Science.gov

Sample records for 3d fibrin matrix

  1. Optical Measurement of Micromechanics and Structure in a 3D Fibrin Extracellular Matrix

    NASA Astrophysics Data System (ADS)

    Kotlarchyk, Maxwell Aaron

    2011-07-01

    In recent years, a significant number of studies have focused on linking substrate mechanics to cell function using standard methodologies to characterize the bulk properties of the hydrogel substrates. However, current understanding of the correlations between the microstructural mechanical properties of hydrogels and cell function in 3D is poor, in part because of a lack of appropriate techniques. Methods for tuning extracellular matrix (ECM) mechanics in 3D cell culture that rely on increasing the concentration of either protein or cross-linking molecules fail to control important parameters such as pore size, ligand density, and molecular diffusivity. Alternatively, ECM stiffness can be modulated independently from protein concentration by mechanically loading the ECM. We have developed an optical tweezers-based microrheology system to investigate the fundamental role of ECM mechanical properties in determining cellular behavior. Further, this thesis outlines the development of a novel device for generating stiffness gradients in naturally derived ECMs, where stiffness is tuned by inducing strain, while local structure and mechanical properties are directly determined by laser tweezers-based passive and active microrheology respectively. Hydrogel substrates polymerized within 35 mm diameter Petri dishes are strained non-uniformly by the precise rotation of an embedded cylindrical post, and exhibit a position-dependent stiffness with little to no modulation of local mesh geometry. Here we present microrheological studies in the context of fibrin hydrogels. Microrheology and confocal imaging were used to directly measure local changes in micromechanics and structure respectively in unstrained hydrogels of increasing fibrinogen concentration, as well as in our strain gradient device, in which the concentration of fibrinogen is held constant. Orbital particle tracking, and raster image correlation analysis are used to quantify changes in fibrin mechanics on the

  2. Fibroblast-fibronectin patterning and network formation in 3D fibrin matrices.

    PubMed

    Miron-Mendoza, Miguel; Graham, Eric; Manohar, Sujal; Petroll, W Matthew

    2017-06-07

    We previously reported that fibroblasts migrating within 3-D collagen matrices move independently, whereas fibroblasts within 3-D fibrin matrices form an interconnected network. Similar networks have been identified previously during in vivo corneal wound healing. In this study, we investigate the role of fibronectin in mediating this mechanism of collective cell spreading, migration and patterning. To assess cell spreading, corneal fibroblasts were plated within fibrillar collagen or fibrin matrices. To assess migration, compacted cell-populated collagen matrices were nested inside cell-free fibrin matrices. Constructs were cultured in serum-free media containing PDGF, with or without RGD peptide, anti-α5 or anti-fibronectin blocking antibodies. In some experiments, LifeAct and fluorescent fibronectin were used to allow dynamic assessment of cell-induced fibronectin reorganization. 3-D and 4-D imaging were used to assess cell mechanical behavior, connectivity, F-actin, α5 integrin and fibronectin organization. Corneal fibroblasts within 3-D fibrin matrices formed an interconnected network that was lined with cell-secreted fibronectin. Live cell imaging demonstrated that fibronectin tracks were formed at the leading edge of spreading and migrating cells. Furthermore, fibroblasts preferentially migrated through fibronectin tracks laid down by other cells. Interfering with cell-fibronectin binding with RGD, anti α5 integrin or anti fibronectin antibodies inhibited cell spreading and migration through fibrin, but did not affect cell behavior in collagen. In this study, a novel mode of cell patterning was identified in which corneal fibroblasts secrete and attach to fibronectin via α5β1 integrin to facilitate spreading and migration within 3-D fibrin matrices, resulting in the formation of localized fibronectin tracks. Other cells use these fibronectin tracks as conduits, resulting in an interconnected cell-fibronectin network. Copyright © 2017 International

  3. Biocompatible 3D Matrix with Antimicrobial Properties.

    PubMed

    Ion, Alberto; Andronescu, Ecaterina; Rădulescu, Dragoș; Rădulescu, Marius; Iordache, Florin; Vasile, Bogdan Ștefan; Surdu, Adrian Vasile; Albu, Madalina Georgiana; Maniu, Horia; Chifiriuc, Mariana Carmen; Grumezescu, Alexandru Mihai; Holban, Alina Maria

    2016-01-20

    The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL), hydroxyapatite (HAp), β-cyclodextrin (β-CD) and usnic acid (UA). The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Microscopy (FT-IRM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA) against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D) anti-infective regeneration matrix for bone tissue engineering.

  4. Automatic segmentation and analysis of fibrin networks in 3D confocal microscopy images

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomin; Mu, Jian; Machlus, Kellie R.; Wolberg, Alisa S.; Rosen, Elliot D.; Xu, Zhiliang; Alber, Mark S.; Chen, Danny Z.

    2012-02-01

    Fibrin networks are a major component of blood clots that provides structural support to the formation of growing clots. Abnormal fibrin networks that are too rigid or too unstable can promote cardiovascular problems and/or bleeding. However, current biological studies of fibrin networks rarely perform quantitative analysis of their structural properties (e.g., the density of branch points) due to the massive branching structures of the networks. In this paper, we present a new approach for segmenting and analyzing fibrin networks in 3D confocal microscopy images. We first identify the target fibrin network by applying the 3D region growing method with global thresholding. We then produce a one-voxel wide centerline for each fiber segment along which the branch points and other structural information of the network can be obtained. Branch points are identified by a novel approach based on the outer medial axis. Cells within the fibrin network are segmented by a new algorithm that combines cluster detection and surface reconstruction based on the α-shape approach. Our algorithm has been evaluated on computer phantom images of fibrin networks for identifying branch points. Experiments on z-stack images of different types of fibrin networks yielded results that are consistent with biological observations.

  5. Individual versus collective fibroblast spreading and migration: regulation by matrix composition in 3D culture.

    PubMed

    Miron-Mendoza, Miguel; Lin, Xihui; Ma, Lisha; Ririe, Peter; Petroll, W Matthew

    2012-06-01

    Extracellular matrix (ECM) supplies both physical and chemical signals to cells and provides a substrate through which fibroblasts migrate during wound repair. To directly assess how ECM composition regulates this process, we used a nested 3D matrix model in which cell-populated collagen buttons were embedded in cell-free collagen or fibrin matrices. Time-lapse microscopy was used to record the dynamic pattern of cell migration into the outer matrices, and 3D confocal imaging was used to assess cell connectivity and cytoskeletal organization. Corneal fibroblasts stimulated with PDGF migrated more rapidly into collagen as compared to fibrin. In addition, the pattern of fibroblast migration into fibrin and collagen ECMs was strikingly different. Corneal fibroblasts migrating into collagen matrices developed dendritic processes and moved independently, whereas cells migrating into fibrin matrices had a more fusiform morphology and formed an interconnected meshwork. A similar pattern was observed when using dermal fibroblasts, suggesting that this response is not unique to corneal cells. We next cultured corneal fibroblasts within and on top of standard collagen and fibrin matrices to assess the impact of ECM composition on the cell spreading response. Similar differences in cell morphology and connectivity were observed – cells remained separated on collagen but coalesced into clusters on fibrin. Cadherin was localized to junctions between interconnected cells, whereas fibronectin was present both between cells and at the tips of extending cell processes. Cells on fibrin matrices also developed more prominent stress fibers than those on collagen matrices. Importantly, these spreading and migration patterns were consistently observed on both rigid and compliant substrates, thus differences in ECM mechanical stiffness were not the underlying cause. Overall, these results demonstrate for the first time that ECM protein composition alone (collagen vs. fibrin) can induce

  6. Fluid and cell behaviors along a 3D printed alginate/gelatin/fibrin channel.

    PubMed

    Xu, Yufan; Wang, Xiaohong

    2015-08-01

    Three-dimensional (3D) cell manipulation is available with the integration of microfluidic technology and rapid prototyping techniques. High-Fidelity (Hi-Fi) constructs hold enormous therapeutic potential for organ manufacturing and regenerative medicine. In the present paper we introduced a quasi-three-dimensional (Q3D) model with parallel biocompatible alginate/gelatin/fibrin hurdles. The behaviors of fluids and cells along the microfluidic channels with various widths were studied. Cells inside the newly designed microfluidic channels attached and grew well. Morphological changes of adipose-derived stem cells (ADSCs) in both two-dimensional (2D) and 3D milieu were found on the printed constructs. Endothelialization occurred with the co-cultures of ADSCs and hepatocytes. This study provides insights into the interactions among fluids, cells and biomaterials, the behaviors of fluids and cells along the microfluidic channels, and the applications of Q3D techniques.

  7. Aligned Human Microvessels Formed in 3D Fibrin Gel by Constraint of Gel Contraction

    PubMed Central

    Morin, Kristen T.; Smith, Annie O.; Davis, George E.; Tranquillo, Robert T.

    2013-01-01

    This study aimed to form microvessels in fibrin gels, which is of interest both for studying the fundamental cell-matrix interactions as well as for tissue engineering purposes, and to align the microvessels, which would provide natural inlet and outlet sides for perfusion. The data reported here demonstrate the formation of highly interconnected microvessels in fibrin gel under defined medium conditions and the ability to align them using two methods, both of which involved anchoring the gel at both ends to constrain the cell-induced compaction. The first method used only defined medium and resulted in moderate alignment. The second method used defined and serum-containing media sequentially to achieve high levels of microvessel alignment. PMID:23938272

  8. Endothelial fibrinolytic response onto an evolving matrix of fibrin.

    PubMed

    Castillo, O; Rojas, H; Domínguez, Z; Anglés-Cano, E; Marchi, R

    2016-01-01

    Fibrin provides a temporary matrix at the site of vascular injury. The aims of the present work were (1) to follow fibrin formation and lysis onto the surface of human dermal microvascular endothelial cells (HMEC-1), and (2) to quantify the secretion of fibrinolytic components in the presence of fibrin. Fibrin clots at different fibrinogen concentrations were formed on top of (model 1) or beneath (model 2) the endothelial cells. Fibrin formation or lysis onto the surface of HMEC-1 cells, was followed by turbidity. Clot structure was visualized by laser scanning confocal microscopy (LSCM). The secretion of uPA and PAI-1 by HMEC-1 cells was quantified by ELISA. The rate of fibrin formation increased approximately 1.5-fold at low fibrinogen content (0.5 and 1 mg/mL; p < 0.05) compared to the condition without cells; however, it was decreased at 2 mg/mL fibrinogen (p < 0.05) and no differences were found at higher fibrinogen concentrations (3 and 5 mg/mL). HMEC-1 retarded dissolution of clots formed onto their surface at 0.5 to 3 mg/mL fibrinogen (p < 0.05). Secretion of uPA was 13 × 10(-6) ng/mL per cell in the absence of RGD and 8 × 10(-6) ng/mL per cell in the presence of RGD, when clots were formed on the top of HMEC-1. However, the opposite was found when cells were grown over fibrin: 6 × 10(-6) ng/mL per cell without RGD vs. 17 × 10(-6) ng/mL per cell with RGD. The secretion of PAI-1 by HMEC-1 cells was unrelated to the presence of fibrin or RGD, 7 × 10(-6) μg/mL per cell and 5 × 10(-6) μg/mL per cell, for the apical (model 1) and basal clots (model 2), respectively. HMEC-1 cells influence fibrin formation and dissolution as a function of the fibrin content of clots. Clot degradation was accentuated at high fibrin concentrations. The secretion of fibrinolytic components by HMEC-1 cells seemed to be modulated by integrins that bind RGD ligands.

  9. Biomimetic interconnected porous keratin-fibrin-gelatin 3D sponge for tissue engineering application.

    PubMed

    Singaravelu, Sivakumar; Ramanathan, Giriprasath; Raja, M D; Nagiah, Naveen; Padmapriya, P; Kaveri, Krishnasamy; Sivagnanam, Uma Tiruchirapalli

    2016-05-01

    The medicated wound dressing material with highly interconnected pores, mimicking the function of the extracellular matrix was fabricated for the promotion of cell growth. In this study, keratin (K), fibrin (F) and gelatin (G) composite scaffold (KFG-SPG) was fabricated by freeze drying technique and the mupirocin (D) drug was successfully incorporated with KFG-SPG (KFG-SPG-D) intended for tissue engineering applications. The fabrication of scaffold was performed without the use of any strong chemical solvents, and the solid sponge scaffold was obtained with well interconnected pores. The porous morphology of the scaffold was confirmed by SEM analysis and exhibited competent mechanical properties. KFG-SPG and KFG-SPG-D possess high level of biocompatibility, cell proliferation and cell adhesion of NIH 3T3 fibroblast and human keratinocytes (HaCaT) cell lines thereby indicating the scaffolds potential as a suitable medicated dressing for wound healing.

  10. First step in developing a 3D biodegradable fibrin scaffold for an artificial ovary

    PubMed Central

    2013-01-01

    Background Although transplantation of cryopreserved ovarian tissue is a promising approach to restore fertility in cancer patients, it is not advisable for women at risk of ovarian involvement due to the threat of reintroducing malignant cells. The aim of this study was therefore to find an alternative for these patients by development of an artificial ovary. Methods For construction of the artificial ovary matrix, we used a central composite design to investigate nine combinations of fibrinogen (mg/ml) and thrombin (IU/mL) (F/T): F1/T4, F12.5/T1, F12.5/T20, F25/T0.1, F25/T4, F25/T500, F50/T1, F50/T20 and F100/T4. From the first qualitative analyses (handling and matrix size), five combinations (F12.5/T1, F25/T4, F50/T20, F50/T1 and F100/T4) yielded positive results. They were further evaluated in order to assess fibrin matrix degradation and homogeneous cell encapsulation (density), survival and proliferation (Ki67), and atresia (TUNEL) before and after 7 days of in vitro culture. To determine the best compromise between maximizing the dynamic density (Y1) and minimizing the apoptosis rate (Y2), we used the desirability function approach. Results Two combinations (F12.5/T1 and F25/T4) showed greater distribution of cells before in vitro culture, reproducible degradation of the fibrin network and adequate support for isolated human ovarian stromal cells, with a high proportion of Ki67-positive cells. SEM analysis revealed a network of fibers with regular pores and healthy stromal cells after in vitro culture with both F/T combinations. Conclusion This study reports two optimal F/T combinations that allow survival and proliferation of isolated human ovarian cells. Further studies are required to determine if such a scaffold will also be a suitable environment for isolated ovarian follicles. PMID:24274108

  11. Fibronectin alters the rate of formation and structure of the fibrin matrix.

    PubMed

    Ramanathan, Anand; Karuri, Nancy

    2014-01-10

    Plasma fibronectin is a vital component of the fibrin clot; however its role on clot structure is not clearly understood. The goal of this study was to examine the influence of fibronectin on the kinetics of formation, structural characteristics and composition of reconstituted fibrin clots or fibrin matrices. Fibrin matrices were formed by adding thrombin to 1, 2 or 4 mg/ml fibrinogen supplemented with 0-0.4 mg/ml fibronectin. The rate of fibrin matrix formation was then monitored by measuring light absorbance properties at different time points. Confocal microscopy of fluorescein conjugated fibrinogen was used to visualize the structural characteristics of fibrin matrices. The amount of fibronectin in fibrin matrices was determined through electrophoresis and immunoblotting of solubilized matrices. Fibronectin concentration positively correlated with the initial rate of fibrin matrix formation and with steady state light absorbance values of fibrin matrices. An increase in fibronectin concentration resulted in thinner and denser fibers in the fibrin matrices. Electrophoresis and immunoblotting showed that fibronectin was covalently and non-covalently bound to fibrin matrices and in the form of high molecular weight multimers. The formation of fibronectin multimers was attributed to cross-linking of fibronectin by trace amounts Factor XIIIa. These findings are novel because they link results from light absorbance studies to microcopy analyses and demonstrate an influence of fibronectin on fibrin matrix structural characteristics. This data is important in developing therapies that destabilize fibrin clots.

  12. Hematopoietic Stem Cell Cytokines and Fibroblast Growth factor-2 Stimulate Human Endothelial Cell-Pericyte Tube Co-Assembly in 3D Fibrin Matrices under Serum-Free Defined Conditions

    PubMed Central

    Smith, Annie O.; Bowers, Stephanie L. K.; Stratman, Amber N.; Davis, George E.

    2013-01-01

    We describe a novel 3D fibrin matrix model using recombinant hematopoietic stem cell cytokines under serum-free defined conditions which promotes the assembly of human endothelial cell (EC) tubes with co-associated pericytes. Individual ECs and pericytes are randomly mixed together and EC tubes form that is accompanied by pericyte recruitment to the EC tube abluminal surface over a 3-5 day period. These morphogenic processes are stimulated by a combination of the hematopoietic stem cell cytokines, stem cell factor, interleukin-3, stromal derived factor-1α, and Flt-3 ligand which are added in conjunction with fibroblast growth factor (FGF)-2 into the fibrin matrix. In contrast, this tube morphogenic response does not occur under serum-free defined conditions when VEGF and FGF-2 are added together in the fibrin matrices. We recently demonstrated that VEGF and FGF-2 are able to prime EC tube morphogenic responses (i.e. added overnight prior to the morphogenic assay) to hematopoietic stem cell cytokines in collagen matrices and, interestingly, they also prime EC tube morphogenesis in 3D fibrin matrices. EC-pericyte interactions in 3D fibrin matrices leads to marked vascular basement membrane assembly as demonstrated using immunofluorescence and transmission electron microscopy. Furthermore, we show that hematopoietic stem cell cytokines and pericytes stimulate EC sprouting in fibrin matrices in a manner dependent on the α5β1 integrin. This novel co-culture system, under serum-free defined conditions, allows for a molecular analysis of EC tube assembly, pericyte recruitment and maturation events in a critical ECM environment (i.e. fibrin matrices) that regulates angiogenic events in postnatal life. PMID:24391990

  13. Modeling Extracellular Matrix Reorganization in 3D Environments

    PubMed Central

    Harjanto, Dewi; Zaman, Muhammad H.

    2013-01-01

    Extracellular matrix (ECM) remodeling is a key physiological process that occurs in a number of contexts, including cell migration, and is especially important for cellular form and function in three-dimensional (3D) matrices. However, there have been few attempts to computationally model how cells modify their environment in a manner that accounts for both cellular properties and the architecture of the surrounding ECM. To this end, we have developed and validated a novel model to simulate matrix remodeling that explicitly defines cells in a 3D collagenous matrix. In our simulation, cells can degrade, deposit, or pull on local fibers, depending on the fiber density around each cell. The cells can also move within the 3D matrix. Different cell phenotypes can be modeled by varying key cellular parameters. Using the model we have studied how two model cancer cell lines, of differing invasiveness, modify matrices with varying fiber density in their vicinity by tracking the metric of fraction of matrix occupied by fibers. Our results quantitatively demonstrate that in low density environments, cells deposit more collagen to uniformly increase fibril fraction. On the other hand, in higher density environments, the less invasive model cell line reduced the fibril fraction as compared to the highly invasive phenotype. These results show good qualitative and quantitative agreement with existing experimental literature. Our simulation is therefore able to function as a novel platform to provide new insights into the clinically relevant and physiologically critical process of matrix remodeling by helping identify critical parameters that dictate cellular behavior in complex native-like environments. PMID:23341900

  14. 3D cancer cell migration in a confined matrix

    NASA Astrophysics Data System (ADS)

    Alobaidi, Amani; Sun, Bo

    Cancer cell migration is widely studied in 2D motion, which does not mimic the invasion processes in vivo. More recently, 3D cell migration studies have been performed. The ability of cancer cells to migrate within the extracellular matrix depends on the physical and biochemical features of the extracellular matrix. We present a model of cell motility in confined matrix geometry. The aim of the study is to study cancer migration in collagen matrix, as a soft tissue, to investigate their motility within the confined and surrounding collagen environment. Different collagen concentrations have been used to show the ability of these cancer cells to move through such a complex structure by measuring Cancer cell migration velocity as well as the displacement. Graduate student physics department.

  15. Concentration of fibrin and presence of plasminogen affect proliferation, fibrinolytic activity, and morphology of human fibroblasts and keratinocytes in 3D fibrin constructs.

    PubMed

    Reinertsen, Erik; Skinner, Michael; Wu, Benjamin; Tawil, Bill

    2014-11-01

    Fibrin is a hemostatic protein found in the clotting cascade. It is used in the operating room to stop bleeding and deliver cells and growth factors to heal wounds. However, formulations of clinically approved fibrin are optimized for hemostasis, and the extent to which biochemical and physical cues in fibrin mediate skin cell behavior is not fully understood nor utilized in the design of biomaterials. To determine if the concentration of fibrinogen and the presence of plasminogen affect cell behavior relevant to wound healing, we fabricated three-dimensional fibrin constructs made from 5, 10, or 20 mg/mL of clinical fibrin or plasminogen-depleted (PD) fibrin. We cultured dermal fibroblasts or epidermal keratinocytes in these constructs. Fibroblasts proliferated similarly in both types of fibrin, but keratinocytes proliferated more in low concentrations of clinical fibrin and less in PD fibrin. Clinical fibrin constructs with fibroblasts were less stiff and degraded faster than PD fibrin constructs with fibroblasts. Similarly, keratinocytes degraded clinical fibrin, but not PD fibrin. Fibroblast spreading varied with fibrin concentration in both types of fibrin. In conclusion, the concentration of fibrinogen and the presence of plasminogen affect fibroblast and keratinocyte proliferation, morphology, and fibrin degradation. Creating materials with heterogeneous regions of fibrin formulations and concentrations could be a novel strategy for controlling the phenotype of encapsulated fibroblasts and keratinocytes, and the subsequent biomechanical properties of the construct. However, other well-investigated aspects of wound healing remain to be utilized in the design of fibrin biomaterials, such as autocrine and paracrine signaling between fibroblasts, keratinocytes, and immune cells.

  16. Fibrin and collagen differentially but synergistically regulate sprout angiogenesis of human dermal microvascular endothelial cells in 3-dimensional matrix.

    PubMed

    Feng, Xiaodong; Tonnesen, Marcia G; Mousa, Shaker A; Clark, Richard A F

    2013-01-01

    Angiogenesis is a highly regulated event involving complex, dynamic interactions between microvascular endothelial cells and extracellular matrix (ECM) proteins. Alteration of ECM composition and architecture is a hallmark feature of wound clot and tumor stroma. We previously reported that during angiogenesis, endothelial cell responses to growth factors are modulated by the compositional and mechanical properties of a surrounding three-dimensional (3D) extracellular matrix (ECM) that is dominated by either cross-linked fibrin or type I collagen. However, the role of 3D ECM in the regulation of angiogenesis associated with wound healing and tumor growth is not well defined. This study investigates the correlation of sprout angiogenesis and ECM microenvironment using in vivo and in vitro 3D angiogenesis models. It demonstrates that fibrin and type I collagen 3D matrices differentially but synergistically regulate sprout angiogenesis. Thus blocking both integrin alpha v beta 3 and integrin alpha 2 beta 1 might be a novel strategy to synergistically block sprout angiogenesis in solid tumors.

  17. A novel bioreactor for the generation of highly aligned 3D skeletal muscle-like constructs through orientation of fibrin via application of static strain.

    PubMed

    Heher, Philipp; Maleiner, Babette; Prüller, Johanna; Teuschl, Andreas Herbert; Kollmitzer, Josef; Monforte, Xavier; Wolbank, Susanne; Redl, Heinz; Rünzler, Dominik; Fuchs, Christiane

    2015-09-01

    The generation of functional biomimetic skeletal muscle constructs is still one of the fundamental challenges in skeletal muscle tissue engineering. With the notion that structure strongly dictates functional capabilities, a myriad of cell types, scaffold materials and stimulation strategies have been combined. To further optimize muscle engineered constructs, we have developed a novel bioreactor system (MagneTissue) for rapid engineering of skeletal muscle-like constructs with the aim to resemble native muscle in terms of structure, gene expression profile and maturity. Myoblasts embedded in fibrin, a natural hydrogel that serves as extracellular matrix, are subjected to mechanical stimulation via magnetic force transmission. We identify static mechanical strain as a trigger for cellular alignment concomitant with the orientation of the scaffold into highly organized fibrin fibrils. This ultimately yields myotubes with a more mature phenotype in terms of sarcomeric patterning, diameter and length. On the molecular level, a faster progression of the myogenic gene expression program is evident as myogenic determination markers MyoD and Myogenin as well as the Ca(2+) dependent contractile structural marker TnnT1 are significantly upregulated when strain is applied. The major advantage of the MagneTissue bioreactor system is that the generated tension is not exclusively relying on the strain generated by the cells themselves in response to scaffold anchoring but its ability to subject the constructs to individually adjustable strain protocols. In future work, this will allow applying mechanical stimulation with different strain regimes in the maturation process of tissue engineered constructs and elucidating the role of mechanotransduction in myogenesis. Mechanical stimulation of tissue engineered skeletal muscle constructs is a promising approach to increase tissue functionality. We have developed a novel bioreactor-based 3D culture system, giving the user the

  18. 3-D Lung Segmentation by Incremental Constrained Nonnegative Matrix Factorization.

    PubMed

    Hosseini-Asl, Ehsan; Zurada, Jacek M; Gimelfarb, Georgy; El-Baz, Ayman

    2016-05-01

    Accurate lung segmentation from large-size 3-D chest-computed tomography images is crucial for computer-assisted cancer diagnostics. To efficiently segment a 3-D lung, we extract voxel-wise features of spatial image contexts by unsupervised learning with a proposed incremental constrained nonnegative matrix factorization (ICNMF). The method applies smoothness constraints to learn the features, which are more robust to lung tissue inhomogeneities, and thus, help to better segment internal lung pathologies than the known state-of-the-art techniques. Compared to the latter, the ICNMF depends less on the domain expert knowledge and is more easily tuned due to only a few control parameters. Also, the proposed slice-wise incremental learning with due regard for interslice signal dependencies decreases the computational complexity of the NMF-based segmentation and is scalable to very large 3-D lung images. The method is quantitatively validated on simulated realistic lung phantoms that mimic different lung pathologies (seven datasets), in vivo datasets for 17 subjects, and 55 datasets from the Lobe and Lung Analysis 2011 (LOLA11) study. For the in vivo data, the accuracy of our segmentation w.r.t. the ground truth is 0.96 by the Dice similarity coefficient, 9.0 mm by the modified Hausdorff distance, and 0.87% by the absolute lung volume difference, which is significantly better than for the NMF-based segmentation. In spite of not being designed for lungs with severe pathologies and of no agreement between radiologists on the ground truth in such cases, the ICNMF with its total accuracy of 0.965 was ranked fifth among all others in the LOLA11. After excluding the nine too pathological cases from the LOLA11 dataset, the ICNMF accuracy increased to 0.986.

  19. Directional conductivity in SWNT-collagen-fibrin composite biomaterials through strain-induced matrix alignment.

    PubMed

    Voge, Christopher M; Kariolis, Mihalis; MacDonald, Rebecca A; Stegemann, Jan P

    2008-07-01

    Composite biomaterials incorporating fibroblast cells, collagen Type I, fibrin, and 2 wt % carboxylated SWNT were created, and their properties were compared with similar control constructs without SWNT. Alignment of the matrix was stimulated by application of 8% cyclic strain for three 12-h periods over three days. All constructs underwent cell-mediated gel compaction to 15-20% of their initial volume, which was not affected by SWNT loading. Mechanical strain increased the rate of compaction, and strained constructs were significantly more compacted than unstrained controls by day 3. Cell viability and morphology were similar in both control and SWNT-loaded constructs, but unstrained samples exhibited a more stellate appearance with more numerous cellular projections. Application of mechanical strain caused clear alignment of both the cells and matrix in the direction of the applied strain. Bioimpedance measurements showed that SWNT loading increased the electrical conductivity of composite constructs, and that mechanically-induced alignment of the matrix/SWNT caused a further increase in conductivity. These results demonstrate that SWNT can be used to augment the electrical properties of 3D protein hydrogels, and that anisotropy in the matrix further enhances these properties. Such electrically conductive biopolymers may have a variety of applications in tissue engineering and biosensor development.

  20. Modeling the formation of cell-matrix adhesions on a single 3D matrix fiber.

    PubMed

    Escribano, J; Sánchez, M T; García-Aznar, J M

    2015-11-07

    Cell-matrix adhesions are crucial in different biological processes like tissue morphogenesis, cell motility, and extracellular matrix remodeling. These interactions that link cell cytoskeleton and matrix fibers are built through protein clutches, generally known as adhesion complexes. The adhesion formation process has been deeply studied in two-dimensional (2D) cases; however, the knowledge is limited for three-dimensional (3D) cases. In this work, we simulate different local extracellular matrix properties in order to unravel the fundamental mechanisms that regulate the formation of cell-matrix adhesions in 3D. We aim to study the mechanical interaction of these biological structures through a three dimensional discrete approach, reproducing the transmission pattern force between the cytoskeleton and a single extracellular matrix fiber. This numerical model provides a discrete analysis of the proteins involved including spatial distribution, interaction between them, and study of the different phenomena, such as protein clutches unbinding or protein unfolding.

  1. Optimization and Use of 3D sintered porous material in medical field for mixing fibrin glue.

    NASA Astrophysics Data System (ADS)

    Delmotte, Y.; Laroumanie, H.; Brossard, G.

    2012-04-01

    In medical field, Mixing of two or more chemical components (liquids and/or gases) is extremely important as improper mixing can affect the physico-chemical properties of the final product. At Baxter Healthcare Corporation, we are using a sintered porous material (PM) as a micro-mixer in medical device for mixing Fibrinogen and Thrombin in order to obtain a homogeneous polymerized Fibrin glue clot used in surgery. First trials were carried out with an interconnected PM from Porvair® (made of PE - porosity: 40% - permeability: 18Darcy). The injection rate is very low, usually about 10mL/min (Re number about 50) which keeps fluids in a laminar flow. Such a low flow rate does not favour mixing of fluids having gradient of viscosity if a mixer is not used. Promising results that were obtained lead the team to understand this ability to mix fluids which will be presented in the poster. Topology of porous media (PM) which associates a solid phase with interconnected (or not) porous structure is known and used in many commodity products. Researches on PM usually focus on flows inside this structure. By opposition to transport and filtration capacity, as well as mechanic and thermic properties, mixing is rarely associated with PM. However over the past few years, we shown that some type of PM have a real capacity to mix certain fluids. Poster will also describe the problematic of mixing complex biological fluids as fibrinogen and Thrombin. They indeed present a large viscosity difference (ratio about 120) limiting the diffusion and the interaction between the two solutions. As those products are expensive, we used Water (1cPo) and Glycerol 87% (120cPo) which are matching the viscosities of Thrombin and Fibrinogen. A parametric investigation of the "porous micro-mixer" as well as a scale up investigation was carried out to examine the influence of both diffusion and advection to successful mix fluids of different viscosity. Experiments were implemented with Planar Laser

  2. Three-dimensional culture of single embryonic stem-derived neural/stem progenitor cells in fibrin hydrogels: neuronal network formation and matrix remodelling.

    PubMed

    Bento, Ana R; Quelhas, Pedro; Oliveira, Maria J; Pêgo, Ana P; Amaral, Isabel F

    2016-12-29

    In an attempt to improve the efficacy of neural stem/progenitor cell (NSPC) based therapies, fibrin hydrogels are being explored to provide a favourable microenvironment for cell survival and differentiation following transplantation. In the present work, the ability of fibrin to support the survival, proliferation, and neuronal differentiation of NSPCs derived from embryonic stem (ES) cells under monolayer culture was explored. Single mouse ES-NSPCs were cultured within fibrin (fibrinogen concentration: 6 mg/ml) under neuronal differentiation conditions up to 14 days. The ES-NSPCs retained high cell viability and proliferated within small-sized spheroids. Neuronal differentiation was confirmed by an increase in the levels of βIII-tubulin and NF200 over time. At day 14, cell-matrix constructs mainly comprised NSPCs and neurons (46.5% βIII-tubulin(+) cells). Gamma-aminobutyric acid (GABA)ergic and dopaminergic/noradrenergic neurons were also observed, along with a network of synaptic proteins. The ES-NSPCs expressed matriptase and secreted MMP-2/9, with MMP-2 activity increasing along time. Fibronectin, laminin and collagen type IV deposition was also detected. Fibrin gels prepared with higher fibrinogen concentrations (8/10 mg/ml) were less permissive to neurite extension and neuronal differentiation, possibly owing to their smaller pore area and higher rigidity. Overall, it is shown that ES-NSPCs within fibrin are able to establish neuronal networks and to remodel fibrin through MMP secretion and extracellular matrix (ECM) deposition. This three-dimensional (3D) culture system was also shown to support cell viability, neuronal differentiation and ECM deposition of human ES-NSPCs. The settled 3D platform is expected to constitute a valuable tool to develop fibrin-based hydrogels for ES-NSPC delivery into the injured central nervous system. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Design of fibrin matrix composition to enhance endothelial cell growth and extracellular matrix deposition for in vitro tissue engineering.

    PubMed

    Pankajakshan, Divya; Krishnan, Lissy K

    2009-01-01

    Tissue-engineered blood vessel substitutes should closely resemble native vessels in terms of structure, composition, mechanical properties, and function. Successful cardiovascular tissue engineering requires optimization of in vitro culture environment that would produce functional constructs. The extracellular matrix (ECM) protein elastin plays an essential role in the cardiovascular system to render elasticity to blood vessel wall, whereas collagen is responsible for providing mechanical strength. The objective of this study was to understand the significance of various ECM components on endothelial cell (EC) growth and tissue generation. We demonstrate that, even though fibrin is a good matrix for EC growth, fibronectin is the crucial component of the fibrin matrix that enhances EC adhesion, spreading, and proliferation. Vascular EC growth factor is known to influence in vitro growth of EC, but, so far, ECM deposition in in vitro culture has not been reported. In this study, it is shown that incorporation of a mixture of hypothalamus-derived angiogenic growth factors with fibrin matrix enhances synthesis and deposition of insoluble elastin and collagen in the matrix, within 10 days of in vitro culture. The results suggest that a carefully engineered fibrin composite matrix may support EC growth, survival, and remodeling of ECM in vitro and impart optimum properties to the construct for resisting the shear stress at the time of implantation.

  4. Co-Culture of Human Endothelial Cells and Foreskin Fibroblasts on 3D Silk-Fibrin Scaffolds Supports Vascularization.

    PubMed

    Samal, Juhi; Weinandy, Stefan; Weinandy, Agnieszka; Helmedag, Marius; Rongen, Lisanne; Hermanns-Sachweh, Benita; Kundu, Subhas C; Jockenhoevel, Stefan

    2015-10-01

    A successful strategy to enhance the in vivo survival of engineered tissues would be to prevascularize them. In this study, fabricated silk fibroin scaffolds from mulberry and non-mulberry silkworms are investigated and compared for supporting the co-culture of human umbilical vein endothelial cells and human foreskin fibroblasts. Scaffolds are cytocompatible and when combined with fibrin gel support capillary-like structure formation. Density and interconnectivity of the formed structures are found to be better in mulberry scaffolds. ELISA shows that levels of vascular endothelial growth factor (VEGF) released in co-cultures with fibrin gel are significantly higher than in co-cultures without fibrin gel. RT PCR shows an increase in VEGFR2 expression in mulberry scaffolds indicating these scaffolds combined with fibrin provide a suitable microenvironment for the development of capillary-like structures.

  5. 3D modeling of human cancer: A PEG-fibrin hydrogel system to study the role of tumor microenvironment and recapitulate the in vivo effect of oncolytic adenovirus.

    PubMed

    Del Bufalo, Francesca; Manzo, Teresa; Hoyos, Valentina; Yagyu, Shigeki; Caruana, Ignazio; Jacot, Jeffrey; Benavides, Omar; Rosen, Daniel; Brenner, Malcolm K

    2016-04-01

    Interactions between malignant and stromal cells and the 3D spatial architecture of the tumor both substantially modify tumor behavior, including the responses to small molecule drugs and biological therapies. Conventional 2D culture systems cannot replicate this complexity. To overcome these limitations and more accurately model solid tumors, we developed a highly versatile 3D PEG-fibrin hydrogel model of human lung adenocarcinoma. Our model relevantly recapitulates the effect of oncolytic adenovirus; tumor responses in this setting nearly reproduce those observed in vivo. We have also validated the use of this model for complex, long-term, 3D cultures of cancer cells and their stroma (fibroblasts and endothelial cells). Both tumor proliferation and invasiveness were enhanced in the presence of stromal components. These results validate our 3D hydrogel model as a relevant platform to study cancer biology and tumor responses to biological treatments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Vinculin Regulates Directionality and Cell Polarity in 2D, 3D Matrix and 3D Microtrack Migration.

    PubMed

    Rahman, Aniqua; Carey, Shawn P; Kraning-Rush, Casey M; Goldblatt, Zachary E; Bordeleau, Francois; Lampi, Marsha C; Lin, Deanna Y; García, Andrés J; Reinhart-King, Cynthia A

    2016-03-09

    During metastasis, cells can use proteolytic activity to form tube-like "microtracks" within the extracellular matrix (ECM). Using these microtracks, cells can migrate unimpeded through the stroma. To investigate the molecular mechanisms of microtrack migration, we developed an in vitro 3D micromolded collagen platform. When in microtracks, cells tend to migrate unidirectionally. Since focal adhesions are the primary mechanism by which cells interact with the ECM, we examined the roles of several focal adhesion molecules in driving unidirectional motion. Vinculin knockdown results in the repeated reversal of migration direction compared with control cells. Tracking the position of the Golgi centroid relative to the position of the nucleus centroid reveals that vinculin knockdown disrupts cell polarity in microtracks. Vinculin also directs migration on 2D substrates and in 3D uniform collagen matrices, indicated by reduced speed, shorter net displacement and decreased directionality in vinculin-deficient cells. In addition, vinculin is necessary for Focal Adhesion Kinase (FAK) activation in 3D as vinculin knockdown results in reduced FAK activation in both 3D uniform collagen matrices and microtracks, but not on 2D substrates, and accordingly, FAK inhibition halts cell migration in 3D microtracks. Together, these data indicate that vinculin plays a key role in polarization during migration.

  7. Collaboration of 3D context and extracellular matrix in the development of glioma stemness in a 3D model.

    PubMed

    Ma, Nina K L; Lim, Jia Kai; Leong, Meng Fatt; Sandanaraj, Edwin; Ang, Beng Ti; Tang, Carol; Wan, Andrew C A

    2016-02-01

    A hierarchy of cellular stemness exists in certain cancers, and any successful strategy to treat such cancers would have to eliminate the self-renewing tumor-initiating cells at the apex of the hierarchy. The cellular microenvironment, in particular the extracellular matrix (ECM), is believed to have a role in regulating stemness. In this work, U251 glioblastoma cells are cultured on electrospun polystyrene (ESPS) scaffolds coated with an array of 7 laminin isoforms to provide a 3D model for stem cell-related genes and proteins expression studies. We observed collaboration between 3D context and laminins in promoting glioma stemness. Depending on the laminin isoform presented, U251 cells cultured on ESPS scaffolds (3D) exhibited increased expression of stemness markers compared to those cultured on tissue culture polystyrene (2D). Our results indicate the influence of 3D (versus 2D) context on integrin expression, specifically, the upregulation of the laminin-binding integrins alpha 6 and beta 4. By a colony forming assay, we showed enhanced clonogenicity of cells grown on ESPS scaffolds in collaboration with laminins 411, 421, 511 and 521. Evaluation of patient glioma databases demonstrated significant enrichment of integrin and ECM pathway networks in tumors of worse prognosis, consistent with our observations. The present results demonstrate how 3D versus 2D context profoundly affects ECM signaling, leading to stemness. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Modeling of 3-D Woven Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Sullivan, Roy M.; Mital, Subodh K.

    2003-01-01

    Three different approaches are being pursued at the NASA Glenn Research Center to predict the nanostructural behavior of three-dimensional woven ceramic matrix composites. These are: a micromechanics-based approach using W-CEMCAN (Woven Ceramic Matrix Composite Analyzer), a laminate analogy method and a structural frame approach (based on the finite element method). All three techniques are applied to predict the thermomechanical properties of a three-dimensional woven angle interlock C/SiC composite. The properties are predicted for room temperature and 1100 C and the predicted properties are compared to measurements. General observations regarding the three approaches for three-dimensional composite modeling are discussed.

  9. Mechanical Properties of 3-D ceramic matrix composites

    SciTech Connect

    Moore, E.H.; Folsom, C.A.; Keller, K.A.; Mah, T.

    1995-12-01

    The mullite-alumina system has been investigated with the goal of fabricating ceramic matrix composites (CMC) for use in turbine engine exhaust components over a range of temperatures from below ambient to 1200{degrees}C. Turbine engine components of interest include flaps and seals, and liners. These CMC are expected to be strong, tough, near-net fabricable and able to retain these properties over their entire range of use.

  10. Hydrogels as extracellular matrix mimics for 3D cell culture.

    PubMed

    Tibbitt, Mark W; Anseth, Kristi S

    2009-07-01

    Methods for culturing mammalian cells ex vivo are increasingly needed to study cell and tissue physiology and to grow replacement tissue for regenerative medicine. Two-dimensional culture has been the paradigm for typical in vitro cell culture; however, it has been demonstrated that cells behave more natively when cultured in three-dimensional environments. Permissive, synthetic hydrogels and promoting, natural hydrogels have become popular as three-dimensional cell culture platforms; yet, both of these systems possess limitations. In this perspective, we discuss the use of both synthetic and natural hydrogels as scaffolds for three-dimensional cell culture as well as synthetic hydrogels that incorporate sophisticated biochemical and mechanical cues as mimics of the native extracellular matrix. Ultimately, advances in synthetic-biologic hydrogel hybrids are needed to provide robust platforms for investigating cell physiology and fabricating tissue outside of the organism. (c) 2009 Wiley Periodicals, Inc.

  11. Local 3D matrix confinement determines division axis through cell shape

    PubMed Central

    He, Lijuan; Chen, Weitong; Wu, Pei-Hsun; Jimenez, Angela; Wong, Bin Sheng; San, Angela; Konstantopoulos, Konstantinos; Wirtz, Denis

    2016-01-01

    How the division axis is determined in mammalian cells embedded in three-dimensional (3D) matrices remains elusive, despite that many types of cells divide in 3D environments. Cells on two-dimensional (2D) substrates typically round up completely to divide. Here, we show that in 3D collagen matrices, mammalian cells such as HT1080 human fibrosarcoma and MDA-MB-231 breast cancer cells exhibit division modes distinct from their Counterparts on 2D substrates, with a markedly higher fraction of cells remaining highly elongated through mitosis in 3D matrices. The long axis of elongated mitotic cells accurately predicts the division axis, independently of matrix density and cell-matrix interactions. This 3D-specific elongated division mode is determined by the local confinement produced by the matrix and the ability of cells to protrude and locally remodel the matrix via β1 integrin. Elongated division is readily recapitulated using collagen-coated microfabricated channels. Cells depleted of β1 integrin still divide in the elongated mode in microchannels, suggesting that 3D confinement is sufficient to induce the elongated cell-division phenotype. PMID:26515603

  12. Local 3D matrix confinement determines division axis through cell shape.

    PubMed

    He, Lijuan; Chen, Weitong; Wu, Pei-Hsun; Jimenez, Angela; Wong, Bin Sheng; San, Angela; Konstantopoulos, Konstantinos; Wirtz, Denis

    2016-02-09

    How the division axis is determined in mammalian cells embedded in three-dimensional (3D) matrices remains elusive, despite that many types of cells divide in 3D environments. Cells on two-dimensional (2D) substrates typically round up completely to divide. Here, we show that in 3D collagen matrices, mammalian cells such as HT1080 human fibrosarcoma and MDA-MB-231 breast cancer cells exhibit division modes distinct from their Counterparts on 2D substrates, with a markedly higher fraction of cells remaining highly elongated through mitosis in 3D matrices. The long axis of elongated mitotic cells accurately predicts the division axis, independently of matrix density and cell-matrix interactions. This 3D-specific elongated division mode is determined by the local confinement produced by the matrix and the ability of cells to protrude and locally remodel the matrix via β1 integrin. Elongated division is readily recapitulated using collagen-coated microfabricated channels. Cells depleted of β1 integrin still divide in the elongated mode in microchannels, suggesting that 3D confinement is sufficient to induce the elongated cell-division phenotype.

  13. Particle image velocimetry on simulated 3D ultrafast ultrasound from pediatric matrix TEE transducers

    NASA Astrophysics Data System (ADS)

    Voorneveld, J. D.; Bera, D.; van der Steen, A. F. W.; de Jong, N.; Bosch, J. G.

    2017-03-01

    Ultrafast 3D transesophageal echocardiographic (TEE) imaging, combined with 3D echo particle image velocimetry (ePIV), would be ideal for tracking the complex blood flow patterns in the heart. We are developing a miniature pediatric matrix TEE transducer that employs micro-beamforming (μBF) and allows high framerate in 3D. In this paper, we assess the feasibility of 3D ePIV with a high frame rate, small aperture transducer and the influence of the micro-beamforming technique. We compare the results of 3D ePIV on simulated images using the μBF transducer and an idealized, fully sampled (FS) matrix transducer. For the two transducers, we have simulated high-framerate imaging of an 8.4mm diameter artery having a known 4D velocity field. The simulations were performed in FieldII. 1000 3D volumes, at a rate of 1000 volumes/sec, were created using a single diverging transmission per volume. The error in the 3D velocity estimation was measured by comparing the ePIV results of both transducers to the ground truth. The results on the simulated volumes show that ePIV can estimate the 4D velocity field of the arterial phantom using these small-aperture transducers suitable for pediatric 3D TEE. The μBF transducer (RMSE 44.0%) achieved comparable ePIV accuracy to that of the FS transducer (RMSE 42.6%).

  14. Fibrin scaffold enhances function of insulin producing cells differentiated from human umbilical cord matrix-derived stem cells.

    PubMed

    Seyedi, Fatemeh; Farsinejad, Alireza; Nematollahi-Mahani, Seyed Noureddin

    2017-04-01

    Tissue engineering is a new strategy which proposed to treat numerous human diseases nowadays. Three dimensional (3D) scaffolds fill the gap between two dimensional cell culture (2D) and animal tissues through mimicking the environmental behaviors surrounding the cells. In this study, hUCMs into insulin producing cells in fibrin scaffold were differentiated compare to conventional culture condition. Differentiation rate was estimated by real time PCR, immunocytochemistry (ICC) and the chemiluminesence (CLIA) and enzyme immunoassay (EIA). Real time PCR's results showed an increasing expression in NKX2.2, PDX1 and INS (producing the hormone insulin) genes in fibrin scaffold. Furthermore ICC analysis exhibited that insulin and pro-insulin proteins were more in fibrin scaffolds. CLIA and EIA on insulin and C peptide secretion indicated that both of groups were sensitive to the glucose challenge test but significant higher response was observed in fibrin scaffold (6.5 fold in 3D, 1.8 fold in 2D culture). It could be concluded that differentiation of hUCM cells into insulin producing cells in fibrin scaffold 3D culture system is much more efficient than 2D conventional culture system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. A fibrin encapsulated liposomes-in-chitosan matrix (FLCM) for delivering water-soluble drugs. Influences of the surface properties of liposomes and the crosslinked fibrin network.

