A literature review points out a large discrepancy in the results of the mechanical tests on dentin that can be explained by stress and strain assessment during the tests. Errors in these assessments during mechanical tests can lead to inaccurate estimation of the mechanical properties of the tested material. On top of that, using the beam theory to analyze the bending test for thick specimens will increase these experimental errors. After summarizing the results of mechanical tests on dentin in the literature, we focus on bending tests and compare the stress assessment obtained by finite element analysis (FEA) and by beam theory application. We show that the difference between the two methods can be quite large in some cases, leading us to prefer the use of FEA to assess stresses. We then propose a new method based on coupling finite element analysis and digital image correlation (DIC) to more accurately evaluate stress distributions, strain distributions and elastic modulus in the case of a three-point bending test. To illustrate and prove the feasibility of the method, it is applied on a dentinal sample so that mean elastic modulus and maximum tensile stress are obtained (11.9 GPa and 143.9 MPa). Note that the main purpose of this study is to focus on the method itself, and not to provide new mechanical values for dentin. When used in standard mechanical testing of dentin, this kind of method should help to narrow the range of obtained mechanical properties values.
| S-EPMC5455261 | biostudies-other
Project description:A novel approach based on full-field indentation measurements to characterize and quantify the effect of contact in thin plates is presented. The proposed method has been employed to evaluate the indentation damage generated in the presence of bending deformation, resulting from the contact between a thin plate and a rigid sphere. For this purpose, the 3D Digital Image Correlation (3D-DIC) technique has been adopted to quantify the out of plane displacements at the back face of the plate. Tests were conducted using aluminum thin plates and a rigid bearing sphere to evaluate the influence of the thickness and the material behavior during contact. Information provided by the 3D-DIC technique has been employed to perform an indirect measurement of the contact area during the loading and unloading path of the test. A symmetrical distribution in the contact damage region due to the symmetry of the indenter was always observed. In the case of aluminum plates, the presence of a high level of plasticity caused shearing deformation as the load increased. Results show the full-field contact damage area for different plates' thicknesses at different loads. The contact damage region was bigger when the thickness of the specimen increased, and therefore, bending deformation was reduced. With the proposed approach, the elastic recovery at the contact location was quantified during the unloading, as well as the remaining permanent indentation damage after releasing the load. Results show the information obtained by full-field measurements at the contact location during the test, which implies a substantial improvement compared with pointwise techniques.
| S-EPMC5551817 | biostudies-other
Project description:The lifetime of steam pipelines in long-term operation in coal-fired power plants are limited due to material damage that resulted from creep exposure. In the present study, the authors comparatively assess the damage of ex-service 12% Cr piping steel with varying degrees of exposure while using accelerated creep tests that employ digital image correlation (DIC) as well as microstructural investigation that is based on electron microscopy. The DIC technique, which allows multiple creep curves to be measured at temperatures ranging from 550-600 °C from a single specimen, revealed higher Zener-Hollomon parameters for a high damage material with a high void density when compared to a material with lower damage and lower void density. Both of the material states showed similar hardness values, subgrain sizes, and boundary character, despite the difference in void densities. Slightly higher inter-particle spacing of MX precipitates results in a lower threshold stress of 79 MPa for the high damage steel when compared to 97 MPa for the low damage material. Besides large Laves phase particles (>0.2 µm) that are found in the higher damaged materials that result in solid solution depletion, the most prominent microstructural damage indicator was a lower density of M23C6 precipitates. Therefore, the observations indicate that the Zener-Hollomon parameter and M23C6 particles are good damage assessment indicators between the most extreme damage states and they predict a lower damage level for a medium void density material.
| S-EPMC6804267 | biostudies-literature
Project description:Architectural heritage is usually built with masonry structures, which present problems under lateral in-plane loading conditions, such as wind pressure or earthquakes. In order to improve the shear behavior of masonry, the use of a fabric-reinforced cementitious matrix (FRCM) has become an interesting solution because of its synergy of mechanical properties and compatibility with masonry substrates. For a proper structural evaluation, the mechanical behavior of reinforced masonry and the FRCM itself needs to be characterized. Hence, a numerical model to evaluate the FRCM reinforcement requires some mechanical parameters that may be difficult to obtain. In this sense, the shear behavior of masonry can be evaluated by means of diagonal tension tests on small specimens (71 × 71 cm). In this work, a digital image correlation (DIC) monitoring system was used to control displacements and cracking patterns of masonry specimens under shear stress (induced by diagonal tension with FRCM layers) applied to one or two sides. In addition, the mechanical behavior of FRCM coupons under uniaxial tensile tests was also registered with DIC. The displacement measurements obtained by DIC were validated with the measurements registered with LVDT. Unlike LVDT-based techniques, DIC monitoring allowed us to measure deformations in masonry during the full test, detecting crack initiation even before it was visible to the eye.