    PubMed

    Chung, Tze-Wen; Yang, Min-Chia; Tsai, Wei-Jean

    2006-03-27

    A depot drug delivery system, fibrin encapsulated liposome-in-chitosan matrix (FLCM), has been developed to deliver a water-soluble drug which is configured by a porous chitosan matrix containing a bovine fibrin network encapsulated different surface properties of liposomes. Quinacrine (QR), a water-soluble, low-molecular weight fluorescent marker, is used as a model drug to evaluate the delivery characteristics of the system. The SEM photographs show that the fibrin network adheres to the surfaces and pores of the chitosan matrix of a FLCM system. The QR release periods of the FLCM are sustained for about four times longer than those of QR encapsulated into the liposomes. However, the QR release periods and profiles of the FLCM are influenced by the surface properties of liposomes. The release of QR from FLCM is sustained for 9 days for neutral liposomes and only 5 days for PEG modified liposomes (PEG-liposome). After crosslinking the fibrin network of the FLCM with 0.5% of glutaldehyde, the release of QR is further sustained for 17 days with good linear profiles (e.g., 13 days) and with 50% of reduced burst release compared with those of without crosslinking, indicating that the stability of the fibrin network plays an important role on QR release of the system. More interestingly, the release periods and profiles of QR of the FLCM system are highly similar to those of Tirofiban, low-molecular weight of a water-soluble clinical cardiovascular drug, although the study has been done by human platelet poor plasma instead of bovine fibrinogen as a source of fibrin network. It suggests that the QR is a suitable model for investigating the drug delivery behaviors for water-soluble, low-molecular weight drugs of the FLCM. In conclusion, with QR as a model drug, FLCM with crosslinked fibrin network can effectively sustain the release of QR for 17 days but the release profiles are influenced by the surface properties of encapsulated liposomes. This study suggests that

  16. Role of dynamin in elongated cell migration in a 3D matrix.

    PubMed

    Lees, Justin G; Gorgani, Nick N; Ammit, Alaina J; McCluskey, Adam; Robinson, Phillip J; O'Neill, Geraldine M

    2015-03-01

    The use of 3-dimensional (3D) collagen gels has yielded new insights into the migratory behaviour of cancer cells. While the large GTPase dynamin has emerged as an important regulator of cancer cell migration and invasion under 2D conditions, its role in 3D migration is unclear. We have used a potent dynamin modulator, a bis-tyrphostin derivative, Ryngo® 1-23, to investigate the role of dynamin in 3D migration in 3 different cell lines. The compound specifically inhibits persistent, elongated 3D migration in U87MG and SMA-560 cells. Treated U87MG cells adopt a rounded morphology that is not due to apoptosis, loss of matrix metalloprotease activity or inhibition of clathrin-mediated endocytosis. Given that Ryngo 1-23 is known to regulate dynamin oligomerisation and actin dynamics at the leading edge, we analysed actin filament distribution. Ryngo 1-23 induced a switch in actin filament organization in 3D cultures resulting in the generation of multiple short actin-rich microspikes. Correlated with the change in actin filament distribution, cells displayed reduced collagen gel contraction. Since acto-myosin force transmission to the extra-cellular matrix underpins persistent, elongated migration, our results suggest that Ryngo 1-23 modulates this process in 3D migration via dynamin-mediated regulation of acto-myosin force transmission to the extra-cellular matrix.

  17. Microrheology and ROCK Signaling of Human Endothelial Cells Embedded in a 3D Matrix

    PubMed Central

    Panorchan, Porntula; Lee, Jerry S. H.; Kole, Thomas P.; Tseng, Yiider; Wirtz, Denis

    2006-01-01

    Cell function is profoundly affected by the geometry of the extracellular environment confining the cell. Whether and how cells plated on a two-dimensional matrix or embedded in a three-dimensional (3D) matrix mechanically sense the dimensionality of their environment is mostly unknown, partly because individual cells in an extended matrix are inaccessible to conventional cell-mechanics probes. Here we develop a functional assay based on multiple particle tracking microrheology coupled with ballistic injection of nanoparticles to measure the local intracellular micromechanical properties of individual cells embedded inside a matrix. With our novel assay, we probe the mechanical properties of the cytoplasm of individual human umbilical vein endothelial cells (HUVECs) embedded in a 3D peptide hydrogel in the presence or absence of vascular endothelial growth factor (VEGF). We found that VEGF treatment, which enhances endothelial migration, increases the compliance and reduces the elasticity of the cytoplasm of HUVECs in a matrix. This VEGF-induced softening response of the cytoplasm is abrogated by specific Rho-kinase (ROCK) inhibition. These results establish combined particle-tracking microrheology and ballistic injection as the first method able to probe the micromechanical properties and mechanical response to agonists and/or drug treatments of individual cells inside a matrix. These results suggest that ROCK plays an essential role in the regulation of the intracellular mechanical response to VEGF of endothelial cells in a 3D matrix. PMID:16891369

  18. Vinculin is required for cell polarization, migration, and extracellular matrix remodeling in 3D collagen.

    PubMed

    Thievessen, Ingo; Fakhri, Nikta; Steinwachs, Julian; Kraus, Viola; McIsaac, R Scott; Gao, Liang; Chen, Bi-Chang; Baird, Michelle A; Davidson, Michael W; Betzig, Eric; Oldenbourg, Rudolf; Waterman, Clare M; Fabry, Ben

    2015-11-01

    Vinculin is filamentous (F)-actin-binding protein enriched in integrin-based adhesions to the extracellular matrix (ECM). Whereas studies in 2-dimensional (2D) tissue culture models have suggested that vinculin negatively regulates cell migration by promoting cytoskeleton-ECM coupling to strengthen and stabilize adhesions, its role in regulating cell migration in more physiologic, 3-dimensional (3D) environments is unclear. To address the role of vinculin in 3D cell migration, we analyzed the morphodynamics, migration, and ECM remodeling of primary murine embryonic fibroblasts (MEFs) with cre/loxP-mediated vinculin gene disruption in 3D collagen I cultures. We found that vinculin promoted 3D cell migration by increasing directional persistence. Vinculin was necessary for persistent cell protrusion, cell elongation, and stable cell orientation in 3D collagen, but was dispensable for lamellipodia formation, suggesting that vinculin-mediated cell adhesion to the ECM is needed to convert actin-based cell protrusion into persistent cell shape change and migration. Consistent with this finding, vinculin was necessary for efficient traction force generation in 3D collagen without affecting myosin II activity and promoted 3D collagen fiber alignment and macroscopical gel contraction. Our results suggest that vinculin promotes directionally persistent cell migration and tension-dependent ECM remodeling in complex 3D environments by increasing cell-ECM adhesion and traction force generation.

  19. Extended gray level co-occurrence matrix computation for 3D image volume

    NASA Astrophysics Data System (ADS)

    Salih, Nurulazirah M.; Dewi, Dyah Ekashanti Octorina

    2017-02-01

    Gray Level Co-occurrence Matrix (GLCM) is one of the main techniques for texture analysis that has been widely used in many applications. Conventional GLCMs usually focus on two-dimensional (2D) image texture analysis only. However, a three-dimensional (3D) image volume requires specific texture analysis computation. In this paper, an extended 2D to 3D GLCM approach based on the concept of multiple 2D plane positions and pixel orientation directions in the 3D environment is proposed. The algorithm was implemented by breaking down the 3D image volume into 2D slices based on five different plane positions (coordinate axes and oblique axes) resulting in 13 independent directions, then calculating the GLCMs. The resulted GLCMs were averaged to obtain normalized values, then the 3D texture features were calculated. A preliminary examination was performed on a 3D image volume (64 x 64 x 64 voxels). Our analysis confirmed that the proposed technique is capable of extracting the 3D texture features from the extended GLCMs approach. It is a simple and comprehensive technique that can contribute to the 3D image analysis.

  20. Cultivation of endothelial progenitor cells on fibrin matrix and layering on dacron/polytetrafluoroethylene vascular grafts.

    PubMed

    Sreerekha, Perumcherry Raman; Krishnan, Lissy K

    2006-04-01

    Completely biological tissue-engineered vascular graft is an upcoming substitute for damaged blood vessel, but its clinical use is currently limited due to poor mechanical strength. Therefore, at present, polymeric small-diameter vascular grafts lined with endothelial cells (ECs) to reduce graft thrombosis may be a more viable option. Successful construction of EC-seeded artificial grafts faces some challenges such as (i) retention of endothelial lining; and (ii) availability of differentiated autologous cells. Biomaterial surfaces that are modified by depositing extracellular matrix (ECM) components may stabilize cells in the lumen against forces of blood flow. Adult stem cells such as endothelial progenitor cells (EPCs) circulate in the blood and they usually attach to the exposed matrix at the injured blood vessel site. Depending on the signaling capabilities of ECM, cells may differentiate into ECs,, and if a similar composition of the matrix is provided in vitro, EPCs isolated from blood might get differentiated and thus autologous cells for tissue engineering may be obtained. In this in vitro study, ECM scaffold consisting of biomolecules such as fibrin, fibronectin, and gelatin along with growth factors is found to have supported differentiation of EPC into EC. Further, the ECM precoated on Dacron and polytetrafluoroethylene is found to have supported the formation of EC monolayer that synthesized nitric oxide, and resisted shear stress. Thus, biomimetic fibrin composite is found to be suitable not only to seed cells on currently available artificial grafts but also to obtain differentiated EC from EPC.

  1. 3D printed nanocomposite matrix for the study of breast cancer bone metastasis.

    PubMed

    Zhu, Wei; Holmes, Benjamin; Glazer, Robert I; Zhang, Lijie Grace

    2016-01-01

    Bone is one of the most common metastatic sites of breast cancer, but the underlying mechanisms remain unclear, in part due to an absence of advanced platforms for cancer culture and study that mimic the bone microenvironment. In the present study, we integrated a novel stereolithography-based 3D printer and a unique 3D printed nano-ink consisting of hydroxyapatite nanoparticles suspended in hydrogel to create a biomimetic bone-specific environment for evaluating breast cancer bone invasion. Breast cancer cells cultured in a geometrically optimized matrix exhibited spheroid morphology and migratory characteristics. Co-culture of tumor cells with bone marrow mesenchymal stem cells increased the formation of spheroid clusters. The 3D matrix also allowed for higher drug resistance of breast cancer cells than 2D culture. These results validate that our 3D bone matrix can mimic tumor bone microenvironments, suggesting that it can serve as a tool for studying metastasis and assessing drug sensitivity. From the Clinical Editor: Cancer remains a major cause of mortality for patients in the clinical setting. For breast cancer, bone is one of the most common metastatic sites. In this intriguing article, the authors developed a bone-like environment using 3D printing technology to investigate the underlying biology of bone metastasis. Their results would also allow a new model for other researchers who work on cancer to use. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. A cell-instructive hydrogel to regulate malignancy of 3D tumor spheroids with matrix rigidity.

    PubMed

    Liang, Youyun; Jeong, Jaehyun; DeVolder, Ross J; Cha, Chaenyung; Wang, Fei; Tong, Yen Wah; Kong, Hyunjoon

    2011-12-01

    Three dimensional (3D) tumor spheroid models are becoming important biomedical tools for both fundamental and applied cancer studies, but current models do not account for different levels of cancer malignancy. Several studies have reported that the mechanical rigidity of a hydrogel plays a significant role in regulating the phenotypes of cancer cells adhered to the gel surface. This finding suggests that matrix rigidity should also modulate the malignancy of 3D tumor spheroids. However, the role of matrix stiffness is often confounded by concurrent changes in 3D matrix permeability. This study reports an advanced strategy to assemble 3D liver tumor spheroids with controlled intercellular organization, phenotypes, and angiogenic activities using hydrogels with controlled stiffness and minimal differences in molecular diffusivity. The elastic moduli of cell-encapsulated collagen gels were increased by stiffening interconnected collagen fibers with varied amounts of poly(ethylene glycol) di-(succinic acid N-hydroxysuccinimidyl ester). Interestingly, hepatocellular carcinoma cells encapsulated in a fat-like, softer hydrogel formed malignant cancer spheroids, while cells cultured in a liver-like, stiffer gel formed compact hepatoids with suppressed malignancy. Overall, both the hydrogel and the 3D tumor spheroids developed in this study will be greatly useful to better understand and regulate the emergent behaviors of various cancer cells. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Screening for Stromal and Matrix Effects in 3D Microenvironments of Breast Cancer Cells

    NASA Astrophysics Data System (ADS)

    Montanez-Sauri, Sara I.

    Breast cancer progression ensures through the acquisition of genetic mutations, the uncontrollable growth of cells, and their progression to invasion. Studies have shown that the surrounding three-dimensional (3D) microenvironment can also influence breast cancer cell progression by controlling the morphology, differentiation, proliferation, and migration of cells. However, most of the currently available in vitro screening platforms are based on the two-dimensional (2D) culture of cells, and do not provide cells with the complex 3D microenvironment that exists in vivo. Therefore, there is a need for more biologically relevant in vitro platforms to help decipher the complexity of the microenvironment and its influence in breast cancer. In this dissertation we present an automated microfluidic platform that allows to efficiently screen for the effect of multiple matrix and stromal microenvironment in 3D cultures of breast cancer cells. Several extracellular matrix (ECM) compositions and stromal cells are included in the 3D microenvironments to examine their influence on breast cancer cell behavior. The screening results suggest that collagen gels with fibronectin might be influencing paracrine signals between breast cancer cells and stromal cells. The ability of the platform to culture and treat cells in 3D microenvironments offers a powerful screening tool for the identification of compounds and interactions using more in vivo-like 3D microenvironments. The identification of these mechanisms will increase our current understanding of breast cancer, and will aid in the identification of potential therapeutics.

  4. Endodontic management of open apex using MTA and platelet – rich fibrin membrane barrier: A newer matrix concept

    PubMed Central

    Chaudhry, Sarika; Talwar, Sangeeta; Verma, Mahesh

    2013-01-01

    Objectives: Endodontic management of open apex using MTA and platelet – rich fibrin membrane as an apical matrix barrier. Study design: An immature tooth with pulpal necrosis and periapical pathology imposes a great difficulty to the endodontist. Endodontic treatment options for such teeth consist of conventional apexification procedure with and without apical barriers. This article demonstrates the use of an apical matrix barrier in form of a platelet rich fibrin membrane for stabilization of MTA in root end apexification procedure. PRF is an autologous fibrin matrix containing a large quantity of platelet and leukocyte cytokines, which enhance healing by release of growth factors. These case reports present apexification and successful healing with combined use of MTA and PRF membrane as an apical barrier Results: PRF membrane can serve as an efficient apical matrix for condensation of MTA. Combination of PRF membrane and MTA is an effective method for management of difficult cases of open apex. PRF is a strong fibrin membrane enriched with platelet and growth factors that accelerate periapical healing. Key words:Apexification, apical barrier, platelet rich fibrin (PRF), mineral trioxide (MTA). PMID:24455097

  5. Quantitative analysis of 3D extracellular matrix remodelling by pancreatic stellate cells

    PubMed Central

    Robinson, Benjamin K.; Cortes, Ernesto; Rice, Alistair J.; Sarper, Muge

    2016-01-01

    ABSTRACT Extracellular matrix (ECM) remodelling is integral to numerous physiological and pathological processes in biology, such as embryogenesis, wound healing, fibrosis and cancer. Until recently, most cellular studies have been conducted on 2D environments where mechanical cues significantly differ from physiologically relevant 3D environments, impacting cellular behaviour and masking the interpretation of cellular function in health and disease. We present an integrated methodology where cell-ECM interactions can be investigated in 3D environments via ECM remodelling. Monitoring and quantification of collagen-I structure in remodelled matrices, through designated algorithms, show that 3D matrices can be used to correlate remodelling with increased ECM stiffness observed in fibrosis. Pancreatic stellate cells (PSCs) are the key effectors of the stromal fibrosis associated to pancreatic cancer. We use PSCs to implement our methodology and demonstrate that PSC matrix remodelling capabilities depend on their contractile machinery and β1 integrin-mediated cell-ECM attachment. PMID:27170254

  6. Generation of compartmentalized pressure by a nuclear piston governs cell motility in a 3D matrix.

    PubMed

    Petrie, Ryan J; Koo, Hyun; Yamada, Kenneth M

    2014-08-29

    Cells use actomyosin contractility to move through three-dimensional (3D) extracellular matrices. Contractility affects the type of protrusions cells use to migrate in 3D, but the mechanisms are unclear. In this work, we found that contractility generated high-pressure lobopodial protrusions in human cells migrating in a 3D matrix. In these cells, the nucleus physically divided the cytoplasm into forward and rear compartments. Actomyosin contractility with the nucleoskeleton-intermediate filament linker protein nesprin-3 pulled the nucleus forward and pressurized the front of the cell. Reducing expression of nesprin-3 decreased and equalized the intracellular pressure. Thus, the nucleus can act as a piston that physically compartmentalizes the cytoplasm and increases the hydrostatic pressure between the nucleus and the leading edge of the cell to drive lamellipodia-independent 3D cell migration. Copyright © 2014, American Association for the Advancement of Science.

  7. Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions.

    PubMed

    Doyle, Andrew D; Carvajal, Nicole; Jin, Albert; Matsumoto, Kazue; Yamada, Kenneth M

    2015-11-09

    The physical properties of two-dimensional (2D) extracellular matrices (ECMs) modulate cell adhesion dynamics and motility, but little is known about the roles of local microenvironmental differences in three-dimensional (3D) ECMs. Here we generate 3D collagen gels of varying matrix microarchitectures to characterize their regulation of 3D adhesion dynamics and cell migration. ECMs containing bundled fibrils demonstrate enhanced local adhesion-scale stiffness and increased adhesion stability through balanced ECM/adhesion coupling, whereas highly pliable reticular matrices promote adhesion retraction. 3D adhesion dynamics are locally regulated by ECM rigidity together with integrin/ECM association and myosin II contractility. Unlike 2D migration, abrogating contractility stalls 3D migration regardless of ECM pore size. We find force is not required for clustering of activated integrins on 3D native collagen fibrils. We propose that efficient 3D migration requires local balancing of contractility with ECM stiffness to stabilize adhesions, which facilitates the detachment of activated integrins from ECM fibrils.

  8. Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions

    NASA Astrophysics Data System (ADS)

    Doyle, Andrew D.; Carvajal, Nicole; Jin, Albert; Matsumoto, Kazue; Yamada, Kenneth M.

    2015-11-01

    The physical properties of two-dimensional (2D) extracellular matrices (ECMs) modulate cell adhesion dynamics and motility, but little is known about the roles of local microenvironmental differences in three-dimensional (3D) ECMs. Here we generate 3D collagen gels of varying matrix microarchitectures to characterize their regulation of 3D adhesion dynamics and cell migration. ECMs containing bundled fibrils demonstrate enhanced local adhesion-scale stiffness and increased adhesion stability through balanced ECM/adhesion coupling, whereas highly pliable reticular matrices promote adhesion retraction. 3D adhesion dynamics are locally regulated by ECM rigidity together with integrin/ECM association and myosin II contractility. Unlike 2D migration, abrogating contractility stalls 3D migration regardless of ECM pore size. We find force is not required for clustering of activated integrins on 3D native collagen fibrils. We propose that efficient 3D migration requires local balancing of contractility with ECM stiffness to stabilize adhesions, which facilitates the detachment of activated integrins from ECM fibrils.

  9. Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions

    PubMed Central

    Doyle, Andrew D.; Carvajal, Nicole; Jin, Albert; Matsumoto, Kazue; Yamada, Kenneth M.

    2015-01-01

    The physical properties of two-dimensional (2D) extracellular matrices (ECMs) modulate cell adhesion dynamics and motility, but little is known about the roles of local microenvironmental differences in three-dimensional (3D) ECMs. Here we generate 3D collagen gels of varying matrix microarchitectures to characterize their regulation of 3D adhesion dynamics and cell migration. ECMs containing bundled fibrils demonstrate enhanced local adhesion-scale stiffness and increased adhesion stability through balanced ECM/adhesion coupling, whereas highly pliable reticular matrices promote adhesion retraction. 3D adhesion dynamics are locally regulated by ECM rigidity together with integrin/ECM association and myosin II contractility. Unlike 2D migration, abrogating contractility stalls 3D migration regardless of ECM pore size. We find force is not required for clustering of activated integrins on 3D native collagen fibrils. We propose that efficient 3D migration requires local balancing of contractility with ECM stiffness to stabilize adhesions, which facilitates the detachment of activated integrins from ECM fibrils. PMID:26548801

  10. Evaluation of bone matrix gelatin/fibrin glue and chitosan/gelatin composite scaffolds for cartilage tissue engineering.

    PubMed

    Wang, Z H; Zhang, J; Zhang, Q; Gao, Y; Yan, J; Zhao, X Y; Yang, Y Y; Kong, D M; Zhao, J; Shi, Y X; Li, X L

    2016-07-15

    This study was designed to evaluate bone matrix gelatin (BMG)/fibrin glue and chitosan/gelatin composite scaffolds for cartilage tissue engineering. Chondrocytes were isolated from costal cartilage of Sprague-Dawley rats and seeded on BMG/fibrin glue or chitosan/gelatin composite scaffolds. After different in vitro culture durations, the scaffolds were subjected to hematoxylin and eosin, Masson's trichrome, and toluidine blue staining, anti-collagen II and anti-aggrecan immunohistochemistry, and scanning electronic microscopy (SEM) analysis. After 2 weeks of culture, chondrocytes were distributed evenly on the surfaces of both scaffolds. Cell numbers and the presence of extracellular matrix components were markedly increased after 8 weeks of culture, and to a greater extent on the chitosan/gelatin scaffold. The BMG/fibrin glue scaffold showed signs of degradation after 8 weeks. Immunofluorescence analysis confirmed higher levels of collagen II and aggrecan using the chitosan/gelatin scaffold. SEM revealed that the majority of cells on the surface of the BMG/fibrin glue scaffold demonstrated a round morphology, while those in the chitosan/gelatin group had a spindle-like shape, with pseudopodia. Chitosan/gelatin scaffolds appear to be superior to BMG/ fibrin glue constructs in supporting chondrocyte attachment, proliferation, and biosynthesis of cartilaginous matrix components.

  11. 3D collagen type I matrix inhibits the antimigratory effect of doxorubicin

    PubMed Central

    2010-01-01

    Background The cell microenvironment, especially extracellular matrix proteins, plays an important role in tumor cell response to chemotherapeutic drugs. The present study was designed to investigate whether this microenvironment can influence the antimigratory effect of an anthracycline drug, doxorubicin, when tumor cells are grown in a matrix of type I collagen, a three-dimensional (3D) context which simulates a natural microenvironment. Methods To this purpose, we studied the migratory parameters, the integrin expression, and the activation state of focal adhesion kinase (FAK) and GTPase RhoA involved in the formation of focal adhesions and cell movement. These parameters were evaluated at non toxic concentrations which did not affect HT1080 cell proliferation. Results We show that while doxorubicin decreased cell migration properties by 70% in conventional two-dimensional (2D) culture, this effect was completely abolished in a 3D one. Regarding the impact of doxorubicin on the focal adhesion complexes, unlike in 2D systems, the data indicated that the drug neither affected β1 integrin expression nor the state of phosphorylation of FAK and RhoA. Conclusion This study suggests the lack of antiinvasive effect of doxorubicin in a 3D environment which is generally considered to better mimic the phenotypic behaviour of cells in vivo. Consistent with the previously shown resistance to the cytotoxic effect in a 3D context, our results highlight the importance of the matrix configuration on the tumor cell response to antiinvasive drugs. PMID:20707917

  12. Carbon nanotube based 3-D matrix for enabling three-dimensional nano-magneto-electronics [corrected].

    PubMed

    Hong, Jeongmin; Stefanescu, Eugenia; Liang, Ping; Joshi, Nikhil; Xue, Song; Litvinov, Dmitri; Khizroev, Sakhrat

    2012-01-01

    This letter describes the use of vertically aligned carbon nanotubes (CNT)-based arrays with estimated 2-nm thick cobalt (Co) nanoparticles deposited inside individual tubes to unravel the possibility of using the unique templates for ultra-high-density low-energy 3-D nano-magneto-electronic devices. The presence of oriented 2-nm thick Co layers within individual nanotubes in the CNT-based 3-D matrix is confirmed through VSM measurements as well as an energy-dispersive X-ray spectroscopy (EDS).

  13. Tension-Compression Fatigue Behavior of 2D and 3D Polymer Matrix Composites at Elevated Temperature

    DTIC Science & Technology

    2015-09-21

    TENSION-COMPRESSION FATIGUE BEHAVIOR OF 2D AND 3D POLYMER MATRIX COMPOSITES AT ELEVATED...BEHAVIOR OF 2D AND 3D POLYMER MATRIX COMPOSITES AT ELEVATED TEMPERATURE THESIS Presented to the Faculty Department of Aeronautics and Astronautics...BEHAVIOR OF 2D AND 3D POLYMER MATRIX COMPOSITES AT ELEVATED TEMPERATURE Saleh A. Alnatifat, B.S.M.E Captain, RSAF Committee Membership

  14. Comparative mechanisms of cancer cell migration through 3D matrix and physiological microtracks.

    PubMed

    Carey, Shawn P; Rahman, Aniqua; Kraning-Rush, Casey M; Romero, Bethsabe; Somasegar, Sahana; Torre, Olivia M; Williams, Rebecca M; Reinhart-King, Cynthia A

    2015-03-15

    Tumor cell invasion through the stromal extracellular matrix (ECM) is a key feature of cancer metastasis, and understanding the cellular mechanisms of invasive migration is critical to the development of effective diagnostic and therapeutic strategies. Since cancer cell migration is highly adaptable to physiochemical properties of the ECM, it is critical to define these migration mechanisms in a context-specific manner. Although extensive work has characterized cancer cell migration in two- and three-dimensional (3D) matrix environments, the migration program employed by cells to move through native and cell-derived microtracks within the stromal ECM remains unclear. We previously reported the development of an in vitro model of patterned type I collagen microtracks that enable matrix metalloproteinase-independent microtrack migration. Here we show that collagen microtracks closely resemble channel-like gaps in native mammary stroma ECM and examine the extracellular and intracellular mechanisms underlying microtrack migration. Cell-matrix mechanocoupling, while critical for migration through 3D matrix, is not necessary for microtrack migration. Instead, cytoskeletal dynamics, including actin polymerization, cortical tension, and microtubule turnover, enable persistent, polarized migration through physiological microtracks. These results indicate that tumor cells employ context-specific mechanisms to migrate and suggest that selective targeting of cytoskeletal dynamics, but not adhesion, proteolysis, or cell traction forces, may effectively inhibit cancer cell migration through preformed matrix microtracks within the tumor stroma.

  15. Longitudinal Measurement of Extracellular Matrix Rigidity in 3D Tumor Models Using Particle-tracking Microrheology

    PubMed Central

    El-Hamidi, Hamid; Celli, Jonathan P.

    2014-01-01

    The mechanical microenvironment has been shown to act as a crucial regulator of tumor growth behavior and signaling, which is itself remodeled and modified as part of a set of complex, two-way mechanosensitive interactions. While the development of biologically-relevant 3D tumor models have facilitated mechanistic studies on the impact of matrix rheology on tumor growth, the inverse problem of mapping changes in the mechanical environment induced by tumors remains challenging. Here, we describe the implementation of particle-tracking microrheology (PTM) in conjunction with 3D models of pancreatic cancer as part of a robust and viable approach for longitudinally monitoring physical changes in the tumor microenvironment, in situ. The methodology described here integrates a system of preparing in vitro 3D models embedded in a model extracellular matrix (ECM) scaffold of Type I collagen with fluorescently labeled probes uniformly distributed for position- and time-dependent microrheology measurements throughout the specimen. In vitro tumors are plated and probed in parallel conditions using multiwell imaging plates. Drawing on established methods, videos of tracer probe movements are transformed via the Generalized Stokes Einstein Relation (GSER) to report the complex frequency-dependent viscoelastic shear modulus, G*(ω). Because this approach is imaging-based, mechanical characterization is also mapped onto large transmitted-light spatial fields to simultaneously report qualitative changes in 3D tumor size and phenotype. Representative results showing contrasting mechanical response in sub-regions associated with localized invasion-induced matrix degradation as well as system calibration, validation data are presented. Undesirable outcomes from common experimental errors and troubleshooting of these issues are also presented. The 96-well 3D culture plating format implemented in this protocol is conducive to correlation of microrheology measurements with therapeutic

  16. Implementation of parallel matrix decomposition for NIKE3D on the KSR1 system

    SciTech Connect

    Su, Philip S.; Fulton, R.E.; Zacharia, T.

    1995-06-01

    New massively parallel computer architecture has revolutionized the design of computer algorithms and promises to have significant influence on algorithms for engineering computations. Realistic engineering problems using finite element analysis typically imply excessively large computational requirements. Parallel supercomputers that have the potential for significantly increasing calculation speeds can meet these computational requirements. This report explores the potential for the parallel Cholesky (U{sup T}DU) matrix decomposition algorithm on NIKE3D through actual computations. The examples of two- and three-dimensional nonlinear dynamic finite element problems are presented on the Kendall Square Research (KSR1) multiprocessor system, with 64 processors, at Oak Ridge National Laboratory. The numerical results indicate that the parallel Cholesky (U{sup T}DU) matrix decomposition algorithm is attractive for NIKE3D under multi-processor system environments.

  17. Measurement Matrix Optimization and Mismatch Problem Compensation for DLSLA 3-D SAR Cross-Track Reconstruction.

    PubMed

    Bao, Qian; Jiang, Chenglong; Lin, Yun; Tan, Weixian; Wang, Zhirui; Hong, Wen

    2016-08-22

    With a short linear array configured in the cross-track direction, downward looking sparse linear array three-dimensional synthetic aperture radar (DLSLA 3-D SAR) can obtain the 3-D image of an imaging scene. To improve the cross-track resolution, sparse recovery methods have been investigated in recent years. In the compressive sensing (CS) framework, the reconstruction performance depends on the property of measurement matrix. This paper concerns the technique to optimize the measurement matrix and deal with the mismatch problem of measurement matrix caused by the off-grid scatterers. In the model of cross-track reconstruction, the measurement matrix is mainly affected by the configuration of antenna phase centers (APC), thus, two mutual coherence based criteria are proposed to optimize the configuration of APCs. On the other hand, to compensate the mismatch problem of the measurement matrix, the sparse Bayesian inference based method is introduced into the cross-track reconstruction by jointly estimate the scatterers and the off-grid error. Experiments demonstrate the performance of the proposed APCs' configuration schemes and the proposed cross-track reconstruction method.

  18. Measurement Matrix Optimization and Mismatch Problem Compensation for DLSLA 3-D SAR Cross-Track Reconstruction

    PubMed Central

    Bao, Qian; Jiang, Chenglong; Lin, Yun; Tan, Weixian; Wang, Zhirui; Hong, Wen

    2016-01-01

    With a short linear array configured in the cross-track direction, downward looking sparse linear array three-dimensional synthetic aperture radar (DLSLA 3-D SAR) can obtain the 3-D image of an imaging scene. To improve the cross-track resolution, sparse recovery methods have been investigated in recent years. In the compressive sensing (CS) framework, the reconstruction performance depends on the property of measurement matrix. This paper concerns the technique to optimize the measurement matrix and deal with the mismatch problem of measurement matrix caused by the off-grid scatterers. In the model of cross-track reconstruction, the measurement matrix is mainly affected by the configuration of antenna phase centers (APC), thus, two mutual coherence based criteria are proposed to optimize the configuration of APCs. On the other hand, to compensate the mismatch problem of the measurement matrix, the sparse Bayesian inference based method is introduced into the cross-track reconstruction by jointly estimate the scatterers and the off-grid error. Experiments demonstrate the performance of the proposed APCs’ configuration schemes and the proposed cross-track reconstruction method. PMID:27556471

  19. A 3D printed nano bone matrix for characterization of breast cancer cell and osteoblast interactions

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Castro, Nathan J.; Cui, Haitao; Zhou, Xuan; Boualam, Benchaa; McGrane, Robert; Glazer, Robert I.; Zhang, Lijie Grace

    2016-08-01

    Bone metastasis is one of the most prevalent complications of late-stage breast cancer, in which the native bone matrix components, including osteoblasts, are intimately involved in tumor progression. The development of a successful in vitro model would greatly facilitate understanding the underlying mechanism of breast cancer bone invasion as well as provide a tool for effective discovery of novel therapeutic strategies. In the current study, we fabricated a series of in vitro bone matrices composed of a polyethylene glycol hydrogel and nanocrystalline hydroxyapatite of varying concentrations to mimic the native bone microenvironment for the investigation of breast cancer bone metastasis. A stereolithography-based three-dimensional (3D) printer was used to fabricate the bone matrices with precisely controlled architecture. The interaction between breast cancer cells and osteoblasts was investigated in the optimized bone matrix. Using a Transwell® system to separate the two cell lines, breast cancer cells inhibited osteoblast proliferation, while osteoblasts stimulated breast cancer cell growth, whereas, both cell lines increased IL-8 secretion. Breast cancer cells co-cultured with osteoblasts within the 3D bone matrix formed multi-cellular spheroids in comparison to two-dimensional monolayers. These findings validate the use of our 3D printed bone matrices as an in vitro metastasis model, and highlights their potential for investigating breast cancer bone metastasis.

  20. Study on the Efficacy of Platelet-rich Fibrin Matrix in Hair Follicular Unit Transplantation in Androgenetic Alopecia Patients

    PubMed Central

    Mahapatra, Sandeep; Kumar, Dhruva; Subramanian, Vignesh; Chakrabarti, Swarup K.

    2016-01-01

    Objective: Hair loss is a significant problem worldwide. The most common cause of hair loss in men is male androgenetic alopecia, male pattern baldness, which is primarily due to the presence of nonfunctional or dead hair follicles in the scalp. Hair follicular unit transplantation has been a widely used technique to transplant hair follicles into bald areas. Although follicular unit transplantation generally gives satisfactory hair transplantation, efforts have been made to further increase the efficacy of follicular unit transplantation in hair regeneration. The crucial discovery of platelet-derived growth factors has resulted in the development of novel autologous therapeutic methods. Platelet-rich fibrin matrix represents a revolutionary step in the platelet gel therapeutic concept. This technique is fast and involves minimal in vitro manipulations. In this paper, the authors studied the efficacy of platelet-rich fibrin matrix in conjunction with follicular unit transplantation for regeneration of new hair in bald areas in male androgenetic alopecia patients. Design: Ten male subjects between 18 and 50 years of age with Norwood Alopecia from Grade 4 to 6 were chosen for the study. Setting: The study was performed at Derma Solutions clinic, Bengaluru, Karnataka, India. Participants: Patients with thyroid disorders, bleeding disorders, or other co-existing morbidities were excluded. Results: The number of hair follicles began to increase progressively after platelet-rich fibrin matrix treatment was performed on the right side of the scalp and the effect was very distinct after six months of platelet-rich fibrin matrix treatment. Conclusion: This study clearly indicates that platelet-rich fibrin matrix plays a key role in hair regeneration using follicular unit transplantation techniques. Further studies are needed to determine how platelet-rich fibrin matrix helps improve hair retention and regeneration. Additionally, it would be interesting to know how long the

  1. A 3D cell culture system: separation distance between INS-1 cell and endothelial cell monolayers co-cultured in fibrin influences INS-1 cells insulin secretion.

    PubMed

    Sabra, Georges; Vermette, Patrick

    2013-02-01

    The aim of this study was to develop an in vitro cell culture system allowing studying the effect of separation distance between monolayers of rat insulinoma cells (INS-1) and human umbilical vein endothelial cells (HUVEC) co-cultured in fibrin over INS-1 cell insulin secretion. For this purpose, a three-dimensional (3D) cell culture chamber was designed, built using micro-fabrication techniques and validated. The co-culture was successfully carried out and the effect on INS-1 cell insulin secretion was investigated. After 48 and 72 h, INS-1 cells co-cultured with HUVEC separated by a distance of 100 µm revealed enhanced insulin secretion compared to INS-1 cells cultured alone or co-cultured with HUVEC monolayers separated by a distance of 200 µm. These results illustrate the importance of the separation distance between two cell niches for cell culture design and the possibility to further enhance the endocrine function of beta cells when this factor is considered. Copyright © 2012 Wiley Periodicals, Inc.

  2. Effects of extracellular fiber architecture on cell membrane shear stress in a 3D fibrous matrix.

    PubMed

    Pedersen, John A; Boschetti, Federica; Swartz, Melody A

    2007-01-01

    Interstitial fluid flow has been shown to affect the organization and behavior of cells in 3D environments in vivo and in vitro, yet the forces driving such responses are not clear. Due to the complex architecture of the extracellular matrix (ECM) and the difficulty of measuring fluid flow near cells embedded in it, the levels of shear stress experienced by cells in this environment are typically estimated using bulk-averaged matrix parameters such as hydraulic permeability. While this is useful for estimating average stresses, it cannot yield insight into how local matrix fiber architecture-which is cell-controlled in the immediate pericellular environment-affects the local stresses imposed on the cell surface. To address this, we used computational fluid dynamics to study flow through an idealized mesh constructed of a cubic lattice of fibers simulating a typical in vitro collagen gel. We found that, in such high porosity matrices, the fibers strongly affect the flow fields near the cell, with peak shear stresses up to five times higher than those predicted by the Brinkman equation. We also found that minor remodeling of the fibers near the cell surface had major effects on the shear stress profile on the cell. These findings demonstrate the importance of fiber architecture to the fluid forces on a cell embedded in a 3D matrix, and also show how small modifications in the local ECM can lead to large changes in the mechanical environment of the cell.

  3. Ornamenting 3D printed scaffolds with cell-laid extracellular matrix for bone tissue regeneration.

    PubMed

    Pati, Falguni; Song, Tae-Ha; Rijal, Girdhari; Jang, Jinah; Kim, Sung Won; Cho, Dong-Woo

    2015-01-01

    3D printing technique is the most sophisticated technique to produce scaffolds with tailorable physical properties. But, these scaffolds often suffer from limited biological functionality as they are typically made from synthetic materials. Cell-laid mineralized ECM was shown to be potential for improving the cellular responses and drive osteogenesis of stem cells. Here, we intend to improve the biological functionality of 3D-printed synthetic scaffolds by ornamenting them with cell-laid mineralized extracellular matrix (ECM) that mimics a bony microenvironment. We developed bone graft substitutes by using 3D printed scaffolds made from a composite of polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and β-tricalcium phosphate (β-TCP) and mineralized ECM laid by human nasal inferior turbinate tissue-derived mesenchymal stromal cells (hTMSCs). A rotary flask bioreactor was used to culture hTMSCs on the scaffolds to foster formation of mineralized ECM. A freeze/thaw cycle in hypotonic buffer was used to efficiently decellularize (97% DNA reduction) the ECM-ornamented scaffolds while preserving its main organic and inorganic components. The ECM-ornamented 3D printed scaffolds supported osteoblastic differentiation of newly-seeded hTMSCs by upregulating four typical osteoblastic genes (4-fold higher RUNX2; 3-fold higher ALP; 4-fold higher osteocalcin; and 4-fold higher osteopontin) and increasing calcium deposition compared to bare 3D printed scaffolds. In vivo, in ectopic and orthotopic models in rats, ECM-ornamented scaffolds induced greater bone formation than that of bare scaffolds. These results suggest a valuable method to produce ECM-ornamented 3D printed scaffolds as off-the-shelf bone graft substitutes that combine tunable physical properties with physiological presentation of biological signals.

  4. Quantitative analysis of 3D extracellular matrix remodelling by pancreatic stellate cells.

    PubMed

    Robinson, Benjamin K; Cortes, Ernesto; Rice, Alistair J; Sarper, Muge; Del Río Hernández, Armando

    2016-06-15

    Extracellular matrix (ECM) remodelling is integral to numerous physiological and pathological processes in biology, such as embryogenesis, wound healing, fibrosis and cancer. Until recently, most cellular studies have been conducted on 2D environments where mechanical cues significantly differ from physiologically relevant 3D environments, impacting cellular behaviour and masking the interpretation of cellular function in health and disease. We present an integrated methodology where cell-ECM interactions can be investigated in 3D environments via ECM remodelling. Monitoring and quantification of collagen-I structure in remodelled matrices, through designated algorithms, show that 3D matrices can be used to correlate remodelling with increased ECM stiffness observed in fibrosis. Pancreatic stellate cells (PSCs) are the key effectors of the stromal fibrosis associated to pancreatic cancer. We use PSCs to implement our methodology and demonstrate that PSC matrix remodelling capabilities depend on their contractile machinery and β1 integrin-mediated cell-ECM attachment. © 2016. Published by The Company of Biologists Ltd.

  5. Human dental pulp stem cells produce mineralized matrix in 2D and 3D cultures

    PubMed Central

    Riccio, M.; Resca, E.; Maraldi, T.; Pisciotta, A.; Ferrari, A.; Bruzzesi, G.; De Pol, A.

    2010-01-01

    The aim of this study was to characterize the in vitro osteogenic differentiation of dental pulp stem cells (DPSCs) in 2D cultures and 3D biomaterials. DPSCs, separated from dental pulp by enzymatic digestion, and isolated by magnetic cell sorting were differentiated toward osteogenic lineage on 2D surface by using an osteogenic medium. During differentiation process, DPSCs express specific bone proteins like Runx-2, Osx, OPN and OCN with a sequential expression, analogous to those occurring during osteoblast differentiation, and produce extracellular calcium deposits. In order to differentiate cells in a 3D space that mimes the physiological environment, DPSCs were cultured in two distinct bioscaffolds, Matrigel™ and Collagen sponge. With the addition of a third dimension, osteogenic differentiation and mineralized extracellular matrix production significantly improved. In particular, in Matrigel™ DPSCs differentiated with osteoblast/osteocyte characteristics and connected by gap junction, and therefore formed calcified nodules with a 3D intercellular network. Furthermore, DPSCs differentiated in collagen sponge actively secrete human type I collagen micro-fibrils and form calcified matrix containing trabecular-like structures. These neo-formed DPSCs-scaffold devices may be used in regenerative surgical applications in order to resolve pathologies and traumas characterized by critical size bone defects. PMID:21263745

  6. Precise stacking of decellularized extracellular matrix based 3D cell-laden constructs by a 3D cell printing system equipped with heating modules.

    PubMed

    Ahn, Geunseon; Min, Kyung-Hyun; Kim, Changhwan; Lee, Jeong-Seok; Kang, Donggu; Won, Joo-Yun; Cho, Dong-Woo; Kim, Jun-Young; Jin, Songwan; Yun, Won-Soo; Shim, Jin-Hyung

    2017-08-17

    Three-dimensional (3D) cell printing systems allow the controlled and precise deposition of multiple cells in 3D constructs. Hydrogel materials have been used extensively as printable bioinks owing to their ability to safely encapsulate living cells. However, hydrogel-based bioinks have drawbacks for cell printing, e.g. inappropriate crosslinking and liquid-like rheological properties, which hinder precise 3D shaping. Therefore, in this study, we investigated the influence of various factors (e.g. bioink concentration, viscosity, and extent of crosslinking) on cell printing and established a new 3D cell printing system equipped with heating modules for the precise stacking of decellularized extracellular matrix (dECM)-based 3D cell-laden constructs. Because the pH-adjusted bioink isolated from native tissue is safely gelled at 37 °C, our heating system facilitated the precise stacking of dECM bioinks by enabling simultaneous gelation during printing. We observed greater printability compared with that of a non-heating system. These results were confirmed by mechanical testing and 3D construct stacking analyses. We also confirmed that our heating system did not elicit negative effects, such as cell death, in the printed cells. Conclusively, these results hold promise for the application of 3D bioprinting to tissue engineering and drug development.

  7. Podosomes in space: macrophage migration and matrix degradation in 2D and 3D settings.

    PubMed

    Wiesner, Christiane; Le-Cabec, Véronique; El Azzouzi, Karim; Maridonneau-Parini, Isabelle; Linder, Stefan

    2014-01-01

    Migration of macrophages is a key process for a variety of physiological functions, such as pathogen clearance or tissue homeostasis. However, it can also be part of pathological scenarios, as in the case of tumor-associated macrophages. This review presents an overview of the different migration modes macrophages can adopt, depending on the physical and chemical properties of specific environments, and the constraints they impose upon cells. We discuss the importance of these environmental and also of cellular parameters, as well as their relative impact on macrophage migration and on the formation of matrix-lytic podosomes in 2D and 3D. Moreover, we present an overview of routinely used and also newly developed assays for the study of macrophage migration in both 2D and 3D contexts, their respective advantages and limitations, and also their potential to reliably mimic in vivo situations.

  8. Binding of Matrix Metalloproteinase Inhibitors to Extracellular Matrix: 3D-QSAR Analysis

    PubMed Central

    Zhang, Yufen; Lukacova, Viera; Bartus, Vladimir; Nie, Xiaoping; Sun, Guorong; Manivannan, Ethirajan; Ghorpade, Sandeep R.; Jin, Xiaomin; Manyem, Shankar; Sibi, Mukund P.; Cook, Gregory R.; Balaz, Stefan

    2008-01-01

    Binding to the extracellular matrix (ECM), one of the most abundant human protein complexes, significantly affects drug disposition. Specifically, the interactions with ECM determine the free concentrations of small molecules acting in tissues, including signaling peptides, inhibitors of tissue remodeling enzymes such as matrix metalloproteinases (MMPs), and other drug candidates. The nature of ECM binding was elucidated for 63 MMP inhibitors, for which the association constants to an ECM mimic were reported here. The data did not correlate with lipophilicity as a common determinant of structure-nonspecific, orientation-averaged binding. A hypothetical structure of the binding site of the solidified ECM surrogate was analyzed using the Comparative Molecular Field Analysis (CoMFA), which needed to be applied in our multi-mode variant. This fact indicates that the compounds bind to ECM in multiple modes, which cannot be considered as completely orientation-averaged and exhibit structural dependence. The novel CoMFA models, exhibiting satisfactory descriptive and predictive abilities, are suitable for prediction of the ECM binding for the untested chemicals, which are within applicability domains. The results contribute to a better prediction of the pharmacokinetic parameters such as the distribution volume and the tissue-blood partition coefficients, in addition to a more imminent benefit for the development of more effective MMP inhibitors. PMID:18844670

  9. Patterning of Fibroblast and Matrix Anisotropy within 3D Confinement is Driven by the Cytoskeleton.

    PubMed

    Serbo, Janna V; Kuo, Scot; Lewis, Shawna; Lehmann, Matthew; Li, Jiuru; Gracias, David H; Romer, Lewis H

    2016-01-07

    Effects of 3D confinement on cellular growth and matrix assembly are important in tissue engineering, developmental biology, and regenerative medicine. Polydimethylsiloxane wells with varying anisotropy are microfabicated using soft-lithography. Microcontact printing of bovine serum albumin is used to block cell adhesion to surfaces between wells. The orientations of fibroblast stress fibers, microtubules, and fibronectin fibrils are examined 1 day after cell seeding using laser scanning confocal microscopy, and anisotropy is quantified using a custom autocorrelation analysis. Actin, microtubules, and fibronectin exhibit higher anisotropy coefficients for cells grown in rectangular wells with aspect ratios of 1:4 and 1:8, as compared to those in wells with lower aspect ratios or in square wells. The effects of disabling individual cytoskeletal components on fibroblast responses to anisotropy are then tested by applying actin or microtubule polymerization inhibitors, Rho kinase inhibitor, or by siRNA-mediated knockdown of AXL or cofilin-1. Latrunculin A decreases cytoskeletal and matrix anisotropy, nocodazole ablates both, and Y27632 mutes cellular polarity while decreasing matrix anisotropy. AXL siRNA knockdown has little effect, as does siRNA knockdown of cofilin-1. These data identify several specific cytoskeletal strategies as targets for the manipulation of anisotropy in 3D tissue constructs.

  10. 3D Bioprinting a Cell-Laden Bone Matrix for Breast Cancer Metastasis Study.

    PubMed

    Zhou, Xuan; Zhu, Wei; Nowicki, Margaret; Miao, Shida; Cui, Haitao; Holmes, Benjamin; Glazer, Robert I; Zhang, Lijie Grace

    2016-11-09

    Metastasis is one of the deadliest consequences of breast cancer, with bone being one of the primary sites of occurrence. Insufficient 3D biomimetic models currently exist to replicate this process in vitro. In this study, we developed a biomimetic bone matrix using 3D bioprinting technology to investigate the interaction between breast cancer (BrCa) cells and bone stromal cells (fetal osteoblasts and human bone marrow mesenchymal stem cells (MSCs)). A tabletop stereolithography 3D bioprinter was employed to fabricate a series of bone matrices consisting of osteoblasts or MSCs encapsulated in gelatin methacrylate (GelMA) hydrogel with nanocrystalline hydroxyapatite (nHA). When BrCa cells were introduced into the stromal cell-laden bioprinted matrices, we found that the growth of BrCa cells was enhanced by the presence of osteoblasts or MSCs, whereas the proliferation of the osteoblasts or MSCs was inhibited by the BrCa cells. The BrCa cells co-cultured with MSCs or osteoblasts presented increased vascular endothelial growth factor (VEGF) secretion in comparison to that of monocultured BrCa cells. Additionally, the alkaline phosphatase activity of MSCs or osteoblasts was reduced after BrCa cell co-culture. These results demonstrate that the 3D bioprinted matrix, with BrCa cells and bone stromal cells, provides a suitable model with which to study the interactive effects of cells in the context of an artificial bone microenvironment and thus may serve as a valuable tool for the investigation of postmetastatic breast cancer progression in bone.

  11. Fatigue of a 3D Orthogonal Non-crimp Woven Polymer Matrix Composite at Elevated Temperature

    NASA Astrophysics Data System (ADS)

    Wilkinson, M. P.; Ruggles-Wrenn, M. B.

    2017-02-01

    Tension-tension fatigue behavior of two polymer matrix composites (PMCs) was studied at elevated temperature. The two PMCs consist of the NRPE polyimide matrix reinforced with carbon fibers, but have different fiber architectures: the 3D PMC is a singly-ply non-crimp 3D orthogonal weave composite and the 2D PMC, a laminated composite reinforced with 15 plies of an eight harness satin weave (8HSW) fabric. In order to assess the performance and suitability of the two composites for use in aerospace components designed to contain high-temperature environments, mechanical tests were performed under temperature conditions simulating the actual operating conditions. In all elevated temperature tests performed in this work, one side of the test specimen was at 329 °C while the other side was open to ambient laboratory air. The tensile stress-strain behavior of the two composites was investigated and the tensile properties measured for both on-axis (0/90) and off-axis (±45) fiber orientations. Elevated temperature had little effect on the on-axis tensile properties of the two composites. The off-axis tensile strength of both PMCs decreased slightly at elevated temperature. Tension-tension fatigue tests were conducted at elevated temperature at a frequency of 1.0 Hz with a ratio of minimum stress to maximum stress of R = 0.05. Fatigue run-out was defined as 2 × 105 cycles. Both strain accumulation and modulus evolution during cycling were analyzed for each fatigue test. The laminated 2D PMC exhibited better fatigue resistance than the 3D composite. Specimens that achieved fatigue run-out were subjected to tensile tests to failure to characterize the retained tensile properties. Post-test examination under optical microscope revealed severe delamination in the laminated 2D PMC. The non-crimp 3D orthogonal weave composite offered improved delamination resistance.

  12. Mean deformation metrics for quantifying 3D cell-matrix interactions without requiring information about matrix material properties.

    PubMed

    Stout, David A; Bar-Kochba, Eyal; Estrada, Jonathan B; Toyjanova, Jennet; Kesari, Haneesh; Reichner, Jonathan S; Franck, Christian

    2016-03-15

    Mechanobiology relates cellular processes to mechanical signals, such as determining the effect of variations in matrix stiffness with cell tractions. Cell traction recorded via traction force microscopy (TFM) commonly takes place on materials such as polyacrylamide- and polyethylene glycol-based gels. Such experiments remain limited in physiological relevance because cells natively migrate within complex tissue microenvironments that are spatially heterogeneous and hierarchical. Yet, TFM requires determination of the matrix constitutive law (stress-strain relationship), which is not always readily available. In addition, the currently achievable displacement resolution limits the accuracy of TFM for relatively small cells. To overcome these limitations, and increase the physiological relevance of in vitro experimental design, we present a new approach and a set of associated biomechanical signatures that are based purely on measurements of the matrix's displacements without requiring any knowledge of its constitutive laws. We show that our mean deformation metrics (MDM) approach can provide significant biophysical information without the need to explicitly determine cell tractions. In the process of demonstrating the use of our MDM approach, we succeeded in expanding the capability of our displacement measurement technique such that it can now measure the 3D deformations around relatively small cells (∼10 micrometers), such as neutrophils. Furthermore, we also report previously unseen deformation patterns generated by motile neutrophils in 3D collagen gels.

  13. Mean deformation metrics for quantifying 3D cell–matrix interactions without requiring information about matrix material properties

    PubMed Central

    Stout, David A.; Bar-Kochba, Eyal; Estrada, Jonathan B.; Toyjanova, Jennet; Kesari, Haneesh; Reichner, Jonathan S.; Franck, Christian

    2016-01-01

    Mechanobiology relates cellular processes to mechanical signals, such as determining the effect of variations in matrix stiffness with cell tractions. Cell traction recorded via traction force microscopy (TFM) commonly takes place on materials such as polyacrylamide- and polyethylene glycol-based gels. Such experiments remain limited in physiological relevance because cells natively migrate within complex tissue microenvironments that are spatially heterogeneous and hierarchical. Yet, TFM requires determination of the matrix constitutive law (stress–strain relationship), which is not always readily available. In addition, the currently achievable displacement resolution limits the accuracy of TFM for relatively small cells. To overcome these limitations, and increase the physiological relevance of in vitro experimental design, we present a new approach and a set of associated biomechanical signatures that are based purely on measurements of the matrix's displacements without requiring any knowledge of its constitutive laws. We show that our mean deformation metrics (MDM) approach can provide significant biophysical information without the need to explicitly determine cell tractions. In the process of demonstrating the use of our MDM approach, we succeeded in expanding the capability of our displacement measurement technique such that it can now measure the 3D deformations around relatively small cells (∼10 micrometers), such as neutrophils. Furthermore, we also report previously unseen deformation patterns generated by motile neutrophils in 3D collagen gels. PMID:26929377

  14. Flow integration transform: detecting shapes in matrix-array 3D ultrasound data

    NASA Astrophysics Data System (ADS)

    Stetten, George D.; Caines, Michael; von Ramm, Olaf T.

    1995-03-01

    Matrix-array ultrasound produces real-time 3D images of the heart, by employing a square array of transducers to steer the ultrasound beam in three dimensions electronically with no moving parts. Other 3D modalities such as MR, MUGA, and CT require the use of gated studies, which combine many cardiac cycles to produce a single average cycle. Three- dimensional ultrasound eliminates this restriction, in theory permitting the continuous measurement of cardiac ventricular volume, which we call the volumetricardiogram. Towards implementing the volumetricardiogram, we have developed the flow integration transform (FIT), which operates on a 2D slice within the volumetric ultrasound data. The 3D ultrasound machine's scan converter produces a set of such slices in real time, at any desired location and orientation, to which the FIT may then be applied. Although lacking rotational or scale invariance, the FIT is designed to operate in dedicated hardware where an entire transform could be completed within a few microseconds with present integrated circuit technology. This speed would permit the application of a large battery of test shapes, or the evolution of the test shape to converge on that of the actual target.

  15. 3D-Printing Composite Polycaprolactone-Decellularized Bone Matrix Scaffolds for Bone Tissue Engineering Applications.

    PubMed

    Rindone, Alexandra N; Nyberg, Ethan; Grayson, Warren L

    2017-05-11

    Millions of patients worldwide require bone grafts for treatment of large, critically sized bone defects from conditions such as trauma, cancer, and congenital defects. Tissue engineered (TE) bone grafts have the potential to provide a more effective treatment than current bone grafts since they would restore fully functional bone tissue in large defects. Most bone TE approaches involve a combination of stem cells with porous, biodegradable scaffolds that provide mechanical support and degrade gradually as bone tissue is regenerated by stem cells. 3D-printing is a key technique in bone TE that can be used to fabricate functionalized scaffolds with patient-specific geometry. Using 3D-printing, composite polycaprolactone (PCL) and decellularized bone matrix (DCB) scaffolds can be produced to have the desired mechanical properties, geometry, and osteoinductivity needed for a TE bone graft. This book chapter will describe the protocols for fabricating and characterizing 3D-printed PCL:DCB scaffolds. Moreover, procedures for culturing adipose-derived stem cells (ASCs) in these scaffolds in vitro will be described to demonstrate the osteoinductivity of the scaffolds.

  16. Front-end receiver electronics for a matrix transducer for 3-D transesophageal echocardiography.

    PubMed

    Yu, Zili; Blaak, Sandra; Chang, Zu-yao; Yao, Jiajian; Bosch, Johan G; Prins, Christian; Lancée, Charles T; de Jong, Nico; Pertijs, Michiel A P; Meijer, Gerard C M

    2012-07-01

    There is a clear clinical need for creating 3-D images of the heart. One promising technique is the use of transesophageal echocardiography (TEE). To enable 3-D TEE, we are developing a miniature ultrasound probe containing a matrix piezoelectric transducer with more than 2000 elements. Because a gastroscopic tube cannot accommodate the cables needed to connect all transducer elements directly to an imaging system, a major challenge is to locally reduce the number of channels, while maintaining a sufficient signal-to-noise ratio. This can be achieved by using front-end receiver electronics bonded to the transducers to provide appropriate signal conditioning in the tip of the probe. This paper presents the design of such electronics, realizing time-gain compensation (TGC) and micro-beamforming using simple, low-power circuits. Prototypes of TGC amplifiers and micro-beamforming cells have been fabricated in 0.35-μm CMOS technology. These prototype chips have been combined on a printed circuit board (PCB) to form an ultrasound-receiver system capable of reading and combining the signals of three transducer elements. Experimental results show that this design is a suitable candidate for 3-D TEE.

  17. 3D extracellular matrix interactions modulate tumour cell growth, invasion and angiogenesis in engineered tumour microenvironments.

    PubMed

    Taubenberger, Anna V; Bray, Laura J; Haller, Barbara; Shaposhnykov, Artem; Binner, Marcus; Freudenberg, Uwe; Guck, Jochen; Werner, Carsten

    2016-05-01

    Interactions between tumour cells and extracellular matrix proteins of the tumour microenvironment play crucial roles in cancer progression. So far, however, there are only a few experimental platforms available that allow us to study these interactions systematically in a mechanically defined three-dimensional (3D) context. Here, we have studied the effect of integrin binding motifs found within common extracellular matrix (ECM) proteins on 3D breast (MCF-7) and prostate (PC-3, LNCaP) cancer cell cultures, and co-cultures with endothelial and mesenchymal stromal cells. For this purpose, matrix metalloproteinase-degradable biohybrid poly(ethylene) glycol-heparin hydrogels were decorated with the peptide motifs RGD, GFOGER (collagen I), or IKVAV (laminin-111). Over 14days, cancer spheroids of 100-200μm formed. While the morphology of poorly invasive MCF-7 and LNCaP cells was not modulated by any of the peptide motifs, the aggressive PC-3 cells exhibited an invasive morphology when cultured in hydrogels comprising IKVAV and GFOGER motifs compared to RGD motifs or nonfunctionalised controls. PC-3 (but not MCF-7 and LNCaP) cell growth and endothelial cell infiltration were also significantly enhanced in IKVAV and GFOGER presenting gels. Taken together, we have established a 3D culture model that allows for dissecting the effect of biochemical cues on processes relevant to early cancer progression. These findings provide a basis for more mechanistic studies that may further advance our understanding of how ECM modulates cancer cell invasion and how to ultimately interfere with this process. Threedimensional in vitro cancer models have generated great interest over the past decade. However, most models are not suitable to systematically study the effects of environmental cues on cancer development and progression. To overcome this limitation, we have developed an innovative hydrogel platform to study the interactions between breast and prostate cancer cells and

  18. Human Astrocytes Develop Physiological Morphology and Remain Quiescent in a Novel 3D Matrix

    PubMed Central

    Placone, Amanda F.; McGuiggan, Patricia M.; Bergles, Dwight E.; Guerrero-Cazares, Hugo; Quiñones-Hinojosa, Alfredo; Searson, Peter C.

    2014-01-01

    Astrocytes are the most abundant glial cells in the brain and are responsible for diverse functions, from modulating synapse function to regulating the blood-brain barrier. In vivo, these cells exhibit a star-shaped morphology with multiple radial processes that contact synapses and completely surround brain capillaries. In response to trauma or CNS disease, astrocytes become reactive, a state associated with profound changes in gene expression, including upregulation of intermediate filament proteins, such as glial fibrillary acidic protein (GFAP). The inability to recapitulate the complex structure of astrocytes and maintain their quiescent state in vitro is a major roadblock to further developments in tissue engineering and regenerative medicine. Here, we characterize astrocyte morphology and activation in various hydrogels to assess the feasibility of developing a matrix that mimics key aspects of the native microenvironment. We show that astrocytes seeded in optimized matrix composed of collagen, hyaluronic acid, and matrigel exhibit a star-shaped morphology with radial processes and do not upregulate GFAP expression, hallmarks of quiescent astrocytes in the brain. In these optimized gels, collagen I provides structural support, HA mimics the brain extracellular matrix, and matrigel provides endothelial cell compatibility and was found to minimize GFAP upregulation. This defined 3D microenvironment for maintaining human astrocytes in vitro provides new opportunities for developing improved models of the blood-brain barrier and studying their response to stress signals. PMID:25542801

  19. Human bronchial epithelial cells differentiate to 3D glandular acini on basement membrane matrix.

    PubMed

    Wu, Xiaofang; Peters-Hall, Jennifer R; Bose, Sumit; Peña, Maria T; Rose, Mary C

    2011-06-01

    To create a model system that investigates mechanisms resulting in hyperplasia and hypertrophy of respiratory tract submucosal glands, we developed an in vitro three-dimensional (3D) system wherein normal human bronchial epithelial (HBE) cells differentiated into glandular acini when grown on a basement membrane matrix. The differentiation of primary HBE cells into glandular acini was monitored temporally by light microscopy. Apoptosis-induced lumen formation was observed by immunofluorescence analysis. The acinar cells expressed and secreted MUC5B mucin (marker for glandular mucous cells) and lysozyme, lactoferrin, and zinc-α2-glycoprotein (markers for glandular serous cells) at Day 22. β-Tubulin IV, a marker for ciliated cells, was not detected. Expression of mucous and serous cell markers in HBE glandular acini demonstrated that HBE cells grown on a basement membrane matrix differentiated into acini that exhibit molecular characteristics of respiratory tract glandular acinar cells. Inhibition studies with neutralizing antibodies resulted in a marked decrease in size of the spheroids at Day 7, demonstrating that laminin (a major component of the basement membrane matrix), the cell surface receptor integrin α6, and the cell junction marker E-cadherin have functional roles in HBE acinar morphogenesis. No significant variability was detected in the average size of glandular acini formed by HBE cells from two normal individuals. These results demonstrated that this in vitro model system is reproducible, stable, and potentially useful for studies of glandular differentiation and hyperplasia.

  20. Invasion-promoting extracellular matrix composition enhances photodynamic therapy response in 3D pancreatic cancer models

    NASA Astrophysics Data System (ADS)

    Cramer, Gwendolyn M.; El-Hamidi, Hamid; Celli, Jonathan P.

    2017-02-01

    Pancreatic ductal adenocarcinoma (PDAC) is characterized by extracellular matrix-rich stromal involvement, but it is not clear how ECM properties that affect invasiveness and chemotherapy response influence efficacy of photodynamic therapy (PDT). To disentangle the mechanical and biochemical effects of ECM composition, we measured the effects of various combinations of ECM proteins on growth behavior, invasive potential, and therapeutic response of multicellular 3D pancreatic tumor models. These spheroids were grown in attachment-free conditions before embedding in combinations of rheologically characterized collagen 1 and Matrigel combinations and treated with oxaliplatin chemotherapy and PDT. We find that cells invading from collagen-embedded tumor spheroids, the least rigid ECM substrate described here, displayed better response to PDT than to oxaliplatin chemotherapy. Overall, our results support that ECM-mediated invading PDAC populations remain responsive to PDT in conditions that induce chemoresistance.

  1. Concentric gel system to study the biophysical role of matrix microenvironment on 3D cell migration.

    PubMed

    Kurniawan, Nicholas Agung; Chaudhuri, Parthiv Kant; Lim, Chwee Teck

    2015-04-03

    The ability of cells to migrate is crucial in a wide variety of cell functions throughout life from embryonic development and wound healing to tumor and cancer metastasis. Despite intense research efforts, the basic biochemical and biophysical principles of cell migration are still not fully understood, especially in the physiologically relevant three-dimensional (3D) microenvironments. Here, we describe an in vitro assay designed to allow quantitative examination of 3D cell migration behaviors. The method exploits the cell's mechanosensing ability and propensity to migrate into previously unoccupied extracellular matrix (ECM). We use the invasion of highly invasive breast cancer cells, MDA-MB-231, in collagen gels as a model system. The spread of cell population and the migration dynamics of individual cells over weeks of culture can be monitored using live-cell imaging and analyzed to extract spatiotemporally-resolved data. Furthermore, the method is easily adaptable for diverse extracellular matrices, thus offering a simple yet powerful way to investigate the role of biophysical factors in the microenvironment on cell migration.

  2. Effects of Matrix Alignment and Mechanical Constraints on Cellular Behavior in 3D Engineered Microtissues

    NASA Astrophysics Data System (ADS)

    Bose, Prasenjit; Eyckmans, Jeroen; Chen, Christopher; Reich, Daniel

    The adhesion of cells to the extracellular matrix (ECM) plays a crucial role in a variety of cellular functions. The main building blocks of the ECM are 3D networks of fibrous proteins whose structure and alignments varies with tissue type. However, the impact of ECM alignment on cellular behaviors such as cell adhesion, spreading, extension and mechanics remains poorly understood. We present results on the development of a microtissue-based system that enables control of the structure, orientation, and degree of fibrillar alignment in 3D fibroblast-populated collagen gels. The tissues self-assemble from cell-laden collagen gels placed in micro-fabricated wells containing sets of elastic pillars. The contractile action of the cells leads to controlled alignment of the fibrous collagen, depending on the number and location of the pillars in each well. The pillars are elastic, and are utilized to measure the contractile forces of the microtissues, and by incorporating magnetic material in selected pillars, time-varying forces can be applied to the tissues for dynamic stimulation and measurement of mechanical properties. Results on the effects of varying pillar shape, spacing, location, and stiffness on microtissue organization and contractility will be presented. This work is supported by NSF CMMI-1463011.

  3. Concentric Gel System to Study the Biophysical Role of Matrix Microenvironment on 3D Cell Migration

    PubMed Central

    Kurniawan, Nicholas Agung; Chaudhuri, Parthiv Kant; Lim, Chwee Teck

    2015-01-01

    The ability of cells to migrate is crucial in a wide variety of cell functions throughout life from embryonic development and wound healing to tumor and cancer metastasis. Despite intense research efforts, the basic biochemical and biophysical principles of cell migration are still not fully understood, especially in the physiologically relevant three-dimensional (3D) microenvironments. Here, we describe an in vitro assay designed to allow quantitative examination of 3D cell migration behaviors. The method exploits the cell’s mechanosensing ability and propensity to migrate into previously unoccupied extracellular matrix (ECM). We use the invasion of highly invasive breast cancer cells, MDA-MB-231, in collagen gels as a model system. The spread of cell population and the migration dynamics of individual cells over weeks of culture can be monitored using live-cell imaging and analyzed to extract spatiotemporally-resolved data. Furthermore, the method is easily adaptable for diverse extracellular matrices, thus offering a simple yet powerful way to investigate the role of biophysical factors in the microenvironment on cell migration. PMID:25867104

  4. Towards the volumetricardiogram: volume determination of cardiac chambers using 3D matrix-array ultrasound

    NASA Astrophysics Data System (ADS)

    Stetten, George D.; Caines, Michael; Ohazama, Chikai J.; von Ramm, Olaf T.

    1995-05-01

    Matrix-array ultrasound is a new medical imaging modality that steers an ultrasound beam electronically in three dimensions. It is the first imaging modality that can view the heart in 3D in real time, making possible the `volumetricardiogram,' i.e., continuous beat to beat measurement of cardiac chamber volume. To create a fully automatic real-time volumetricardiogram, we have developed the flow integration transform (FIT), which operates on 2D images produced by slicing through the 3D ultrasound data. Although lacking rotational or scale invariance, the FIT is designed to operate eventually in dedicated hardware at very high speed, permitting the application of a large battery of test shapes within the period of a single ultrasound frame (approximately 45 milliseconds). To test the FIT, we have volumetrically scanned a series of 21 fluid-filled balloons. We used the FIT to detect circular cross-sections of the balloons by applying a battery of circles over a range of radii. The detected circles were used to compute volumes, which were then compared to volumes determined independently by weight. Our results are encouraging towards further development of this completely automated method of volume determination.

  5. Development of a 3D matrix for modeling mammalian spinal cord injury in vitro.

    PubMed

    Diaz Quiroz, Juan Felipe; Li, Yuping; Aparicio, Conrado; Echeverri, Karen

    2016-11-01

    Spinal cord injury affects millions of people around the world, however, limited therapies are available to improve the quality of life of these patients. Spinal cord injury is usually modeled in rats and mice using contusion or complete transection models and this has led to a deeper understanding of the molecular and cellular complexities of the injury. However, it has not to date led to development of successful novel therapies, this is in part due to the complexity of the injury and the difficulty of deciphering the exact roles and interactions of different cells within this complex environment. Here we developed a collagen matrix that can be molded into the 3D tubular shape with a lumen and can hence support cell interactions in a similar architecture to a spinal cord. We show that astrocytes can be successfully grown on this matrix in vitro and when injured, the cells respond as they do in vivo and undergo reactive gliosis, one of the steps that lead to formation of a glial scar, the main barrier to spinal cord regeneration. In the future, this system can be used to quickly assess the effect of drugs on glial scar protein activity or to perform live imaging of labeled cells after exposure to drugs.

  6. Development of a 3D matrix for modeling mammalian spinal cord injury in vitro

    PubMed Central

    Diaz Quiroz, Juan Felipe; Li, Yuping; Aparicio, Conrado; Echeverri, Karen

    2016-01-01

    Spinal cord injury affects millions of people around the world, however, limited therapies are available to improve the quality of life of these patients. Spinal cord injury is usually modeled in rats and mice using contusion or complete transection models and this has led to a deeper understanding of the molecular and cellular complexities of the injury. However, it has not to date led to development of successful novel therapies, this is in part due to the complexity of the injury and the difficulty of deciphering the exact roles and interactions of different cells within this complex environment. Here we developed a collagen matrix that can be molded into the 3D tubular shape with a lumen and can hence support cell interactions in a similar architecture to a spinal cord. We show that astrocytes can be successfully grown on this matrix in vitro and when injured, the cells respond as they do in vivo and undergo reactive gliosis, one of the steps that lead to formation of a glial scar, the main barrier to spinal cord regeneration. In the future, this system can be used to quickly assess the effect of drugs on glial scar protein activity or to perform live imaging of labeled cells after exposure to drugs. PMID:28123426

  7. Modulation of fibrin matrix properties via knob:hole affinity interactions using peptide-PEG conjugates

    PubMed Central

    Soon, Allyson S.C.; Lee, Christine S.; Barker, Thomas H.

    2011-01-01

    Fibrin is a widely used biological scaffold in tissue engineering and regenerative medicine. While the polymerization dynamics from its soluble precursor fibrinogen has been studied for decades, few attempts have been made to modulate fibrin network structure through the addition of external agents that actively engage this process. We propose the use of polyethylene glycol (PEG)-based linkers that interact with fibrinogen via knob:hole affinity interactions as a means of controlling thrombin-mediated fibrin polymerization dynamics and resulting network structure. Using bivalent and tetravalent knob-PEG conjugates with sizes ranging from 2 to 20 kDa, we demonstrate that the clotting characteristics of fibrinogen solutions can be altered in a dose-dependent manner, with conjugate size playing a major role in altering fibrin network structure. Interestingly, factor XIIIa-catalyzed fibrin(ogen) crosslinking and plasmin-mediated degradation were not significantly impacted. This work demonstrates the feasibility of modulating fibrin network structure through the addition of knob-PEG conjugates that perturb the polymerization process through non-covalent knob:hole interactions. PMID:21435714

  8. Tracking immune-related cell responses to drug delivery microparticles in 3D dense collagen matrix.

    PubMed

    Obarzanek-Fojt, Magdalena; Curdy, Catherine; Loggia, Nicoletta; Di Lena, Fabio; Grieder, Kathrin; Bitar, Malak; Wick, Peter

    2016-10-01

    Beyond the therapeutic purpose, the impact of drug delivery microparticles on the local tissue and inflammatory responses remains to be further elucidated specifically for reactions mediated by the host immune cells. Such immediate and prolonged reactions may adversely influence the release efficacy and intended therapeutic pathway. The lack of suitable in vitro platforms limits our ability to gain insight into the nature of immune responses at a single cell level. In order to establish an in vitro 3D system mimicking the connective host tissue counterpart, we utilized reproducible, compressed, rat-tail collagen polymerized matrices. THP1 cells (human acute monocytic leukaemia cells) differentiated into macrophage-like cells were chosen as cell model and their functionality was retained in the dense rat-tail collagen matrix. Placebo microparticles were later combined in the immune cell seeded system during collagen polymerization and secreted pro-inflammatory factors: TNFα and IL-8 were used as immune response readout (ELISA). Our data showed an elevated TNFα and IL-8 secretion by macrophage THP1 cells indicating that Placebo microparticles trigger certain immune cell responses under 3D in vivo like conditions. Furthermore, we have shown that the system is sensitive to measure the differences in THP1 macrophage pro-inflammatory responses to Active Pharmaceutical Ingredient (API) microparticles with different API release kinetics. We have successfully developed a tissue-like, advanced, in vitro system enabling selective "readouts" of specific responses of immune-related cells. Such system may provide the basis of an advanced toolbox enabling systemic evaluation and prediction of in vivo microparticle reactions on human immune-related cells.

  9. A spectrophotometer-based diffusivity assay reveals that diffusion hindrance of small molecules in extracellular matrix gels used in 3D cultures is dominated by viscous effects.

    PubMed

    Galgoczy, Roland; Pastor, Isabel; Colom, Adai; Giménez, Alicia; Mas, Francesc; Alcaraz, Jordi

    2014-08-01

    The design of 3D culture studies remains challenging due to the limited understanding of extracellular matrix (ECM)-dependent hindered diffusion and the lack of simple diffusivity assays. To address these limitations, we set up a cost-effective diffusivity assay based on a Transwell plate and the spectrophotometer of a Microplate Reader, which are readily accessible to cell biology groups. The spectrophotometer-based assay was used to assess the apparent diffusivity D of FITC-dextrans with molecular weight (4-70kDa) spanning the physiological range of signaling factors in a panel of acellular ECM gels including Matrigel, fibrin and type I collagen. Despite their technical differences, D data exhibited ∼15% relative difference with respect to FRAP measurements. Our results revealed that diffusion hindrance of small particles is controlled by the enhanced viscosity of the ECM gel in conformance with the Stokes-Einstein equation rather than by geometrical factors. Moreover, we provided a strong rationale that the enhanced ECM viscosity is largely contributed to by unassembled ECM macromolecules. We also reported that gels with the lowest D exhibited diffusion hindrance closest to the large physiologic hindrance of brain tissue, which has a typical pore size much smaller than ECM gels. Conversely, sparse gels (≤1mg/ml), which are extensively used in 3D cultures, failed to reproduce the hindered diffusion of tissues, thereby supporting that dense (but not sparse) ECM gels are suitable tissue surrogates in terms of macromolecular transport. Finally, the consequences of reduced diffusivity in terms of optimizing the design of 3D culture experiments were addressed in detail. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Effects of Matrix Metalloproteinases on the Performance of Platelet Fibrin Gel Spiked With Cardiac Stem Cells in Heart Repair.

    PubMed

    Shen, Deliang; Tang, Junnan; Hensley, Michael Taylor; Li, Taosheng; Caranasos, Thomas George; Zhang, Tianxia; Zhang, Jinying; Cheng, Ke

    2016-06-01

    Stem cells and biomaterials have been studied for therapeutic cardiac repair. Previous studies have shown the beneficial effects of platelet fibrin gel and cardiac stem cells when cotransplanted into rodent hearts with myocardial infarction (MI). We hypothesized that matrix metalloproteinases (MMPs) play an important role in such protection. Thus, the present study is designed to elucidate the effects of MMP inhibition on the therapeutic benefits of intramyocardial injection of platelet fibrin gel spiked with cardiac stem cells (cell-gel) in a rat model of acute MI. In vitro, broad-spectrum MMP inhibitor GM6001 undermines cell spreading and cardiomyocyte contraction. In a syngeneic rat model of myocardial infarction, MMP inhibition blunted the recruitment of endogenous cardiovascular cells into the injected biomaterials, therefore hindering de novo angiogenesis and cardiomyogenesis. Echocardiography and histology 3 weeks after treatment revealed that metalloproteinase inhibition diminished the functional and structural benefits of cell-gel in treating MI. Reduction of host angiogenesis, cardiomyocyte cycling, and MMP-2 activities was evident in animals treated with GM6001. Our findings suggest that MMPs play a critical role in the therapeutic benefits of platelet fibrin gel spiked with cardiac stem cells for treating MI. In this study, the effects of matrix metalloproteinase inhibition on the performance of platelet gel spiked with cardiac stem cells (cell-gel) for heart regeneration are explored. The results demonstrate that matrix metalloproteinases are required for cell-gel to exert its benefits in cardiac repair. Inhibition of matrix metalloproteinases reduces cell engraftment, host angiogenesis, and recruitment of endogenous cardiovascular cells in rats with heart attack. ©AlphaMed Press.

  11. Effects of Matrix Metalloproteinases on the Performance of Platelet Fibrin Gel Spiked With Cardiac Stem Cells in Heart Repair

    PubMed Central

    Shen, Deliang; Tang, Junnan; Hensley, Michael Taylor; Li, Taosheng; Caranasos, Thomas George; Zhang, Tianxia

    2016-01-01

    Stem cells and biomaterials have been studied for therapeutic cardiac repair. Previous studies have shown the beneficial effects of platelet fibrin gel and cardiac stem cells when cotransplanted into rodent hearts with myocardial infarction (MI). We hypothesized that matrix metalloproteinases (MMPs) play an important role in such protection. Thus, the present study is designed to elucidate the effects of MMP inhibition on the therapeutic benefits of intramyocardial injection of platelet fibrin gel spiked with cardiac stem cells (cell-gel) in a rat model of acute MI. In vitro, broad-spectrum MMP inhibitor GM6001 undermines cell spreading and cardiomyocyte contraction. In a syngeneic rat model of myocardial infarction, MMP inhibition blunted the recruitment of endogenous cardiovascular cells into the injected biomaterials, therefore hindering de novo angiogenesis and cardiomyogenesis. Echocardiography and histology 3 weeks after treatment revealed that metalloproteinase inhibition diminished the functional and structural benefits of cell-gel in treating MI. Reduction of host angiogenesis, cardiomyocyte cycling, and MMP-2 activities was evident in animals treated with GM6001. Our findings suggest that MMPs play a critical role in the therapeutic benefits of platelet fibrin gel spiked with cardiac stem cells for treating MI. Significance In this study, the effects of matrix metalloproteinase inhibition on the performance of platelet gel spiked with cardiac stem cells (cell-gel) for heart regeneration are explored. The results demonstrate that matrix metalloproteinases are required for cell-gel to exert its benefits in cardiac repair. Inhibition of matrix metalloproteinases reduces cell engraftment, host angiogenesis, and recruitment of endogenous cardiovascular cells in rats with heart attack. PMID:27112177

  12. BIOCOMPATIBILITY OF A SYNTHETIC EXTRACELLULAR MATRIX ON IMMORTALIZED VOCAL FOLD FIBROBLASTS IN 3D CULTURE

    PubMed Central

    Chen, Xia

    2010-01-01

    In order to promote wound repair and induce tissue regeneration, an engineered hyaluronan (HA) hydrogel – Carbylan GSX, which contains di(thiopropionyl) bishydrazide-modified hyaluronic acid (HA-DTPH), di(thiopropionyl) bishydrazide-modified gelatin (Gtn-DTPH) and polyethylene glycol diacrylate (PEGDA), has been developed for extracellular matrix (ECM) defects of the superficial and middle layers of the lamina propria. The purpose of this study was to evaluate the biocompatibility of Carbylan GSX in a previously established immortalized human vocal fold fibroblast (hVFF) cell line prior to human clinical trials. Immortalized hVFF proliferation, viability, apoptosis and transcript analysis for both ECM constituents and inflammatory markers were measured for two-dimensional and three-dimensional culture conditions. There were no significant differences in morphology, cell marker protein expression, proliferation, viability and apoptosis of hVFF cultured with Carbylan GSX compared to Matrigel, a commercial 3D control, after one week. Gene expression levels for fibromodulin, TGF-β1, and TNF-α were similar between Carbylan GSX and Matrigel. Fibronectin, hyaluronidase 1 and COX2 expression levels were induced by Carbylan GSX; whereas IL6, IL8. COL1 and hyaluronic acid synthase 3 expression levels were decreased by Carbylan GSX. This investigation demonstrates that Carbylan GSX may serve as a natural biomaterial for tissue engineering of human vocal folds. PMID:20109588

  13. 3-D-Observation of Matrix of MIL 090657 Meteorite by Absorption-Phase Tomography

    NASA Technical Reports Server (NTRS)

    Miyama, Sugimoto; Tsuchiyama, Akira; Matsuno, Junya; Miyake, Akira; Nakano, Tsukasa; Uesugi, Kentaro; Takeuchi, Akihisa; Takigawa, Aki; Takayama, Akiko; Nakamura-Messenger, Keiko; hide

    2017-01-01

    MIL 090657 meteorite (CR2.7) is one of the least altered primitive carbonaceous c hondrites [1]. This meteorite has amorphous silicates like GEMS (glass with embedded metal and sulfide), which are characteristically contained in cometary dust, in matrix [2,3] as with the Paris meteorite [4]. Three lithologies have been recognized; lithology-1 (L 1) dominated by submicron anhydrous silicates, lithology-2 (L2) by GEMS-like amorphous silicates and lithology-3 (L3) by phyllosilicates [2]. Organic materials are abundant in L 1 and L2 [2,3]. L 1 and L2 were further divided into sub-lithology respectively based on their textures and compositions [5]. These studies were performed by 2D SEM and TEM observations of sample surfaces and thin sections that are unable to reveal what constitute each lithology and how these lithologies are distributed and related to each other. This information will provide important insights into alteration and aggregation processes on asteroids and in the early solar nebula. In this study, MIL 090657 matrix was examined in 3D using two types of X-ray tomography; DET (dual-energy tomography) [6] and SIXM (scanning-imaging X-ray microscopy) [7]. Mineral phases can be discriminated based on absorption contrasts at two different X-ray energies in DET. In SIXM, materials composed of light elements such as water or organic materials can be identified based on phase and absorption contrasts. By combining these methods, we can discriminate not only organic materials from voids but also hydrous alteration products, such as hydrated silicates and carbonates, from anhydrous minerals [8]. In this study, we first observed cross sections of MIL 090657 matrix fragments C1 00 mm) in detail using FE-SEM/ EDS. Based on the results, three house-shaped samples (3 0 -50 mm) were extracted from L 1, L2 and their boundary (H1, H3 and H5, respectively) using FIB. 3D imaging of these samples were conducted at BL47XU of SPring-8, a synchrotron radiation facility, with

  14. 3D texture analysis of solitary pulmonary nodules using co-occurrence matrix from volumetric lung CT images

    NASA Astrophysics Data System (ADS)

    Dhara, Ashis Kumar; Mukhopadhyay, Sudipta; Khandelwal, Niranjan

    2013-02-01

    In this paper we have investigated a new approach for texture features extraction using co-occurrence matrix from volumetric lung CT image. Traditionally texture analysis is performed in 2D and is suitable for images collected from 2D imaging modality. The use of 3D imaging modalities provide the scope of texture analysis from 3D object and 3D texture feature are more realistic to represent 3D object. In this work, Haralick's texture features are extended in 3D and computed from volumetric data considering 26 neighbors. The optimal texture features to characterize the internal structure of Solitary Pulmonary Nodules (SPN) are selected based on area under curve (AUC) values of ROC curve and p values from 2-tailed Student's t-test. The selected texture feature in 3D to represent SPN can be used in efficient Computer Aided Diagnostic (CAD) design plays an important role in fast and accurate lung cancer screening. The reduced number of input features to the CAD system will decrease the computational time and classification errors caused by irrelevant features. In the present work, SPN are classified from Ground Glass Nodule (GGN) using Artificial Neural Network (ANN) classifier considering top five 3D texture features and top five 2D texture features separately. The classification is performed on 92 SPN and 25 GGN from Imaging Database Resources Initiative (IDRI) public database and classification accuracy using 3D texture features and 2D texture features provide 97.17% and 89.1% respectively.

  15. Accurate 3-D Profile Extraction of Skull Bone using an Ultrasound Matrix Array.

    PubMed

    Hajian, Mehdi; Gaspar, Robert; Maev, Roman

    2017-03-08

    The present study investigates the feasibility, accuracy, and precision of 3-D profile extraction of the human skull bone using a custom-designed ultrasound matrix transducer in Pulse-Echo. Due to the attenuative scattering properties of the skull, the backscattered echoes from the inner surface of the skull are severely degraded, attenuated, and at some points overlapped. Furthermore, the speed of sound (SOS) in the skull varies significantly in different zones and also from case to case; if considered constant, it introduces significant error to the profile measurement. A new method for simultaneous estimation of the skull profiles and the sound speed value is presented. The proposed method is a two-folded procedure: first, the arrival times of the backscattered echoes from the skull bone are estimated using multi-lag phase delay (MLPD) and modified space alternating generalized expectation maximization (SAGE) algorithms. Next, these arrival times are fed into an adaptive sound speed estimation algorithm to compute the optimal SOS value and subsequently, the skull bone thickness. For quantitative evaluation, the estimated bone phantom thicknesses were compared with the mechanical measurements. The accuracies of the bone thickness measurements using MLPD and modified SAGE algorithms combined with the adaptive SOS estimation were 7.93% and 4.21%, respectively. These values were 14.44% and 10.75% for the autocorrelation and crosscorrelation methods. Additionally, the Bland-Altman plots showed the modified SAGE outperformed the other methods with -0.35 mm and 0.44 mm limits of agreement. No systematic error that could be related to the skull bone thickness was observed for this method.

  16. One-step direct-laser metal writing of sub-100 nm 3D silver nanostructures in a gelatin matrix

    NASA Astrophysics Data System (ADS)

    Kang, SeungYeon; Vora, Kevin; Mazur, Eric

    2015-03-01

    Developing an ability to fabricate high-resolution, 3D metal nanostructures in a stretchable 3D matrix is a critical step to realizing novel optoelectronic devices such as tunable bulk metal-dielectric optical devices and THz metamaterial devices that are not feasible with alternative techniques. We report a new chemistry method to fabricate high-resolution, 3D silver nanostructures using a femtosecond-laser direct metal writing technique. Previously, only fabrication of 3D polymeric structures or single-/few-layer metal structures was possible. Our method takes advantage of unique gelatin properties to overcome such previous limitations as limited freedom in 3D material design and short sample lifetime. We fabricate more than 15 layers of 3D silver nanostructures with a resolution of less than 100 nm in a stable dielectric matrix that is flexible and has high large transparency that is well-matched for potential applications in the optical and THz metamaterial regimes. This is a single-step process that does not require any further processing. This work will be of interest to those interested in fabrication methods that utilize nonlinear light-matter interactions and the realization of future metamaterials.

  17. An extracellular-matrix-specific GEF-GAP interaction regulates Rho GTPase crosstalk for 3D collagen migration.

    PubMed

    Kutys, Matthew L; Yamada, Kenneth M

    2014-09-01

    Rho-family GTPases govern distinct types of cell migration on different extracellular matrix proteins in tissue culture or three-dimensional (3D) matrices. We searched for mechanisms selectively regulating 3D cell migration in different matrix environments and discovered a form of Cdc42-RhoA crosstalk governing cell migration through a specific pair of GTPase activator and inhibitor molecules. We first identified βPix, a guanine nucleotide exchange factor (GEF), as a specific regulator of migration in 3D collagen using an affinity-precipitation-based GEF screen. Knockdown of βPix specifically blocks cell migration in fibrillar collagen microenvironments, leading to hyperactive cellular protrusion accompanied by increased collagen matrix contraction. Live FRET imaging and RNAi knockdown linked this βPix knockdown phenotype to loss of polarized Cdc42 but not Rac1 activity, accompanied by enhanced, de-localized RhoA activity. Mechanistically, collagen phospho-regulates βPix, leading to its association with srGAP1, a GTPase-activating protein (GAP), needed to suppress RhoA activity. Our results reveal a matrix-specific pathway controlling migration involving a GEF-GAP interaction of βPix with srGAP1 that is critical for maintaining suppressive crosstalk between Cdc42 and RhoA during 3D collagen migration.

  18. Increasing 3D Matrix Rigidity Strengthens Proliferation and Spheroid Development of Human Liver Cells in a Constant Growth Factor Environment.

    PubMed

    Bomo, Jérémy; Ezan, Frédéric; Tiaho, François; Bellamri, Medjda; Langouët, Sophie; Theret, Nathalie; Baffet, Georges

    2016-03-01

    Mechanical forces influence the growth and shape of virtually all tissues and organs. Recent studies show that increased cell contractibility, growth and differentiation might be normalized by modulating cell tensions. Particularly, the role of these tensions applied by the extracellular matrix during liver fibrosis could influence the hepatocarcinogenesis process. The objective of this study is to determine if 3D stiffness could influence growth and phenotype of normal and transformed hepatocytes and to integrate extracellular matrix (ECM) stiffness to tensional homeostasis. We have developed an appropriate 3D culture model: hepatic cells within three-dimensional collagen matrices with varying rigidity. Our results demonstrate that the rigidity influenced the cell phenotype and induced spheroid clusters development whereas in soft matrices, Huh7 transformed cells were less proliferative, well-spread and flattened. We confirmed that ERK1 played a predominant role over ERK2 in cisplatin-induced death, whereas ERK2 mainly controlled proliferation. As compared to 2D culture, 3D cultures are associated with epithelial markers expression. Interestingly, proliferation of normal hepatocytes was also induced in rigid gels. Furthermore, biotransformation activities are increased in 3D gels, where CYP1A2 enzyme can be highly induced/activated in primary culture of human hepatocytes embedded in the matrix. In conclusion, we demonstrated that increasing 3D rigidity could promote proliferation and spheroid developments of liver cells demonstrating that 3D collagen gels are an attractive tool for studying rigidity-dependent homeostasis of the liver cells embedded in the matrix and should be privileged for both chronic toxicological and pharmacological drug screening. © 2015 Wiley Periodicals, Inc.

  19. Autologous Platelet-rich Fibrin Matrix in Non-healing Trophic Ulcers in Patients with Hansen's Disease.

    PubMed

    Nagaraju, Umashankar; Sundar, Priya K; Agarwal, Priyanka; Raju, Belliappa P; Kumar, Mahesh

    2017-01-01

    Non-healing trophic ulcers in Hansen's disease patients is one of the major causes for disability. It has been shown that autologous platelet-rich fibrin matrix (PRFM) is effective in healing chronic non-healing leg ulcers. The objective of this study is to demonstrate the efficacy of autologous platelet-rich fibrin matrix (PRFM) in non-healing trophic ulcers in patients treated for Hansen's disease. A prospective study. An institution-based clinic. Seven treated patients with Hansen's disease, with a mean age of 38.33 years, with nine non-healing trophic ulcer of more than 6 weeks duration. Photographs were taken before treatment and at every subsequent sitting. Area and volume were calculated at baseline and every subsequent sitting till the closure was achieved. The healthy ulcers were treated with PRFM at weekly intervals, repeated once a week for a maximum of five sittings as per requirement. The mean percentage improvement in the area was 93.52%, and volume was 97.74% at the end of the second sitting. All ulcers closed by a maximum of five sittings. No adverse events were noted. PRFM for the treatment of trophic ulcers in treated patients with Hansen's disease is a feasible, safe, simple and inexpensive method.

  20. Human lung fibroblast-derived matrix facilitates vascular morphogenesis in 3D environment and enhances skin wound healing.

    PubMed

    Du, Ping; Suhaeri, Muhammad; Ha, Sang Su; Oh, Seung Ja; Kim, Sang-Heon; Park, Kwideok

    2017-05-01

    Extracellular matrix (ECM) is crucial to many aspects of vascular morphogenesis and maintenance of vasculature function. Currently the recapitulation of angiogenic ECM microenvironment is still challenging, due mainly to its diverse components and complex organization. Here we investigate the angiogenic potential of human lung fibroblast-derived matrix (hFDM) in creating a three-dimensional (3D) vascular construct. hFDM was obtained via decellularization of in vitro cultured human lung fibroblasts and analyzed via immunofluorescence staining and ELISA, which detect multiple ECM macromolecules and angiogenic growth factors (GFs). Human umbilical vein endothelial cells (HUVECs) morphology was more elongated and better proliferative on hFDM than on gelatin-coated substrate. To prepare 3D construct, hFDM is collected, quantitatively analyzed, and incorporated in collagen hydrogel (Col) with HUVECs. Capillary-like structure (CLS) formation at 7day was significantly better with the groups containing higher doses of hFDM compared to the Col group (control). Moreover, the group (Col/hFDM/GFs) with both hFDM and angiogenic GFs (VEGF, bFGF, SDF-1) showed the synergistic activity on CLS formation and found much larger capillary lumen diameters with time. Further analysis of hFDM via angiogenesis antibody array kit reveals abundant biochemical cues, such as angiogenesis-related cytokines, GFs, and proteolytic enzymes. Significantly up-regulated expression of VE-cadherin and ECM-specific integrin subunits was also noticed in Col/hFDM/GFs. In addition, transplantation of Col/hFMD/GFs with HUVECs in skin wound model presents more effective re-epithelialization, many regenerated hair follicles, better transplanted cells viability, and advanced neovascularization. We believe that current system is a very promising platform for 3D vasculature construction in vitro and for cell delivery toward therapeutic applications in vivo. Functional 3D vasculature construction in vitro is still

  1. 3D porous sol-gel matrix incorporated microdevice for effective large volume cell sample pretreatment.

    PubMed

    Lee, Chan Joo; Jung, Jae Hwan; Seo, Tae Seok

    2012-06-05

    In this study, we demonstrated an effective sample pretreatment microdevice that could perform the capture, purification, and release of pathogenic bacteria with a large-volume sample and at a high speed and high-capture yield. We integrated a sol-gel matrix into the microdevice which forms three-dimensional (3D) micropores for the cell solution to pass through and provides a large surface area for the immobilization of antibodies to capture the target Staphylococcus aureus (S. aureus) cells. The antibody was linked to the surface of the sol-gel via a photocleavable linker, allowing the cell-captured antibody moiety to be released by UV irradiation. In addition to the optimization of the antibody immobilization and UV cleavage processes, the cell-capture efficiency was maximized by controlling the sample flow rate with a pumping scheme (3 steps, 5 steps: 3 steps with one flutter step, 7 steps: 3 steps with two flutter steps) and the pumping time (100, 200, and 300 ms). A quantitative capture analysis was performed by targeting a specific gene site of protein A of S. aureus in real-time PCR (RT-PCR). While the 3-step process with an actuation time of 100 ms showed the fastest flow rate (1 mL sample processing time in 10 min), the pumping scheme with the 7-step process and the 300 ms actuation time revealed the highest cell-capture efficiency. A limit of detection study with the 7-step and the 300 ms pumping scheme demonstrated that 100 cells per 100 μL were detected with a 70% yield, and even a single cell could be analyzed via on-chip sample preparation. Thus, our novel sol-gel based microdevice was proven more cost-effective, simple, and efficient in terms of its sample pretreatment ability compared to the use of a conventional 2D flat microdevice. This proposed sample pretreatment device can be further incorporated to an analytical functional unit to realize a micrototal analysis system (μTAS) with sample-in-answer-out capability in the fields of biomedical

  2. The Exopolysaccharide Matrix Modulates the Interaction between 3D Architecture and Virulence of a Mixed-Species Oral Biofilm

    PubMed Central

    Xiao, Jin; Klein, Marlise I.; Falsetta, Megan L.; Lu, Bingwen; Delahunty, Claire M.; Yates, John R.; Heydorn, Arne; Koo, Hyun

    2012-01-01

    Virulent biofilms are responsible for a range of infections, including oral diseases. All biofilms harbor a microbial-derived extracellular-matrix. The exopolysaccharides (EPS) formed on tooth-pellicle and bacterial surfaces provide binding sites for microorganisms; eventually the accumulated EPS enmeshes microbial cells. The metabolic activity of the bacteria within this matrix leads to acidification of the milieu. We explored the mechanisms through which the Streptococcus mutans-produced EPS-matrix modulates the three-dimensional (3D) architecture and the population shifts during morphogenesis of biofilms on a saliva-coated-apatitic surface using a mixed-bacterial species system. Concomitantly, we examined whether the matrix influences the development of pH-microenvironments within intact-biofilms using a novel 3D in situ pH-mapping technique. Data reveal that the production of the EPS-matrix helps to create spatial heterogeneities by forming an intricate network of exopolysaccharide-enmeshed bacterial-islets (microcolonies) through localized cell-to-matrix interactions. This complex 3D architecture creates compartmentalized acidic and EPS-rich microenvironments throughout the biofilm, which triggers the dominance of pathogenic S. mutans within a mixed-species system. The establishment of a 3D-matrix and EPS-enmeshed microcolonies were largely mediated by the S. mutans gtfB/gtfC genes, expression of which was enhanced in the presence of Actinomyces naeslundii and Streptococcus oralis. Acidic pockets were found only in the interiors of bacterial-islets that are protected by EPS, which impedes rapid neutralization by buffer (pH 7.0). As a result, regions of low pH (<5.5) were detected at specific locations along the surface of attachment. Resistance to chlorhexidine was enhanced in cells within EPS-microcolony complexes compared to those outside such structures within the biofilm. Our results illustrate the critical interaction between matrix architecture and p

  3. Influence of vanadate on migrating fibroblast orientation within a fibrin matrix.

    PubMed

    Lee, Michael Y; Ehrlich, H Paul

    2008-10-01

    Treating rats with vanadate, a nonspecific inhibitor of protein tyrosine phosphatases, optimizes the uniform packing of collagen fiber bundles in wound granulation tissue and doubles wound breaking strength in rat incisional wounds. The speculation is vanadate optimizes the packing of collagen fiber bundles through the orientation of newly arrived wound fibroblasts in the fibrin clot filling the defect. Segments of 14 day chick embryo tendons were placed on fibrin clots and maintained in organ culture with and without 30 microM vanadate. On day 7 explants were examined histologically and biochemically. Tendon fibroblast outgrowth from untreated explants migrated in a random fashion, while fibroblasts from vanadate-treated explants migrated out in linear arrays. Fibroblasts were elongated by 20% form vanadate treated explant compared to controls. Myosin ATPase, required for optimal cell motility, is optimized by the phosphorylation of its myosin light chain (MLC). Western blot analysis of lysates from the fibroblasts that migrated into the fibrin showed vanadate increased MLC-P levles. These findings support the notion that vanadate promotes the deposition of regular, parallel collagen fiber bundles by advancing the orientation of fibroblasts in parallel linear arrays early in the wound repair process. (c) 2008 Wiley-Liss, Inc.