| S-EPMC7180737 | biostudies-literature
Project description:Technologies for digitizing tissues provide important quantitative data for liver histopathology investigation. We aimed to assess liver fibrosis degree with quantitative morphometric measurements of histopathological sections utilizing digital image analysis (DIA) and to further investigate if a correlation with histopathologic scoring (Scheuer staging) exists. A retrospective study of patients with at least two post-liver transplant biopsies having a Scheuer stage of ? 2 at baseline were gathered. Portal tract fibrotic percentage (%) and size (?m2) were measured by DIA, while clinical fibrosis score was measured by the Scheuer system. Correlations between DIA measurements and Scheuer scores were computed by Spearman correlation analysis. Differences between mean levels of fibrosis (score, size, and percentage) at baseline versus second visit were computed by Student's t-test. P values < 0.05 were considered significant. Of 22 patients who met the study criteria, 54 biopsies were included for analysis. Average levels ±standard error [S.E.] of portal tract fibrotic percentage (%) and size (?m2) progressed from 46.5 ± 3.6% at baseline to 61.8 ± 3.8% at the second visit (P = 0.005 by Student's t-test), and from 28,075 ± 3,232 ?m2 at base line to 67,146 ± 10,639 ?m2 at the second visit (P = 0.002 by Student's t-test), respectively. Average levels of Scheuer fibrosis scores progressed from 0.55±0.19 at baseline to 1.14±0.26 at the second visit (P = 0.02 by Student's t-test). Portal tract fibrotic percentage (%) and portal tract fibrotic size were directly correlated with clinical Scheuer fibrosis stage, with Spearman correlation coefficient and P value computed as r = 0.70, P < 0.0001 and r = 0.41, P = 0.002, respectively. Digital quantitative assessment of portal triad size and fibrosis percentage demonstrates a strong correlation with visually assessed histologic stage of liver fibrosis and complements the standard assessment for allograft monitoring, suggesting the utility of future WSI analysis.
| S-EPMC7521727 | biostudies-literature
Project description:We developed an Adaptive Reference-Digital Image Correlation (AR-DIC) method that enables unbiased and accurate mechanics measurements of moving biological tissue samples. We applied the AR-DIC analysis to a spontaneously beating cardiomyocyte (CM) tissue, and could provide correct quantifications of tissue displacement and strain for the beating CMs utilizing physiologically-relevant, sarcomere displacement length-based contraction criteria. The data were further synthesized into novel spatiotemporal parameters of CM contraction to account for the CM beating homogeneity, synchronicity, and propagation as holistic measures of functional myocardial tissue development. Our AR-DIC analyses may thus provide advanced non-invasive characterization tools for assessing the development of spontaneously contracting CMs, suggesting an applicability in myocardial regenerative medicine.
| S-EPMC6895104 | biostudies-literature
Project description:Extracellular matrix bioscaffolds can influence the cardiac microenvironment and modulate endogenous cellular mechanisms. These materials can optimize cardiac surgery for repair and reconstruction. We investigated the biocompatibility and bioinductivity of bovine pericardium fixed via dye-mediated photo-oxidation on human cardiac fibroblast activity. We compared a dye-mediated photo-oxidation fixed bioscaffold to glutaraldehyde-fixed and non-fixed bioscaffolds reported in contemporary literature in cardiac surgery. Human cardiac fibroblasts from consenting patients were seeded on to bioscaffold materials to assess the biocompatibility and bioinductivity. Human cardiac fibroblast gene expression, secretome, morphology and viability were studied. Dye-mediated photo-oxidation fixed acellular bovine pericardium preserves human cardiac fibroblast phenotype and viability; and potentiates a pro-vasculogenic paracrine response. Material tensile properties were compared with biomechanical testing. Dye-mediated photo-oxidation fixed acellular bovine pericardium had higher compliance compared to glutaraldehyde-fixed bioscaffold in response to tensile force. The biocompatibility, bioinductivity, and biomechanical properties of dye-mediated photo-oxidation fixed bovine pericardium demonstrate its feasibility as a bioscaffold for use in cardiac surgery. As a fixed yet bioinductive solution, this bioscaffold demonstrates enhanced compliance and retains bioinductive properties that may leverage endogenous reparative pathways. Dye-mediated photo-oxidation fixed bioscaffold warrants further investigation as a viable tool for cardiac repair and reconstruction.
| S-EPMC8509588 | biostudies-literature