  4. Comparison of 3D reconstructive technologies used for morphometric research and the translation of knowledge using a decision matrix.

    PubMed

    Martin, Charys M; Roach, Victoria A; Nguyen, Ngan; Rice, Charles L; Wilson, Timothy D

    2013-01-01

    The use of three-dimensional (3D) models for education, pre-operative assessment, presurgical planning, and measurement have become more prevalent. With the increase in prevalence of 3D models there has also been an increase in 3D reconstructive software programs that are used to create these models. These software programs differ in reconstruction concepts, operating system requirements, user features, cost, and no one program has emerged as the standard. The purpose of this study was to conduct a systematic comparison of three widely available 3D reconstructive software programs, Amira(®), OsiriX, and Mimics(®) , with respect to the software's ability to be used in two broad themes: morphometric research and education to translate morphological knowledge. Cost, system requirements, and inherent features of each program were compared. A novel concept selection tool, a decision matrix, was used to objectify comparisons of usability of the interface, quality of the output, and efficiency of the tools. Findings indicate that Mimics was the best-suited program for construction of 3D anatomical models and morphometric analysis, but for creating a learning tool the results were less clear. OsiriX was very user-friendly; however, it had limited capabilities. Conversely, although Amira had endless potential and could create complex dynamic videos, it had a challenging interface. These results provide a resource for morphometric researchers and educators to assist the selection of appropriate reconstruction programs when starting a new 3D modeling project.

  5. Laser nanostructuring 3-D bioconstruction based on carbon nanotubes in a water matrix of albumin

    NASA Astrophysics Data System (ADS)

    Gerasimenko, Alexander Y.; Ichkitidze, Levan P.; Podgaetsky, Vitaly M.; Savelyev, Mikhail S.; Selishchev, Sergey V.

    2016-04-01

    3-D bioconstructions were created using the evaporation method of the water-albumin solution with carbon nanotubes (CNTs) by the continuous and pulsed femtosecond laser radiation. It is determined that the volume structure of the samples created by the femtosecond radiation has more cavities than the one created by the continuous radiation. The average diameter for multi-walled carbon nanotubes (MWCNTs) samples was almost two times higher (35-40 nm) than for single-walled carbon nanotubes (SWCNTs) samples (20-30 nm). The most homogenous 3-D bioconstruction was formed from MWCNTs by the continuous laser radiation. The hardness of such samples totaled up to 370 MPa at the nanoscale. High strength properties and the resistance of the 3-D bioconstructions produced by the laser irradiation depend on the volume nanotubes scaffold forming inside them. The scaffold was formed by the electric field of the directed laser irradiation. The covalent bond energy between the nanotube carbon molecule and the oxygen of the bovine serum albumin aminoacid residue amounts 580 kJ/mol. The 3-D bioconstructions based on MWCNTs and SWCNTs becomes overgrown with the cells (fibroblasts) over the course of 72 hours. The samples based on the both types of CNTs are not toxic for the cells and don't change its normal composition and structure. Thus the 3-D bioconstructions that are nanostructured by the pulsed and continuous laser radiation can be applied as implant materials for the recovery of the connecting tissues of the living body.

  6. Computational model of mesenchymal migration in 3D under chemotaxis.

    PubMed

    Ribeiro, F O; Gómez-Benito, M J; Folgado, J; Fernandes, P R; García-Aznar, J M

    2017-01-01

    Cell chemotaxis is an important characteristic of cellular migration, which takes part in crucial aspects of life and development. In this work, we propose a novel in silico model of mesenchymal 3D migration with competing protrusions under a chemotactic gradient. Based on recent experimental observations, we identify three main stages that can regulate mesenchymal chemotaxis: chemosensing, dendritic protrusion dynamics and cell-matrix interactions. Therefore, each of these features is considered as a different module of the main regulatory computational algorithm. The numerical model was particularized for the case of fibroblast chemotaxis under a PDGF-bb gradient. Fibroblasts migration was simulated embedded in two different 3D matrices - collagen and fibrin - and under several PDGF-bb concentrations. Validation of the model results was provided through qualitative and quantitative comparison with in vitro studies. Our numerical predictions of cell trajectories and speeds were within the measured in vitro ranges in both collagen and fibrin matrices. Although in fibrin, the migration speed of fibroblasts is very low, because fibrin is a stiffer and more entangling matrix. Testing PDGF-bb concentrations, we noticed that an increment of this factor produces a speed increment. At 1 ng mL(-1) a speed peak is reached after which the migration speed diminishes again. Moreover, we observed that fibrin exerts a dampening behavior on migration, significantly affecting the migration efficiency.

  7. Computational model of mesenchymal migration in 3D under chemotaxis

    PubMed Central

    Ribeiro, F. O.; Gómez-Benito, M. J.; Folgado, J.; Fernandes, P. R.; García-Aznar, J. M.

    2017-01-01

    Abstract Cell chemotaxis is an important characteristic of cellular migration, which takes part in crucial aspects of life and development. In this work, we propose a novel in silico model of mesenchymal 3D migration with competing protrusions under a chemotactic gradient. Based on recent experimental observations, we identify three main stages that can regulate mesenchymal chemotaxis: chemosensing, dendritic protrusion dynamics and cell–matrix interactions. Therefore, each of these features is considered as a different module of the main regulatory computational algorithm. The numerical model was particularized for the case of fibroblast chemotaxis under a PDGF-bb gradient. Fibroblasts migration was simulated embedded in two different 3D matrices – collagen and fibrin – and under several PDGF-bb concentrations. Validation of the model results was provided through qualitative and quantitative comparison with in vitro studies. Our numerical predictions of cell trajectories and speeds were within the measured in vitro ranges in both collagen and fibrin matrices. Although in fibrin, the migration speed of fibroblasts is very low, because fibrin is a stiffer and more entangling matrix. Testing PDGF-bb concentrations, we noticed that an increment of this factor produces a speed increment. At 1 ng mL−1 a speed peak is reached after which the migration speed diminishes again. Moreover, we observed that fibrin exerts a dampening behavior on migration, significantly affecting the migration efficiency. PMID:27336322

  8. Design and characterization of 3D hybrid collagen matrixes as a dermal substitute in skin tissue engineering.

    PubMed

    Ramanathan, Giriprasath; Singaravelu, Sivakumar; Muthukumar, Thangavelu; Thyagarajan, Sitalakshmi; Perumal, Paramasivan Thirumalai; Sivagnanam, Uma Tiruchirapalli

    2017-03-01

    The highly interconnected porous dressing material was fabricated with the utilization of novel collagen (COL-SPG) for the efficient healing of the wound. Herein, we report the fabrication of 3D collagen impregnated with bioactive extract (COL-SPG-CPE) to get rid of infection at the wound site. The resultant 3D collagen matrix was characterized physiochemically using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and mechanical property. The dressing substrate possesses the high swelling ability, increase in the porosity, in vitro enzymatic degradability and antibacterial property. The in vitro biocompatibility and fluorescence activity of the collagen scaffold against both NIH 3T3 fibroblast and Human keratinocyte (HaCaT) cell lines assisted in excellent cell adhesion and proliferation over the collagen matrix. Furthermore, the in vivo evaluation of the COL-SPG-CPE 3D sponge exhibited with enhanced collagen synthesis and aids in faster reepithelialization. However, the rate of wound healing was influenced by the expression of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and transforming growth factor (TGF-β) growth factors promotes the collagen synthesis, thereby increases the healing efficiency. Based on the results, COL-SPG-CPE has a potential ability in the remodeling of the wound with the 3D collagen as wound dressing material. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Real-time 3-d intracranial ultrasound with an endoscopic matrix array transducer.

    PubMed

    Light, Edward D; Mukundan, Srinivasan; Wolf, Patrick D; Smith, Stephen W

    2007-08-01

    A transducer originally designed for transesophageal echocardiography (TEE) was adapted for real-time volumetric endoscopic imaging of the brain. The transducer consists of a 36 x 36 array with an interelement spacing of 0.18 mm. There are 504 transmitting and 252 receive channels placed in a regular pattern in the array. The operating frequency is 4.5 MHz with a -6 dB bandwidth of 30%. The transducer is fabricated on a 10-layer flexible circuit from Microconnex (Snoqualmie, WA, USA). The purpose of this study is to evaluate the clinical feasibility of real-time 3-D intracranial ultrasound with this device. The Volumetrics Medical Imaging (Durham, NC, USA) 3-D scanner was used to obtain images in a canine model. A transcalvarial acoustic window was created under general anesthesia in the animal laboratory by placing a 10-mm burr hole in the high parietal calvarium of a 50-kg canine subject. The burr-hole was placed in a left parasagittal location to avoid the sagittal sinus, and the transducer was placed against the intact dura mater for ultrasound imaging. Images of the lateral ventricles were produced, including real-time 3-D guidance of a needle puncture of one ventricle. In a second canine subject, contrast-enhanced 3-D Doppler color flow images were made of the cerebral vessels including the complete Circle of Willis. Clinical applications may include real-time 3-D guidance of cerebrospinal fluid extraction from the lateral ventricles and bedside evaluation of critically ill patients where computed tomography and magnetic resonance imaging techniques are unavailable.

  10. Monte Carlo - Metropolis Investigations of Shape and Matrix Effects in 2D and 3D Spin-Crossover Nanoparticles

    NASA Astrophysics Data System (ADS)

    Guerroudj, Salim; Caballero, Rafael; De Zela, Francisco; Jureschi, Catalin; Linares, Jorge; Boukheddaden, Kamel

    2016-08-01

    The Ising like model, taking into account short-, long-range interaction as well as surface effects is used to investigate size and shape effects on the thermal behaviour of 2D and 3D spin crossover (SCO) nanoparticles embedded in a matrix. We analyze the role of the parametert, representing the ratio between the number of surface and volume molecules, on the unusual thermal hysteresis behaviour (appearance of the hysteresis and a re-entrance phase transition) at small scales.

  11. Migration of tumor cells in 3D matrices is governed by matrix stiffness along with cell-matrix adhesion and proteolysis.

    PubMed

    Zaman, Muhammad H; Trapani, Linda M; Sieminski, Alisha L; Siemeski, Alisha; Mackellar, Drew; Gong, Haiyan; Kamm, Roger D; Wells, Alan; Lauffenburger, Douglas A; Matsudaira, Paul

    2006-07-18

    Cell migration on 2D surfaces is governed by a balance between counteracting tractile and adhesion forces. Although biochemical factors such as adhesion receptor and ligand concentration and binding, signaling through cell adhesion complexes, and cytoskeletal structure assembly/disassembly have been studied in detail in a 2D context, the critical biochemical and biophysical parameters that affect cell migration in 3D matrices have not been quantitatively investigated. We demonstrate that, in addition to adhesion and tractile forces, matrix stiffness is a key factor that influences cell movement in 3D. Cell migration assays in which Matrigel density, fibronectin concentration, and beta1 integrin binding are systematically varied show that at a specific Matrigel density the migration speed of DU-145 human prostate carcinoma cells is a balance between tractile and adhesion forces. However, when biochemical parameters such as matrix ligand and cell integrin receptor levels are held constant, maximal cell movement shifts to matrices exhibiting lesser stiffness. This behavior contradicts current 2D models but is predicted by a recent force-based computational model of cell movement in a 3D matrix. As expected, this 3D motility through an extracellular environment of pore size much smaller than cellular dimensions does depend on proteolytic activity as broad-spectrum matrix metalloproteinase (MMP) inhibitors limit the migration of DU-145 cells and also HT-1080 fibrosarcoma cells. Our experimental findings here represent, to our knowledge, discovery of a previously undescribed set of balances of cell and matrix properties that govern the ability of tumor cells to migration in 3D environments.

  12. Migration of tumor cells in 3D matrices is governed by matrix stiffness along with cell-matrix adhesion and proteolysis

    PubMed Central

    Zaman, Muhammad H.; Trapani, Linda M.; Sieminski, Alisha; MacKellar, Drew; Gong, Haiyan; Kamm, Roger D.; Wells, Alan; Lauffenburger, Douglas A.; Matsudaira, Paul

    2006-01-01

    Cell migration on 2D surfaces is governed by a balance between counteracting tractile and adhesion forces. Although biochemical factors such as adhesion receptor and ligand concentration and binding, signaling through cell adhesion complexes, and cytoskeletal structure assembly/disassembly have been studied in detail in a 2D context, the critical biochemical and biophysical parameters that affect cell migration in 3D matrices have not been quantitatively investigated. We demonstrate that, in addition to adhesion and tractile forces, matrix stiffness is a key factor that influences cell movement in 3D. Cell migration assays in which Matrigel density, fibronectin concentration, and β1 integrin binding are systematically varied show that at a specific Matrigel density the migration speed of DU-145 human prostate carcinoma cells is a balance between tractile and adhesion forces. However, when biochemical parameters such as matrix ligand and cell integrin receptor levels are held constant, maximal cell movement shifts to matrices exhibiting lesser stiffness. This behavior contradicts current 2D models but is predicted by a recent force-based computational model of cell movement in a 3D matrix. As expected, this 3D motility through an extracellular environment of pore size much smaller than cellular dimensions does depend on proteolytic activity as broad-spectrum matrix metalloproteinase (MMP) inhibitors limit the migration of DU-145 cells and also HT-1080 fibrosarcoma cells. Our experimental findings here represent, to our knowledge, discovery of a previously undescribed set of balances of cell and matrix properties that govern the ability of tumor cells to migration in 3D environments. PMID:16832052

  13. Elucidating the role of matrix stiffness in 3D cell migration and remodeling.

    PubMed

    Ehrbar, M; Sala, A; Lienemann, P; Ranga, A; Mosiewicz, K; Bittermann, A; Rizzi, S C; Weber, F E; Lutolf, M P

    2011-01-19

    Reductionist in vitro model systems which mimic specific extracellular matrix functions in a highly controlled manner, termed artificial extracellular matrices (aECM), have increasingly been used to elucidate the role of cell-ECM interactions in regulating cell fate. To better understand the interplay of biophysical and biochemical effectors in controlling three-dimensional cell migration, a poly(ethylene glycol)-based aECM platform was used in this study to explore the influence of matrix cross-linking density, represented here by stiffness, on cell migration in vitro and in vivo. In vitro, the migration behavior of single preosteoblastic cells within hydrogels of varying stiffness and susceptibilities to degradation by matrix metalloproteases was assessed by time-lapse microscopy. Migration behavior was seen to be strongly dependent on matrix stiffness, with two regimes identified: a nonproteolytic migration mode dominating at relatively low matrix stiffness and proteolytic migration at higher stiffness. Subsequent in vivo experiments revealed a similar stiffness dependence of matrix remodeling, albeit less sensitive to the matrix metalloprotease sensitivity. Therefore, our aECM model system is well suited to unveil the role of biophysical and biochemical determinants of physiologically relevant cell migration phenomena.

  14. Evaluation of platelet-rich plasma and fibrin matrix to assist in healing and repair of rotator cuff injuries: a systematic review and meta-analysis.

    PubMed

    Fu, Chun-Jiang; Sun, Jia-Bing; Bi, Zheng-Gang; Wang, Xu-Ming; Yang, Cheng-Lin

    2017-02-01

    To perform a meta-analysis examining the effectiveness of platelet-rich plasma and platelet-rich fibrin matrix for improving healing of rotator cuff injuries. Data sources/design: A meta-analysis of eligible studies was performed after searching Medline, Cochrane, and EMBASE on 14 December 2015. University hospital. Patients with rotator cuff injuries. Review methods/intervention: Databases were searched using the keywords "PRP or platelet-rich plasma," "PRFM or platelet-rich fibrin matrix," "rotator cuff," and "platelet-rich" for studies comparing outcomes of patients with rotator cuff injuries that did and did not receive a platelet-rich product. The primary outcome was a functional score change from pre- to post-treatment (Scorepost-Scorepre). The secondary outcome was a visual analogue scale (VAS) pain score change from pre- to post-treatment (VASpost-VASpre). A total of 11 studies were included in the meta-analysis. The total number of patients that received platelet-rich plasma or platelet-rich fibrin matrix was 320 and the number of control patients was 318. The standard difference in means of the functional scores was similar between patients administered platelet-rich plasma/fibrin matrix and patients in the control group (standard difference in means for functional scores = 0.029; 95% confidence interval (CI): -0.132 to 0.190; p = 0.725). The standard difference in means was similar between patients administered platelet-rich plasma and the controls (standard difference in means = 0.142; 95% CI: -0.080 to 0.364; p = 0.209). The results of this meta-analysis do not support the use of platelet-rich plasma/platelet-rich fibrin matrix in patients with rotator cuff injuries.

  15. Planar Gradient Diffusion System to Investigate Chemotaxis in a 3D Collagen Matrix.

    PubMed

    Stout, David A; Toyjanova, Jennet; Franck, Christian

    2015-06-12

    The importance of cell migration can be seen through the development of human life. When cells migrate, they generate forces and transfer these forces to their surrounding area, leading to cell movement and migration. In order to understand the mechanisms that can alter and/or affect cell migration, one can study these forces. In theory, understanding the fundamental mechanisms and forces underlying cell migration holds the promise of effective approaches for treating diseases and promoting cellular transplantation. Unfortunately, modern chemotaxis chambers that have been developed are usually restricted to two dimensions (2D) and have complex diffusion gradients that make the experiment difficult to interpret. To this end, we have developed, and describe in this paper, a direct-viewing chamber for chemotaxis studies, which allows one to overcome modern chemotaxis chamber obstacles able to measure cell forces and specific concentration within the chamber in a 3D environment to study cell 3D migration. More compelling, this approach allows one to successfully model diffusion through 3D collagen matrices and calculate the coefficient of diffusion of a chemoattractant through multiple different concentrations of collagen, while keeping the system simple and user friendly for traction force microscopy (TFM) and digital volume correlation (DVC) analysis.

  16. Degradation of fibrin and elastin by intact human alveolar macrophages in vitro. Characterization of a plasminogen activator and its role in matrix degradation.

    PubMed Central

    Chapman, H A; Stone, O L; Vavrin, Z

    1984-01-01

    Fibrin deposition is prominent in the histopathology of a number of inflammatory lung diseases. Plasmin, activated locally in the lung, can degrade not only this fibrin but potentially structural proteins important to normal lung architecture. Because alveolar macrophages are prominent in inflammatory processes of the lung, we examined the plasminogen activator (PA) activity of human alveolar macrophages. Intact alveolar macrophages from each of 10 healthy subjects expressed PA activity. There was no difference in activity between smoking and nonsmoking individuals. The activator activity was largely cell-associated, but under certain culture conditions, macrophages released a soluble activator into the culture medium. The membrane-bound activator had an apparent molecular mass of 52-55 kD in nonreduced sodium dodecyl sulfate (SDS) gels, and monospecific antibody to urokinase neutralized the enzyme activity. Immunoprecipitation of [35S]methionine-labeled cells showed that human alveolar macrophages actually synthesize the PA in vitro. SDS-gel analysis of the immunoprecipitated material revealed the predominant species of PA to be structurally similar to reduced, active urokinase. We also examined the role of PA in the degradation of both insoluble fibrin and elastin matrices by live macrophages. Cells degraded an insoluble fibrin matrix in the presence of plasminogen whether or not the macrophages contacted the fibrin as long as proteinase inhibitors were not in the culture medium. In the presence of serum proteinase inhibitors, macrophages still degraded a fibrin matrix, but only if they were in contact with the fibrin. Live macrophages also degraded insoluble elastin only when in contact with the elastin but could do so even in the presence of serum proteinase inhibitors. In matrices containing a mixture of fibrin and elastin, cells did not degrade elastin unless plasminogen was added to the medium. These results indicate that normal alveolar macrophages

  17. Using a decellularized splenic matrix as a 3D scaffold for hepatocyte cultivation in vitro: a preliminary trial.

    PubMed

    Zheng, Xing-Long; Xiang, Jun-Xi; Wu, Wan-Quan; Wang, Bo; Liu, Wen-Yan; Gao, Rui; Dong, Ding-Hui; Lv, Yi

    2015-08-18

    Using a decellularized liver matrix (DLM) to reengineer liver tissue is a promising therapy for end-stage liver disease. However, the limited supply of donor organs still hampers its potential clinical application, while a xenogenic decellularized matrix may bring a risk of zoonosis and immunological rejection. Therefore, an appropriate alternative scaffold is needed. In this research, we established a decellularized splenic matrix (DSM) in a rodent model, which preserved the 3D ultrastructure, the components of the extracellular matrix (ECM) and the native vascular network. The DSM and DLM had similar components of ECM, and similar mechanical properties. Hepatocytes were seeded to the DSM and DLM for dynamic culturing up to 6 d, and distributed both in decellularized sinusoidal spaces and around the vessels. The TUNEL-positive cell percentage in a dynamic culturing decellularized splenic matrix (dDSM) was 10.7%  ±  3.6% at 3d and 25.8%  ±  5.6% at 5d, although 14.2%  ±  4.5% and 24.8%  ±  2.9%, respectively, in a dynamic culturing decellularized liver matrix (dDLM) at the same time point (p  >  0.05). Primary hepatocytes in the dDSM and dDLM expressed albumin, G6pc and Ugt1a1. The gene expression of Cyp2b1, Cyp1a2 and HNF1α in the gene transcription level revealed hepatocytes had lower gene expression levels in the dDSM compared with the dDLM at 3d, but better than those in a sandwich culture. The cumulative albumin production at 6 d of culture was 80.7   ±   9.6 μg per million cells in the dDSM and 89.6   ±   4.6 μg per million cells in the dDLM (p  >  0.05). In summary, the DSM is a promising 3D scaffold for hepatocyte cultivation in vitro.

  18. Engineering 3D bio-artificial heart muscle: the acellular ventricular extracellular matrix model.

    PubMed

    Patel, Nikita M; Tao, Ze-Wei; Mohamed, Mohamed A; Hogan, Matt K; Gutierrez, Laura; Birla, Ravi K

    2015-01-01

    Current therapies in left ventricular systolic dysfunction and end-stage heart failure include mechanical assist devices or transplant. The development of a tissue-engineered integrative platform would present a therapeutic option that overcomes the limitations associated with current treatment modalities. This study provides a foundation for the fabrication and preliminary viability of the acellular ventricular extracellular matrix (AVEM) model. Acellular ventricular extracellular matrix was fabricated by culturing 4 million rat neonatal cardiac cells around an excised acellular ventricular segment. Acellular ventricular extracellular matrix generated a maximum spontaneous contractile force of 388.3 μN and demonstrated a Frank-Starling relationship at varying pretensions. Histologic assessment displayed cell cohesion and adhesion within the AVEM as a result of passive cell seeding.

  19. Platelet-Rich Fibrin Facilitates Rabbit Meniscal Repair by Promoting Meniscocytes Proliferation, Migration, and Extracellular Matrix Synthesis

    PubMed Central

    Wong, Chin-Chean; Kuo, Tzong-Fu; Yang, Tsung-Lin; Tsuang, Yang-Hwei; Lin, Ming-Fang; Chang, Chung-Hsun; Lin, Yun-Ho

    2017-01-01

    Although platelet-rich fibrin (PRF) has been used in clinical practice for some time, to date, few studies reveal its role as a bioactive scaffold in facilitating meniscal repair. Here, the positive anabolic effects of PRF on meniscocytes harvested from the primary culture of a rabbit meniscus were revealed. The rabbit meniscocytes were cultured with different concentrations of PRF-conditioned medium, and were evaluated for their ability to stimulate cell migration, proliferation, and extracellular matrix formation. In vivo, meniscal defects were created via an established rabbit animal model and were evaluated by a histology-based four-stage scoring system to validate the treatment outcome three months postoperatively. The in vitro results showed that PRF could induce cellular migration and promote proliferation and meniscocyte extracellular matrix (ECM) synthesis of cultured meniscocytes. In addition, PRF increased the formation and deposition of cartilaginous matrix produced by cultured meniscocytes. Morphological and histological evaluations demonstrated that PRF could facilitate rabbit meniscal repair. The data highlight the potential utility of using PRF in augmenting the healing of meniscal injuries. These advantages would benefit clinical translation, and are a potential new treatment strategy for meniscal repair. PMID:28783120

  20. [Experimental study of the collagen matrix for increase the gums using a 3D-modeling].

    PubMed

    Baulin, I M; Badalyan, V A; Ryakhovsky, A N

    2015-01-01

    In an experimental study on mini-pigs demonstrated that the use of collagen matrix Mucograft open method leads to the formation of mature connective tissue around the implants, more pronounced after 70 days, and the width of attached mucosa already 45th day (from 4.4 ± 0.3 to 7.7 ± 0.5 mm) is comparable to that of free gingival graft. Three-dimensional computer modeling of jaws experimental animals showed the soft tissue augmentation by 0.8 ± 0.1 cm3 after use of collagen matrix Mucograft and 1.1 ± 0.12 cm3 after free gingival graft.

  1. Surface Topography and Mechanical Strain Promote Keratocyte Phenotype and Extracellular Matrix Formation in a Biomimetic 3D Corneal Model.

    PubMed

    Zhang, Wei; Chen, Jialin; Backman, Ludvig J; Malm, Adam D; Danielson, Patrik

    2017-03-01

    The optimal functionality of the native corneal stroma is mainly dependent on the well-ordered arrangement of extracellular matrix (ECM) and the pressurized structure. In order to develop an in vitro corneal model, it is crucial to mimic the in vivo microenvironment of the cornea. In this study, the influence of surface topography and mechanical strain on keratocyte phenotype and ECM formation within a biomimetic 3D corneal model is studied. By modifying the surface topography of materials, it is found that patterned silk fibroin film with 600 grooves mm(-1) optimally supports cell alignment and ECM arrangement. Furthermore, treatment with 3% dome-shaped mechanical strain, which resembles the shape and mechanics of native cornea, significantly enhances the expression of keratocyte markers as compared to flat-shaped strain. Accordingly, a biomimetic 3D corneal model, in the form of a collagen-modified, silk fibroin-patterned construct subjected to 3% dome-shaped strain, is created. Compared to traditional 2D cultures, it supports a significantly higher expression of keratocyte and ECM markers, and in conclusion better maintains keratocyte phenotype, alignment, and fusiform cell shape. Therefore, the novel biomimetic 3D corneal model developed in this study serves as a useful in vitro 3D culture model to improve current 2D cultures for corneal studies.

  2. 3D ToF-SIMS Analysis of Peptide Incorporation into MALDI Matrix Crystals with Sub-micrometer Resolution

    NASA Astrophysics Data System (ADS)

    Körsgen, Martin; Pelster, Andreas; Dreisewerd, Klaus; Arlinghaus, Heinrich F.

    2016-02-01

    The analytical sensitivity in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is largely affected by the specific analyte-matrix interaction, in particular by the possible incorporation of the analytes into crystalline MALDI matrices. Here we used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to visualize the incorporation of three peptides with different hydrophobicities, bradykinin, Substance P, and vasopressin, into two classic MALDI matrices, 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (HCCA). For depth profiling, an Ar cluster ion beam was used to gradually sputter through the matrix crystals without causing significant degradation of matrix or biomolecules. A pulsed Bi3 ion cluster beam was used to image the lateral analyte distribution in the center of the sputter crater. Using this dual beam technique, the 3D distribution of the analytes and spatial segregation effects within the matrix crystals were imaged with sub-μm resolution. The technique could in the future enable matrix-enhanced (ME)-ToF-SIMS imaging of peptides in tissue slices at ultra-high resolution.

  3. 3D ToF-SIMS Analysis of Peptide Incorporation into MALDI Matrix Crystals with Sub-micrometer Resolution.

    PubMed

    Körsgen, Martin; Pelster, Andreas; Dreisewerd, Klaus; Arlinghaus, Heinrich F

    2016-02-01

    The analytical sensitivity in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is largely affected by the specific analyte-matrix interaction, in particular by the possible incorporation of the analytes into crystalline MALDI matrices. Here we used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to visualize the incorporation of three peptides with different hydrophobicities, bradykinin, Substance P, and vasopressin, into two classic MALDI matrices, 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (HCCA). For depth profiling, an Ar cluster ion beam was used to gradually sputter through the matrix crystals without causing significant degradation of matrix or biomolecules. A pulsed Bi3 ion cluster beam was used to image the lateral analyte distribution in the center of the sputter crater. Using this dual beam technique, the 3D distribution of the analytes and spatial segregation effects within the matrix crystals were imaged with sub-μm resolution. The technique could in the future enable matrix-enhanced (ME)-ToF-SIMS imaging of peptides in tissue slices at ultra-high resolution. Graphical Abstract ᅟ.

  4. Experimental studies of cobalt ferrite nanoparticles doped silica matrix 3D magneto-photonic crystals

    NASA Astrophysics Data System (ADS)

    Abou Diwan, E.; Royer, F.; Kekesi, R.; Jamon, D.; Blanc-Mignon, M. F.; Neveu, S.; Rousseau, J. J.

    2013-05-01

    In this paper, we present the synthesis and the optical properties of 3D magneto-photonic structures. The elaboration process consists in firstly preparing then infiltrating polystyrene direct opals with a homogeneous solution of sol-gel silica precursors doped by cobalt ferrite nanoparticles, and finally dissolving the polystyrene spheres. Scanning Electron Microscopy (SEM) images of the prepared samples clearly evidence a periodic arrangement. Using a home-made polarimetric optical bench, the transmittance as a function of the wavelength, the Faraday rotation as a function of the applied magnetic field, and the Faraday ellipticity as a function of the wavelength and as a function of the applied magnetic field were measured. The existence of deep photonic band gaps (PBG), the unambiguous magnetic character of the samples and the qualitative modification of the Faraday ellipticity in the area of the PBG are evidenced.

  5. Environmental Dependence of Artifact CD Peaks of Chiral Schiff Base 3d-4f Complexes in Soft Mater PMMA Matrix

    PubMed Central

    Okamoto, Yu; Nidaira, Keisuke; Akitsu, Takashiro

    2011-01-01

    Four chiral Schiff base binuclear 3d-4f complexes (NdNi, NdCu, GdNi, and GdCu) have been prepared and characterized by means of electronic and CD spectra, IR spectra, magnetic measurements, and X-ray crystallography (NdNi). A so-called artifact peak of solid state CD spectra, which was characteristic of oriented molecules without free molecular rotation, appeared at about 470 nm. Magnetic data of the complexes in the solid state (powder) and in PMMA cast films or solutions indicated that only GdCu preserved molecular structures in various matrixes of soft maters. For the first time, we have used the changes of intensity of artifact CD peaks to detect properties of environmental (media solid state (KBr pellets), PMMA cast films, concentration dependence of PMMA in acetone solutions, and pure acetone solution) for chiral 3d-4f complexes (GdCu). Rigid matrix keeping anisotropic orientation exhibited a decrease in the intensity of the artifact CD peak toward negative values. The present results suggest that solid state artifact CD peaks can be affected by environmental viscosity of a soft mater matrix. PMID:22072930

  6. Microvesicles shed from fibroblasts act as metalloproteinase carriers in a 3-D collagen matrix.

    PubMed

    Laghezza Masci, Valentina; Taddei, Anna Rita; Gambellini, Gabriella; Giorgi, Franco; Fausto, Anna Maria

    2016-01-01

    This study shows that fibroblasts migrating into a collagen matrix release numerous microvesicles into the surrounding medium. By spreading in regions of the matrix far distant from cells of origin, microvesicles carry metalloproteinase 9 (MMP-9) to act upon the collagen fibrils. As a result, the collagen matrix is gradually transformed from a laminar to a fibrillar type of architecture. As shown by western blots and gelatin zymography, MMP-9 is secreted as a 92 kDa precursor and activated upon release of 82 kDa product into the culture medium. Activation is more efficient under three-dimensional than in two-dimensional culturing conditions. While MMP-9 labeling is associated with intraluminal vesicles clustered inside the microvesicles, the microvesicle's integrin β1 marker is bound to the outer membrane. The intraluminal vesicles are recruited from the cortical cytoplasm and eventually released following uploading inside the microvesicle. Here, we propose that fusion of the intraluminal vesicles with the outer microvesicle's membrane could work as a mechanism controlling the extent to which MMP-9 is first activated and then released extracellularly.

  7. Microvesicles shed from fibroblasts act as metalloproteinase carriers in a 3-D collagen matrix

    PubMed Central

    Taddei, Anna Rita; Gambellini, Gabriella; Giorgi, Franco; Fausto, Anna Maria

    2016-01-01

    This study shows that fibroblasts migrating into a collagen matrix release numerous microvesicles into the surrounding medium. By spreading in regions of the matrix far distant from cells of origin, microvesicles carry metalloproteinase 9 (MMP-9) to act upon the collagen fibrils. As a result, the collagen matrix is gradually transformed from a laminar to a fibrillar type of architecture. As shown by western blots and gelatin zymography, MMP-9 is secreted as a 92 kDa precursor and activated upon release of 82 kDa product into the culture medium. Activation is more efficient under three-dimensional than in two-dimensional culturing conditions. While MMP-9 labeling is associated with intraluminal vesicles clustered inside the microvesicles, the microvesicle’s integrin β1 marker is bound to the outer membrane. The intraluminal vesicles are recruited from the cortical cytoplasm and eventually released following uploading inside the microvesicle. Here, we propose that fusion of the intraluminal vesicles with the outer microvesicle’s membrane could work as a mechanism controlling the extent to which MMP-9 is first activated and then released extracellularly. PMID:28936262

  8. Direct measurement of matrix metalloproteinase activity in 3D cellular microenvironments using a fluorogenic peptide substrate.

    PubMed

    Leight, Jennifer L; Alge, Daniel L; Maier, Andrew J; Anseth, Kristi S

    2013-10-01

    Incorporation of degradable moieties into synthetic hydrogels has greatly increased the utility of these three-dimensional matrices for in vitro cell culture as well as tissue engineering applications. A common method for introducing degradability is the inclusion of oligopeptides sensitive to cleavage by matrix metalloproteinases (MMPs), enabling cell-mediated remodeling and migration within the material. While this strategy has been effective, characterization and measurement of cell-mediated degradation in these materials has remained challenging. There are 20+ MMP family members whose activity is regulated in space and time by a number of biochemical and biophysical cues. Thus, the typical approach of characterizing cleavage of degradable moieties in solution with recombinant enzymes does not easily translate to three-dimensional cell-mediated matrix remodeling. To address this challenge, we report here the synthesis of a cell-laden hydrogel matrix functionalized with a fluorogenic peptide substrate to provide real-time, quantitative monitoring of global MMP activity. Using this system, stimulation of MMP activity was observed with growth factor treatment in mammary epithelial cells and compared to classical zymography results. Further, the effect of biophysical cues on MMP activity of human mesenchymal stem cells was also investigated where more rigid hydrogels were observed to increase MMP activity. The regulation of MMP activity by these biochemical and biophysical cues highlights the need for in situ, real-time measurement of hydrogel degradation, and use of these functionalized hydrogels will aid in future rational design of degradable synthetic hydrogels for in vitro cell studies and tissue engineering applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Globular and Optically Transparent Photonic Crystals Based on 3D-opal Matrix and REE

    NASA Astrophysics Data System (ADS)

    Ivicheva, S. N.; Kargin, Yu. F.; Gorelik, V. S.

    By repeatedly filling the octahedral and tetrahedral pores of 3D-silica opal matrices with silica sol doped with rare-earth elements with subsequent heat treatment globular photonic crystals filled with mesoporous glass and optically transparent photonic crystals (quantytes) containing 10-30 ppm REE were produced, depending on the annealing temperature. Voids of fcc lattice formed by amorphous spherical globules of SiO2 in globular photonic crystals are filled (up to 70%) by mesoporous glass doped with rare earth elements. Pores in the transparent photonic crystals disappear during sintering of globules of silica and mesoporous glass, but the periodic arrangement of REE-enriched silica areas (quantum dots) is retained. The reflection and luminescence spectra of photonic crystals filled with sols doped with europium Eu3+ and terbium Tb3+ were experimentally studied. A significant increase in the photoluminescence intensity of Eu3+ ions at the approach of the spectral position of the transition 5D0 → 7F2 to the edge of the bandgaps of the photonic crystal was determined. The authors come to the conclusion that a lowering of the threshold for lasing transitions in ions of rare elements is possible.

  10. Response of microscale cell/matrix constructs to successive force application in a 3D environment

    NASA Astrophysics Data System (ADS)

    Liu, Alan; Chen, Christopher; Reich, Daniel

    2014-03-01

    Mechanical dilation of arteries by pulsatile blood flow is directly opposed by coordinated contraction of a band of smooth muscle tissue that envelops the vessels. This mechanical adaptation of smooth muscle cells to external loading is a critical feature of normal blood vessel function. While most previous studies on biomechanical systems have focused on single cells or large excised tissue, we utilize a device to apply forces to engineered smooth muscle microtissues. This device consists of arrayed pairs of elastomeric micro-cantilevers capable of magnetic actuation. Tissues are formed through self-assembly following the introduction of cell-infused collagen gel to the array. With this system, we are able to dynamically stretch and relax these sub-millimeter sized tissues. The timing and magnitude of the force application can be precisely controlled and thus can be used to mimic a wide range of physiological behavior. In particular, we will discuss results that show that the interval between successive force applications mediates the both the subsequent mechanical and active dynamics of the cell/matrix composite system. Understanding this process will lead to better understanding of the interplay between cell and extracellular matrix responses to mechanical stimulus at a novel length scale.

  11. Microscale Diffusion Properties of the Cartilage Pericellular Matrix Measured Using 3D Scanning Microphotolysis

    PubMed Central

    Leddy, Holly A.; Christensen, Susan E.; Guilak, Farshid

    2009-01-01

    Chondrocytes (cartilage cells) are enclosed within a pericellular matrix (PCM) whose composition and structure differ from those of the extracellular matrix (ECM). Since the PCM surrounds each cell, molecules that interact with the chondrocyte must pass through the pericellular environment. A quantitative understanding of the diffusional properties of the PCM will help elucidate the PCM’s regulatory role in controlling transport to and from the chondrocyte. The diffusivity of a fluorescently-labeled 70 kDa dextran was quantified within the PCM of porcine articular cartilage using a newly-developed mathematical model of scanning microphotolysis (SCAMP). SCAMP is a rapid, line photobleaching method that accounts for out-of-plane bleaching attributable to high magnification. Data were analyzed by best-fit comparison to simulations generated using a discretization of the diffusion-reaction equation in conjunction with the microscope-specific three-dimensional excitation and detection profiles. The diffusion coefficient of dextran was significantly lower in the PCM than in the ECM in normal cartilage. In early-stage arthritic tissue, however, no significant differences in diffusivity were detectable. These results support the hypothesis that the diffusivity of the PCM is lower than that of the ECM, presumably due to differences in proteoglycan content, and that osteoarthritic changes in tissue affect the transport properties of the PCM. PMID:19045531

  12. Incorporation of Ag metallic nanoparticles in 3D gelatin matrix via the green strategy solution plasma.

    PubMed

    Pootawang, Panuphong; Kim, Seong Cheol; Kim, Jung Wan; Lee, Sang Yul

    2013-01-01

    The environmental concern pays much attention to the recent cause of the global warming effect. The reduction of the chemical uses is one of many ways to avoid this crucial problem. Herein, the green process for silver nanometallic particle formation and incorporation in gelatin are proposed. By using a novel discharge process in solution named solution plasma, the silver nanometallic particle formation and its incorporation in gelatin could be accomplished in one-batch reactor during discharge by using silver nitrate (AgNO3) solution as the precursor and controlling systematical parameters. The three-dimensional scaffolds of gelatin/silver biocomposite were fabricated using lyophilizer and the water-soluble property of gelatin was improved by irradiation of ultraviolet ray. The well dispersed silver nanoparticles with the mean particle size 10-20 nm in the good texture of gelatin matrix were obtained. The density of micropore in gelatin/silver scaffold was proportional to the gelatin concentration. In addition, thermal stability of prepared samples had no change comparing with pure gelatin, indicating that the incorporation of silver nanoparticles in gelatin matrix did not affect to the nature of gelatin.

  13. Ridge preservation using a new 3D collagen matrix: a preclinical study.

    PubMed

    Roman, Alexandra; Cioban, Cosmin; Stratul, Stefan-Ioan; Schwarz, Frank; Muste, Aurel; Petrutiu, Stefan-Adrian; Zaganescu, Raluca; Mihatovic, Ilja

    2015-07-01

    The success of ridge preservation techniques in reducing bone resorption is well documented, but no clear guidelines have been provided regarding the type of the biomaterial or technique to be used. This experimental animal study aimed at comparing the effectiveness of two ridge preservation techniques. Following the extraction of the distal roots of the mandibular second and fourth premolars of four dogs, the sockets were preserved using a combination of a collagen membrane intimately covering the socket plus a collagen matrix or a collagen membrane alone. The mandibular quadrants were randomly assigned to one of the treatment groups. Histomorphometrical analyses as well as microscopic observations were performed. After 5 months of healing, the histological analysis revealed a similar picture of bone formation in both groups. No significant differences between the buccal and lingual dimensions were calculated between the two treatment groups. The mucosa covering the alveolar ridges is significantly more abundant in post-extraction sockets preserved with the double-layered approach. The double-layered approach used to treat post-extraction sockets may result in a better preservation of the mucosal seal than the single-layered approach. The use of the new collagen matrix associated with a collagen membrane could be a clinical option to preserve post-extraction ridges, especially when an improvement in soft tissue dimension and quality is desired. However, the cost-benefit ratio of this approach should be thoroughly evaluated in further studies.

  14. Multi-scale Characterisation of the 3D Microstructure of a Thermally-Shocked Bulk Metallic Glass Matrix Composite

    PubMed Central

    Zhang, Wei; Bodey, Andrew J.; Sui, Tan; Kockelmann, Winfried; Rau, Christoph; Korsunsky, Alexander M.; Mi, Jiawei

    2016-01-01

    Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods. PMID:26725519

  15. Multi-scale Characterisation of the 3D Microstructure of a Thermally-Shocked Bulk Metallic Glass Matrix Composite

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Bodey, Andrew J.; Sui, Tan; Kockelmann, Winfried; Rau, Christoph; Korsunsky, Alexander M.; Mi, Jiawei

    2016-01-01

    Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods.

  16. Multi-scale Characterisation of the 3D Microstructure of a Thermally-Shocked Bulk Metallic Glass Matrix Composite.

    PubMed

    Zhang, Wei; Bodey, Andrew J; Sui, Tan; Kockelmann, Winfried; Rau, Christoph; Korsunsky, Alexander M; Mi, Jiawei

    2016-01-04

    Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods.

  17. A multiparallel bioreactor for the cultivation of mammalian cells in a 3D-ceramic matrix.

    PubMed

    Goralczyk, Vicky; Driemel, Gregor; Bischof, Andreas; Peter, Andrea; Berthold, Almuth; Kroh, Lothar; Blessing, Lucienne; Schubert, Helmut; King, Rudibert

    2010-01-01

    For adherently growing cells, cultivation is limited by the provided growth surface. Excellent surface-to-volume ratios are found in highly porous matrices, which have to face the challenge of nutrient supply inside the matrices' caverns. Therefore, perfusion strategies are recommended which often have to deal with the need of developing an encompassing bioreactor periphery. We present a modular bioreactor system based on a porous ceramic matrix that enables the supply of cells with oxygen and nutrients by perfusion. The present version of the reactor system focuses on simple testing of various inoculation and operation modes. Moreover, it can be used to efficiently test different foam structures. Protocols are given to set-up the system together with handling procedures for long-time cultivation of a CHO cell line. Experimental results confirm vital growth of cells inside the matrices' caverns.

  18. 3D printed complex tissue construct using stem cell-laden decellularized extracellular matrix bioinks for cardiac repair.

    PubMed

    Jang, Jinah; Park, Hun-Jun; Kim, Seok-Won; Kim, Heejin; Park, Ju Young; Na, Soo Jin; Kim, Hyeon Ji; Park, Moon Nyeo; Choi, Seung Hyun; Park, Sun Hwa; Kim, Sung Won; Kwon, Sang-Mo; Kim, Pum-Joon; Cho, Dong-Woo

    2017-01-01

    Stem cell therapy is a promising therapeutic method for the treatment of ischemic heart diseases; however, some challenges prohibit the efficacy after cell delivery due to hostile microenvironment of the injured myocardium. 3D printed pre-vascularized stem cell patch can enhance the therapeutic efficacy for cardiac repair through promotion of rapid vascularization after patch transplantation. In this study, stem cell-laden decellularized extracellular matrix bioinks are used in 3D printing of pre-vascularized and functional multi-material structures. The printed structure composed of spatial patterning of dual stem cells improves cell-to-cell interactions and differentiation capability and promotes functionality for tissue regeneration. The developed stem cell patch promoted strong vascularization and tissue matrix formation in vivo. The patterned patch exhibited enhanced cardiac functions, reduced cardiac hypertrophy and fibrosis, increased migration from patch to the infarct area, neo-muscle and capillary formation along with improvements in cardiac functions. Therefore, pre-vascularized stem cell patch provides cardiac niche-like microenvironment, resulting in beneficial effects on cardiac repair.

  19. Cells in 3D matrices under interstitial flow: effects of extracellular matrix alignment on cell shear stress and drag forces.

    PubMed

    Pedersen, John A; Lichter, Seth; Swartz, Melody A

    2010-03-22

    Interstitial flow is an important regulator of various cell behaviors both in vitro and in vivo, yet the forces that fluid flow imposes on cells embedded in a 3D extracellular matrix (ECM), and the effects of matrix architecture on those forces, are not well understood. Here, we demonstrate how fiber alignment can affect the shear and pressure forces on the cell and ECM. Using computational fluid dynamics simulations, we show that while the solutions of the Brinkman equation accurately estimate the average fluid shear stress and the drag forces on a cell within a 3D fibrous medium, the distribution of shear stress on the cellular surface as well as the peak shear stresses remain intimately related to the pericellular fiber architecture and cannot be estimated using bulk-averaged properties. We demonstrate that perpendicular fiber alignment of the ECM yields lower shear stress and pressure forces on the cells and higher stresses on the ECM, leading to decreased permeability, while parallel fiber alignment leads to higher stresses on cells and increased permeability, as compared to a cubic lattice arrangement. The Spielman-Goren permeability relationships for fibrous media agreed well with CFD simulations of flow with explicitly considered fibers. These results suggest that the experimentally observed active remodeling of ECM fibers by fibroblasts under interstitial flow to a perpendicular alignment could serve to decrease the shear and drag forces on the cell.

  20. Second harmonic generation imaging of collagen matrix remodeling in a stimulated 3D cellular environment: forward versus backward detection

    NASA Astrophysics Data System (ADS)

    Abraham, Thomas; Scott, Alex; Carthy, Jon; McManus, Bruce

    2011-03-01

    The structural remodeling of collagen is important in several biological processes such as wound healing, tendon repair, fibrosis and developmental morphogenesis. Multiphoton microscopy, which uses ultra-short femto-second laser pulses as an excitation source, is efficient in the multiphoton excitation fluorescence (MPEF) of exogenous fluorescent labels tagged to various cellular macromolecular objects, as well as in the induction of a highly specific second harmonic generation (SHG) signal from non-centrosymmetric macromolecules such as fibrillar collagens. Although the non-descanned detectors in the reflection geometry have normally been employed for capturing the backward scattered SHG as well as the MPEF signals, considering the wide range of engineered thick tissue imaging applications, there are still un-answered questions about the generated 3D collagen structures because of the directional pattern of SHG signals. The present study dealt with an in vitro collagen-fibroblast raft model in which the stimulation of fibroblast cells induced the lateral orientation of collagen molecules. The SHG signals originating from the 3D collagen matrix were captured simultaneously in both forward and backward scattering directions to understand the collagen structural differences and to generate a comprehensive understanding of collagen matrix remodeling.

  1. Primary chicken embryo fibroblasts seeded acellular dermal matrix (3-D ADM) improve regeneration of full thickness skin wounds in rats.

    PubMed

    Gangwar, Anil Kumar; Kumar, Naveen; Khangembam, Sangeeta Devi; Kumar, Vineet; Singh, Rajendra

    2015-06-01

    Rat skins were deepithelialized and decellularized by hypertonic saline and sodium deoxycholate (SDC), respectively. Primary chicken embryo fibroblasts (P-CEF) were cultured and seeded on prepared acellular dermal matrix (ADM). A full thickness skin defect (20×20 mm(2)) was created in thirty-six rats and randomly divided into three equal groups. Defect was left open, repaired with ADM and ADM seeded with P-CEF (3-D ADM) in groups 1, 2 and 3, respectively. By day 28, the treated wounds healed completely without scar. By day 7 hydroxyproline contents was higher in group 3 as compared to groups 1 and 2. There was slightly more B cell response in animals implanted with ADM and 3-D ADM. At day 21, stimulation index was lower with acellular dermis antigen as compared to 3-D ADM antigen. In group 1 on day 3, the granulation tissue showed more inflammatory reaction, fibroplasia and neovascularization as compared to group 2 and 3. By day 28, there was complete epithelization was observed in all groups over. However, a large scar was observed in group 1. The graft was completely absorbed and replaced with densely thick and best arranged collagen fibers. On day 7, malonyldialdehyde and superoxide dismutase levels were significantly (P<0.05) increased in group 1. Reduced glutathione values increased and reached to near normal in groups 2 and 3. Catalase values were significantly (P<0.05) higher in group 1 at different time intervals. SEM samples of group 2 showed ingrowth of fibroblasts into acellular matrix at host graft junction. However, in group 3 fibroblasts were infiltrated within the pores of graft. It was concluded that P-CEF cells seeded ADM facilitated early and better healing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Parallel, ‘large', dense matrix problems: Application to 3D sequential integrated inversion of seismological and gravity data

    NASA Astrophysics Data System (ADS)

    Tondi, R.; Cavazzoni, C.; Danecek, P.; Morelli, A.

    2012-11-01

    To obtain accurate and reliable estimations of the major lithological properties of the rock within a studied volume, geophysics uses the joint information provided by different geophysical datasets (e.g. gravimetric, magnetic, seismic). Representation of the different types of information entering the problem using probability density functions can provide the mathematical framework to formulate their combination. The maximum likelihood estimator of the resulting joint posterior probability density functions leads to the solution of the problem. However, one key problem appears to limit the use of this solver to an extensive range of real applications: information coming from potential fields that implies the presence of dense matrices in the resolving estimator. It is well known that dense matrix systems rapidly challenge both the algorithms and the computing platforms, and are not suited to high-resolution 3D geophysical analysis. In this study, we propose a procedure that allows us to obtain fast and reliable solutions of the joint posterior probability density functions in the presence of large gravity datasets and using sophisticated model parametrization. As it is particularly CPU-consuming, this 3D problem makes use of parallel computing to improve the performance and the accuracy of the simulations. Analysis of the correctness of the results, and the performance on different parallel environments, shows the portability and the efficiency of the code. This code is applied to a real experiment, where we succeed in recovering a 3D shear-wave velocity and density distribution within the upper mantle of the European continent, satisfying both the seismological and gravity data. On a multiprocessor machine, we have been able to handle forward and inverse calculations with a dense matrix of 215.66 Gb in 18 min, 20 s and 20 min, 54 s, respectively.

  3. 3D Epitaxy of Graphene nanostructures in the Matrix of Ag, Al and Cu

    NASA Astrophysics Data System (ADS)

    Salamanca-Riba, Lourdes; Isaacs, Romaine; Wuttig, Manfred; Lemieux, Melburne; Hu, Liangbing; Iftekhar, Jaim; Rashkeev, Sergey; Kukla, Maija; Rabin, Oded; Mansour, Azzam

    2015-03-01

    Graphene nanostructures in the form ribbons were embedded in the lattice of metals such as Ag, Cu, and Al in concentrations up to 36.4 at.%, 21.8 at% and 10.5 at.%, respectively. These materials are called covetics. Raman scattering from Ag and Al covetics indicate variations in the intensity of peaks at ~ 1,300 cm-1 and 1,600 cm-1 with position on the sample. These peaks are associated with the D (defects) and G (graphite E2g mode) peaks of graphitic carbon with sp2 bonding and reveal various degrees of imperfections in the graphene layers. First principles calculations of the dynamic matrix of Ag and Al covetics show bonding between C and the metal. EELS mapping of the C-K edge and high resolution lattice images show that the graphene-like regions form ribbons with epitaxial orientation with the metal lattice of Ag and Al. The temperature dependences of the resistivites of Ag and Cu covetics are similar to those of the pure metals with only slight increase in resistivity. Films of Cu covetic deposited by e-beam evaporation and PLD show higher transmittance and resistance to oxidation than pure metal films of the same thickness indicating that copper covetic films can be used for transparent electrodes. Funded by DARPA/ARL Grant No. W911NF-13-1-0058, and ONR Award No N000141410042.

  4. Amelioration of Duchenne muscular dystrophy in mdx mice by elimination of matrix-associated fibrin-driven inflammation coupled to the αMβ2 leukocyte integrin receptor.

    PubMed

    Vidal, Berta; Ardite, Esther; Suelves, Mònica; Ruiz-Bonilla, Vanessa; Janué, Anna; Flick, Matthew J; Degen, Jay L; Serrano, Antonio L; Muñoz-Cánoves, Pura

    2012-05-01

    In Duchenne muscular dystrophy (DMD), a persistently altered and reorganizing extracellular matrix (ECM) within inflamed muscle promotes damage and dysfunction. However, the molecular determinants of the ECM that mediate inflammatory changes and faulty tissue reorganization remain poorly defined. Here, we show that fibrin deposition is a conspicuous consequence of muscle-vascular damage in dystrophic muscles of DMD patients and mdx mice and that elimination of fibrin(ogen) attenuated dystrophy progression in mdx mice. These benefits appear to be tied to: (i) a decrease in leukocyte integrin α(M)β(2)-mediated proinflammatory programs, thereby attenuating counterproductive inflammation and muscle degeneration; and (ii) a release of satellite cells from persistent inhibitory signals, thereby promoting regeneration. Remarkably, Fib-gamma(390-396A) (Fibγ(390-396A)) mice expressing a mutant form of fibrinogen with normal clotting function, but lacking the α(M)β(2) binding motif, ameliorated dystrophic pathology. Delivery of a fibrinogen/α(M)β(2) blocking peptide was similarly beneficial. Conversely, intramuscular fibrinogen delivery sufficed to induce inflammation and degeneration in fibrinogen-null mice. Thus, local fibrin(ogen) deposition drives dystrophic muscle inflammation and dysfunction, and disruption of fibrin(ogen)-α(M)β(2) interactions may provide a novel strategy for DMD treatment.

  5. Microstructural and Mechanical Differences Between Digested Collagen-Fibrin Co-Gels and Pure Collagen and Fibrin Gels

    PubMed Central

    Lai, Victor K.; Frey, Christina R.; Kerandi, Allan M.; Lake, Spencer P.; Tranquillo, Robert T.; Barocas, Victor H.

    2012-01-01

    Collagen and fibrin are important extra-cellular matrix (ECM) components in the body, providing structural integrity to various tissues. These biopolymers are also common scaffolds used in tissue engineering. This study investigated how co-gelation of collagen and fibrin affected the properties of each individual protein network. Collagen-fibrin co-gels were cast and subsequently digested using either plasmin or collagenase; the microstructure and mechanical behavior of the resulting networks were then compared with respective pure collagen or fibrin gels of the same protein concentration. The morphologies of the collagen networks were further analyzed via 3-D network reconstruction from confocal image z-stacks. Both collagen and fibrin exhibited a decrease in mean fiber diameter when formed in the co-gels compared to the pure gels; this microstructural change was accompanied by increased failure strain and decreased tangent modulus for both collagen and fibrin following selected digestion of the co-gels. In addition, analysis of the reconstructed collagen networks indicated presence of very long fibers and clustering of fibrils, resulting in very high connectivities for collagen networks formed in co-gels. PMID:22828381

  6. 3D bioprinting of urethra with PCL/PLCL blend and dual autologous cells in fibrin hydrogel: An in vitro evaluation of biomimetic mechanical property and cell growth environment.

    PubMed

    Zhang, Kaile; Fu, Qiang; Yoo, James; Chen, Xiangxian; Chandra, Prafulla; Mo, Xiumei; Song, Lujie; Atala, Anthony; Zhao, Weixin

    2017-03-01

    Urethral stricture is a common condition seen after urethral injury. The currently available treatments are inadequate and there is a scarcity of substitute materials used for treatment of urethral stricture. The traditional tissue engineering of urethra involves scaffold design, fabrication and processing of multiple cell types. In this study, we have used 3D bioprinting technology to fabricate cell-laden urethra in vitro with different polymer types and structural characteristics. We hypothesized that use of PCL and PLCL polymers with a spiral scaffold design could mimic the structure and mechanical properties of natural urethra of rabbits, and cell-laden fibrin hydrogel could give a better microenvironment for cell growth. With using an integrated bioprinting system, tubular scaffold was formed with the biomaterials; meanwhile, urothelial cells (UCs) and smooth muscle cells (SMCs) were delivered evenly into inner and outer layers of the scaffold separately within the cell-laden hydrogel. The PCL/PLCL (50:50) spiral scaffold demonstrated mechanical properties equivalent to the native urethra in rabbit. Evaluation of the cell bioactivity in the bioprinted urethra revealed that UCs and SMCs maintained more than 80% viability even at 7days after printing. Both cell types also showed active proliferation and maintained the specific biomarkers in the cell-laden hydrogel. These results provided a foundation for further studies in 3D bioprinting of urethral constructs that mimic the natural urethral tissue in mechanical properties and cell bioactivity, as well a possibility of using the bioprinted construct for in vivo study of urethral implantation in animal model. The 3D bioprinting is a new technique to replace traditional tissue engineering. The present study is the first demonstration that it is feasible to create a urethral construct. Two kinds of biomaterials were used and achieved mechanical properties equivalent to that of native rabbit urethra. Bladder

  7. Mass production of nanofibrous extracellular matrix with controlled 3D morphology for large-scale soft tissue regeneration.

    PubMed

    Alamein, Mohammad A; Stephens, Sebastien; Liu, Qin; Skabo, Stuart; Warnke, Patrick H

    2013-06-01

    Biomaterials that mimic the nanofibrous architecture of the natural extracellular matrix (ECM) are in the focus for stem cell hosting or delivery in tissue engineering of multilayered soft tissues such as skin, mucosa, or retina. Synthetic nanofibers for such ECM are usually produced by single-syringe electrospinning with only one needle-jet at very low production rates of 0.005-0.008 g·min⁻¹. The aim of this study was to utilize a novel industrial needle-free multijet electrospinning device with the potential for mass production of nanofibrous ECM (NF-ECM) exhibiting a controlled three-dimensional (3D) morphology for large-scale applications such as large area skin regeneration in patients with burns. The novel NanoSpider™ NS200, an industrial apparatus originally designed for electrospinning of nanofibrous textile meshes, was used to fabricate 3D NF-ECMs of the following synthetic and natural biopolymers: collagen, gelatin, poly(caprolactone) (PCL), and poly(L-lactide-co-glycolide) (PLGA). Different concentrations of Gelatin polymer solution were electrospun under varying processing conditions, namely speed of spinning electrode rotation (u) and electric field intensity (E) by altering applied voltage (v) or the distance between electrodes (h) to achieve homogeneous desirable 3D morphology. Nanofiber diameters were assessed by scanning electron microscopy (SEM). Biocompatibility was tested by WST-1 (water-soluble tetrazolium salt) proliferation assay of seeded human mesenchymal stem cells (HMSCs). Biological performance of HMSCs on 3D PLGA NF-ECM was compared to two-dimensional (2D) PLGA film controls via SEM and confocal microscopy. Western blotting addressed the expression of surface adhesion proteins; focal adhesion kinase (FAK), phosphorylated FAK (pY397), α-tubulin, paxillin, vinculin. and integrin subunits; α5, αv, and β1 proteins. Large-scale mass production of NF-ECM membranes with a highly homogenous nanofiber morphology and 3D architecture

  8. Multiphoton microscopy of engineered dermal substitutes: assessment of 3D collagen matrix remodeling induced by fibroblasts contraction

    NASA Astrophysics Data System (ADS)

    Pena, A.-M.; Olive, C.; Michelet, J.-F.; Galey, J.-B.; Fagot, D.; Leroy, F.; Martin, J.-L.; Colonna, A.; Schanne-Klein, M.-C.

    2010-02-01

    One of the main functions of dermal fibroblasts is the generation of mechanical forces within their surrounding extracellular matrix. Investigating molecules that could modulate fibroblast contraction and act as potent anti aging ingredients requires the development of three-dimensional in situ imaging methodologies for dermal substitute analysis. Here we use multiphoton microscopy in order to investigate the fibroblast-induced collagen matrix reorganization in engineered dermal tissue and to evaluate the effect of Y27632, a RhoA kinase inhibitor on dermal substitutes contraction. We observe that collagen fibrils rearrange around fibroblast with increasing density in control samples, whereas collagen fibrils show no remodeling in the samples containing the RhoA kinase inhibitor. Moreover, when the culture medium containing the inhibitor was replaced with a control medium, the dermal substitutes presented the same 3D reorganization as the control samples, which indicates that the inhibitory effects are reversible. In conclusion, our study demonstrates the relevance of multiphoton microscopy to visualize three-dimensional remodeling of the matrix induced by fibroblast contraction.

  9. The Synergistic Effects of Matrix Stiffness and Composition on the Response of Chondroprogenitor Cells in a 3D Precondensation Microenvironment.

    PubMed

    Carrion, Bita; Souzanchi, Mohammad F; Wang, Victor T; Tiruchinapally, Gopinath; Shikanov, Ariella; Putnam, Andrew J; Coleman, Rhima M

    2016-05-01

    Improve functional quality of cartilage tissue engineered from stem cells requires a better understanding of the functional evolution of native cartilage tissue. Therefore, a biosynthetic hydrogel was developed containing RGD, hyaluronic acid and/or type-I collagen conjugated to poly(ethylene glycol) acrylate to recapitulate the precondensation microenvironment of the developing limb. Conjugation of any combination of the three ligands did not alter the shear moduli or diffusion properties of the PEG hydrogels; thus, the influence of ligand composition on chondrogenesis could be investigated in the context of varying matrix stiffness. Gene expression of ligand receptors (CD44 and the b1-integrin) as well as markers of condensation (cell clustering and N-cadherin gene expression) and chondrogenesis (Col2a1 gene expression and sGAG production) by chondroprogenitor cells in this system were modulated by both matrix stiffness and ligand composition, with the highest gene expression occurring in softer hydrogels containing all three ligands. Cell proliferation in these 3D matrices for 7 d prior to chondrogenic induction increased the rate of sGAG production in a stiffness-dependent manner. This biosynthetic hydrogel supports the features of early limb-bud condensation and chondrogenesis and is a novel platform in which the influence of the matrix physicochemical properties on these processes can be elucidated.

  10. Reproducing electric field observations during magnetic storms by means of rigorous 3-D modelling and distortion matrix co-estimation

    NASA Astrophysics Data System (ADS)

    Püthe, Christoph; Manoj, Chandrasekharan; Kuvshinov, Alexey

    2014-12-01

    Electric fields induced in the conducting Earth by geomagnetic disturbances drive currents in power transmission grids, telecommunication lines or buried pipelines, which can cause service disruptions. A key step in the prediction of the hazard to technological systems during magnetic storms is the calculation of the geoelectric field. To address this issue for mid-latitude regions, we revisit a method that involves 3-D modelling of induction processes in a heterogeneous Earth and the construction of a magnetospheric source model described by low-degree spherical harmonics from observatory magnetic data. The actual electric field, however, is known to be perturbed by galvanic effects, arising from very local near-surface heterogeneities or topography, which cannot be included in the model. Galvanic effects are commonly accounted for with a real-valued time-independent distortion matrix, which linearly relates measured and modelled electric fields. Using data of six magnetic storms that occurred between 2000 and 2003, we estimate distortion matrices for observatory sites onshore and on the ocean bottom. Reliable estimates are obtained, and the modellings are found to explain up to 90% of the measurements. We further find that 3-D modelling is crucial for a correct separation of galvanic and inductive effects and a precise prediction of the shape of electric field time series during magnetic storms. Since the method relies on precomputed responses of a 3-D Earth to geomagnetic disturbances, which can be recycled for each storm, the required computational resources are negligible. Our approach is thus suitable for real-time prediction of geomagnetically induced currents by combining it with reliable forecasts of the source field.

  11. Characterization of Leukocyte-platelet Rich Fibrin, A Novel Biomaterial.

    PubMed

    Madurantakam, Parthasarathy; Yoganarasimha, Suyog; Hasan, Fadi K

    2015-09-29

    Autologous platelet concentrates represent promising innovative tools in the field of regenerative medicine and have been extensively used in oral surgery. Unlike platelet rich plasma (PRP) that is a gel or a suspension, Leukocyte-Platelet Rich Fibrin (L-PRF) is a solid 3D fibrin membrane generated chair-side from whole blood containing no anti-coagulant. The membrane has a dense three dimensional fibrin matrix with enriched platelets and abundant growth factors. L-PRF is a popular adjunct in surgeries because of its superior handling characteristics as well as its suturability to the wound bed. The goal of the study is to demonstrate generation as well as provide detailed characterization of relevant properties of L-PRF that underlie its clinical success.

  12. Representing 3-D cloud radiation effects in two-stream schemes: 2. Matrix formulation and broadband evaluation

    NASA Astrophysics Data System (ADS)

    Hogan, Robin J.; Schäfer, Sophia A. K.; Klinger, Carolin; Chiu, J. Christine; Mayer, Bernhard

    2016-07-01

    Estimating the impact of radiation transport through cloud sides on the global energy budget is hampered by the lack of a fast radiation scheme suitable for use in global atmospheric models that can represent these effects in both the shortwave and longwave. This two-part paper describes the development of such a scheme, which we refer to as the Speedy Algorithm for Radiative Transfer through Cloud Sides (SPARTACUS). The principle of the method is to add extra terms to the two-stream equations to represent lateral transport between clear and cloudy regions, which vary in proportion to the length of cloud edge as a function of height. The present paper describes a robust and accurate method for solving the coupled system of equations in both the shortwave and longwave in terms of matrix exponentials. This solver has been coupled to a correlated-k model for gas absorption. We then confirm the accuracy of SPARTACUS by performing broadband comparisons with fully 3-D radiation calculations by the Monte Carlo model "MYSTIC" for a cumulus cloud field, examining particularly the percentage change in cloud radiative effect (CRE) when 3-D effects are introduced. In the shortwave, SPARTACUS correctly captures this change to CRE, which varies with solar zenith angle between -25% and +120%. In the longwave, SPARTACUS captures well the increase in radiative cooling of the cloud, although it is only able to correctly simulate the 30% increase in surface CRE (around 4 W m-2) if an approximate correction is made for cloud clustering.

  13. 3-D phantom and in vivo cardiac speckle tracking using a matrix array and raw echo data.

    PubMed

    Byram, Brett; Holley, Greg; Giannantonio, Doug; Trahey, Gregg

    2010-04-01

    Cardiac motion has been tracked using various methods, which vary in their invasiveness and dimensionality. One such noninvasive modality for cardiac motion tracking is ultrasound. Three-dimensional ultrasound motion tracking has been demonstrated using detected data at low volume rates. However, the effects of volume rate, kernel size, and data type (raw and detected) have not been sufficiently explored. First comparisons are made within the stated variables for 3-D speckle tracking. Volumetric data were obtained in a raw, baseband format using a matrix array attached to a high parallel receive beam count scanner. The scanner was used to acquire phantom and human in vivo cardiac volumetric data at 1000-Hz volume rates. Motion was tracked using phase-sensitive normalized cross-correlation. Subsample estimation in the lateral and elevational dimensions used the grid-slopes algorithm. The effects of frame rate, kernel size, and data type on 3-D tracking are shown. In general, the results show improvement of motion estimates at volume rates up to 200 Hz, above which they become stable. However, peak and pixel hopping continue to decrease at volume rates higher than 200 Hz. The tracking method and data show, qualitatively, good temporal and spatial stability (for independent kernels) at high volume rates.

  14. 3-D Phantom and In Vivo Cardiac Speckle Tracking Using a Matrix Array and Raw Echo Data

    PubMed Central

    Byram, Brett C.; Holley, Greg; Giannantonio, Doug M.; Trahey, Gregg E.

    2012-01-01

    Cardiac motion has been tracked using various methods, which vary in their invasiveness and dimensionality. One such noninvasive modality for cardiac motion tracking is ultrasound. Three-dimensional ultrasound motion tracking has been demonstrated using detected data at low volume rates. However, the effects of volume rate, kernel size, and data type (raw and detected) have not been sufficiently explored. First comparisons are made within the stated variables for 3-D speckle tracking. Volumetric data were obtained in a raw, baseband format using a matrix array attached to a high parallel receive beam count scanner. The scanner was used to acquire phantom and human in vivo cardiac volumetric data at 1000-Hz volume rates. Motion was tracked using phase-sensitive normalized cross-correlation. Subsample estimation in the lateral and elevational dimensions used the grid-slopes algorithm. The effects of frame rate, kernel size, and data type on 3-D tracking are shown. In general, the results show improvement of motion estimates at volume rates up to 200 Hz, above which they become stable. However, peak and pixel hopping continue to decrease at volume rates higher than 200 Hz. The tracking method and data show, qualitatively, good temporal and spatial stability (for independent kernels) at high volume rates. PMID:20378447

  15. Reproducing Electric Field Observations during Magnetic Storms by means of Rigorous 3-D Modelling and Distortion Matrix Co-estimation

    NASA Astrophysics Data System (ADS)

    Püthe, Christoph; Manoj, Chandrasekharan; Kuvshinov, Alexey

    2015-04-01

    Electric fields induced in the conducting Earth during magnetic storms drive currents in power transmission grids, telecommunication lines or buried pipelines. These geomagnetically induced currents (GIC) can cause severe service disruptions. The prediction of GIC is thus of great importance for public and industry. A key step in the prediction of the hazard to technological systems during magnetic storms is the calculation of the geoelectric field. To address this issue for mid-latitude regions, we developed a method that involves 3-D modelling of induction processes in a heterogeneous Earth and the construction of a model of the magnetospheric source. The latter is described by low-degree spherical harmonics; its temporal evolution is derived from observatory magnetic data. Time series of the electric field can be computed for every location on Earth's surface. The actual electric field however is known to be perturbed by galvanic effects, arising from very local near-surface heterogeneities or topography, which cannot be included in the conductivity model. Galvanic effects are commonly accounted for with a real-valued time-independent distortion matrix, which linearly relates measured and computed electric fields. Using data of various magnetic storms that occurred between 2000 and 2003, we estimated distortion matrices for observatory sites onshore and on the ocean bottom. Strong correlations between modellings and measurements validate our method. The distortion matrix estimates prove to be reliable, as they are accurately reproduced for different magnetic storms. We further show that 3-D modelling is crucial for a correct separation of galvanic and inductive effects and a precise prediction of electric field time series during magnetic storms. Since the required computational resources are negligible, our approach is suitable for a real-time prediction of GIC. For this purpose, a reliable forecast of the source field, e.g. based on data from satellites

  16. 3D model of a matrix source of negative ions: RF driving by a large area planar coil

    NASA Astrophysics Data System (ADS)

    Demerdzhiev, A.; Lishev, St.; Tarnev, Kh.; Shivarova, A.

    2015-04-01

    Based on three-dimensional (3D) modeling, different manners of a planar-coil inductive discharge driving of a plasma source completed as a matrix of small-radius hydrogen discharges are studied regarding a proper choice of an efficient and alike rf power deposition into the separate discharges of the matrix. Driving the whole matrix by a single coil and splitting it to blocks of discharge tubes, with single coil driving of each block, are the two cases considered. The results from the self-consistent model presented for a block of discharge tubes show its reliability in ensuring the same spatial distribution of the plasma parameters in the discharges completing the block. Since regarding the construction of the matrix, its driving as a whole by a single coil is the most reasonable decision, three modifications of the coil design have been tested: two zigzag coils with straight conductors passing, respectively, between and through the bottoms of the discharge tubes and a coil with an "omega" shaped conductor on the bottom of each tube. Among these three configurations, the latter ‒ a coil with an Ω-shaped conductor on the bottom of each tube ‒ shows up with the highest rf efficiency of an inductive discharge driving, shown by results for the rf current induced in the discharges obtained from an electrodynamical description. In all the cases considered the spatial distribution of the induced current density is analysed based on the manner of the penetration into the plasma of the wave field sustaining the inductive discharges.

  17. Leishmania amazonensis promastigotes in 3D Collagen I culture: an in vitro physiological environment for the study of extracellular matrix and host cell interactions.

    PubMed

    Petropolis, Debora B; Rodrigues, Juliany C F; Viana, Nathan B; Pontes, Bruno; Pereira, Camila F A; Silva-Filho, Fernando C

    2014-01-01

    Leishmania amazonensis is the causative agent of American cutaneous leishmaniasis, an important neglected tropical disease. Once Leishmania amazonensis is inoculated into the human host, promastigotes are exposed to the extracellular matrix (ECM) of the dermis. However, little is known about the interaction between the ECM and Leishmania promastigotes. In this study we established L. amazonensis promastigote culture in a three-dimensional (3D) environment mainly composed of Collagen I (COL I). This 3D culture recreates in vitro some aspects of the human host infection site, enabling the study of the interaction mechanisms of L. amazonensis with the host ECM. Promastigotes exhibited "freeze and run" migration in the 3D COL I matrix, which is completely different from the conventional in vitro swimming mode of migration. Moreover, L. amazonensis promastigotes were able to invade, migrate inside, and remodel the 3D COL I matrix. Promastigote trans-matrix invasion and the freeze and run migration mode were also observed when macrophages were present in the matrix. At least two classes of proteases, metallo- and cysteine proteases, are involved in the 3D COL I matrix degradation caused by Leishmania. Treatment with a mixture of protease inhibitors significantly reduced promastigote invasion and migration through this matrix. Together our results demonstrate that L. amazonensis promastigotes release proteases and actively remodel their 3D environment, facilitating their migration. This raises the possibility that promastigotes actively interact with their 3D environment during the search for their cellular "home"-macrophages. Supporting this hypothesis, promastigotes migrated faster than macrophages in a novel 3D co-culture model.

  18. Leishmania amazonensis promastigotes in 3D Collagen I culture: an in vitro physiological environment for the study of extracellular matrix and host cell interactions

    PubMed Central

    Rodrigues, Juliany C.F.; Viana, Nathan B.; Pontes, Bruno; Pereira, Camila F.A.; Silva-Filho, Fernando C.

    2014-01-01

    Leishmania amazonensis is the causative agent of American cutaneous leishmaniasis, an important neglected tropical disease. Once Leishmania amazonensis is inoculated into the human host, promastigotes are exposed to the extracellular matrix (ECM) of the dermis. However, little is known about the interaction between the ECM and Leishmania promastigotes. In this study we established L. amazonensis promastigote culture in a three-dimensional (3D) environment mainly composed of Collagen I (COL I). This 3D culture recreates in vitro some aspects of the human host infection site, enabling the study of the interaction mechanisms of L. amazonensis with the host ECM. Promastigotes exhibited “freeze and run” migration in the 3D COL I matrix, which is completely different from the conventional in vitro swimming mode of migration. Moreover, L. amazonensis promastigotes were able to invade, migrate inside, and remodel the 3D COL I matrix. Promastigote trans-matrix invasion and the freeze and run migration mode were also observed when macrophages were present in the matrix. At least two classes of proteases, metallo- and cysteine proteases, are involved in the 3D COL I matrix degradation caused by Leishmania. Treatment with a mixture of protease inhibitors significantly reduced promastigote invasion and migration through this matrix. Together our results demonstrate that L. amazonensis promastigotes release proteases and actively remodel their 3D environment, facilitating their migration. This raises the possibility that promastigotes actively interact with their 3D environment during the search for their cellular “home”—macrophages. Supporting this hypothesis, promastigotes migrated faster than macrophages in a novel 3D co-culture model. PMID:24765565

  19. A Safe and Efficient Method to Retrieve Mesenchymal Stem Cells from Three-Dimensional Fibrin Gels

    PubMed Central

    Carrion, Bita; Janson, Isaac A.; Kong, Yen P.

    2014-01-01

    Mesenchymal stem cells (MSCs) display multipotent characteristics that make them ideal for potential therapeutic applications. MSCs are typically cultured as monolayers on tissue culture plastic, but there is increasing evidence suggesting that they may lose their multipotency over time in vitro and eventually cease to retain any resemblance to in vivo resident MSCs. Three-dimensional (3D) culture systems that more closely recapitulate the physiological environment of MSCs and other cell types are increasingly explored for their capacity to support and maintain the cell phenotypes. In much of our own work, we have utilized fibrin, a natural protein-based material that serves as the provisional extracellular matrix during wound healing. Fibrin has proven to be useful in numerous tissue engineering applications and has been used clinically as a hemostatic material. Its rapid self-assembly driven by thrombin-mediated alteration of fibrinogen makes fibrin an attractive 3D substrate, in which cells can adhere, spread, proliferate, and undergo complex morphogenetic programs. However, there is a significant need for simple cost-effective methods to safely retrieve cells encapsulated within fibrin hydrogels to perform additional analyses or use the cells for therapy. Here, we present a safe and efficient protocol for the isolation of MSCs from 3D fibrin gels. The key ingredient of our successful extraction method is nattokinase, a serine protease of the subtilisin family that has a strong fibrinolytic activity. Our data show that MSCs recovered from 3D fibrin gels using nattokinase are not only viable but also retain their proliferative and multilineage potentials. Demonstrated for MSCs, this method can be readily adapted to retrieve any other cell type from 3D fibrin gel constructs for various applications, including expansion, bioassays, and in vivo implantation. PMID:23808842

  20. A safe and efficient method to retrieve mesenchymal stem cells from three-dimensional fibrin gels.

    PubMed

    Carrion, Bita; Janson, Isaac A; Kong, Yen P; Putnam, Andrew J

    2014-03-01

    Mesenchymal stem cells (MSCs) display multipotent characteristics that make them ideal for potential therapeutic applications. MSCs are typically cultured as monolayers on tissue culture plastic, but there is increasing evidence suggesting that they may lose their multipotency over time in vitro and eventually cease to retain any resemblance to in vivo resident MSCs. Three-dimensional (3D) culture systems that more closely recapitulate the physiological environment of MSCs and other cell types are increasingly explored for their capacity to support and maintain the cell phenotypes. In much of our own work, we have utilized fibrin, a natural protein-based material that serves as the provisional extracellular matrix during wound healing. Fibrin has proven to be useful in numerous tissue engineering applications and has been used clinically as a hemostatic material. Its rapid self-assembly driven by thrombin-mediated alteration of fibrinogen makes fibrin an attractive 3D substrate, in which cells can adhere, spread, proliferate, and undergo complex morphogenetic programs. However, there is a significant need for simple cost-effective methods to safely retrieve cells encapsulated within fibrin hydrogels to perform additional analyses or use the cells for therapy. Here, we present a safe and efficient protocol for the isolation of MSCs from 3D fibrin gels. The key ingredient of our successful extraction method is nattokinase, a serine protease of the subtilisin family that has a strong fibrinolytic activity. Our data show that MSCs recovered from 3D fibrin gels using nattokinase are not only viable but also retain their proliferative and multilineage potentials. Demonstrated for MSCs, this method can be readily adapted to retrieve any other cell type from 3D fibrin gel constructs for various applications, including expansion, bioassays, and in vivo implantation.

  1. Bile canaliculi formation and biliary transport in 3D sandwich-cultured hepatocytes in dependence of the extracellular matrix composition.

    PubMed

    Deharde, Daniela; Schneider, Christin; Hiller, Thomas; Fischer, Nicolas; Kegel, Victoria; Lübberstedt, Marc; Freyer, Nora; Hengstler, Jan G; Andersson, Tommy B; Seehofer, Daniel; Pratschke, Johann; Zeilinger, Katrin; Damm, Georg

    2016-10-01

    Primary human hepatocytes (PHH) are still considered as gold standard for investigation of in vitro metabolism and hepatotoxicity in pharmaceutical research. It has been shown that the three-dimensional (3D) cultivation of PHH in a sandwich configuration between two layers of extracellular matrix (ECM) enables the hepatocytes to adhere three dimensionally leading to formation of in vivo like cell-cell contacts and cell-matrix interactions. The aim of the present study was to investigate the influence of different ECM compositions on morphology, cellular arrangement and bile canaliculi formation as well as bile excretion processes in PHH sandwich cultures systematically. Freshly isolated PHH were cultured for 6 days between two ECM layers made of collagen and/or Matrigel in four different combinations. The cultures were investigated by phase contrast microscopy and immunofluorescence analysis with respect to cell-cell connections, repolarization as well as bile canaliculi formation. The influence of the ECM composition on cell activity and viability was measured using the XTT assay and a fluorescent dead or alive assay. Finally, the bile canalicular transport was analyzed by live cell imaging to monitor the secretion and accumulation of the fluorescent substance CDF in bile canaliculi. Using collagen and Matrigel in different compositions in sandwich cultures of hepatocytes, we observed differences in morphology, cellular arrangement and cell activity of PHH in dependence of the ECM composition. Sandwich-cultured hepatocytes with an underlay of collagen seem to represent the best in vivo tissue architecture in terms of formation of trabecular cell arrangement. Cultures overlaid with collagen were characterized by the formation of abundant bile canaliculi, while the bile canaliculi network in hepatocytes cultured on a layer of Matrigel and overlaid with collagen showed the most branched and stable canalicular network. All cultures showed a time-dependent leakage of

  2. Modeling and Analysis of Granite Matrix Pore Structure and Hydraulic Characteristics in 2D and 3D Networks

    NASA Astrophysics Data System (ADS)

    Gvozdik, L.; Polak, M.; Zaruba, J.; Vanecek, M.

    2010-12-01

    A geological environment labeled as a Granite massif represents in terms of groundwater flow and transport a distinct hydrogeological environment from that of sedimentary basins, the characterisation of which is generally more complex and uncertain. Massifs are composed of hard crystalline rocks with the very low effective porosity. Due to their rheological properties such rocks are predisposed to brittle deformation resulting from changes in stress conditions. Our specific research project (Research on the influence of intergrangular porosity on deep geological disposal: geological formations, methodology and the development of measurement apparatus) is focussed on the problem of permeable zones within apparently undisturbed granitic rock matrix. The project including the both laboratory and in-situ tracer tests study migration along and through mineral grains in fresh and altered granite. The objective of the project is to assess whether intergranular porosity is a general characteristic of the granitic rock matrix or subject to significant evolution resulting from geochemical and/or hydrogeochemical processes, geotechnical and/or mechanical processes. Moreover, the research is focussed on evaluating methods quantifying intergranular porosity by both physical testing and mathematical modelling using verified standard hydrological software tools. Groundwater flow in microfractures and intergranular pores in granite rock matrix were simulated in three standard hydrogeological modeling programs with completely different conceptual approaches: MODFLOW (Equivalent Continuum concept), FEFLOW (Discrete Fracture and Equivalent Continuum concepts) and NAPSAC (Discrete Fracture Network concept). Specialized random fracture generators were used for creation of several 2D and 3D models in each of the chosen program. Percolation characteristics of these models were tested and analyzed. Several scenarios of laboratory tests of the rock samples permeability made in triaxial

  3. A volume of intersection approach for on-the-fly system matrix calculation in 3D PET image reconstruction

    NASA Astrophysics Data System (ADS)

    Lougovski, A.; Hofheinz, F.; Maus, J.; Schramm, G.; Will, E.; van den Hoff, J.

    2014-02-01

    The aim of this study is the evaluation of on-the-fly volume of intersection computation for system’s geometry modelling in 3D PET image reconstruction. For this purpose we propose a simple geometrical model in which the cubic image voxels on the given Cartesian grid are approximated with spheres and the rectangular tubes of response (ToRs) are approximated with cylinders. The model was integrated into a fully 3D list-mode PET reconstruction for performance evaluation. In our model the volume of intersection between a voxel and the ToR is only a function of the impact parameter (the distance between voxel centre to ToR axis) but is independent of the relative orientation of voxel and ToR. This substantially reduces the computational complexity of the system matrix calculation. Based on phantom measurements it was determined that adjusting the diameters of the spherical voxel size and the ToR in such a way that the actual voxel and ToR volumes are conserved leads to the best compromise between high spatial resolution, low noise, and suppression of Gibbs artefacts in the reconstructed images. Phantom as well as clinical datasets from two different PET systems (Siemens ECAT HR+ and Philips Ingenuity-TF PET/MR) were processed using the developed and the respective vendor-provided (line of intersection related) reconstruction algorithms. A comparison of the reconstructed images demonstrated very good performance of the new approach. The evaluation showed the respective vendor-provided reconstruction algorithms to possess 34-41% lower resolution compared to the developed one while exhibiting comparable noise levels. Contrary to explicit point spread function modelling our model has a simple straight-forward implementation and it should be easy to integrate into existing reconstruction software, making it competitive to other existing resolution recovery techniques.

  4. Matrix density alters zyxin phosphorylation, which limits peripheral process formation and extension in endothelial cells invading 3D collagen matrices.

    PubMed

    Abbey, Colette A; Bayless, Kayla J

    2014-09-01

    This study was designed to determine the optimal conditions required for known pro-angiogenic stimuli to elicit successful endothelial sprouting responses. We used an established, quantifiable model of endothelial cell (EC) sprout initiation where ECs were tested for invasion in low (1 mg/mL) and high density (5 mg/mL) 3D collagen matrices. Sphingosine 1-phosphate (S1P) alone, or S1P combined with stromal derived factor-1α (SDF) and phorbol ester (TPA), elicited robust sprouting responses. The ability of these factors to stimulate sprouting was more effective in higher density collagen matrices. S1P stimulation resulted in a significant increase in invasion distance, and with the exception of treatment groups containing phorbol ester, invasion distance was longer in 1mg/mL compared to 5mg/mL collagen matrices. Closer examination of cell morphology revealed that increasing matrix density and supplementing with SDF and TPA enhanced the formation of multicellular structures more closely resembling capillaries. TPA enhanced the frequency and size of lumen formation and correlated with a robust increase in phosphorylation of p42/p44 Erk kinase, while S1P and SDF did not. Also, a higher number of significantly longer extended processes formed in 5mg/mL compared to 1mg/mL collagen matrices. Because collagen matrices at higher density have been reported to be stiffer, we tested for changes in the mechanosensitive protein, zyxin. Interestingly, zyxin phosphorylation levels inversely correlated with matrix density, while levels of total zyxin did not change significantly. Immunofluorescence and localization studies revealed that total zyxin was distributed evenly throughout invading structures, while phosphorylated zyxin was slightly more intense in extended peripheral processes. Silencing zyxin expression increased extended process length and number of processes, while increasing zyxin levels decreased extended process length. Altogether these data indicate that ECs

  5. Comparison of 3D Reconstructive Technologies Used for Morphometric Research and the Translation of Knowledge Using a Decision Matrix

    ERIC Educational Resources Information Center

    Martin, Charys M.; Roach, Victoria A.; Nguyen, Ngan; Rice, Charles L.; Wilson, Timothy D.

    2013-01-01

    The use of three-dimensional (3D) models for education, pre-operative assessment, presurgical planning, and measurement have become more prevalent. With the increase in prevalence of 3D models there has also been an increase in 3D reconstructive software programs that are used to create these models. These software programs differ in…

  6. Comparison of 3D Reconstructive Technologies Used for Morphometric Research and the Translation of Knowledge Using a Decision Matrix

    ERIC Educational Resources Information Center

    Martin, Charys M.; Roach, Victoria A.; Nguyen, Ngan; Rice, Charles L.; Wilson, Timothy D.

    2013-01-01

    The use of three-dimensional (3D) models for education, pre-operative assessment, presurgical planning, and measurement have become more prevalent. With the increase in prevalence of 3D models there has also been an increase in 3D reconstructive software programs that are used to create these models. These software programs differ in…

  7. Bioengineered 3D brain tumor model to elucidate the effects of matrix stiffness on glioblastoma cell behavior using PEG-based hydrogels.

    PubMed

    Wang, Christine; Tong, Xinming; Yang, Fan

    2014-07-07

    Glioblastoma (GBM) is the most common and aggressive form of primary brain tumor with a median survival of 12-15 months, and the mechanisms underlying GBM tumor progression remain largely elusive. Given the importance of tumor niche signaling in driving GBM progression, there is a strong need to develop in vitro models to facilitate analysis of brain tumor cell-niche interactions in a physiologically relevant and controllable manner. Here we report the development of a bioengineered 3D brain tumor model to help elucidate the effects of matrix stiffness on GBM cell fate using poly(ethylene-glycol) (PEG)-based hydrogels with brain-mimicking biochemical and mechanical properties. We have chosen PEG given its bioinert nature and tunable physical property, and the resulting hydrogels allow tunable matrix stiffness without changing the biochemical contents. To facilitate cell proliferation and migration, CRGDS and a MMP-cleavable peptide were chemically incorporated. Hyaluronic acid (HA) was also incorporated to mimic the concentration in the brain extracellular matrix. Using U87 cells as a model GBM cell line, we demonstrate that such biomimetic hydrogels support U87 cell growth, spreading, and migration in 3D over the course of 3 weeks in culture. Gene expression analyses showed U87 cells actively deposited extracellular matrix and continued to upregulate matrix remodeling genes. To examine the effects of matrix stiffness on GBM cell fate in 3D, we encapsulated U87 cells in soft (1 kPa) or stiff (26 kPa) hydrogels, which respectively mimics the matrix stiffness of normal brain or GBM tumor tissues. Our results suggest that changes in matrix stiffness induce differential GBM cell proliferation, morphology, and migration modes in 3D. Increasing matrix stiffness led to delayed U87 cell proliferation inside hydrogels, but cells formed denser spheroids with extended cell protrusions. Cells cultured in stiff hydrogels also showed upregulation of HA synthase 1 and matrix

  8. Fluid flow increases mineralized matrix deposition in 3D perfusion culture of marrow stromal osteoblasts in a dose-dependent manner

    NASA Technical Reports Server (NTRS)

    Bancroft, Gregory N.; Sikavitsas, Vassilios I.; van den Dolder, Juliette; Sheffield, Tiffany L.; Ambrose, Catherine G.; Jansen, John A.; Mikos, Antonios G.; McIntire, L. V. (Principal Investigator)

    2002-01-01

    Bone is a complex highly structured mechanically active 3D tissue composed of cellular and matrix elements. The true biological environment of a bone cell is thus derived from a dynamic interaction between responsively active cells experiencing mechanical forces and a continuously changing 3D matrix architecture. To investigate this phenomenon in vitro, marrow stromal osteoblasts were cultured on 3D scaffolds under flow perfusion with different rates of flow for an extended period to permit osteoblast differentiation and significant matrix production and mineralization. With all flow conditions, mineralized matrix production was dramatically increased over statically cultured constructs with the total calcium content of the cultured scaffolds increasing with increasing flow rate. Flow perfusion induced de novo tissue modeling with the formation of pore-like structures in the scaffolds and enhanced the distribution of cells and matrix throughout the scaffolds. These results represent reporting of the long-term effects of fluid flow on primary differentiating osteoblasts and indicate that fluid flow has far-reaching effects on osteoblast differentiation and phenotypic expression in vitro. Flow perfusion culture permits the generation and study of a 3D, actively modeled, mineralized matrix and can therefore be a valuable tool for both bone biology and tissue engineering.

  9. Fluid flow increases mineralized matrix deposition in 3D perfusion culture of marrow stromal osteoblasts in a dose-dependent manner

    PubMed Central

    Bancroft, Gregory N.; Sikavitsas, Vassilios I.; van den Dolder, Juliette; Sheffield, Tiffany L.; Ambrose, Catherine G.; Jansen, John A.; Mikos, Antonios G.

    2002-01-01

    Bone is a complex highly structured mechanically active 3D tissue composed of cellular and matrix elements. The true biological environment of a bone cell is thus derived from a dynamic interaction between responsively active cells experiencing mechanical forces and a continuously changing 3D matrix architecture. To investigate this phenomenon in vitro, marrow stromal osteoblasts were cultured on 3D scaffolds under flow perfusion with different rates of flow for an extended period to permit osteoblast differentiation and significant matrix production and mineralization. With all flow conditions, mineralized matrix production was dramatically increased over statically cultured constructs with the total calcium content of the cultured scaffolds increasing with increasing flow rate. Flow perfusion induced de novo tissue modeling with the formation of pore-like structures in the scaffolds and enhanced the distribution of cells and matrix throughout the scaffolds. These results represent reporting of the long-term effects of fluid flow on primary differentiating osteoblasts and indicate that fluid flow has far-reaching effects on osteoblast differentiation and phenotypic expression in vitro. Flow perfusion culture permits the generation and study of a 3D, actively modeled, mineralized matrix and can therefore be a valuable tool for both bone biology and tissue engineering. PMID:12242339

  10. Extracellular matrix composition and rigidity regulate invasive behavior and response to PDT in 3D pancreatic tumor models

    NASA Astrophysics Data System (ADS)

    Cramer, Gwendolyn; El-Hamidi, Hamid; Jafari, Seyedehrojin; Jones, Dustin P.; Celli, Jonathan P.

    2016-03-01

    The composition and mechanical compliance of the extracellular matrix (ECM) have been shown to serve as regulators of tumor growth and invasive behavior. These effects may be particularly relevant in tumors of the pancreas, noted for a profound desmoplastic reaction and an abundance of stroma rich in ECM. In view of recent progress in the clinical implementation of photodynamic therapy (PDT) for pancreatic tumors, in this report we examine how ECM composition and rheological properties impact upon invasive behavior and response to PDT in 3D multicellular pancreatic tumor spheroids in ECM environments with characterized rheological properties. Tumor spheroids were cultured initially in attachment-free conditions to form millimeter-sized spheroids that were transplanted into reconstituted ECM microenvironments (Matrigel and Type I Collagen) that were characterized using bulk oscillatory shear rheology. Analysis of growth behavior shows that the soft collagen ECM promoted growth and extensive invasion and this microenvironment was used in subsequent assessment of PDT and chemotherapy response. Evaluation of treatment response revealed that primary tumor nodule growth is inhibited more effectively with PDT, while verteporfin PDT response is significantly enhanced in the ECM-infiltrating populations that are non-responsive to oxaliplatin chemotherapy. This finding is potentially significant, suggesting the potential for PDT to target these clinically problematic invasive populations that are associated with aggressive metastatic progression and chemoresistance. Experiments to further validate and identify the mechanistic basis of this observation are ongoing.

  11. Intracellular nanomanipulation by a photonic-force microscope with real-time acquisition of a 3D stiffness matrix

    NASA Astrophysics Data System (ADS)

    Bertseva, E.; Singh, A. S. G.; Lekki, J.; Thévenaz, P.; Lekka, M.; Jeney, S.; Gremaud, G.; Puttini, S.; Nowak, W.; Dietler, G.; Forró, L.; Unser, M.; Kulik, A. J.

    2009-07-01

    A traditional photonic-force microscope (PFM) results in huge sets of data, which requires tedious numerical analysis. In this paper, we propose instead an analog signal processor to attain real-time capabilities while retaining the richness of the traditional PFM data. Our system is devoted to intracellular measurements and is fully interactive through the use of a haptic joystick. Using our specialized analog hardware along with a dedicated algorithm, we can extract the full 3D stiffness matrix of the optical trap in real time, including the off-diagonal cross-terms. Our system is also capable of simultaneously recording data for subsequent offline analysis. This allows us to check that a good correlation exists between the classical analysis of stiffness and our real-time measurements. We monitor the PFM beads using an optical microscope. The force-feedback mechanism of the haptic joystick helps us in interactively guiding the bead inside living cells and collecting information from its (possibly anisotropic) environment. The instantaneous stiffness measurements are also displayed in real time on a graphical user interface. The whole system has been built and is operational; here we present early results that confirm the consistency of the real-time measurements with offline computations.

  12. Fibrin hydrogels functionalized with cartilage extracellular matrix and incorporating freshly isolated stromal cells as an injectable for cartilage regeneration.

    PubMed

    Almeida, H V; Eswaramoorthy, R; Cunniffe, G M; Buckley, C T; O'Brien, F J; Kelly, D J

    2016-05-01

    Freshly isolated stromal cells can potentially be used as an alternative to in vitro expanded cells in regenerative medicine. Their use requires the development of bioactive hydrogels or scaffolds which provide an environment to enhance their proliferation and tissue-specific differentiation in vivo. The goal of the current study was to develop an injectable fibrin hydrogel functionalized with cartilage ECM microparticles and transforming growth factor (TGF)-β3 as a putative therapeutic for articular cartilage regeneration. ECM microparticles were produced by cryomilling and freeze-drying porcine articular cartilage. Up to 2% (w/v) ECM could be incorporated into fibrin without detrimentally affecting its capacity to form stable hydrogels. To access the chondroinductivity of cartilage ECM, we compared chondrogenesis of infrapatellar fat pad-derived stem cells in fibrin hydrogels functionalized with either particulated ECM or control gelatin microspheres. Cartilage ECM particles could be used to control the delivery of TGF-β3 to IFP-derived stem cells within fibrin hydrogels in vitro, and furthermore, led to higher levels of sulphated glycosaminoglycan (sGAG) and collagen accumulation compared to control constructs loaded with gelatin microspheres. In vivo, freshly isolated stromal cells generated a more cartilage-like tissue within fibrin hydrogels functionalized with cartilage ECM particles compared to the control gelatin loaded constructs. These tissues stained strongly for type II collagen and contained higher levels of sGAGs. These results support the use of fibrin hydrogels functionalized with cartilage ECM components in single-stage, cell-based therapies for joint regeneration. An alternative to the use of in vitro expanded cells in regenerative medicine is the use of freshly isolated stromal cells, where a bioactive scaffold or hydrogel is used to provide an environment that enhances their proliferation and tissue-specific differentiation in vivo. The

  13. Implementing a Matrix-free Analytical Jacobian to Handle Nonlinearities in Models of 3D Lithospheric Deformation

    NASA Astrophysics Data System (ADS)

    Kaus, B.; Popov, A.

    2015-12-01

    The analytical expression for the Jacobian is a key component to achieve fast and robust convergence of the nonlinear Newton-Raphson iterative solver. Accomplishing this task in practice often requires a significant algebraic effort. Therefore it is quite common to use a cheap alternative instead, for example by approximating the Jacobian with a finite difference estimation. Despite its simplicity it is a relatively fragile and unreliable technique that is sensitive to the scaling of the residual and unknowns, as well as to the perturbation parameter selection. Unfortunately no universal rule can be applied to provide both a robust scaling and a perturbation. The approach we use here is to derive the analytical Jacobian for the coupled set of momentum, mass, and energy conservation equations together with the elasto-visco-plastic rheology and a marker in cell/staggered finite difference method. The software project LaMEM (Lithosphere and Mantle Evolution Model) is primarily developed for the thermo-mechanically coupled modeling of the 3D lithospheric deformation. The code is based on a staggered grid finite difference discretization in space, and uses customized scalable solvers form PETSc library to efficiently run on the massively parallel machines (such as IBM Blue Gene/Q). Currently LaMEM relies on the Jacobian-Free Newton-Krylov (JFNK) nonlinear solver, which approximates the Jacobian-vector product using a simple finite difference formula. This approach never requires an assembled Jacobian matrix and uses only the residual computation routine. We use an approximate Jacobian (Picard) matrix to precondition the Krylov solver with the Galerkin geometric multigrid. Because of the inherent problems of the finite difference Jacobian estimation, this approach doesn't always result in stable convergence. In this work we present and discuss a matrix-free technique in which the Jacobian-vector product is replaced by analytically-derived expressions and compare results

  14. A 3D in situ cell counter reveals that breast tumor cell (MDA-MB-231) proliferation rate is reduced by the collagen matrix density.

    PubMed

    Kim, Beum Jun; Zhao, Shuting; Bunaciu, Rodica P; Yen, Andrew; Wu, Mingming

    2015-01-01

    Many cell types require the biophysical and biochemical cues within the 3D extracellular matrix (ECM) to exhibit their true physiologically relevant behavior. As a result, cell culture platforms have been evolving from traditional 2D petridish plates into 3D biomatrices, and there is a need for developing analytic tools to characterize 3D cell culture. The existing cell counting method, using a hemocytometer or coulter counter, requires that cells are suspended in fluids prior to counting. This poses a challenge for 3D cell culture as cells are embedded in a 3D biomatrix. We use a facile 3D cell counting method that overcomes this limitation and allows for in situ cell counting in a 3D cell culture using equipment that is commonly available in a biology lab. Using a breast tumor cell line, MDA-MB-231, as a model system, we demonstrated that MDA-MB-231 cells (1) grow slower within a 3D collagen matrix than on a 2D substrate for an extended growth time (a week) with a comparable, initial cell-to-cell distance, (2) their cell growth rate decreases with the increase of collagen concentration, showing a linear growth rate rather than an exponential growth rate. Further work using flow cytometry showed that the observed growth rate reduction was consistent with the retardation of the transition to S (synthesis) phase in the cell cycle. This work demonstrates the validity of the 3D cell counting method and the importance of cell-ECM interactions in cell proliferation. © 2015 American Institute of Chemical Engineers.

  15. A 3D in situ cell counter reveals that breast tumor cell (MDA-MB-231) proliferation rate is reduced by the collagen matrix density

    PubMed Central

    Bunaciu, Rodica P.; Yen, Andrew; Wu, Mingming

    2015-01-01

    Many cell types require the biophysical and biochemical cues within the 3D extracellular matrix (ECM) to exhibit their true physiologically relevant behavior. As a result, cell culture platforms have been evolving from traditional 2D petri-dish plates into 3D biomatrices, and there is a need for developing analytic tools to characterize 3D cell culture. The existing cell counting method, using a hemocytometer or coulter counter, requires that cells are suspended in fluids prior to counting. This poses a challenge for 3D cell culture as cells are embedded in a 3D biomatrix. We use a facile 3D cell counting method that overcomes this limitation and allows for in situ cell counting in a 3D cell culture using equipment that is commonly available in a biology lab. Using a breast tumor cell line, MDA-MB-231, as a model system, we demonstrated that MDA-MB-231 cells (1) grow slower within a 3D collagen matrix than on a 2D substrate for an extended growth time (a week) with a comparable, initial cell-to-cell distance, (2) their cell growth rate decreases with the increase of collagen concentration, showing a linear growth rate rather than an exponential growth rate. Further work using flow cytometry showed that the observed growth rate reduction was consistent with the retardation of the transition to S (synthesis) phase in the cell cycle. This work demonstrates the validity of the 3D cell counting method and the importance of cell-ECM interactions in cell proliferation. PMID:25683564

  16. One-step apexification in immature tooth using grey mineral trioxide aggregate as an apical barrier and autologus platelet rich fibrin membrane as an internal matrix

    PubMed Central

    Rudagi, Kavitarani B; Rudagi, BM

    2012-01-01

    Immature teeth with necrotic pulp and periapical lesion are difficult to treat via conventional endodontic therapy. Numerous procedures and materials have been utilized to induce root-end barrier formation. Traditionally, calcium hydroxide has been the material of choice for the apexification of immature permanent teeth; however, Mineral Trioxide Aggregate holds significant promise as an alternative to multiple treatments with calcium hydroxide. One of the technical problems associated with the placement of the restorative materials used as artificial barrier is to prevent overfill and underfill. Using a matrix avoids the extrusion of the material into the periodontal tissues. This case report presents the successful healing and apexification with combined use of Mineral Trioxide Aggregate as an apical barrier, and autologus platelet rich fibrin membrane as an internal matrix. PMID:22557824

  17. Development of a synthetic tissue engineered 3D printed bioceramic-based bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro.

    PubMed

    Adel-Khattab, Doaa; Giacomini, Francesca; Gildenhaar, Renate; Berger, Georg; Gomes, Cynthia; Linow, Ulf; Hardt, Martin; Peleska, Barbara; Günster, Jens; Stiller, Michael; Houshmand, Alireza; Abdel Ghaffar, Khaled; Gamal, Ahmed; El-Mofty, Mohamed; Knabe, Christine

    2016-11-15

    Over the last decade there have been increasing efforts to develop 3D scaffolds for bone tissue engineering from bioactive ceramics with 3D printing emerging as a promising technology. The overall objective of the present study was to generate a tissue engineered synthetic bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro, thereby mimicking the advantageous properties of autogenous bone grafts and facilitating usage for reconstructing segmental discontinuity defects in vivo. To this end, 3D scaffolds were developed from a silica containing calciumalkaliorthophosphate utilizing first a replica technique namely the Schwartzwalder Somers method (SSM), and second 3D printing, (i.e. rapid prototyping, RP). The mechanical and physical scaffold properties and their potential to facilitate homogenous colonization by osteogenic cells and extracellular bone matrix formation throughout the porous scaffold architecture were examined. To this end, osteoblastic cells were dynamically cultured for 7d on both scaffold types with two different concentrations of 1.5 and 3x10(6) cells/ml. The amount of cells and bone matrix formed and osteogenic marker expression were evaluated using hard tissue histology, immunohistochemical and histomorphometric analysis. 3D printed scaffolds (RPS) exhibited more micropores, greater compressive strength and silica release. RPS seeded with 3x10(6) cells/ml displayed greatest cell and extracellular matrix formation, mineralization and osteocalcin expression. In conclusion, RPS displayed superior mechanical and biological properties and facilitated generating a tissue engineered synthetic bone graft in vitro, which mimics the advantageous properties of autogenous bone grafts, by containing homogenously distributed terminally differentiated osteoblasts and mineralizing bone matrix and therefore is suitable for subsequent in vivo implantation for regenerating segmental discontinuity bone defects.

  18. Fibrin matrices enhance the transplant and efficacy of cytotoxic stem cell therapy for post-surgical cancer

    PubMed Central

    Bagó, Juli R.; Pegna, Guillaume J.; Okolie, Onyi; Hingtgen, Shawn D.

    2016-01-01

    Tumor-homing cytotoxic stem cell (SC) therapy is a promising new approach for treating the incurable brain cancer glioblastoma (GBM). However, problems of retaining cytotoxic SCs within the post-surgical GBM resection cavity are likely to significantly limit the clinical utility of this strategy. Here, we describe a new fibrin-based transplant approach capable of increasing cytotoxic SC retention and persistence within the resection cavity, yet remaining permissive to tumoritropic migration. This fibrin-based transplant can effectively treat both solid and post-surgical human GBM in mice. Using our murine model of image-guided model of GBM resection, we discovered that suspending human mesenchymal stem cells (hMSCS) in a fibrin matrix increased initial retention in the surgical resection cavity 2-fold and prolonged persistence in the cavity 3-fold compared to conventional delivery strategies. Time-lapse motion analysis revealed that cytotoxic hMSCs in the fibrin matrix remain tumoritropic, rapidly migrating from the fibrin matrix to co-localize with cultured human GBM cells. We encapsulated hMSCs releasing the cytotoxic agent TRAIL (hMSC-sTR) in fibrin, and found hMSC-sTR/fibrin therapy reduced the viability of multiple 3-D human GBM spheroids and regressed established human GBM xenografts 3-fold in 11 days. Mimicking clinical therapy of surgically resected GBM, intra-cavity seeding of therapeutic hMSC-sTR encapsulated in fibrin reduced post-surgical GBM volumes 6-fold, increased time to recurrence 4-fold, and prolonged median survival from 15 to 36 days compared to control-treated animals. Fibrin-based SC therapy could represent a clinically compatible, viable treatment to suppress recurrence of post-surgical GBM and other lethal cancer types. PMID:26803410

  19. Fibrin matrices enhance the transplant and efficacy of cytotoxic stem cell therapy for post-surgical cancer.

    PubMed

    Bagó, Juli R; Pegna, Guillaume J; Okolie, Onyi; Hingtgen, Shawn D

    2016-04-01

    Tumor-homing cytotoxic stem cell (SC) therapy is a promising new approach for treating the incurable brain cancer glioblastoma (GBM). However, problems of retaining cytotoxic SCs within the post-surgical GBM resection cavity are likely to significantly limit the clinical utility of this strategy. Here, we describe a new fibrin-based transplant approach capable of increasing cytotoxic SC retention and persistence within the resection cavity, yet remaining permissive to tumoritropic migration. This fibrin-based transplant can effectively treat both solid and post-surgical human GBM in mice. Using our murine model of image-guided model of GBM resection, we discovered that suspending human mesenchymal stem cells (hMSCS) in a fibrin matrix increased initial retention in the surgical resection cavity 2-fold and prolonged persistence in the cavity 3-fold compared to conventional delivery strategies. Time-lapse motion analysis revealed that cytotoxic hMSCs in the fibrin matrix remain tumoritropic, rapidly migrating from the fibrin matrix to co-localize with cultured human GBM cells. We encapsulated hMSCs releasing the cytotoxic agent TRAIL (hMSC-sTR) in fibrin, and found hMSC-sTR/fibrin therapy reduced the viability of multiple 3-D human GBM spheroids and regressed established human GBM xenografts 3-fold in 11 days. Mimicking clinical therapy of surgically resected GBM, intra-cavity seeding of therapeutic hMSC-sTR encapsulated in fibrin reduced post-surgical GBM volumes 6-fold, increased time to recurrence 4-fold, and prolonged median survival from 15 to 36 days compared to control-treated animals. Fibrin-based SC therapy could represent a clinically compatible, viable treatment to suppress recurrence of post-surgical GBM and other lethal cancer types.

  20. Matrix Cracking in 3D Orthogonal Melt-Infiltrated SiC/SiC Composites with Various Z-Fiber Types

    NASA Technical Reports Server (NTRS)

    Morscher, Gregory N.; Yun, Hee Mann; DiCarlo, James A.

    2003-01-01

    The occurrence of matrix cracks in melt-infiltrated SiC/SiC composites with a 3D orthogonal architecture was determined at room temperature for specimens tested in tension oriented in the X-direction (parallel to Z-bundle weave direction) and Y-direction (perpendicular to Z-bundle weave direction) and Y-direction (perpendicular to Z-bundle weave direction). The fiber-types were Sylramic and Sylramic-IBN in the X and Y-directions and lower modulus ZMI, T300, and rayon in the Z-direction. Acoustic emission (AE) was used to monitor the matrix cracking activity. For Y-direction composites, the AE data was used to determine the exact (+/- 0.25 mm) location where matrix cracks occurred in the 3D orthogonal architecture. This enabled the determination of the stress-dependent matrix crack distributions for small but repeatable matrix rich 'unidirectional' and the matrix poor 'cross-ply' regions within the architecture. It was found that matrix cracking initiated at very low stresses (approx. 40 MPa) in the 'unidirectional' regions for the largest z-direction fiber tow composites. Decreasing the size of the z-fiber bundle, increased the stress for matrix cracking in the 'unidirectional' regions. Matrix cracking in the 'cross-ply' regions always occurred at higher stresses than in 'unidirectional' regions, and the stress-dependent matrix crack distribution of the 'cross-ply' regions was always over a wider stress-range than the 'unidirectional' regions. For composites tested in the X-direction, a lower elastic modulus and a narrower and lower stress-range for matrix cracking were observed compared to composites tested in the Y-direction.

  1. Study of the structure of 3-D composites based on carbon nanotubes in bovine serum albumin matrix by X-ray microtomography

    NASA Astrophysics Data System (ADS)

    Ignatov, D.; Zhurbina, N.; Gerasimenko, A.

    2017-01-01

    3-D composites are widely used in tissue engineering. A comprehensive analysis by X-ray microtomography was conducted to study the structure of the 3-D composites. Comprehensive analysis of the structure of the 3-D composites consisted of scanning, image reconstruction of shadow projections, two-dimensional and three-dimensional visualization of the reconstructed images and quantitative analysis of the samples. Experimental samples of composites were formed by laser vaporization of the aqueous dispersion BSA and single-walled (SWCNTs) and multi-layer (MWCNTs) carbon nanotubes. The samples have a homogeneous structure over the entire volume, the percentage of porosity of 3-D composites based on SWCNTs and MWCNTs - 16.44%, 28.31%, respectively. An average pore diameter of 3-D composites based on SWCNTs and MWCNTs - 45 μm 93 μm. 3-D composites based on carbon nanotubes in bovine serum albumin matrix can be used in tissue engineering of bone and cartilage, providing cell proliferation and blood vessel sprouting.

  2. The use of adipose mesenchymal stem cells and human umbilical vascular endothelial cells on a fibrin matrix for endothelialized skin substitute.

    PubMed

    Sánchez-Muñoz, Isabel; Granados, Rosario; Holguín Holgado, Purificación; García-Vela, José Antonio; Casares, Celia; Casares, Miguel

    2015-01-01

    In recent years, the reconstruction of human skin by tissue engineering represents a clinical challenge and has offered a therapeutic alternative. Avascular engineered skin equivalents have been available for several years and used to treat wounds due to burns, nonhealing ulcers, and surgical excisions. They are constituted by different types of cultured cells included in a three-dimensional structure that permits cellular proliferation to create tissue substitutes. The major drawback of these artificial skin substitutes is their lack of blood supply, since the endurance and cell proliferation of the substitute depend on an adequate oxygen and nutrient supply and on toxin removal. These functions are served by the vascular system. We have produced a new model of endothelialized skin substitute that promotes the formation of capillary-like structures by seeding human umbilical vein endothelial cells (HUVECs) with dermal fibroblasts and human adipose-derived mesenchymal stem cells (hADMSCs) in a fibrin matrix. Dermal fibroblasts and hADMSCs produce extracellular matrix that stimulates cellular growth and proliferation. hADMSCs secrete significant quantities of angiogenic and antiapoptotic factors (vascular endothelial growth factor and hepatocyte growth factor), which induce in vitro differentiation of these cells into endothelial cells promoting angiogenesis and participating in tissue repair and skin regeneration processes. We obtained the artificial skin substitute with similar structure to native skin, including dermis and epidermis. We demonstrated that endothelial cells (CD31 and von Willebrand factor positive) proliferated and organized themselves into capillary-like structures within the fibrin matrix. The epidermis showed a complete epithelization by squamous cells (AE1/AE3 cytokeratin positive) with intracytoplasmic keratohyalin granules, hyperkeratosis, and parakeratosis. We have established a novel artificial skin substitute that facilitates the formation

  3. Human lung cancer cells grown in an ex vivo 3D lung model produce matrix metalloproteinases not produced in 2D culture.

    PubMed

    Mishra, Dhruva K; Sakamoto, Jason H; Thrall, Michael J; Baird, Brandi N; Blackmon, Shanda H; Ferrari, Mauro; Kurie, Jonathan M; Kim, Min P

    2012-01-01

    We compared the growth of human lung cancer cells in an ex vivo three-dimensional (3D) lung model and 2D culture to determine which better mimics lung cancer growth in patients. A549 cells were grown in an ex vivo 3D lung model and in 2D culture for 15 days. We measured the size and formation of tumor nodules and counted the cells after 15 days. We also stained the tissue/cells for Ki-67, and Caspase-3. We measured matrix metalloproteinase (MMP) levels in the conditioned media and in blood plasma from patients with adenocarcinoma of the lung. Organized tumor nodules with intact vascular space formed in the ex vivo 3D lung model but not in 2D culture. Proliferation and apoptosis were greater in the ex vivo 3D lung model compared to the 2D culture. After 15 days, there were significantly more cells in the 2D culture than the 3D model. MMP-1, MMP-9, and MMP-10 production were significantly greater in the ex vivo 3D lung model. There was no production of MMP-9 in the 2D culture. The patient samples contained MMP-1, MMP-2, MMP-9, and MMP-10. The human lung cancer cells grown on ex vivo 3D model form perfusable nodules that grow over time. It also produced MMPs that were not produced in 2D culture but seen in human lung cancer patients. The ex vivo 3D lung model may more closely mimic the biology of human lung cancer development than the 2D culture.

  4. Concentration independent modulation of local micromechanics in a fibrin gel.

    PubMed

    Kotlarchyk, Maxwell A; Shreim, Samir G; Alvarez-Elizondo, Martha B; Estrada, Laura C; Singh, Rahul; Valdevit, Lorenzo; Kniazeva, Ekaterina; Gratton, Enrico; Putnam, Andrew J; Botvinick, Elliot L

    2011-01-01

    Methods for tuning extracellular matrix (ECM) mechanics in 3D cell culture that rely on increasing the concentration of either protein or cross-linking molecules fail to control important parameters such as pore size, ligand density, and molecular diffusivity. Alternatively, ECM stiffness can be modulated independently from protein concentration by mechanically loading the ECM. We have developed a novel device for generating stiffness gradients in naturally derived ECMs, where stiffness is tuned by inducing strain, while local mechanical properties are directly determined by laser tweezers based active microrheology (AMR). Hydrogel substrates polymerized within 35 mm diameter Petri dishes are strained non-uniformly by the precise rotation of an embedded cylindrical post, and exhibit a position-dependent stiffness with little to no modulation of local mesh geometry. Here we present the device in the context of fibrin hydrogels. First AMR is used to directly measure local micromechanics in unstrained hydrogels of increasing fibrin concentration. Changes in stiffness are then mapped within our device, where fibrin concentration is held constant. Fluorescence confocal imaging and orbital particle tracking are used to quantify structural changes in fibrin on the micro and nano levels respectively. The micromechanical strain stiffening measured by microrheology is not accompanied by ECM microstructural changes under our applied loads, as measured by confocal microscopy. However, super-resolution orbital tracking reveals nanostructural straightening, lengthening, and reduced movement of fibrin fibers. Furthermore, we show that aortic smooth muscle cells cultured within our device are morphologically sensitive to the induced mechanical gradient. Our results demonstrate a powerful cell culture tool that can be used in the study of mechanical effects on cellular physiology in naturally derived 3D ECM tissues.

  5. Concentration Independent Modulation of Local Micromechanics in a Fibrin Gel

    PubMed Central

    Alvarez-Elizondo, Martha B.; Estrada, Laura C.; Singh, Rahul; Valdevit, Lorenzo; Kniazeva, Ekaterina; Gratton, Enrico; Putnam, Andrew J.; Botvinick, Elliot L.

    2011-01-01

    Methods for tuning extracellular matrix (ECM) mechanics in 3D cell culture that rely on increasing the concentration of either protein or cross-linking molecules fail to control important parameters such as pore size, ligand density, and molecular diffusivity. Alternatively, ECM stiffness can be modulated independently from protein concentration by mechanically loading the ECM. We have developed a novel device for generating stiffness gradients in naturally derived ECMs, where stiffness is tuned by inducing strain, while local mechanical properties are directly determined by laser tweezers based active microrheology (AMR). Hydrogel substrates polymerized within 35 mm diameter Petri dishes are strained non-uniformly by the precise rotation of an embedded cylindrical post, and exhibit a position-dependent stiffness with little to no modulation of local mesh geometry. Here we present the device in the context of fibrin hydrogels. First AMR is used to directly measure local micromechanics in unstrained hydrogels of increasing fibrin concentration. Changes in stiffness are then mapped within our device, where fibrin concentration is held constant. Fluorescence confocal imaging and orbital particle tracking are used to quantify structural changes in fibrin on the micro and nano levels respectively. The micromechanical strain stiffening measured by microrheology is not accompanied by ECM microstructural changes under our applied loads, as measured by confocal microscopy. However, super-resolution orbital tracking reveals nanostructural straightening, lengthening, and reduced movement of fibrin fibers. Furthermore, we show that aortic smooth muscle cells cultured within our device are morphologically sensitive to the induced mechanical gradient. Our results demonstrate a powerful cell culture tool that can be used in the study of mechanical effects on cellular physiology in naturally derived 3D ECM tissues. PMID:21629793

  6. Initial Fiber Alignment Pattern Alters Extracellular Matrix Synthesis in Fibroblast Populated Fibrin Gel Cruciforms and Correlates with Predicted Tension

    PubMed Central

    Sander, E.A.; Barocas, V.H.; Tranquillo, R.T.

    2013-01-01

    Human dermal fibroblasts entrapped in fibrin gels cast in cross-shaped (cruciform) geometries with 1:1 and 1:0.5 ratios of arm widths were studied to assess whether tension and alignment of the cells and fibrils affected ECM deposition. The cruciforms of contrasting geometry (symmetric vs. asymmetric), which developed different fiber alignment patterns, were harvested at 2, 5, and 10 weeks of culture. Cruciforms were subjected to planar biaxial testing, polarimetric imaging, DNA and biochemical analyses, histological staining, and SEM imaging. As the cruciforms compacted and developed fiber alignment, fibrin was degraded and elastin and collagen were produced in a geometry-dependent manner. Using a continuum mechanical model that accounts for direction-dependent stress due to cell traction forces and cell contact guidance with aligned fibers that occurs in the cruciforms, the mechanical stress environment was concluded to influence collagen deposition, with deposition being greatest in the narrow arms of the asymmetric cruciform where stress was predicted to be largest. PMID:21046467

  7. Rapid onset of perfused blood vessels after implantation of ECFCs and MPCs in collagen, PuraMatrix and fibrin provisional matrices.

    PubMed

    Allen, Patrick; Kang, Kyu-Tae; Bischoff, Joyce

    2015-05-01

    We developed an in vivo vascularization model in which human endothelial colony-forming cells (ECFCs) and human mesenchymal progenitor cells (MPCs) form blood vessel networks when co-injected (ECFC + MPC) into nude mice in rat tail type I collagen, bovine fibrin or synthetic peptide PuraMatrix matrices. We used three approaches to determine the onset of functional vascularization when ECFC + MPC suspended in these matrices were implanted in vivo. The first was immunohistochemistry to detect vessels lined by human endothelial cells and filled with red blood cells. The second was in vivo vascular staining by tail vein injection of a mixture of Ulex europaeus agglutinin I (UEA-I), a lectin specific for human endothelium, and Griffonia simplicifolia isolectin B4 (GS-IB4 ), a lectin specific for rodent endothelium. The third approach employed contrast-enhanced ultrasound to measure the perfusion volumes of implants in individual animals over time. Human endothelial-lined tubular structures were detected in vivo on days 1 and 2 after implantation, with perfused human vessels detected on days 3 and 4. Contrast-enhanced ultrasound revealed significant perfusion of ECFC + MPC/collagen implants on days 1-4, at up to 14% perfused vascular volume. ECFC + MPC implanted in fibrin and PuraMatrix matrices also supported perfusion at day 1, as assessed by ultrasound (at 12% and 23% perfused vascular volume, respectively). This model demonstrates that ECFC + MPC suspended in any of the three matrices initiated a rapid onset of vascularization. We propose that ECFC + MPC delivered in vivo provide a means to achieve rapid perfusion of tissue-engineered organs or for in situ tissue repair.

  8. Contractile force generation by 3D hiPSC-derived cardiac tissues is enhanced by rapid establishment of cellular interconnection in matrix with muscle-mimicking stiffness.

    PubMed

    Lee, Soah; Serpooshan, Vahid; Tong, Xinming; Venkatraman, Sneha; Lee, Meelim; Lee, Jaecheol; Chirikian, Orlando; Wu, Joseph C; Wu, Sean M; Yang, Fan

    2017-03-30

    Engineering 3D human cardiac tissues is of great importance for therapeutic and pharmaceutical applications. As cardiac tissue substitutes, extracellular matrix-derived hydrogels have been widely explored. However, they exhibit premature degradation and their stiffness is often orders of magnitude lower than that of native cardiac tissue. There are no reports on establishing interconnected cardiomyocytes in 3D hydrogels at physiologically-relevant cell density and matrix stiffness. Here we bioengineer human cardiac microtissues by encapsulating human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in chemically-crosslinked gelatin hydrogels (1.25 × 10(8)/mL) with tunable stiffness and degradation. In comparison to the cells in high stiffness (16 kPa)/slow degrading hydrogels, hiPSC-CMs in low stiffness (2 kPa)/fast degrading and intermediate stiffness (9 kPa)/intermediate degrading hydrogels exhibit increased intercellular network formation, α-actinin and connexin-43 expression, and contraction velocity. Only the 9 kPa microtissues exhibit organized sarcomeric structure and significantly increased contractile stress. This demonstrates that muscle-mimicking stiffness together with robust cellular interconnection contributes to enhancement in sarcomeric organization and contractile function of the engineered cardiac tissue. This study highlights the importance of intercellular connectivity, physiologically-relevant cell density, and matrix stiffness to best support 3D cardiac tissue engineering.

  9. Microenvironment complexity and matrix stiffness regulate breast cancer cell activity in a 3D in vitro model

    PubMed Central

    Cavo, Marta; Fato, Marco; Peñuela, Leonardo; Beltrame, Francesco; Raiteri, Roberto; Scaglione, Silvia

    2016-01-01

    Three-dimensional (3D) cell cultures represent fundamental tools for the comprehension of cellular phenomena both in normal and in pathological conditions. In particular, mechanical and chemical stimuli play a relevant role on cell fate, cancer onset and malignant evolution. Here, we use mechanically-tuned alginate hydrogels to study the role of substrate elasticity on breast adenocarcinoma cell activity. The hydrogel elastic modulus (E) was measured via atomic force microscopy (AFM) and a remarkable range (150–4000 kPa) was obtained. A breast cancer cell line, MCF-7, was seeded within the 3D gels, on standard Petri and alginate-coated dishes (2D controls). Cells showed dramatic morphological differences when cultured in 3D versus 2D, exhibiting a flat shape in both 2D conditions, while maintaining a circular, spheroid-organized (cluster) conformation within the gels, similar to those in vivo. Moreover, we observed a strict correlation between cell viability and substrate elasticity; in particular, the number of MCF-7 cells decreased constantly with increasing hydrogel elasticity. Remarkably, the highest cellular proliferation rate, associated with the formation of cell clusters, occurred at two weeks only in the softest hydrogels (E = 150–200 kPa), highlighting the need to adopt more realistic and a priori defined models for in vitro cancer studies. PMID:27734939

  10. Cell-laden 3D bioprinting hydrogel matrix depending on different compositions for soft tissue engineering: Characterization and evaluation.

    PubMed

    Park, Jisun; Lee, Sang Jin; Chung, Solchan; Lee, Jun Hee; Kim, Wan Doo; Lee, Jae Young; Park, Su A

    2017-02-01

    Cell-printing techniques that can construct three-dimensional (3D) structures with biocompatible materials and cells are of great interest for various biomedical applications, such as tissue engineering and drug-screening studies. For successful cell-printing with cells, bioinks are critical for both the processability of printing and the viability of printed cells. However, the influence of composition on 3D bio-printing with cells has not been well explored. In this study, we investigated different compositions of alginate bioinks by varying the concentrations of high molecular weight alginate (High Alg) and low molecular weight alginate (Low Alg). Bioinks of 3wt% alginate containing High Alg alone or a 1:2 (Low Alg:High Alg) composite allowed for the construction of 3D scaffolds with good processability and shapes. Cell-printing with fibroblasts and in vitro culture studies revealed good viability and growth of the printed cells after up to 7days of culture. Bioinks prepared with High and Low Alg at a 2:1 ratio exhibited better cell growth compared with those of other compositions. This study progresses the design and applications of alginate-based bioinks for cell-printing platforms in soft tissue engineering. Copyright © 2016. Published by Elsevier B.V.

  11. Effects of serum and compressive loading on the cartilage matrix synthesis and spatiotemporal deposition around chondrocytes in 3D culture.

    PubMed

    Wu, Peihui; DeLassus, Elizabeth; Patra, Debabrata; Liao, Weiming; Sandell, Linda J

    2013-05-01

    The aim of this study was to investigate the effects of serum and compressive dynamic loading on the cartilaginous matrix spatiotemporal distribution around chondrocytes in vitro. Murine chondrocytes suspended in agarose were cultured in serum-free media or in varying concentrations of serum with or without compressive dynamic loading. Gene expression was assayed by quantitative polymerase chain reaction. Immunohistochemistry was performed for type II collagen and type VI collagen, aggrecan, or cartilage oligomeric matrix protein (COMP) to study the effect of serum and dynamic loading on the spatiotemporal distribution of cartilage matrix components. Chondrocytes in serum-free culture exhibited negligible differences in type II collagen, aggrecan, and COMP mRNA expression levels over 15 days of cultivation. However, higher serum concentrations decreased matrix gene expression. Expression of the matrix metalloproteinases (MMP)-3 and MMP-13 mRNA increased over time in serum-free or reduced serum levels, but was significantly suppressed in 10% fetal bovine serum (FBS). Compressive loading significantly stimulated MMP-3 expression on days 7 and 15. Immunohistochemical analysis demonstrated that maximum pericellular matrix deposition was achieved in 10% FBS culture in the absence of compressive loading. The pericellular distribution of type II and VI collagens, aggrecan, and COMP proteins tended to be more co-localized in the pericellular region from day 9 to day 21; compressive loading helped promote this co-localization of matrix proteins. The results of this study suggest that the quantity, quality, and spatial distribution of cartilaginous matrix can be altered by serum concentrations and compressive loading.

  12. Highlighting the impact of aging on type I collagen: label-free investigation using confocal reflectance microscopy and diffuse reflectance spectroscopy in 3D matrix model.

    PubMed

    Guilbert, Marie; Roig, Blandine; Terryn, Christine; Garnotel, Roselyne; Jeannesson, Pierre; Sockalingum, Ganesh D; Manfait, Michel; Perraut, François; Dinten, Jean-Marc; Koenig, Anne; Piot, Olivier

    2016-02-23

    During aging, alterations of extracellular matrix proteins contribute to various pathological phenotypes. Among these alterations, type I collagen cross-linking and associated glycation products accumulation over time detrimentally affects its physico-chemical properties, leading to alterations of tissue biomechanical stability. Here, different-age collagen 3D matrices using non-destructive and label-free biophotonic techniques were analysed to highlight the impact of collagen I aging on 3D constructs, at macroscopic and microscopic levels. Matrices were prepared with collagens extracted from tail tendons of rats (newborns, young and old adults) to be within the physiological aging process. The data of diffuse reflectance spectroscopy reveal that aging leads to an inhibition of fibril assembly and a resulting decrease of gel density. Investigations by confocal reflectance microscopy highlight poor-fibrillar structures in oldest collagen networks most likely related to the glycation products accumulation. Complementarily, an infrared analysis brings out marked spectral variations in the Amide I profile, specific of the peptidic bond conformation and for carbohydrates vibrations as function of collagen-age. Interestingly, we also highlight an unexpected behavior for newborn collagen, exhibiting poorly-organized networks and microscopic features close to the oldest collagen. These results demonstrate that changes in collagen optical properties are relevant for investigating the incidence of aging in 3D matrix models.

  13. Highlighting the impact of aging on type I collagen: label-free investigation using confocal reflectance microscopy and diffuse reflectance spectroscopy in 3D matrix model

    PubMed Central

    Terryn, Christine; Garnotel, Roselyne; Jeannesson, Pierre; Sockalingum, Ganesh D.; Manfait, Michel; Perraut, François; Dinten, Jean-Marc; Koenig, Anne; Piot, Olivier

    2016-01-01

    During aging, alterations of extracellular matrix proteins contribute to various pathological phenotypes. Among these alterations, type I collagen cross-linking and associated glycation products accumulation over time detrimentally affects its physico-chemical properties, leading to alterations of tissue biomechanical stability. Here, different-age collagen 3D matrices using non-destructive and label-free biophotonic techniques were analysed to highlight the impact of collagen I aging on 3D constructs, at macroscopic and microscopic levels. Matrices were prepared with collagens extracted from tail tendons of rats (newborns, young and old adults) to be within the physiological aging process. The data of diffuse reflectance spectroscopy reveal that aging leads to an inhibition of fibril assembly and a resulting decrease of gel density. Investigations by confocal reflectance microscopy highlight poor-fibrillar structures in oldest collagen networks most likely related to the glycation products accumulation. Complementarily, an infrared analysis brings out marked spectral variations in the Amide I profile, specific of the peptidic bond conformation and for carbohydrates vibrations as function of collagen-age. Interestingly, we also highlight an unexpected behavior for newborn collagen, exhibiting poorly-organized networks and microscopic features close to the oldest collagen. These results demonstrate that changes in collagen optical properties are relevant for investigating the incidence of aging in 3D matrix models. PMID:26885896

  14. Breast epithelial tissue morphology is affected in 3D cultures by species-specific collagen-based extracellular matrix.

    PubMed

    Dhimolea, Eugen; Soto, Ana M; Sonnenschein, Carlos

    2012-11-01

    Collagen-based gels have been widely used to determine the factors that regulate branching morphogenesis in the mammary gland. The patterns of biomechanical gradients and collagen reorganization influence the shape and orientation of epithelial structures in three-dimensional (3D) conditions. We explored in greater detail whether collagen type I fibers with distinct biomechanical and fiber-assembling properties, isolated from either bovine or rat tail tendon, differentially affected the epithelial phenotype in a tissue culture model of the human breast. Rat tail collagen fibers were densely packed into significantly longer and thicker bundles compared to those of the bovine type (average fascicle length 7.35 and 2.29 μm, respectively; p = 0.0001), indicating increased fiber alignment and biomechanical enablement in the former. MCF10A epithelial cells formed elaborated branched tubular structures in bovine but only nonbranched ducts and acini in rat tail collagen matrices. Ductal branching in bovine collagen was associated with interactions between neighboring structures mediated through packed collagen fibers; these fiber-mediated interactions were absent in rat tail collagen gels. Normal breast fibroblasts increased the final size and number of ducts only in rat tail collagen gels while not affecting branching. Our results suggest that the species of origin of collagen used in organotypic cultures may influence epithelial differentiation into alveolar or ductal structures and the patterns of epithelial branching. These observations underscore the importance of considering the species of origin and fiber alignment properties of collagen when engineering branching organs in 3D matrices and interpreting their role in the tissue phenotype.

  15. Multiphoton microscopy of engineered dermal substitutes: assessment of 3-D collagen matrix remodeling induced by fibroblast contraction

    NASA Astrophysics Data System (ADS)

    Pena, Ana-Maria; Fagot, Dominique; Olive, Christian; Michelet, Jean-François; Galey, Jean-Baptiste; Leroy, Frédéric; Beaurepaire, Emmanuel; Martin, Jean-Louis; Colonna, Anne; Schanne-Klein, Marie-Claire

    2010-09-01

    Dermal fibroblasts are responsible for the generation of mechanical forces within their surrounding extracellular matrix and can be potentially targeted by anti-aging ingredients. Investigation of the modulation of fibroblast contraction by these ingredients requires the implementation of three-dimensional in situ imaging methodologies. We use multiphoton microscopy to visualize unstained engineered dermal tissue by combining second-harmonic generation that reveals specifically fibrillar collagen and two-photon excited fluorescence from endogenous cellular chromophores. We study the fibroblast-induced reorganization of the collagen matrix and quantitatively evaluate the effect of Y-27632, a RhoA-kinase inhibitor, on dermal substitute contraction. We observe that collagen fibrils rearrange around fibroblasts with increasing density in control samples, whereas collagen fibrils show no remodeling in the samples containing the RhoA-kinase inhibitor. Moreover, we show that the inhibitory effects are reversible. Our study demonstrates the relevance of multiphoton microscopy to visualize three-dimensional remodeling of the extracellular matrix induced by fibroblast contraction or other processes.

  16. The TLR4 agonist fibronectin extra domain A is cryptic, exposed by elastase-2; use in a fibrin matrix cancer vaccine

    SciTech Connect

    Julier, Ziad; Martino, Mikaël M.; de Titta, Alexandre; Jeanbart, Laura; Hubbell, Jeffrey A.

    2015-02-24

    Fibronectin (FN) is an extracellular matrix (ECM) protein including numerous fibronectin type III (FNIII) repeats with different functions. The alternatively spliced FN variant containing the extra domain A (FNIII EDA), located between FNIII 11 and FNIII 12, is expressed in sites of injury, chronic inflammation, and solid tumors. Although its function is not well understood, FNIII EDA is known to agonize Toll-like receptor 4 (TLR4). Here, by producing various FN fragments containing FNIII EDA, we found that FNIII EDA's immunological activity depends upon its local intramolecular context within the FN chain. N-terminal extension of the isolated FNIII EDA with its neighboring FNIII repeats (FNIII 9-10-11) enhanced its activity in agonizing TLR4, while C-terminal extension with the native FNIII 12-13-14 heparin-binding domain abrogated it. We reveal that an elastase 2 cleavage site is present between FNIII EDA and FNIII 12. Activity of the C-terminally extended FNIII EDA could be restored after cleavage of the FNIII 12-13-14 domain by elastase 2. FN being naturally bound to the ECM, we immobilized FNIII EDA-containing FN fragments within a fibrin matrix model along with antigenic peptides. Such matrices were shown to stimulate cytotoxic CD8+ T cell responses in two murine cancer models.

  17. The TLR4 agonist fibronectin extra domain A is cryptic, exposed by elastase-2; use in a fibrin matrix cancer vaccine

    DOE PAGES

    Julier, Ziad; Martino, Mikaël M.; de Titta, Alexandre; ...

    2015-02-24

    Fibronectin (FN) is an extracellular matrix (ECM) protein including numerous fibronectin type III (FNIII) repeats with different functions. The alternatively spliced FN variant containing the extra domain A (FNIII EDA), located between FNIII 11 and FNIII 12, is expressed in sites of injury, chronic inflammation, and solid tumors. Although its function is not well understood, FNIII EDA is known to agonize Toll-like receptor 4 (TLR4). Here, by producing various FN fragments containing FNIII EDA, we found that FNIII EDA's immunological activity depends upon its local intramolecular context within the FN chain. N-terminal extension of the isolated FNIII EDA with itsmore » neighboring FNIII repeats (FNIII 9-10-11) enhanced its activity in agonizing TLR4, while C-terminal extension with the native FNIII 12-13-14 heparin-binding domain abrogated it. We reveal that an elastase 2 cleavage site is present between FNIII EDA and FNIII 12. Activity of the C-terminally extended FNIII EDA could be restored after cleavage of the FNIII 12-13-14 domain by elastase 2. FN being naturally bound to the ECM, we immobilized FNIII EDA-containing FN fragments within a fibrin matrix model along with antigenic peptides. Such matrices were shown to stimulate cytotoxic CD8+ T cell responses in two murine cancer models.« less

  18. The TLR4 agonist fibronectin extra domain A is cryptic, exposed by elastase-2; use in a fibrin matrix cancer vaccine

    DOE PAGES

    Julier, Ziad; Martino, Mikaël M.; de Titta, Alexandre; ...

    2015-02-24

    Fibronectin (FN) is an extracellular matrix (ECM) protein including numerous fibronectin type III (FNIII) repeats with different functions. The alternatively spliced FN variant containing the extra domain A (FNIII EDA), located between FNIII 11 and FNIII 12, is expressed in sites of injury, chronic inflammation, and solid tumors. Although its function is not well understood, FNIII EDA is known to agonize Toll-like receptor 4 (TLR4). Here, by producing various FN fragments containing FNIII EDA, we found that FNIII EDA's immunological activity depends upon its local intramolecular context within the FN chain. N-terminal extension of the isolated FNIII EDA with itsmore » neighboring FNIII repeats (FNIII 9-10-11) enhanced its activity in agonizing TLR4, while C-terminal extension with the native FNIII 12-13-14 heparin-binding domain abrogated it. We reveal that an elastase 2 cleavage site is present between FNIII EDA and FNIII 12. Activity of the C-terminally extended FNIII EDA could be restored after cleavage of the FNIII 12-13-14 domain by elastase 2. FN being naturally bound to the ECM, we immobilized FNIII EDA-containing FN fragments within a fibrin matrix model along with antigenic peptides. Such matrices were shown to stimulate cytotoxic CD8+ T cell responses in two murine cancer models.« less

  19. The TLR4 agonist fibronectin extra domain A is cryptic, exposed by elastase-2; use in a fibrin matrix cancer vaccine

    SciTech Connect

    Julier, Ziad; Martino, Mikaël M.; de Titta, Alexandre; Jeanbart, Laura; Hubbell, Jeffrey A.

    2015-02-24

    Fibronectin (FN) is an extracellular matrix (ECM) protein including numerous fibronectin type III (FNIII) repeats with different functions. The alternatively spliced FN variant containing the extra domain A (FNIII EDA), located between FNIII 11 and FNIII 12, is expressed in sites of injury, chronic inflammation, and solid tumors. Although its function is not well understood, FNIII EDA is known to agonize Toll-like receptor 4 (TLR4). Here, by producing various FN fragments containing FNIII EDA, we found that FNIII EDA's immunological activity depends upon its local intramolecular context within the FN chain. N-terminal extension of the isolated FNIII EDA with its neighboring FNIII repeats (FNIII 9-10-11) enhanced its activity in agonizing TLR4, while C-terminal extension with the native FNIII 12-13-14 heparin-binding domain abrogated it. We reveal that an elastase 2 cleavage site is present between FNIII EDA and FNIII 12. Activity of the C-terminally extended FNIII EDA could be restored after cleavage of the FNIII 12-13-14 domain by elastase 2. FN being naturally bound to the ECM, we immobilized FNIII EDA-containing FN fragments within a fibrin matrix model along with antigenic peptides. Such matrices were shown to stimulate cytotoxic CD8+ T cell responses in two murine cancer models.

  20. Efficient fully 3D list-mode TOF PET image reconstruction using a factorized system matrix with an image domain resolution model

    PubMed Central

    Zhou, Jian; Qi, Jinyi

    2014-01-01

    A factorized system matrix utilizing an image domain resolution model is attractive in fully 3D TOF PET image reconstruction using list-mode data. In this paper, we study a factored model based on sparse matrix factorization that is comprised primarily of a simplified geometrical projection matrix and an image blurring matrix. Beside the commonly-used Siddon's raytracer, we propose another more simplified geometrical projector based on the Bresenham's raytracer which further reduces the computational cost. We discuss in general how to obtain an image blurring matrix associated with a geometrical projector, and provide theoretical analysis that can be used to inspect the efficiency in model factorization. In simulation studies, we investigate the performance of the proposed sparse factorization model in terms of spatial resolution, noise properties and computational cost. The quantitative results reveal that the factorization model can be as efficient as a nonfactored model such as the analytical model while its computational cost can be much lower. In addition we conduct Monte Carlo simulations to identify the conditions under which the image resolution model can become more efficient in terms of image contrast recovery. We verify our observations using the provided theoretical analysis. The result offers a general guide to achieve optimal reconstruction performance based on a sparse factorization model with an only image domain resolution model. PMID:24434568

  1. Efficient fully 3D list-mode TOF PET image reconstruction using a factorized system matrix with an image domain resolution model.

    PubMed

    Zhou, Jian; Qi, Jinyi

    2014-02-07

    A factorized system matrix utilizing an image domain resolution model is attractive in fully 3D time-of-flight PET image reconstruction using list-mode data. In this paper, we study a factored model based on sparse matrix factorization that is comprised primarily of a simplified geometrical projection matrix and an image blurring matrix. Beside the commonly-used Siddon's ray-tracer, we propose another more simplified geometrical projector based on the Bresenham's ray-tracer which further reduces the computational cost. We discuss in general how to obtain an image blurring matrix associated with a geometrical projector, and provide theoretical analysis that can be used to inspect the efficiency in model factorization. In simulation studies, we investigate the performance of the proposed sparse factorization model in terms of spatial resolution, noise properties and computational cost. The quantitative results reveal that the factorization model can be as efficient as a non-factored model, while its computational cost can be much lower. In addition we conduct Monte Carlo simulations to identify the conditions under which the image resolution model can become more efficient in terms of image contrast recovery. We verify our observations using the provided theoretical analysis. The result offers a general guide to achieve the optimal reconstruction performance based on a sparse factorization model with an image domain resolution model.

  2. FTIR imaging of the 3D extracellular matrix used to grow colonies of breast cancer cell lines.

    PubMed

    Smolina, Margarita; Goormaghtigh, Erik

    2016-01-21

    Infrared imaging was applied to investigate a reconstituted basement membrane, known as Matrigel, in three-dimensional cell cultures. Matrigel, in the vicinity of the colonies, was examined for four breast cancer cell lines presenting different 3D colony morphologies. MCF-7 and T-47D present mass colonies, SKBR-3 grape-like colonies and MDA-MB-231 stellate colonies associated with a more invasive phenotype. The edge of the cell colonies was found to be significantly depleted in Matrigel. Except in a limited number of cases, Matrigel appeared to be thinner at the edges of the colonies but not completely destroyed or torn off as it would be for a purely mechanical effect. When a PCA was run on the spectra of one or several colonies, the score images on PC#3 and PC#4 presented structures in the Matrigel areas which appeared as fringes, lines, dots or regular patterns. This effect represents a very small fraction of the total variance but is reproducible for all the 4 cell lines. PC#4 presents systematically a maximum near 1624 cm(-1) and a minimum around 1700 cm(-1). When spectra are normalized, the effect is less marked but does not disappear. The nature of the variations that exist in the Matrigel layer is therefore not solely related to thickness but also to the chemical composition. At this stage, the weakness of the effect prevents a thorough investigation.

  3. Chondrocyte calcium signaling in response to fluid flow is regulated by matrix adhesion in 3-D alginate scaffolds.

    PubMed

    Degala, Satish; Zipfel, Warren R; Bonassar, Lawrence J

    2011-01-01

    The interaction between chondrocytes and their surrounding extracellular matrix plays an important role in regulating cartilage metabolism in response to environmental cues. This study characterized the role of cell adhesion on the calcium signaling response of chondrocytes to fluid flow. Bovine chondrocytes were suspended in alginate hydrogels functionalized with RGD at concentrations of 0-400μM. The hydrogels were perfused and the calcium signaling response of the cells was measured over a range of fluid velocities from 0 to 68μm/s. Attachment to RGD-alginate doubled the sensitivity of chondrocytes to flows in the range of 8-13μm/s, but at higher fluid velocities, the contribution of cell adhesion to the observed calcium signaling response was no longer apparent. The enhanced sensitivity to flow was dependent on the density of RGD-ligand present in the scaffolds. The RGD-enhanced sensitivity to flow was completely inhibited by the addition of soluble RGD which acted as a competitive inhibitor. The results of this study indicate a role for matrix adhesion in regulating chondrocyte response to fluid flow through a calcium dependent mechanism.

  4. Mechanical, Electromagnetic, and X-ray Shielding Characterization of a 3D Printable Tungsten-Polycarbonate Polymer Matrix Composite for Space-Based Applications

    NASA Astrophysics Data System (ADS)

    Shemelya, Corey M.; Rivera, Armando; Perez, Angel Torrado; Rocha, Carmen; Liang, Min; Yu, Xiaoju; Kief, Craig; Alexander, David; Stegeman, James; Xin, Hao; Wicker, Ryan B.; MacDonald, Eric; Roberson, David A.

    2015-08-01

    Material-extrusion three-dimensional (3D) printing has recently attracted much interest because of its process flexibility, rapid response to design alterations, and ability to create structures "on-the-go". For this reason, 3D printing has possible applications in rapid creation of space-based devices, for example cube satellites (CubeSat). This work focused on fabrication and characterization of tungsten-doped polycarbonate polymer matrix composites specifically designed for x-ray radiation-shielding applications. The polycarbonate-tungsten polymer composite obtained intentionally utilizes low loading levels to provide x-ray shielding while limiting effects on other properties of the material, for example weight, electromagnetic functionality, and mechanical strength. The fabrication process, from tungsten functionalization to filament extrusion and material characterization, is described, including printability, determination of x-ray attenuation, tensile strength, impact resistance, and gigahertz permittivity, and failure analysis. The proposed materials are uniquely advantageous when implemented in 3D printed structures, because even a small volume fraction of tungsten has been shown to substantially alter the properties of the resulting composite.

  5. Two-Photon Imaging of 3D Organization of Bimetallic AuAg Nanoclusters in DNA Matrix.

    PubMed

    Brach, Katarzyna; Waszkielewicz, Magdalena; Olesiak-Banska, Joanna; Samoc, Marek; Matczyszyn, Katarzyna

    2017-09-12

    We report on two-photon excitation properties of small silver-doped gold nanoclusters (AuAgNCs) and on their three-dimensional arrangement in a hybrid system composed of DNA liquid crystals (LCs) and AuAgNCs. UV-vis and fluorescence spectroscopy, transmission electron microscopy (TEM), and multiphoton excitation spectroscopy were used to characterize the nanoparticles. We show that AuAgNCs exhibit two-photon excited luminescence (2PL) emission and second-harmonic generation (SHG) and that these properties remain the same in liquid crystalline matrix. The results are described in detail and discussed in the context of possible imaging application of AuAgNC and specific AuAgNCs organization induced by liquid crystalline ordering of DNA molecules.

  6. Optimum 3D Matrix Stiffness for Maintenance of Cancer Stem Cells Is Dependent on Tissue Origin of Cancer Cells

    PubMed Central

    Jabbari, Esmaiel; Sarvestani, Samaneh K.; Daneshian, Leily; Moeinzadeh, Seyedsina

    2015-01-01

    Introduction The growth and expression of cancer stem cells (CSCs) depend on many factors in the tumor microenvironment. The objective of this work was to investigate the effect of cancer cells’ tissue origin on the optimum matrix stiffness for CSC growth and marker expression in a model polyethylene glycol diacrylate (PEGDA) hydrogel without the interference of other factors in the microenvironment. Methods Human MCF7 and MDA-MB-231 breast carcinoma, HCT116 colorectal and AGS gastric carcinoma, and U2OS osteosarcoma cells were used. The cells were encapsulated in PEGDA gels with compressive moduli in the 2-70 kPa range and optimized cell seeding density of 0.6x106 cells/mL. Micropatterning was used to optimize the growth of encapsulated cells with respect to average tumorsphere size. The CSC sub-population of the encapsulated cells was characterized by cell number, tumorsphere size and number density, and mRNA expression of CSC markers. Results The optimum matrix stiffness for growth and marker expression of CSC sub-population of cancer cells was 5 kPa for breast MCF7 and MDA231, 25 kPa for colorectal HCT116 and gastric AGS, and 50 kPa for bone U2OS cells. Conjugation of a CD44 binding peptide to the gel stopped tumorsphere formation by cancer cells from different tissue origin. The expression of YAP/TAZ transcription factors by the encapsulated cancer cells was highest at the optimum stiffness indicating a link between the Hippo transducers and CSC growth. The optimum average tumorsphere size for CSC growth and marker expression was 50 μm. Conclusion The marker expression results suggest that the CSC sub-population of cancer cells resides within a niche with optimum stiffness which depends on the cancer cells’ tissue origin. PMID:26168187

  7. NEDD9 stabilizes focal adhesions, increases binding to the extra-cellular matrix and differentially effects 2D versus 3D cell migration.

    PubMed

    Zhong, Jessie; Baquiran, Jaime B; Bonakdar, Navid; Lees, Justin; Ching, Yu Wooi; Pugacheva, Elena; Fabry, Ben; O'Neill, Geraldine M

    2012-01-01

    The speed of cell migration on 2-dimensional (2D) surfaces is determined by the rate of assembly and disassembly of clustered integrin receptors known as focal adhesions. Different modes of cell migration that have been described in 3D environments are distinguished by their dependence on integrin-mediated interactions with the extra-cellular matrix. In particular, the mesenchymal invasion mode is the most dependent on focal adhesion dynamics. The focal adhesion protein NEDD9 is a key signalling intermediary in mesenchymal cell migration, however whether NEDD9 plays a role in regulating focal adhesion dynamics has not previously been reported. As NEDD9 effects on 2D migration speed appear to depend on the cell type examined, in the present study we have used mouse embryo fibroblasts (MEFs) from mice in which the NEDD9 gene has been depleted (NEDD9 -/- MEFs). This allows comparison with effects of other focal adhesion proteins that have previously been demonstrated using MEFs. We show that focal adhesion disassembly rates are increased in the absence of NEDD9 expression and this is correlated with increased paxillin phosphorylation at focal adhesions. NEDD9-/- MEFs have increased rates of migration on 2D surfaces, but conversely, migration of these cells is significantly reduced in 3D collagen gels. Importantly we show that myosin light chain kinase is activated in 3D in the absence of NEDD9 and is conversely inhibited in 2D cultures. Measurement of adhesion strength reveals that NEDD9-/- MEFs have decreased adhesion to fibronectin, despite upregulated α5β1 fibronectin receptor expression. We find that β1 integrin activation is significantly suppressed in the NEDD9-/-, suggesting that in the absence of NEDD9 there is decreased integrin receptor activation. Collectively our data suggest that NEDD9 may promote 3D cell migration by slowing focal adhesion disassembly, promoting integrin receptor activation and increasing adhesion force to the ECM.

  8. Establishment of a human 3D lung cancer model based on a biological tissue matrix combined with a Boolean in silico model.

    PubMed

    Stratmann, Anna T; Fecher, David; Wangorsch, Gaby; Göttlich, Claudia; Walles, Thorsten; Walles, Heike; Dandekar, Thomas; Dandekar, Gudrun; Nietzer, Sarah L

    2014-03-01

    For the development of new treatment strategies against cancer, understanding signaling networks and their changes upon drug response is a promising approach to identify new drug targets and biomarker profiles. Pre-requisites are tumor models with multiple read-out options that accurately reflect the clinical situation. Tissue engineering technologies offer the integration of components of the tumor microenvironment which are known to impair drug response of cancer cells. We established three-dimensional (3D) lung carcinoma models on a decellularized tissue matrix, providing a complex microenvironment for cell growth. For model generation, we used two cell lines with (HCC827) or without (A549) an activating mutation of the epidermal growth factor receptor (EGFR), exhibiting different sensitivities to the EGFR inhibitor gefitinib. EGFR activation in HCC827 was inhibited by gefitinib, resulting in a significant reduction of proliferation (Ki-67 proliferation index) and in the induction of apoptosis (TUNEL staining, M30-ELISA). No significant effect was observed in conventional cell culture. Results from the 3D model correlated with the results of an in silico model that integrates the EGFR signaling network according to clinical data. The application of TGFβ1 induced tumor cell invasion, accompanied by epithelial-mesenchymal transition (EMT) both in vitro and in silico. This was confirmed in the 3D model by acquisition of mesenchymal cell morphology and modified expression of fibronectin, E-cadherin, β-catenin and mucin-1. Quantitative read-outs for proliferation, apoptosis and invasion were established in the complex 3D tumor model. The combined in vitro and in silico model represents a powerful tool for systems analysis. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  9. 3-D ultrastructure and collagen composition of healthy and overloaded human tendon: evidence of tenocyte and matrix buckling

    PubMed Central

    Pingel, Jessica; Lu, Yinhui; Starborg, Tobias; Fredberg, Ulrich; Langberg, Henning; Nedergaard, Anders; Weis, MaryAnn; Eyre, David; Kjaer, Michael; Kadler, Karl E

    2014-01-01

    Achilles tendinopathies display focal tissue thickening with pain and ultrasonography changes. Whilst complete rupture might be expected to induce changes in tissue organization and protein composition, little is known about the consequences of non-rupture-associated tendinopathies, especially with regards to changes in the content of collagen type I and III (the major collagens in tendon), and changes in tendon fibroblast (tenocyte) shape and organization of the extracellular matrix (ECM). To gain new insights, we took biopsies from the tendinopathic region and flanking healthy region of Achilles tendons of six individuals with clinically diagnosed tendinopathy who had no evidence of cholesterol, uric acid and amyloid accumulation. Biochemical analyses of collagen III/I ratio were performed on all six individuals, and electron microscope analysis using transmission electron microscopy and serial block face-scanning electron microscopy were made on two individuals. In the tendinopathic regions, compared with the flanking healthy tissue, we observed: (i) an increase in the ratio of collagen III : I proteins; (ii) buckling of the collagen fascicles in the ECM; (iii) buckling of tenocytes and their nuclei; and (iv) an increase in the ratio of small-diameter : large-diameter collagen fibrils. In summary, load-induced non-rupture tendinopathy in humans is associated with localized biochemical changes, a shift from large-to small-diameter fibrils, buckling of the tendon ECM, and buckling of the cells and their nuclei. PMID:24571576

  10. Biophysical properties of dermal building-blocks affects extra cellular matrix assembly in 3D endogenous macrotissue.

    PubMed

    Urciuolo, F; Garziano, A; Imparato, G; Panzetta, V; Fusco, S; Casale, C; Netti, P A

    2016-01-29

    The fabrication of functional tissue units is one of the major challenges in tissue engineering due to their in vitro use in tissue-on-chip systems, as well as in modular tissue engineering for the construction of macrotissue analogs. In this work, we aim to engineer dermal tissue micromodules obtained by culturing human dermal fibroblasts into porous gelatine microscaffold. We proved that such stromal cells coupled with gelatine microscaffolds are able to synthesize and to assemble an endogenous extracellular matrix (ECM) resulting in tissue micromodules, which evolve their biophysical features over the time. In particular, we found a time-dependent variation of oxygen consumption kinetic parameters, of newly formed ECM stiffness and of micromodules self-aggregation properties. As consequence when used as building blocks to fabricate larger tissues, the initial tissue micromodules state strongly affects the ECM organization and maturation in the final macrotissue. Such results highlight the role of the micromodules properties in controlling the formation of three-dimensional macrotissue in vitro, defining an innovative design criterion for selecting tissue-building blocks for modular tissue engineering.

  11. Ion-channel regulation of chondrocyte matrix synthesis in 3D culture under static and dynamic compression.

    PubMed

    Mouw, J K; Imler, S M; Levenston, M E

    2007-01-01

    GAG synthesis. This modulation potentially occurs through direct interactions with the extracellular matrix.

  12. The coronally advanced flap in combination with platelet-rich fibrin (PRF) and enamel matrix derivative in the treatment of gingival recession: a comparative study.

    PubMed

    Jankovic, Sasha; Aleksic, Zoran; Milinkovic, Iva; Dimitrijevic, Bozidar

    2010-01-01

    The main objective of this study was to evaluate the clinical effectiveness of platelet-rich fibrin membrane used in combination with a coronally advanced flap (CAF) and to compare it with the use of an enamel matrix derivative (EMD) in combination with a coronally advanced flap in gingival recession treatment. 20 split-mouth cases of maxillary anterior teeth or bicuspids presenting with Miller Class I or II gingival recession were treated with a CAF combined with a platelet-rich fibrin membrane (PRF group) or with EMD (EMD group) placed under a CAF. The following parameters were measured at baseline and at 12 months post treatment: gingival recession (GR), apicocoronal width of the keratinized tissue (WKT), and probing depth (PD). Complete rot coverage in the PRF group was 65% (13 out of 20 recessions) and 60% in the EMD group (12 out of 20 recessions). GR was 4.10 ± 1.05 mm in the PRF group and 3.90 ± 1.00 mm in the EMD group at baseline, and 1.05 ± 0.45 mm in the PRF group and 1.15 ± 0.65 mm in the EMD group at 12 months. The difference observed between the tow groups at 12 months was statistically significant. Average root coverage was 70.5% in the EMD group and 72.1% in the PRF group. WKT was 1.30 ± 0.56 mm in the EMD group and 1.45 ± 0.86 mm in the PRF group at baseline, and 1.90 ± 0.81 mm in the EMD group and 1.62 ± 0.28 mm in the PRF group at 12 months. The difference observed between the two groups at 12 months was not statistically significant. Twelve-month changes in PD were not significantly different between the two groups. The pain intensity was statistically different between the two groups. The pain intensity was statistically different between groups for the first 5 days, favoring the PRF group. The present study did not succeed in demonstrating any clinical advantage of the use of PRF compared to EMD in the coverage of gingival recession with the CAF procedure. The EMD group showed a higher success rate in increasing WKT than did the PRF

  13. Refined 3d-3d correspondence

    NASA Astrophysics Data System (ADS)

    Alday, Luis F.; Genolini, Pietro Benetti; Bullimore, Mathew; van Loon, Mark

    2017-04-01

    We explore aspects of the correspondence between Seifert 3-manifolds and 3d N = 2 supersymmetric theories with a distinguished abelian flavour symmetry. We give a prescription for computing the squashed three-sphere partition functions of such 3d N = 2 theories constructed from boundary conditions and interfaces in a 4d N = 2∗ theory, mirroring the construction of Seifert manifold invariants via Dehn surgery. This is extended to include links in the Seifert manifold by the insertion of supersymmetric Wilson-'t Hooft loops in the 4d N = 2∗ theory. In the presence of a mass parameter cfor the distinguished flavour symmetry, we recover aspects of refined Chern-Simons theory with complex gauge group, and in particular construct an analytic continuation of the S-matrix of refined Chern-Simons theory.

  14. Lagrangian advection scheme with shape matrix (LASM) v0.2: interparcel mixing, physics-dynamics coupling and 3-D extension

    NASA Astrophysics Data System (ADS)

    Dong, L.; Wang, B.; Liu, L.; Huang, Y.

    2015-08-01

    The interparcel mixing algorithm in the Lagrangian advection scheme with shape matrix (LASM) is updated to make the scheme more robust. The linear degeneration criterion is replaced by the maximum deviation of the skeleton points so that the new algorithm is more effective in controlling the shape of parcels, which is vital for long time simulation. LASM is inherently shape-preserving without any complicated filter or limiter, and it is linear. This fact contributes to the ability to preserve the sum of multiple tracers exactly on the parcels in LASM. A newly proposed terminator "toy"-chemistry test is used to test LASM, which shows that LASM can preserve the weighted sum of two reactive species precisely. The physics-dynamics coupling (i.e., tendency evaluation type) is also discussed. A flow generated by a WRF large-eddy simulation is also used to test the 3-D extension of LASM.

  15. Fabrication of 3D lawn-shaped N-doped porous carbon matrix/polyaniline nanocomposite as the electrode material for supercapacitors

    NASA Astrophysics Data System (ADS)

    Zhang, Xiuling; Ma, Li; Gan, Mengyu; Fu, Gang; Jin, Meng; Lei, Yao; Yang, Peishu; Yan, Maofa

    2017-02-01

    A facile approach to acquire electrode materials with prominent electrochemical property is pivotal to the progress of supercapacitors. 3D nitrogen-doped porous carbon matrix (PCM), with high specific surface area (SSA) up to 2720 m2 g-1, was obtained from the carbonization and activation of the nitrogen-enriched composite precursor (graphene/polyaniline). Then 3D lawn-shaped PCM/PANI composite was obtained by the simple in-situ polymerization. The morphology and structure of these resulting composites were characterized by combining SEM and TEM measurements, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) spectroscopy analyses and Raman spectroscope. The element content of all samples was evaluated using CHN analysis. The results of electrochemical testing indicated that the PCM/PANI composite displays a higher capacitance value of 527 F g-1 at 1 A g-1 compared to 338 F g-1 for pure PANI, and exhibits appreciable rate capability with a retention of 76% at 20 A g-1 as well as fine long-term cycling performance (with 88% retention of specific capacitance after 1000 cycles at 10 A g-1). Simultaneously, the excellent capacitance performance coupled with the facile synthesis of PCM/PANI indicates it is a promising electrode material for supercapacitors.

  16. Epidermal growth factor promotes a mesenchymal over an amoeboid motility of MDA-MB-231 cells embedded within a 3D collagen matrix

    NASA Astrophysics Data System (ADS)

    Geum, Dongil T.; Kim, Beum Jun; Chang, Audrey E.; Hall, Matthew S.; Wu, Mingming

    2016-01-01

    The receptor of epidermal growth factor (EGFR) critically regulates tumor cell invasion and is a potent therapeutic target for treatment of many types of cancers, including carcinomas and glioblastomas. It is known that EGF regulates cell motility when tumor cells are embedded within a 3D biomatrix. However, roles of EGF in modulating tumor cell motility phenotype are largely unknown. In this article, we report that EGF promotes a mesenchymal over an amoeboid motility phenotype using a malignant breast tumor cell line, MDA-MB-231, embedded within a 3D collagen matrix. Amoeboid cells are rounded in shape, while mesenchymal cells are elongated, and their migrations are governed by a distinctly different set of biomolecules. Using single cell tracking analysis, we also show that EGF promotes cell dissemination through a significant increase in cell persistence along with a moderate increase of speed. The increase of persistence is correlated with the increase of the percentage of the mesenchymal cells within the population. Our work reveals a novel role of microenvironmental cue, EGF, in modulating heterogeneity and plasticity of tumor cell motility phenotype. In addition, it suggests a potential visual cue for diagnosing invasive states of breast cancer cells. This work can be easily extended beyond breast cancer cells.

  17. Maturation of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) in 3D collagen matrix: Effects of niche cell supplementation and mechanical stimulation.

    PubMed

    Zhang, W; Kong, C W; Tong, M H; Chooi, W H; Huang, N; Li, R A; Chan, B P

    2017-02-01

    Cardiomyocytes derived from human embryonic stem cells (hESC-CMs) are regarded as a promising source for regenerative medicine, drug testing and disease modeling. Nevertheless, cardiomyocytes are immature in terms of their contractile structure, metabolism and electrophysiological properties. Here, we fabricate cardiac muscle strips by encapsulating hESC-CMs in collagen-based biomaterials. Supplementation of niche cells at 3% to the number of hESC-CMs enhance the maturation of the hESC-CMs in 3D tissue matrix. The benefits of adding mesenchymal stem cells (MSCs) are comparable to that of adding fibroblasts. These two cell types demonstrate similar effects in promoting the compaction and cell spreading, as well as expression of maturation markers at both gene and protein levels. Mechanical loading, particularly cyclic stretch, produces engineered cardiac tissues with higher maturity in terms of twitch force, elastic modulus, sarcomere length and molecular signature, when comparing to static stretch or non-stretched controls. The current study demonstrates that the application of niche cells and mechanical stretch both stimulate the maturation of hESC-CMs in 3D architecture. Our results therefore suggest that this 3D model can be used for in vitro cardiac maturation study. Cardiomyocytes derived from human embryonic stem cells (hESC-CMs) are regarded as being a promising source of cells for regenerative medicine, drug testing and disease modeling. Nevertheless, cardiomyocytes are immature in terms of their contractile structure, metabolism and electrophysiological properties. In the current study, we have fabricated cardiac muscle strips by encapsulating hESC-CMs in collagen-based biomaterials and demonstrated that supplementation of mesenchymal niche cells as well as provision of mechanical loading particularly stretching have significantly promoted the maturation of the cardiomyocytes and hence improved the mechanical functional characteristics of the tissue strips

  18. RNA Interference and BMP-2 Stimulation Allows Equine Chondrocytes Redifferentiation in 3D-Hypoxia Cell Culture Model: Application for Matrix-Induced Autologous Chondrocyte Implantation.

    PubMed

    Rakic, Rodolphe; Bourdon, Bastien; Hervieu, Magalie; Branly, Thomas; Legendre, Florence; Saulnier, Nathalie; Audigié, Fabrice; Maddens, Stéphane; Demoor, Magali; Galera, Philippe

    2017-08-24

    As in humans, osteoarthritis (OA) causes considerable economic loss to the equine industry. New hopes for cartilage repair have emerged with the matrix-associated autologous chondrocyte implantation (MACI). Nevertheless, its limitation is due to the dedifferentiation occurring during the chondrocyte amplification phase, leading to the loss of its capacity to produce a hyaline extracellular matrix (ECM). To enhance the MACI therapy efficiency, we have developed a strategy for chondrocyte redifferentiation, and demonstrated its feasibility in the equine model. Thus, to mimic the cartilage microenvironment, the equine dedifferentiated chondrocytes were cultured in type I/III collagen sponges for 7 days under hypoxia in the presence of BMP-2. In addition, chondrocytes were transfected by siRNA targeting Col1a1 and Htra1 mRNAs, which are overexpressed during dedifferentiation and OA. To investigate the quality of the neo-synthesized ECM, specific and atypical cartilage markers were evaluated by RT-qPCR and Western blot. Our results show that the combination of 3D hypoxia cell culture, BMP-2 (Bone morphogenetic protein-2), and RNA interference, increases the chondrocytes functional indexes (Col2a1/Col1a1, Acan/Col1a1), leading to an effective chondrocyte redifferentiation. These data represent a proof of concept for this process of application, in vitro, in the equine model, and will lead to the improvement of the MACI efficiency for cartilage tissue engineering therapy in preclinical/clinical trials, both in equine and human medicine.

  19. Biocompatible nanoparticles sensing the matrix metallo-proteinase 2 for the on-demand release of anticancer drugs in 3D tumor spheroids.

    PubMed

    Cantisani, Marco; Guarnieri, Daniela; Biondi, Marco; Belli, Valentina; Profeta, Martina; Raiola, Luca; Netti, Paolo A

    2015-11-01

    The balance between dose-dependent tolerability, effectiveness and toxicity of systemically administered antitumor drugs is extremely delicate. This issue highlights the striking need for targeted release of chemotherapeutic drugs within tumors. In this work, a smart strategy of drug targeting to tumors relying upon biodegradable/biocompatible nanoparticles releasing cytotoxic drugs after sensing physiological variations intrinsic to the very nature of tumor tissues is exploited. Here, the well-known over-expression of matrix metallo-proteinase 2 (MMP2) enzyme in tumors has been chosen as a trigger for the release of a cytotoxic drug. Nanoparticles made up of a biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA)--block--polyethylene glycol (PEG) copolymer (namely PELGA), blended with a tumor-activated prodrug (TAP) composed of a MMP2-sensitive peptide bound to doxorubicin (Dox) and to PLGA chain have been produced. The obtained devices are able to release Dox specifically upon MMP2 cleavage of the TAP. More interestingly, they can sense the differences in the expression levels of endogenous MMP2 protein, thus modulating drug penetration within a three-dimensional (3D) tumor spheroid matrix, accordingly. Therefore, the proposed nanoparticles hold promise as a useful tool for in vivo investigations aimed at an improved therapeutic efficacy of the conjugated drug payload. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Integrating focal adhesion dynamics, cytoskeleton remodeling, and actin motor activity for predicting cell migration on 3D curved surfaces of the extracellular matrix.

    PubMed

    Kim, Min-Cheol; Kim, Choong; Wood, Levi; Neal, Devin; Kamm, Roger D; Asada, H Harry

    2012-11-01

    An integrative cell migration model incorporating focal adhesion (FA) dynamics, cytoskeleton and nucleus remodeling and actin motor activity is developed for predicting cell migration behaviors on 3-dimensional curved surfaces, such as cylindrical lumens in the 3-D extracellular matrix (ECM). The work is motivated by 3-D microfluidic migration experiments suggesting that the migration speed and direction may vary depending on the cross sectional shape of the lumen along which the cell migrates. In this paper, the mechanical structure of the cell is modeled as double elastic membranes of cell and nucleus. The two elastic membranes are connected by stress fibers, which are extended from focal adhesions on the cell surface to the nuclear membrane. The cell deforms and gains traction as transmembrane integrins distributed over the outer cell membrane bind to ligands on the ECM, form focal adhesions, and activate stress fibers. Probabilities at which integrin ligand-receptor bonds are formed as well as ruptures are affected by the surface geometry, resulting in diverse migration behaviors that depend on the curvature of the surface. Monte Carlo simulations of the integrative model reveal that (a) the cell migration speed is dependent on the cross sectional area of the lumen with a maximum speed at a particular diameter or width, (b) as the lumen diameter increases, the cell tends to spread and migrate around the circumference of the lumen, while it moves in the longitudinal direction as the lumen diameter narrows, (c) once the cell moves in one direction, it tends to stay migrating in the same direction despite the stochastic nature of migration. The relationship between the cell migration speed and the lumen width agrees with microfluidic experimental data for cancer cell migration.

  1. Comparison of 3D-Printed Poly-ɛ-Caprolactone Scaffolds Functionalized with Tricalcium Phosphate, Hydroxyapatite, Bio-Oss, or Decellularized Bone Matrix.

    PubMed

    Nyberg, Ethan; Rindone, Alexandra; Dorafshar, Amir; Grayson, Warren L

    2017-02-07

    Three-dimensional (3D)-printing facilitates rapid, custom manufacturing of bone scaffolds with a wide range of material choices. Recent studies have demonstrated the potential for 3D-printing bioactive (i.e., osteo-inductive) scaffolds for use in bone regeneration applications. In this study, we 3D-printed porous poly-ɛ-caprolactone (PCL) scaffolds using a fused deposition modeling (FDM) process and functionalized them with mineral additives that have been widely used commercially and clinically: tricalcium phosphate (TCP), hydroxyapatite (HA), Bio-Oss (BO), or decellularized bone matrix (DCB). We assessed the "print quality" of the composite scaffolds and found that the print quality of PCL-TCP, PCL-BO, and PCL-DCB measured ∼0.7 and was statistically lower than PCL and PCL-HA scaffolds (∼0.8). We found that the incorporation of mineral particles did not significantly decrease the compressive modulus of the graft, which was on the order of 260 MPa for solid blocks and ranged from 32 to 83 MPa for porous scaffolds. Raman spectroscopy revealed the surfaces of the scaffolds maintained the chemical profile of their dopants following the printing process. We evaluated the osteo-inductive properties of each scaffold composite by culturing adipose-derived stromal/stem cells in vitro and assessing their differentiation into osteoblasts. The calcium content (normalized to DNA) increased significantly in PCL-TCP (p < 0.05), PCL-BO (p < 0.001), and PCL-DCB (p < 0.0001) groups relative to PCL only. The calcium content also increased in PCL-HA but was not statistically significant (p > 0.05). Collagen 1 expression was 10-fold greater than PCL in PCL-BO and PCL-DCB (p < 0.05) and osteocalcin expression was 10-fold greater in PCL-BO and PCL-DCB (p < 0.05) as measured by quantitative-real time-polymerase chain reaction. This study suggests that PCL-BO and PCL-DCB hybrid material may be advantageous for bone healing applications over PCL-HA or PCL

  2. Incorporation of exudates of human platelet-rich fibrin gel in biodegradable fibrin scaffolds for tissue engineering of cartilage.

    PubMed

    Chien, Chi-Sheng; Ho, Hsiu-O; Liang, Yu-Chih; Ko, Pai-Hung; Sheu, Ming-Thau; Chen, Chien-Ho

    2012-05-01

    The goal of this study was to assess the incorporation of exudates of human platelet-rich fibrin (hPRF) that is abundant in platelet cytokines and growth factors into biodegradable fibrin (FB) scaffolds as a regeneration matrix for promoting chondrocyte proliferation and re-differentiation. hPRF was obtained from human blood by centrifugation without an anticoagulant, and the exudate of hPRF was collected and mixed with bovine fibrinogen, and then thrombin was added to form the FB scaffold. Proliferation and differentiation of human primary chondrocytes and a human chondrosarcoma cell line, the SW-1353, embedded in the three-dimensional (3D) scaffolds and on the two-dimensional (2D) surface of the FB scaffolds so produced were evaluated in comparison with an agarose (AG) scaffold serving as the control. Results demonstrated that the amounts of these cytokines and growth factors in hPRF exudates were higher than those in the blood-derived products except for TGF-β1. Chondrocytes and SW1353 cells on the 2D and 3D FB scaffolds with the addition of the exudates of PRF exhibited more-available proliferation and differentiation than cells on 2D and 3D FB and AG scaffolds. It was concluded that FB scaffolds can provide an appropriate environment for chondrocyte proliferation and re-differentiation, and it could be improved by adding exudates of hPRF. These 3D scaffolds have great promise for cartilage tissue engineering. Copyright © 2012 Wiley Periodicals, Inc.

  3. Experimental Evaluation of the Effectiveness of Demineralized Bone Matrix and Collagenated Heterologous Bone Grafts Used Alone or in Combination with Platelet-Rich Fibrin on Bone Healing in Sinus Floor Augmentation.

    PubMed

    Peker, Elif; Karaca, Inci Rana; Yildirim, Benay

    2016-01-01

    The aim of this study was an experimental evaluation of the effectiveness of demineralized bone matrix (DBM) and collagenated heterologous bone graft (CHBG) used alone or in combination with platelet-rich fibrin on bone healing in sinus floor augmentation procedures. In this study, 36 New Zealand rabbits were used. The bilateral sinus elevation was performed, and 72 defects were obtained. The rabbit maxillary sinuses were divided into four groups according to the augmentation biomaterials obtained: demineralized bone matrix (Grafton DBM Putty, Osteotech; DBM group), DBM combined with platelet-rich fibrin (PRF; DBM + PRF group), collagenated heterologous bone graft (CHBG; Apatos Mix, OsteoBiol, Tecnoss; CHBG group), CHBG combined with PRF (CHBG + PRF group). All groups were sacrificed at 2, 4, and 8 weeks after surgery for histologic, histomorphometric, and immunohistochemical analyses. The inflammatory reaction was moderate to intense at the second week in all groups and declined from 2 to 8 weeks. New bone formation was started at the second week and increased from 2 to 8 weeks in all groups. There was no significant difference in bone formation between the experimental groups that used PRF mixed graft material and control groups that used only graft material. The percentage of new bone formation showed a significant difference in DBM groups and DBM + PRF groups compared with other groups. There were osteoclasts around all the bone graft materials used, but the percentage of residual graft particles was significantly higher in CHBG groups and CHBG + PRF groups at the eighth week. There is no beneficial effect of the application of PRF in combination with demineralized bone matrix or collagenated heterologous bone graft on bone formation in sinus floor augmentation. The results of this study showed that both collagenated heterologous bone graft and demineralized bone matrix have osteoconductive properties, but demineralized bone matrix showed more bone formation

  4. A Novel 2D Image Compression Algorithm Based on Two Levels DWT and DCT Transforms with Enhanced Minimize-Matrix-Size Algorithm for High Resolution Structured Light 3D Surface Reconstruction

    NASA Astrophysics Data System (ADS)

    Siddeq, M. M.; Rodrigues, M. A.

    2015-09-01

    Image compression techniques are widely used on 2D image 2D video 3D images and 3D video. There are many types of compression techniques and among the most popular are JPEG and JPEG2000. In this research, we introduce a new compression method based on applying a two level discrete cosine transform (DCT) and a two level discrete wavelet transform (DWT) in connection with novel compression steps for high-resolution images. The proposed image compression algorithm consists of four steps. (1) Transform an image by a two level DWT followed by a DCT to produce two matrices: DC- and AC-Matrix, or low and high frequency matrix, respectively, (2) apply a second level DCT on the DC-Matrix to generate two arrays, namely nonzero-array and zero-array, (3) apply the Minimize-Matrix-Size algorithm to the AC-Matrix and to the other high-frequencies generated by the second level DWT, (4) apply arithmetic coding to the output of previous steps. A novel decompression algorithm, Fast-Match-Search algorithm (FMS), is used to reconstruct all high-frequency matrices. The FMS-algorithm computes all compressed data probabilities by using a table of data, and then using a binary search algorithm for finding decompressed data inside the table. Thereafter, all decoded DC-values with the decoded AC-coefficients are combined in one matrix followed by inverse two levels DCT with two levels DWT. The technique is tested by compression and reconstruction of 3D surface patches. Additionally, this technique is compared with JPEG and JPEG2000 algorithm through 2D and 3D root-mean-square-error following reconstruction. The results demonstrate that the proposed compression method has better visual properties than JPEG and JPEG2000 and is able to more accurately reconstruct surface patches in 3D.

  5. The Effect of Chondroitin Sulphate and Hyaluronic Acid on Chondrocytes Cultured within a Fibrin-Alginate Hydrogel.

    PubMed

    Little, Christopher J; Kulyk, William M; Chen, Xiongbiao

    2014-09-18

    Osteoarthritis is a painful degenerative joint disease that could be better managed if tissue engineers can develop methods to create long-term engineered articular cartilage tissue substitutes. Many of the tissue engineered cartilage constructs currently available lack the chemical stimuli and cell-friendly environment that promote the matrix accumulation and cell proliferation needed for use in joint cartilage repair. The goal of this research was to test the efficacy of using a fibrin-alginate hydrogel containing hyaluronic acid (HA) and/or chondroitin sulphate (CS) supplements for chondrocyte culture. Neonatal porcine chondrocytes cultured in fibrin-alginate hydrogels retained their phenotype better than chondrocytes cultured in monolayer, as evidenced by analysis of their relative expression of type II versus type I collagen mRNA transcripts. HA or CS supplementation of the hydrogels increased matrix glycosaminoglycan (GAG) production during the first week of culture. However, the effects of these supplements on matrix accumulation were not additive and were no longer observed after two weeks of culture. Supplementation of the hydrogels with CS or a combination of both CS and HA increased the chondrocyte cell population after two weeks of culture. Statistical analysis indicated that the HA and CS treatment effects on chondrocyte numbers may be additive. This research suggests that supplementation with CS and/or HA has positive effects on cartilage matrix production and chondrocyte proliferation in three-dimensional (3D) fibrin-alginate hydrogels.

  6. Enhancing neuronal growth from human endometrial stem cells derived neuron-like cells in three-dimensional fibrin gel for nerve tissue engineering.

    PubMed

    Navaei-Nigjeh, Mona; Amoabedini, Ghasem; Noroozi, Abbas; Azami, Mahmoud; Asmani, Mohammad N; Ebrahimi-Barough, Somayeh; Saberi, Hooshang; Ai, Armin; Ai, Jafar

    2014-08-01

    Nerve tissue engineering (NTE) is one of the most promising methods to restore central nerve systems in human health care. Three-dimensional (3D) distribution and growth of cells within the porous scaffold composed of nanofibers are of clinical significance for NTE. In this study, an attempt was made to develop and characterize the use of fibrin gel and human endometrial stem cells (hEnSCs)-derived neuron-like cells simultaneously to support cell behavior especially neuron outgrowth. The structural and mechanical characteristics of fibrin gel scaffold were examined with SEM and rheometer. Also, hEnSCs-derived neuron-like cells were cultured in fibrin gel and were subsequently analyzed with immunofluorescent staining against neuronal markers. In parallel, the survival and growth rates of the cells were determined by MTT assay and neurite extension. At the end, cell-matrix interactions were investigated with SEM and TEM micrographs. Mechanical properties of fabricated scaffold were studied and results indicated appropriate choice of material, SEM and TEM showed excellent integration of cells with nanofibers regarding the relation between cells and fibrin gel. Immunofluorescent staining of fibrin gel after 6 days of cell seeding and culture demonstrated well expanded and incorporated network of neurons. In addition, viability, proliferation, and neuronal growth of seeded cells were analyzed at days 1, 3, and 6. Comparing those results with 2D culture of seeded cells showed positive effect of 3D culture. Taken together, the results suggest that fibrin can provide a suitable, three-dimensional scaffold for neuronal survival and outgrowth for regeneration of the central nervous system.

  7. Macrophage podosomes go 3D.

    PubMed

    Van Goethem, Emeline; Guiet, Romain; Balor, Stéphanie; Charrière, Guillaume M; Poincloux, Renaud; Labrousse, Arnaud; Maridonneau-Parini, Isabelle; Le Cabec, Véronique

    2011-01-01

    Macrophage tissue infiltration is a critical step in the immune response against microorganisms and is also associated with disease progression in chronic inflammation and cancer. Macrophages are constitutively equipped with specialized structures called podosomes dedicated to extracellular matrix (ECM) degradation. We recently reported that these structures play a critical role in trans-matrix mesenchymal migration mode, a protease-dependent mechanism. Podosome molecular components and their ECM-degrading activity have been extensively studied in two dimensions (2D), but yet very little is known about their fate in three-dimensional (3D) environments. Therefore, localization of podosome markers and proteolytic activity were carefully examined in human macrophages performing mesenchymal migration. Using our gelled collagen I 3D matrix model to obligate human macrophages to perform mesenchymal migration, classical podosome markers including talin, paxillin, vinculin, gelsolin, cortactin were found to accumulate at the tip of F-actin-rich cell protrusions together with β1 integrin and CD44 but not β2 integrin. Macrophage proteolytic activity was observed at podosome-like protrusion sites using confocal fluorescence microscopy and electron microscopy. The formation of migration tunnels by macrophages inside the matrix was accomplished by degradation, engulfment and mechanic compaction of the matrix. In addition, videomicroscopy revealed that 3D F-actin-rich protrusions of migrating macrophages were as dynamic as their 2D counterparts. Overall, the specifications of 3D podosomes resembled those of 2D podosome rosettes rather than those of individual podosomes. This observation was further supported by the aspect of 3D podosomes in fibroblasts expressing Hck, a master regulator of podosome rosettes in macrophages. In conclusion, human macrophage podosomes go 3D and take the shape of spherical podosome rosettes when the cells perform mesenchymal migration. This work

  8. Sandwiched polymer fibre in fibrin matrices for the dictation of endothelial cells undergoing angiogenesis

    NASA Astrophysics Data System (ADS)

    Sukmana, I.; Djuansjah, J. R. P.

    2013-04-01

    We present here a three-dimensional (3D) sandwich system made by poly(ethylene terephthalate) (PET) fibre and fibrin extracellular matrix (ECM) for endothelial cell dictation and angiogenesis guidance. In this three-dimensional system, Human Umbilical Vein Endothelial cells (HUVECs) were firstly cultured for 2 (two) days to cover the PET fibre before sandwiched in two layer fibrin gel containing HUVECs. After 4 (four) days of culture, cel-to-cel connection, tube-like structure and multi-cellular lumen formation were then assessed and validated. Phase contrast and fluorescence imaging using an inverted microscope were used to determine cell-to-cell and cell-ECM interactions. Laser scanning confocal microscopy and histological techniques were used to confirm the development of tube-like structure and multi-cellular lumen formation. This study shows that polymer fibres sandwiched in fibrin gel can be used to dictate endothelial cells undergoing angiogenesis with potential application in cancer and cardiovascular study and tissue engineering vascularisation.

  9. Endodontic management of nonvital permanent teeth having immature roots with one step apexification, using mineral trioxide aggregate apical plug and autogenous platelet-rich fibrin membrane as an internal matrix: Case series

    PubMed Central

    Sharma, Vivek; Sharma, Sarang; Dudeja, Pooja; Grover, Shibani

    2016-01-01

    A tooth with blunderbuss canal and open apex can be an endodontic challenge because of difficulty in obtaining an apical seal, and existing thin radicular walls which are susceptible to fracture. To overcome the limitations of traditional long-term calcium hydroxide apexification procedures, nonsurgical one step apexification using an array of materials such as mineral trioxide aggregate (MTA) has been suggested. However, adequate compaction of MTA in teeth with wide open apices can be an arduous task, and an internal matrix is required for controlled placement of MTA against which obturating material can be condensed. Platelet-rich fibrin (PRF), a second generation platelet concentrate containing several growth factors that promotes hard and soft-tissue healing, has been used as an internal matrix to create an apical plug of MTA and hence prevent extrusion of filling materials. This case series presents the endodontic management of immature permanent teeth with open apices using internal matrix of autologous PRF membrane and one step apical barrier placement of MTA. PMID:27041904

  10. Structural basis for the nonlinear mechanics of fibrin networks under compression

    PubMed Central

    Kim, Oleg V.; Litvinov, Rustem I.; Weisel, John W.; Alber, Mark S.

    2014-01-01

    Fibrin is a protein polymer that forms a 3D filamentous network, a major structural component of protective physiological blood clots as well as life threatening pathological thrombi. It plays an important role in wound healing, tissue regeneration and is widely employed in surgery as a sealant and in tissue engineering as a scaffold. The goal of this study was to establish correlations between structural changes and mechanical responses of fibrin networks exposed to compressive loads. Rheological measurements revealed nonlinear changes of fibrin network viscoelastic properties under dynamic compression, resulting in network softening followed by its dramatic hardening. Repeated compression/decompression enhanced fibrin clot stiffening. Combining fibrin network rheology with simultaneous confocal microscopy provided direct evidence of structural modulations underlying nonlinear viscoelasticity of compressed fibrin networks. Fibrin clot softening in response to compression strongly correlated with fiber buckling and bending, while hardening was associated with fibrin network densification. Our results suggest a complex interplay of entropic and enthalpic mechanisms accompanying structural changes and accounting for the nonlinear mechanical response in fibrin networks undergoing compressive deformations. These findings provide new insight into the fibrin clot structural mechanics and can be useful for designing fibrin-based biomaterials with modulated viscoelastic properties. PMID:24840618

  11. Structural basis for the nonlinear mechanics of fibrin networks under compression.

    PubMed

    Kim, Oleg V; Litvinov, Rustem I; Weisel, John W; Alber, Mark S

    2014-08-01

    Fibrin is a protein polymer that forms a 3D filamentous network, a major structural component of protective physiological blood clots as well as life threatening pathological thrombi. It plays an important role in wound healing, tissue regeneration and is widely employed in surgery as a sealant and in tissue engineering as a scaffold. The goal of this study was to establish correlations between structural changes and mechanical responses of fibrin networks exposed to compressive loads. Rheological measurements revealed nonlinear changes of fibrin network viscoelastic properties under dynamic compression, resulting in network softening followed by its dramatic hardening. Repeated compression/decompression enhanced fibrin clot stiffening. Combining fibrin network rheology with simultaneous confocal microscopy provided direct evidence of structural modulations underlying nonlinear viscoelasticity of compressed fibrin networks. Fibrin clot softening in response to compression strongly correlated with fiber buckling and bending, while hardening was associated with fibrin network densification. Our results suggest a complex interplay of entropic and enthalpic mechanisms accompanying structural changes and accounting for the nonlinear mechanical response in fibrin networks undergoing compressive deformations. These findings provide new insight into the fibrin clot structural mechanics and can be useful for designing fibrin-based biomaterials with modulated viscoelastic properties.

  12. A quasi steady state method for solving transient Darcy flow in complex 3D fractured networks accounting for matrix to fracture flow

    NASA Astrophysics Data System (ADS)

    Nœtinger, B.

    2015-02-01

    Modeling natural Discrete Fracture Networks (DFN) receives more and more attention in applied geosciences, from oil and gas industry, to geothermal recovery and aquifer management. The fractures may be either natural, or artificial in case of well stimulation. Accounting for the flow inside the fracture network, and accounting for the transfers between the matrix and the fractures, with the same level of accuracy is an important issue for calibrating the well architecture and for setting up optimal resources recovery strategies. Recently, we proposed an original method allowing to model transient pressure diffusion in the fracture network only [1]. The matrix was assumed to be impervious. A systematic approximation scheme was built, allowing to model the initial DFN by a set of N unknowns located at each identified intersection between fractures. The higher N, the higher the accuracy of the model. The main assumption was using a quasi steady state hypothesis, that states that the characteristic diffusion time over one single fracture is negligible compared with the characteristic time of the macroscopic problem, e.g. change of boundary conditions. In that context, the lowest order approximation N = 1 has the form of solving a transient problem in a resistor/capacitor network, a so-called pipe network. Its topology is the same as the network of geometrical intersections between fractures. In this paper, we generalize this approach in order to account for fluxes from matrix to fractures. The quasi steady state hypothesis at the fracture level is still kept. Then, we show that in the case of well separated time scales between matrix and fractures, the preceding model needs only to be slightly modified in order to incorporate these fluxes. The additional knowledge of the so-called matrix to fracture transfer function allows to modify the mass matrix that becomes a time convolution operator. This is reminiscent of existing space averaged transient dual porosity models.

  13. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  14. Endothelial sprouting and network formation in collagen- and fibrin-based modular microbeads.

    PubMed

    Rioja, Ana Y; Tiruvannamalai Annamalai, Ramkumar; Paris, Spencer; Putnam, Andrew J; Stegemann, Jan P

    2016-01-01

    A modular tissue engineering approach may have advantages over current therapies in providing rapid and sustained revascularization of ischemic tissue. In this study, modular protein microbeads were prepared from pure fibrin (FIB) and collagen-fibrin composites (COL-FIB) using a simple water-in-oil emulsification technique. Human endothelial cells and fibroblasts were embedded directly in the microbead matrix. The resulting microbeads were generally spheroidal with a diameter of 100-200μm. Cell viability was high (75-80% viable) in microbeads, but was marginally lower than in bulk hydrogels of corresponding composition (85-90% viable). Cell proliferation was significantly greater in COL-FIB microbeads after two weeks in culture, compared to pure FIB microbeads. Upon embedding of microbeads in a surrounding fibrin hydrogel, endothelial cell networks formed inside the microbead matrix and extended into the surrounding matrix. The number of vessel segments, average segment length, and number of branch points was higher in FIB samples, compared to COL-FIB samples, resulting in significantly longer total vessel networks. Anastomosis of vessel networks from adjacent microbeads was also observed. These studies demonstrate that primitive vessel networks can be formed by modular protein microbeads containing embedded endothelial cells and fibroblasts. Such microbeads may find utility as prevascularized tissue modules that can be delivered minimally invasively as a therapy to restore blood flow to ischemic tissues. Vascularization is critically important for tissue engineering and regenerative medicine, and materials that support and/or promote neovascularization are of value both for translational applications and for mechanistic studies and discovery-based research. Therefore, we fabricated small modular microbeads formulated from pure fibrin (FIB) and collagen-fibrin (COL-FIB) containing endothelial cells and supportive fibroblasts. We explored how cells encapsulated

  15. Development of three-dimensional memory (3D-M)

    NASA Astrophysics Data System (ADS)

    Yu, Hong-Yu; Shen, Chen; Jiang, Lingli; Dong, Bin; Zhang, Guobiao

    2016-10-01

    Since the invention of 3-D ROM in 1996, three-dimensional memory (3D-M) has been under development for nearly two decades. In this presentation, we'll review the 3D-M history and compare different 3D-Ms (including 3D-OTP from Matrix Semiconductor, 3D-NAND from Samsung and 3D-XPoint from Intel/Micron).

  16. 3D Viscoelastic traction force microscopy.

    PubMed

    Toyjanova, Jennet; Hannen, Erin; Bar-Kochba, Eyal; Darling, Eric M; Henann, David L; Franck, Christian

    2014-10-28

    Native cell-material interactions occur on materials differing in their structural composition, chemistry, and physical compliance. While the last two decades have shown the importance of traction forces during cell-material interactions, they have been almost exclusively presented on purely elastic in vitro materials. Yet, most bodily tissue materials exhibit some level of viscoelasticity, which could play an important role in how cells sense and transduce tractions. To expand the realm of cell traction measurements and to encompass all materials from elastic to viscoelastic, this paper presents a general, and comprehensive approach for quantifying 3D cell tractions in viscoelastic materials. This methodology includes the experimental characterization of the time-dependent material properties for any viscoelastic material with the subsequent mathematical implementation of the determined material model into a 3D traction force microscopy (3D TFM) framework. Utilizing this new 3D viscoelastic TFM (3D VTFM) approach, we quantify the influence of viscosity on the overall material traction calculations and quantify the error associated with omitting time-dependent material effects, as is the case for all other TFM formulations. We anticipate that the 3D VTFM technique will open up new avenues of cell-material investigations on even more physiologically relevant time-dependent materials including collagen and fibrin gels.

  17. A 3d-3d appetizer

    NASA Astrophysics Data System (ADS)

    Pei, Du; Ye, Ke

    2016-11-01

    We test the 3d-3d correspondence for theories that are labeled by Lens spaces. We find a full agreement between the index of the 3d N=2 "Lens space theory" T [ L( p, 1)] and the partition function of complex Chern-Simons theory on L( p, 1). In particular, for p = 1, we show how the familiar S 3 partition function of Chern-Simons theory arises from the index of a free theory. For large p, we find that the index of T[ L( p, 1)] becomes a constant independent of p. In addition, we study T[ L( p, 1)] on the squashed three-sphere S b 3 . This enables us to see clearly, at the level of partition function, to what extent G ℂ complex Chern-Simons theory can be thought of as two copies of Chern-Simons theory with compact gauge group G.

  18. 3d-3d correspondence revisited

    DOE PAGES

    Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; ...

    2016-04-21

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  19. 3d-3d correspondence revisited

    SciTech Connect

    Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr

    2016-04-21

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  20. Traction Force Microscopy in 3-Dimensional Extracellular Matrix Networks.

    PubMed

    Cóndor, M; Steinwachs, J; Mark, C; García-Aznar, J M; Fabry, B

    2017-06-19

    Cell migration through a three-dimensional (3-D) matrix depends strongly on the ability of cells to generate traction forces. To overcome the steric hindrance of the matrix, cells need to generate sufficiently high traction forces but also need to distribute these forces spatially in a migration-promoting way. This unit describes a protocol to measure spatial maps of cell traction forces in 3-D biopolymer networks such as collagen, fibrin, or Matrigel. Traction forces are computed from the relationship between measured force-induced matrix deformations surrounding the cell and the known mechanical properties of the matrix. The method does not rely on knowledge of the cell surface coordinates and takes nonlinear mechanical properties of the matrix into account. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  1. 3D Characterization of Recrystallization Boundaries

    NASA Astrophysics Data System (ADS)

    Zhang, Yubin; Godfrey, Andrew; MacDonald, Nicole; Jensen, Dorte Juul

    A three-dimensional (3D) volume containing a recrystallizing grain and a deformed matrix in a partially recrystallized pure aluminum was characterized using the 3D electron backscattering diffraction technique. The 3D shape of a recrystallizing boundary, separating the recrystallizing grain and deformed matrix, was reconstructed. The result shows a very complex structure containing several large protrusions and retrusions. A correlation between the protrusions/retrusions and the deformed matrix in front of the boundary shows that the deformed microstructure has a very strong influence on the formation of protrusions/retrusions.

  2. Linear expansion of the eigenvalues of a Hermitian matrix and its application to the analysis of the electronic spectra of 3 d ions in crystals

    NASA Astrophysics Data System (ADS)

    Seijo, L.; Pueyo, L.

    1985-02-01

    It is shown that the eigenvalues Ei of a Hermitian matrix H with matrix elements Hij = ΣkAkijak, where Akij are known numbers and ak a set of parameters, can be exactly expanded as E i = Σ k( {∂E i}/{∂a k})a k. This property is applied to the analysis of the optical spectra of transition metal ions in crystals proposed by L. Pueyo, M. Bermejo, and J. W. Richardson ( J. Solid State Chem.31, 217, 1980), and it is shown that this method represents the best fit of the Hamiltonian eigenvalues to the observed (or calculated) spectrum. Further advantages of using this property, in connection with the spectral analysis, are the minimization of the errors associated with the numerical approximations and a reduction in computer time. In the molecular orbital calculation of the optical or uv spectra of these systems, this linear expansion of the eigenvalues give a detailed interpretation of the improvements produced by refined calculations, such as those including configuration interaction. In particular, the changes in one-electron energy and in open-shell repulsion interactions associated with the refinement can be clearly and easily formulated. As examples, the computed spectra of CrF 4-6 and CrF 3-6 are discussed.

  3. 3D-isotropic high-resolution morphological imaging and quantitative T2 mapping as biomarkers for gender related differences after matrix-associated autologous chondrocyte transplantation (MACT).

    PubMed

    Pachowsky, Milena L; Werner, Sven; Marlovits, Stefan; Stelzeneder, David; Renner, Nina; Trattnig, Siegfried; Welsch, Goetz H

    2014-10-01

    The aim of this study was to determine in vivo high-resolution morphological and biochemical gender related differences in cartilage repair tissue (MACT). Forty patients were examined clinically and by MR scans at 3T-MRI (coronal 3D True-FISP sequence for morphologic assessment and multi-echo spin-echo T2-mapping for biochemical assessment of healthy cartilage and MACT cartilage). Mean T2 values in repair tissue in the deep zone showed significantly shorter T2 times in females (p = 0.009, female 43.5 ± 9.8 vs. male 48.2 ± 7.7 ms). The superficial zone showed higher T2 values than the deep zone in both the groups (female 48.5 ± 9.8, males 52.6 ± 11.0 ms) without significant difference between female and male patients. Native control cartilage showed no statistically significant differences for T2 between females and males. The subdivisions "structure of the repair tissue" and "subchondral bone" of the MOCART score showed statistically significant differences between females and males (p = 0.026 and p = 0.007) as well as the Lysholm score (p = 0.03). Our investigations revealed differences between female and male patients after MACT of the knee in clinical outcome and advanced morphological and biochemical MRI. The presented imaging biomarkers can depict subtle changes after cartilage regeneration procedures and might help to understand gender related differences after cartilage repair procedures. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  4. 3D and Education

    NASA Astrophysics Data System (ADS)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  5. Short stimulation of electro-responsive PAA/fibrin hydrogel induces collagen production.

    PubMed

    Rahimi, Nastaran; Swennen, Geertje; Verbruggen, Sanne; Scibiorek, Martyna; Molin, Daniel G; Post, Mark J

    2014-09-01

    Acrylic acid/fibrin hydrogel can mechanically stimulate cells when an external electrical field is applied, enabling them to migrate and align throughout the depth of the gel. The ability of electro-responsive polyacrylic acid (PAA)/fibrin hydrogel to promote collagen production and remodeling has been investigated by three-dimensional (3D) culturing and conditioning of smooth muscle cells (SMCs). SMCs-seeded hydrogels were subjected to an alternating electrical field (0.06 V/mm) for 2 h for one, two, or three times per week during 4 weeks of culturing. Fluorescent images of collagen structure and accumulation, assessed by CNA-35 probe, showed increased collagen content (>100-fold at 1× stimulation/week) in the center of the hydrogels after 4 weeks of culture. The increase in collagen production correlated with increasing extracellular matrix gene expression and resulted in significantly improved mechanical properties of the stimulated hydrogels. Matrix metalloproteinase (MMP)-2 activity was also significantly enhanced by stimulation, which probably has a role in the reorganization of the collagen. Short stimulation (2 h) induced a favorable response in the cells and enhanced tissue formation and integrity of the scaffold by inducing collagen production. The presented set up could be used for conditioning and improving the functionality of current tissue-engineered vascular grafts.

  6. A 3d-3d appetizer

    DOE PAGES

    Pei, Du; Ye, Ke

    2016-11-02

    Here, we test the 3d-3d correspondence for theories that are labeled by Lens spaces. We find a full agreement between the index of the 3d N=2 “Lens space theory” T [L(p, 1)] and the partition function of complex Chern-Simons theory on L(p, 1). In particular, for p = 1, we show how the familiar S3 partition function of Chern-Simons theory arises from the index of a free theory. For large p, we find that the index of T[L(p, 1)] becomes a constant independent of p. In addition, we study T[L(p, 1)] on the squashed three-sphere Sb3. This enables us tomore » see clearly, at the level of partition function, to what extent GC complex Chern-Simons theory can be thought of as two copies of Chern-Simons theory with compact gauge group G.« less

  7. A 3d-3d appetizer

    SciTech Connect

    Pei, Du; Ye, Ke

    2016-11-02

    Here, we test the 3d-3d correspondence for theories that are labeled by Lens spaces. We find a full agreement between the index of the 3d N=2 “Lens space theory” T [L(p, 1)] and the partition function of complex Chern-Simons theory on L(p, 1). In particular, for p = 1, we show how the familiar S3 partition function of Chern-Simons theory arises from the index of a free theory. For large p, we find that the index of T[L(p, 1)] becomes a constant independent of p. In addition, we study T[L(p, 1)] on the squashed three-sphere Sb3. This enables us to see clearly, at the level of partition function, to what extent GC complex Chern-Simons theory can be thought of as two copies of Chern-Simons theory with compact gauge group G.

  8. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  9. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  10. Diamond in 3-D

    NASA Image and Video Library

    2004-08-20

    This 3-D, microscopic imager mosaic of a target area on a rock called Diamond Jenness was taken after NASA Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time. 3D glasses are necessary.

  11. The calcification of fibrin in vitro

    NASA Astrophysics Data System (ADS)

    Koutsopoulos, S.; Dalas, E.

    2000-06-01

    In the present work we employed fibrin in order to assess its capability to induce biological mineralization. Fibrin is a very important factor in the blood-clotting system. Structurally, fibrin is an ordered organic matrix which has a periodic structure that repeats every 230 Å. Hydroxyapatite, HAP and octacalcium phosphate (OCP) are the most interesting calcium phosphate salts. Hydroxyapatite is thermodynamically the most stable calcium phosphate which is mostly used as a model compound for the study of biological-calcification processes. On the other hand, octacalcium phosphate has been proposed as a precursor of hydroxyapatite whose formation is favoured kinetically in solutions supersaturated to both salts. The kinetics of crystallization of HAP and OCP on fibrin were studied using the constant composition technique. The onset of HAP crystallization started immediately after introducing the substrate in the supersaturated solution. Unlike HAP crystallization induction periods were observed before the appearance of OCP precipitate in a solution supersaturated with respect to both HAP and OCP. Using nucleation rate equations derived from the classical homogeneous nucleation theory, interfacial energies and the size of the critical nucleus for both HAP and OCP were calculated. Phosphate was taken up extensively by the biological molecule studied. The dependence of adsorption upon ionic strength and pH of the medium suggests an appreciable contribution of electrostatic forces. Controversially calcium ions did not exhibit any detectable adsorption from solutions containing calcium dichloride at concentrations ranging from 1×10 -4 to 5×10 -3 M in 0.15 M NaCl supporting electrolyte, 37°C, pH=7.4. From the results above it follows that formation of HAP on fibrin may be initiated via adsorption of inorganic phosphate on the biological substrate.

  12. Platelet interaction with polymerizing fibrin.

    PubMed

    Niewiarowski, S; Regoeczi, E; Stewart, G J; Senyl, A F; Mustard, J F

    1972-03-01

    Interaction of washed pig, rabbit, or human platelets with fibrinogen was studied during its transition to fibrin using photometric, isotopic, and electron microscopic techniques. Untreated fibrinogen and fully polymerized fibrin had no detectable effect on platelets. Fibrinogen, incubated with low concentrations of reptilase or thrombin, formed intermediate products which readily became associated with platelets and caused their aggregation. Neutralization of the thrombin did not prevent this interaction. In the absence of fibrinogen, reptilase did not affect platelets. The interaction of polymerizing fibrin with platelets was accompanied by small losses of platelet constituents (serotonin, adenine nucleotides, platelet factor 4, and lactic dehydrogenase). This loss did not appear to be the result of the platelet release reaction. Inhibitors of the release reaction or of adenosine diphosphate (ADP)-induced aggregation did not prevent the interaction of platelets with polymerizing fibrin. Apyrase or prostaglandin E(1) (PGE(1)) reduced the extent of platelet aggregation by polymerizing fibrin, but the amount of protein associated with platelets was slightly increased. The interaction of polymerizing fibrin with platelets was completely inhibited by ethylenediaminetetraacetate (EDTA) or ethylene glycol bis (beta-aminoethyl ether) N, N,N',N'-tetraacetic acid (EGTA).Fibers formed in solutions of polymerizing fibrin were larger in the presence than in the absence of washed platelets, suggesting that platelets affect fibrin polymerization. The adherence of platelets to polymerizing fibrin may be responsible for the establishment of links between platelets and fibrin in hemostatic plugs and thrombi.

  13. Potential of nanocrystalline cellulose-fibrin nanocomposites for artificial vascular graft applications

    SciTech Connect

    Brown, Elvie; Hu, Dehong; Abu-Lail, Nehal; Zhang, Xiao

    2013-02-19

    Nanocrystalline cellulose, a new bio-nanomaterial is utilized as a reinforcing material for biocompatible fibrin matrix to form into a nanocomposite for small-diameter replacement vascular graft application (SDRVG). The periodate oxidation of NCC, which provided it with a reactive carbonyl group, allowed molecular interaction between NCC and fibrin. Such interaction resulted into an effective mechanical reinforcement indicated by the improvement of max. force, elongation at break and modulus when oxidized NCC (ONCC) was incorporated into fibrin. The nanocomposite’s mechanical properties can be manipulated to conform to the native blood vessel by varying the ONCC to fibrin ratio and/or by controlling the degree of oxidation of NCC. Using atomic force microscopy had provided fundamental information on the effects of molecular interactions to the nanolevel mechanical properties of NCC/fibrin nanocomposites. This fundamental information established the positive feasibility and commenced continuing investigation for the practical SDRVG application of NCC/fibrin nanocomposite.

  14. 3D Plasmon Ruler

    SciTech Connect

    2011-01-01

    In this animation of a 3D plasmon ruler, the plasmonic assembly acts as a transducer to deliver optical information about the structural dynamics of an attached protein. (courtesy of Paul Alivisatos group)

  15. Prominent Rocks - 3-D

    NASA Image and Video Library

    1997-07-13

    Many prominent rocks near the Sagan Memorial Station are featured in this image from NASA Mars Pathfinder. Shark, Half-Dome, and Pumpkin are at center 3D glasses are necessary to identify surface detail.

  16. 3D Laser System

    NASA Image and Video Library

    2015-09-16

    NASA Glenn's Icing Research Tunnel 3D Laser System used for digitizing ice shapes created in the wind tunnel. The ice shapes are later utilized for characterization, analysis, and software development.

  17. AE3D

    SciTech Connect

    Spong, Donald A

    2016-06-20

    AE3D solves for the shear Alfven eigenmodes and eigenfrequencies in a torodal magnetic fusion confinement device. The configuration can be either 2D (e.g. tokamak, reversed field pinch) or 3D (e.g. stellarator, helical reversed field pinch, tokamak with ripple). The equations solved are based on a reduced MHD model and sound wave coupling effects are not currently included.

  18. Nasal chondrocytes and fibrin sealant for cartilage tissue engineering.

    PubMed

    Vinatier, C; Gauthier, O; Masson, M; Malard, O; Moreau, A; Fellah, B H; Bilban, M; Spaethe, R; Daculsi, G; Guicheux, J

    2009-04-01

    Hybrid constructs associating a biodegradable matrix and autologous chondrocytes hold promise for the treatment of articular cartilage defects. In this context, our objective was to investigate the potential use of nasal chondrocytes associated with a fibrin sealant for the treatment of articular cartilage defects. The phenotype of primary nasal chondrocytes (NC) from human (HNC) and rabbit (RNC) origin were characterized by RT-PCR. The ability of constructs associating fibrin sealant and NC to form a cartilaginous tissue in vivo was investigated, firstly in a subcutaneous site in nude mice and secondly in an articular cartilage defect in rabbit. HNC express type II collagen and aggrecan, the two major hallmarks of a chondrocytic phenotype. Furthermore, when injected subcutaneously into nude mice within a fibrin sealant, these chondrocytes were able to form a cartilage-like tissue. Our data indicate that RNC also express type II collagen and aggrecan and maintained their phenotype in three-dimensional culture within a fibrin sealant. Moreover, treatment of rabbit articular cartilage defects with autologous RNC embedded in a fibrin sealant led to the formation of a hyalin-like repair tissue. The use of fibrin sealant containing hybrid autologous NC therefore appears as a promising approach for cell-based therapy of articular cartilage. Copyright 2008 Wiley Periodicals, Inc.

  19. Microporous Nanofibrous Fibrin-based Scaffolds for Bone Tissue Engineering

    PubMed Central

    Osathanon, Thanaphum; Linnes, Michael L.; Rajachar, Rupak M.; Ratner, Buddy D.; Somerman, Martha J.; Giachelli, Cecilia M.

    2008-01-01

    The fibrotic response of the body to synthetic polymers limits their success in tissue engineering and other applications. Though porous polymers have demonstrated improved healing, difficulty in controlling their pore sizes and pore interconnections has clouded the understanding of this phenomenon. In this study, a novel method to fabricate natural polymer/calcium phosphate composite scaffolds with tightly controllable pore size, pore interconnection, and calcium phosphate deposition was developed. Microporous, nanofibrous fibrin scaffolds were fabricated using sphere-templating methods. Composite scaffolds were created by solution deposition of calcium phosphate on fibrin surfaces or by direct incorporation of nanocrystalline hydroxyapatite (nHA). The SEM results showed that fibrin scaffolds exhibited a highly porous and interconnected structure. Osteoblast-like cells, obtained from murine calvaria, attached, spread and showed a polygonal morphology on the surface of the biomaterial. Multiple cell layers and fibrillar matrix deposition were observed. Moreover, cells seeded on mineralized fibrin scaffolds exhibited significantly higher alkaline phosphatase activity as well as osteoblast marker gene expression compared to fibrin scaffolds and nHA incorporated fibrin scaffolds (0.25 g and 0.5 g). All types of scaffolds were degraded both in vitro and in vivo. Furthermore, these scaffolds promoted bone formation in a mouse calvarial defect model and the bone formation was enhanced by addition of rhBMP-2. PMID:18640716

  20. 3-D woven, mullite matrix, composite filter

    SciTech Connect

    Lane, J.E.; Painter, C.J.; Radford, K.C. LeCostaouec, J.F.

    1995-12-01

    Westinghouse, with Techniweave as a major subcontractor, is conducting a three-phase program aimed at providing advanced candle filters for a 1996 pilot scale demonstration in one of the two hot gas filter systems at Southern Company Service`s Wilsonville PSD Facility. The Base Program (Phases I and II) objective is to develop and demonstrate the suitability of the Westinghouse/Techniweave next generation composite candle filter for use in Pressurized Fluidized Bed Combustion (PFBC) and/or Integrated Gasification Combined Cycle (IGCC) power generation systems. The Optional Task (Phase M, Task 5) objective is to fabricate, inspect and ship to Wilsonville Hot gas particulate filters are key components for the successful commercializaion of advanced coal-based power-generation systems such as Pressurized Fluidized-bed Combustion (PFBC), including second-generation PFBC, and Integrated Gasification Combined Cycles (IGCC). Current generation monolithic ceramic filters are subject to catastrophic failure because they have very low resistance to crack propagation. To overcome this problem, a damage-tolerant ceramic filter element is needed.

  1. Microstructural and mechanical differences between digested collagen-fibrin co-gels and pure collagen and fibrin gels.

    PubMed

    Lai, Victor K; Frey, Christina R; Kerandi, Allan M; Lake, Spencer P; Tranquillo, Robert T; Barocas, Victor H

    2012-11-01

    Collagen and fibrin are important extracellular matrix (ECM) components in the body, providing structural integrity to various tissues. These biopolymers are also common scaffolds used in tissue engineering. This study investigated how co-gelation of collagen and fibrin affected the properties of each individual protein network. Collagen-fibrin co-gels were cast and subsequently digested using either plasmin or collagenase; the microstructure and mechanical behavior of the resulting networks were then compared with the respective pure collagen or fibrin gels of the same protein concentration. The morphologies of the collagen networks were further analyzed via three-dimensional network reconstruction from confocal image z-stacks. Both collagen and fibrin exhibited a decrease in mean fiber diameter when formed in co-gels compared with the pure gels. This microstructural change was accompanied by an increased failure strain and decreased tangent modulus for both collagen and fibrin following selective digestion of the co-gels. In addition, analysis of the reconstructed collagen networks indicated the presence of very long fibers and the clustering of fibrils, resulting in very high connectivities for collagen networks formed in co-gels.

  2. Fibrin glue mixed with platelet-rich fibrin as a scaffold seeded with dental bud cells for tooth regeneration.

    PubMed

    Yang, Kai-Chiang; Wang, Chun-Hao; Chang, Hao-Hueng; Chan, Wing P; Chi, Chau-Hwa; Kuo, Tzong-Fu

    2012-11-01

    Odontogenesis is a complex process with a series of epithelial-mesenchymal interactions and odontogenic molecular cascades. In tissue engineering of teeth from stem cells, platelet-rich fibrin (PRF), which is rich in growth factors and cytokines, may improve regeneration. Accordingly, PRF was added into fibrin glue to enrich the microenvironment with growth factors. Unerupted second molar tooth buds were harvested from miniature swine and cultured in vitro for 3 weeks to obtain dental bud cells (DBCs). Whole blood was collected for the preparation of PRF and fibrin glue before surgery. DBCs were suspended in fibrin glue and then enclosed with PRF, and the DBC-fibrin glue-PRF composite was autografted back into the original alveolar sockets. Radiographic and histological examinations were used to identify the regenerated tooth structure 36 weeks after implantation. Immunohistochemical staining was used to detect proteins specific to tooth regeneration. One pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessels, and periodontal ligaments in indiscriminate shape. Another animal had an unerupted tooth that expressed cytokeratin 14, dentin matrix protein-1, vascular endothelial growth factor, and osteopontin. This study demonstrated, using autogenic cell transplantation in a porcine model, that DBCs seeded into fibrin glue-PRF could regenerate a complete tooth. Copyright © 2011 John Wiley & Sons, Ltd.

  3. A multichamber fluidic device for 3D cultures under interstitial flow with live imaging: development, characterization, and applications.

    PubMed

    Bonvin, Carmen; Overney, Jan; Shieh, Adrian C; Dixon, J Brandon; Swartz, Melody A

    2010-04-01

    Interstitial flow is an important biophysical cue that can affect capillary morphogenesis, tumor cell migration, and fibroblast remodeling of the extracellular matrix, among others. Current models that incorporate interstitial flow and that are suitable for live imaging lack the ability to perform multiple simultaneous experiments, for example, to compare effects of growth factors, extracellular matrix composition, etc. We present a nine-chamber radial flow device that allows simultaneous 3D fluidic experiments for relatively long-term culture with live imaging capabilities. Flow velocity profiles were characterized by fluorescence recovery after photobleaching (FRAP) for flow uniformity and estimating the hydraulic conductivity. We demonstrate lymphatic and blood capillary morphogenesis in fibrin gels over 10 days, comparing flow with static conditions as well as the effects of an engineered variant of VEGF that binds fibrin via Factor XIII. We also demonstrate the culture of contractile fibroblasts and co-cultures with tumor cells for modeling the tumor microenvironment. Therefore, this device is useful for studies of capillary morphogenesis, cell migration, contractile cells like fibroblasts, and multicellular cultures, all under interstitial flow. (c) 2009 Wiley Periodicals, Inc.

  4. Tissue-Engineered Fibrin-Based Heart Valve with Bio-Inspired Textile Reinforcement.

    PubMed

    Moreira, Ricardo; Neusser, Christine; Kruse, Magnus; Mulderrig, Shane; Wolf, Frederic; Spillner, Jan; Schmitz-Rode, Thomas; Jockenhoevel, Stefan; Mela, Petra

    2016-08-01

    The mechanical properties of tissue-engineered heart valves still need to be improved to enable their implantation in the systemic circulation. The aim of this study is to develop a tissue-engineered valve for the aortic position - the BioTexValve - by exploiting a bio-inspired composite textile scaffold to confer native-like mechanical strength and anisotropy to the leaflets. This is achieved by multifilament fibers arranged similarly to the collagen bundles in the native aortic leaflet, fixed by a thin electrospun layer directly deposited on the pattern. The textile-based leaflets are positioned into a 3D mould where the components to form a fibrin gel containing human vascular smooth muscle cells are introduced. Upon fibrin polymerization, a complete valve is obtained. After 21 d of maturation by static and dynamic stimulation in a custom-made bioreactor, the valve shows excellent functionality under aortic pressure and flow conditions, as demonstrated by hydrodynamic tests performed according to ISO standards in a mock circulation system. The leaflets possess remarkable burst strength (1086 mmHg) while remaining pliable; pronounced extracellular matrix production is revealed by immunohistochemistry and biochemical assay. This study demonstrates the potential of bio-inspired textile-reinforcement for the fabrication of functional tissue-engineered heart valves for the aortic position.

  5. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  6. 3-D Seismic Interpretation

    NASA Astrophysics Data System (ADS)

    Moore, Gregory F.

    2009-05-01

    This volume is a brief introduction aimed at those who wish to gain a basic and relatively quick understanding of the interpretation of three-dimensional (3-D) seismic reflection data. The book is well written, clearly illustrated, and easy to follow. Enough elementary mathematics are presented for a basic understanding of seismic methods, but more complex mathematical derivations are avoided. References are listed for readers interested in more advanced explanations. After a brief introduction, the book logically begins with a succinct chapter on modern 3-D seismic data acquisition and processing. Standard 3-D acquisition methods are presented, and an appendix expands on more recent acquisition techniques, such as multiple-azimuth and wide-azimuth acquisition. Although this chapter covers the basics of standard time processing quite well, there is only a single sentence about prestack depth imaging, and anisotropic processing is not mentioned at all, even though both techniques are now becoming standard.

  7. Behavior of human dermal fibroblasts in three-dimensional fibrin clots: dependence on fibrinogen and thrombin concentration.

    PubMed

    Cox, Steve; Cole, Marietta; Tawil, Bill

    2004-01-01

    Fibrin sealant products are used in hemostasis and tissue sealing, and potentially as a cell delivery vehicle. In this study, fibrin sealant was evaluated as a delivery vehicle for human dermal fibroblasts. Fibroblast proliferation and migration were assessed in various dilutions of fibrin sealant by changing the fibrinogen and thrombin concentration. Fibroblasts proliferated well within three-dimensional (3-D) fibrin clots consisting of fibrinogen (5-17 mg/mL) and thrombin (1-167 U/mL). These fibroblasts also retained good morphology and growth characteristics after migrating out of the 3-D fibrin clots. Furthermore, using Western blot and fluorescence-activated cell-sorting analysis, we found that the expression of growth factors and interleukins in the entire fibroblast-fibrin construct was dependent on the fibrin sealant formulation. For example, in a formulation in which fibroblasts showed modest proliferation and migration, interleukin 8 was secreted to a lesser extent than in a formulation that supported robust proliferation and migration. To our knowledge, this is the first time that it has been shown that modifying the concentration of fibrinogen and thrombin affects fibroblast behavior within formed 3-D fibrin clots. In addition, some of these formulations present an ideal delivery vehicle for fibroblasts that could be used for the treatment of chronic wounds.

  8. Bootstrapping 3D fermions

    DOE PAGES

    Iliesiu, Luca; Kos, Filip; Poland, David; ...

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  9. Bootstrapping 3D fermions

    SciTech Connect

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  10. Medical 3-D Printing.

    PubMed

    Furlow, Bryant

    2017-05-01

    Three-dimensional printing is used in the manufacturing industry, medical and pharmaceutical research, drug production, clinical medicine, and dentistry, with implications for precision and personalized medicine. This technology is advancing the development of patient-specific prosthetics, stents, splints, and fixation devices and is changing medical education, treatment decision making, and surgical planning. Diagnostic imaging modalities play a fundamental role in the creation of 3-D printed models. Although most 3-D printed objects are rigid, flexible soft-tissue-like prosthetics also can be produced. ©2017 American Society of Radiologic Technologists.

  11. Fibrin promotes development and function of macaque primary follicles during encapsulated three-dimensional culture.

    PubMed

    Xu, J; Lawson, M S; Yeoman, R R; Molskness, T A; Ting, A Y; Stouffer, R L; Zelinski, M B

    2013-08-01

    Does fibrin introduced into the extracellular matrix affect the growth and maturation of individual primate follicles during encapsulated three-dimensional (3D) culture? While not altering follicle survival, fibrin-alginate (FIBRIN) improves macaque primary, but not secondary, follicle development during encapsulated 3D culture in terms of growth, steroidogenesis, anti-Müllerian hormone (AMH)/vascular endothelial growth factor (VEGF) production and oocyte maturation. Efforts to grow non-human primate ovarian follicles from the secondary to the antral stage during encapsulated 3D culture have been successful. However, the growth and maturation of primary follicles in vitro has not been reported in primates, especially in chemically defined conditions. In vitro follicle maturation was investigated using the rhesus macaque (Macaca mulatta). Ovaries (n = 7 pairs) were obtained during the early follicular phase of the menstrual cycle (cycle day 1-4). Primary (80-120 µm diameter) and secondary (125-225 µm diameter) follicles were isolated mechanically, randomly assigned to experimental groups, encapsulated into alginate (0.25% w/v) or FIBRIN (25 mg/ml fibrinogen-0.25% alginate) and cultured for 13 and 5 weeks, respectively. Individual follicles were cultured in alpha minimum essential medium supplemented with FSH. Follicle survival and growth were assessed by microscopy. Follicles that reached the antral stage were treated with recombinant hCG. Metaphase II (MII) oocytes were inseminated via ICSI. Follicle morphology was evaluated by hematoxylin and eosin (H&E) staining. Immunohistochemistry was performed for cytochrome P450 family 17 subfamily A polypeptide 1 (CYP17A1) and 19 subfamily A polypeptide 1 (CYP19A1). Culture medium was analyzed for estradiol (E2) and progesterone by chemiluminescence, androstenedione (A4) by radioimmunoassay, as well as anti-Müllerian hormone (AMH) and vascular endothelial growth factor (VEGF) by enzyme-linked immunosorbent assay. A

  12. Phase-separated chitosan–fibrin microbeads for cell delivery

    PubMed Central

    Chen, Zhewei; Wang, Limin; Stegemann, Jan P.

    2011-01-01

    Matrix-enhanced delivery of cells is a promising approach to improving current cell therapies. Our objective was to create cell-laden composite microbeads that combine the attractive features of the natural polymers chitosan and fibrin. Liquid polydimethylsiloxane was used to emulsify a chitosan–fibrinogen solution containing suspended human fibroblast cells, followed by initiation of thrombin-mediated polymerization of fibrin and thermal/pH-mediated gelation of chitosan. Chitosan/fibrin weight percent (wt%) ratios of 100/0, 75/25, 50/50 and 25/75 were investigated. Microbead diameters ranged from 275 ± 99 μm to 38 ± 10 μm using impeller speeds from 600 to 1400 rpm. Fibroblasts remained viable on day 1 post-fabrication in all matrices, but cell viability was markedly higher in high-fibrin microbeads by day 8 post-fabrication. Cell spreading and interaction with the extracellular matrix was also markedly increased in high-fibrin matrices. Such composite microbeads containing viable entrapped cells have potential for minimally invasive delivery of cells for a variety of tissue repair applications. PMID:21736519

  13. Phase-separated chitosan-fibrin microbeads for cell delivery.

    PubMed

    Chen, Zhewei; Wang, Limin; Stegemann, Jan P

    2011-01-01

    Matrix-enhanced delivery of cells is a promising approach to improving current cell therapies. Our objective was to create cell-laden composite microbeads that combine the attractive features of the natural polymers chitosan and fibrin. Liquid polydimethylsiloxane was used to emulsify a chitosan-fibrinogen solution containing suspended human fibroblast cells, followed by initiation of thrombin-mediated polymerization of fibrin and thermal/pH-mediated gelation of chitosan. Chitosan/fibrin weight percent (wt%) ratios of 100/0, 75/25, 50/50 and 25/75 were investigated. Microbead diameters ranged from 275 ± 99 µm to 38 ± 10 µm using impeller speeds from 600 to 1400 rpm. Fibroblasts remained viable on day 1 post-fabrication in all matrices, but cell viability was markedly higher in high-fibrin microbeads by day 8 post-fabrication. Cell spreading and interaction with the extracellular matrix was also markedly increased in high-fibrin matrices. Such composite microbeads containing viable entrapped cells have potential for minimally invasive delivery of cells for a variety of tissue repair applications.

  14. Computational imaging analysis of fibrin matrices with the inclusion of erythrocytes from homozygous SS blood reveals agglomerated and amorphous structures.

    PubMed

    Averett, Rodney D; Norton, David G; Fan, Natalie K; Platt, Manu O

    2017-01-01

    Sickle cell disease is a single point mutation disease that is known to alter the coagulation system, leading to hypercoagulable plasma conditions. These hypercoagulable conditions can lead to complications in the vasculature, caused by fibrin clots that form undesirably. There is a need to understand the morphology and structure of fibrin clots from patients with sickle cell disease, as this could lead to further discovery of treatments and life-saving therapies. In this work, a computational imaging analysis method is presented to evaluate fibrin agglomeration in the presence of erythrocytes (RBCs) homozygous for the sickle cell mutation (SS). Numerical algorithms were used to determine agglomeration of fibrin fibers within a matrix with SS RBCs to test the hypothesis that fibrin matrices with the inclusion of SS RBCs possess a more agglomerated structure than native fibrin matrices with AA RBCs. The numerical results showed that fibrin structures with SS RBCs displayed an overall higher degree of agglomeration as compared to native fibrin structures. The computational algorithm was also used to evaluate fibrin fiber overlap (aggregation) and anisotropy (orientation) in normal fibrin matrices compared to fibrin matrices polymerized around SS RBCs; however, there was no statistical difference. Ultrasound measurements of stiffness revealed rigid RBCs in the case of samples derived from homozygous SS blood, and densely evolving matrices, when compared to normal fibrin with the inclusion of AA RBCs. An agglomeration model is suggested to quantify the fibrin aggregation/clustering near RBCs for both normal fibrin matrices and for the altered structures. The results of this work are important in the sense that the understanding of aggregation and morphology in fibrin clots with incorporation of RBCs from persons living with sickle cell anemia may elucidate the complexities of comorbidities and other disease complications.

  15. The potential applications of fibrin-coated electrospun polylactide nanofibers in skin tissue engineering

    PubMed Central

    Bacakova, Marketa; Musilkova, Jana; Riedel, Tomas; Stranska, Denisa; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

    2016-01-01

    Fibrin plays an important role during wound healing and skin regeneration. It is often applied in clinical practice for treatment of skin injuries or as a component of skin substitutes. We prepared electrospun nanofibrous membranes made from poly(l-lactide) modified with a thin fibrin nanocoating. Fibrin surrounded the individual fibers in the membrane and also formed a thin fibrous mesh on several places on the membrane surface. The cell-free fibrin nanocoating remained stable in the cell culture medium for 14 days and did not change its morphology. On membranes populated with human dermal fibroblasts, the rate of fibrin degradation correlated with the degree of cell proliferation. The cell spreading, mitochondrial activity, and cell population density were significantly higher on membranes coated with fibrin than on nonmodified membranes, and this cell performance was further improved by the addition of ascorbic acid in the cell culture medium. Similarly, fibrin stimulated the expression and synthesis of collagen I in human dermal fibroblasts, and this effect was further enhanced by ascorbic acid. The expression of beta1-integrins was also improved by fibrin, and on pure polylactide membranes, it was slightly enhanced by ascorbic acid. In addition, ascorbic acid promoted deposition of collagen I in the form of a fibrous extracellular matrix. Thus, the combination of nanofibrous membranes with a fibrin nanocoating and ascorbic acid seems to be particularly advantageous for skin tissue engineering. PMID:26955273

  16. The potential applications of fibrin-coated electrospun polylactide nanofibers in skin tissue engineering.

    PubMed

    Bacakova, Marketa; Musilkova, Jana; Riedel, Tomas; Stranska, Denisa; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

    2016-01-01

    Fibrin plays an important role during wound healing and skin regeneration. It is often applied in clinical practice for treatment of skin injuries or as a component of skin substitutes. We prepared electrospun nanofibrous membranes made from poly(l-lactide) modified with a thin fibrin nanocoating. Fibrin surrounded the individual fibers in the membrane and also formed a thin fibrous mesh on several places on the membrane surface. The cell-free fibrin nanocoating remained stable in the cell culture medium for 14 days and did not change its morphology. On membranes populated with human dermal fibroblasts, the rate of fibrin degradation correlated with the degree of cell proliferation. The cell spreading, mitochondrial activity, and cell population density were significantly higher on membranes coated with fibrin than on nonmodified membranes, and this cell performance was further improved by the addition of ascorbic acid in the cell culture medium. Similarly, fibrin stimulated the expression and synthesis of collagen I in human dermal fibroblasts, and this effect was further enhanced by ascorbic acid. The expression of beta1-integrins was also improved by fibrin, and on pure polylactide membranes, it was slightly enhanced by ascorbic acid. In addition, ascorbic acid promoted deposition of collagen I in the form of a fibrous extracellular matrix. Thus, the combination of nanofibrous membranes with a fibrin nanocoating and ascorbic acid seems to be particularly advantageous for skin tissue engineering.

  17. Venus in 3D

    NASA Technical Reports Server (NTRS)

    Plaut, Jeffrey J.

    1993-01-01

    Stereographic images of the surface of Venus which enable geologists to reconstruct the details of the planet's evolution are discussed. The 120-meter resolution of these 3D images make it possible to construct digital topographic maps from which precise measurements can be made of the heights, depths, slopes, and volumes of geologic structures.

  18. 3D photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Carson, Jeffrey J. L.; Roumeliotis, Michael; Chaudhary, Govind; Stodilka, Robert Z.; Anastasio, Mark A.

    2010-06-01

    Our group has concentrated on development of a 3D photoacoustic imaging system for biomedical imaging research. The technology employs a sparse parallel detection scheme and specialized reconstruction software to obtain 3D optical images using a single laser pulse. With the technology we have been able to capture 3D movies of translating point targets and rotating line targets. The current limitation of our 3D photoacoustic imaging approach is its inability ability to reconstruct complex objects in the field of view. This is primarily due to the relatively small number of projections used to reconstruct objects. However, in many photoacoustic imaging situations, only a few objects may be present in the field of view and these objects may have very high contrast compared to background. That is, the objects have sparse properties. Therefore, our work had two objectives: (i) to utilize mathematical tools to evaluate 3D photoacoustic imaging performance, and (ii) to test image reconstruction algorithms that prefer sparseness in the reconstructed images. Our approach was to utilize singular value decomposition techniques to study the imaging operator of the system and evaluate the complexity of objects that could potentially be reconstructed. We also compared the performance of two image reconstruction algorithms (algebraic reconstruction and l1-norm techniques) at reconstructing objects of increasing sparseness. We observed that for a 15-element detection scheme, the number of measureable singular vectors representative of the imaging operator was consistent with the demonstrated ability to reconstruct point and line targets in the field of view. We also observed that the l1-norm reconstruction technique, which is known to prefer sparseness in reconstructed images, was superior to the algebraic reconstruction technique. Based on these findings, we concluded (i) that singular value decomposition of the imaging operator provides valuable insight into the capabilities of

  19. Vasculogenesis and Angiogenesis in Modular Collagen-Fibrin Microtissues.

    PubMed

    Peterson, A W; Caldwell, D J; Rioja, A Y; Rao, R R; Putnam, A J; Stegemann, J P

    2014-10-01

    The process of new blood vessel formation is critical in tissue development, remodeling and regeneration. Modular tissue engineering approaches have been developed to enable the bottom-up assembly of more complex tissues, including vascular networks. In this study, collagen-fibrin composite microbeads (100-300 μm in diameter) were fabricated using a water-in-oil emulsion technique. Human endothelial cells and human fibroblasts were embedded directly in the microbead matrix at the time of fabrication. Microbead populations were characterized and cultured for 14 days either as free-floating populations or embedded in a surrounding fibrin gel. The collagen-fibrin matrix efficiently entrapped cells and supported their viability and spreading. By 7 days in culture, endothelial cell networks were evident within microbeads, and these structures became more prominent by day 14. Fibroblasts co-localized with endothelial cells, suggesting a pericyte-like function, and laminin deposition indicated maturation of the vessel networks over time. Microbeads embedded in a fibrin gel immediately after fabrication showed the emergence of cells and the coalescence of vessel structures in the surrounding matrix by day 7. By day 14, inosculation of neighboring cords and prominent vessel structures were observed. Microbeads pre-cultured for 7 days prior to embedding in fibrin gave rise to vessel networks that emanated radially from the microbead by day 7, and developed into connected networks by day 14. Lumen formation in endothelial cell networks was confirmed using confocal sectioning. These data show that collagen-fibrin composite microbeads support vascular network formation. Microbeads embedded directly after fabrication emulated the process of vasculogenesis, while the branching and joining of vessels from pre-cultured microbeads resembled angiogenesis. This modular microtissue system has utility in studying the processes involved in new vessel formation, and may be developed into

  20. Different combinations of growth factors for the tenogenic differentiation of bone marrow mesenchymal stem cells in monolayer culture and in fibrin-based three-dimensional constructs.

    PubMed

    Bottagisio, Marta; Lopa, Silvia; Granata, Valentina; Talò, Giuseppe; Bazzocchi, Chiara; Moretti, Matteo; Barbara Lovati, Arianna

    2017-03-16

    Tendon injuries are severe burdens in clinics. The poor tendon healing is related to an ineffective response of resident cells and inadequate vascularization. Thanks to the high proliferation and multi-lineage differentiation capability, bone marrow-derived mesenchymal stem cells (BMSCs) are a promising cell source to support the tendon repair. To date, the association of various growth factors to induce the in vitro tenogenic differentiation of multipotent progenitor cells is poorly investigated. This study aimed to investigate the tenogenic differentiation of rabbit BMSCs by testing the combination of bone morphogenetic proteins (BMP-12 and 14) with transforming growth factor beta (TGF-β) and vascular endothelial growth factor (VEGF) both in 2D and 3D cultures within fibrin-based constructs. After 7 and 14 days, the tenogenic differentiation was assessed by analyzing cell metabolism and collagen content, the gene expression of tenogenic markers and the histological cell distribution and collagen deposition within 3D constructs. Our results demonstrated that the association of BMP-14 with TGF-β3 and VEGF enhanced the BMSC tenogenic differentiation both in 2D and 3D cultures. This study supports the use of fibrin as hydrogel-based matrix to generate spheroids loaded with tenogenic differentiated BMSCs that could be used to treat tendon lesions in the future.

  1. 3-D Grab!

    NASA Astrophysics Data System (ADS)

    Connors, M. G.; Schofield, I. S.

    2012-12-01

    Modern technologies in imaging greatly extend the potential to present visual information. With recently developed software tools, the perception of the third dimension can not only dramatically enhance presentation, but also allow spatial data to be better encoded. 3-D images can be taken for many subjects with only one camera, carefully moved to generate a stereo pair. Color anaglyph viewing now can be very effective using computer screens, and active filter technologies can enhance visual effects with ever-decreasing cost. We will present various novel results of 3-D imaging, including those from the auroral observations of the new twinned Athabasca University Geophysical Observatories.; Single camera stereo image for viewing with red/cyan glasses.

  2. Unoriented 3d TFTs

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Lakshya

    2017-05-01

    This paper generalizes two facts about oriented 3d TFTs to the unoriented case. On one hand, it is known that oriented 3d TFTs having a topological boundary condition admit a state-sum construction known as the Turaev-Viro construction. This is related to the string-net construction of fermionic phases of matter. We show how Turaev-Viro construction can be generalized to unoriented 3d TFTs. On the other hand, it is known that the "fermionic" versions of oriented TFTs, known as Spin-TFTs, can be constructed in terms of "shadow" TFTs which are ordinary oriented TFTs with an anomalous ℤ 2 1-form symmetry. We generalize this correspondence to Pin+-TFTs by showing that they can be constructed in terms of ordinary unoriented TFTs with anomalous ℤ 2 1-form symmetry having a mixed anomaly with time-reversal symmetry. The corresponding Pin+-TFT does not have any anomaly for time-reversal symmetry however and hence it can be unambiguously defined on a non-orientable manifold. In case a Pin+-TFT admits a topological boundary condition, one can combine the above two statements to obtain a Turaev-Viro-like construction of Pin+-TFTs. As an application of these ideas, we construct a large class of Pin+-SPT phases.

  3. Failure mechanisms of fibrin-based surgical tissue adhesives

    NASA Astrophysics Data System (ADS)

    Sierra, David Hugh

    A series of studies was performed to investigate the potential impact of heterogeneity in the matrix of multiple-component fibrin-based tissue adhesives upon their mechanical and biomechanical properties both in vivo and in vitro. Investigations into the failure mechanisms by stereological techniques demonstrated that heterogeneity could be measured quantitatively and that the variation in heterogeneity could be altered both by the means of component mixing and delivery and by the formulation of the sealant. Ex vivo tensile adhesive strength was found to be inversely proportional to the amount of heterogeneity. In contrast, in vivo tensile wound-closure strength was found to be relatively unaffected by the degree of heterogeneity, while in vivo parenchymal organ hemostasis in rabbits was found to be affected: greater heterogeneity appeared to correlate with an increase in hemostasis time and amount of sealant necessary to effect hemostasis. Tensile testing of the bulk sealant showed that mechanical parameters were proportional to fibrin concentration and that the physical characteristics of the failure supported a ductile mechanism. Strain hardening as a function of percentage of strain, and strain rate was observed for both concentrations, and syneresis was observed at low strain rates for the lower fibrin concentration. Blister testing demonstrated that burst pressure and failure energy were proportional to fibrin concentration and decreased with increasing flow rate. Higher fibrin concentration demonstrated predominately compact morphology debonds with cohesive failure loci, demonstrating shear or viscous failure in a viscoelastic rubbery adhesive. The lower fibrin concentration sealant exhibited predominately fractal morphology debonds with cohesive failure loci, supporting an elastoviscous material condition. The failure mechanism for these was hypothesized and shown to be flow-induced ductile fracture. Based on these findings, the failure mechanism was

  4. 3D ultrafast ultrasound imaging in vivo

    NASA Astrophysics Data System (ADS)

    Provost, Jean; Papadacci, Clement; Esteban Arango, Juan; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability.

  5. 3D ultrafast ultrasound imaging in vivo.

    PubMed

    Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-07

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability.

  6. Fibrin-based biomaterials: Modulation of macroscopic properties through rational design at the molecular level

    PubMed Central

    Brown, Ashley C.; Barker, Thomas H.

    2013-01-01

    Fibrinogen is one of the primary components of the coagulation cascade and rapidly forms an insoluble matrix following tissue injury. In addition to its important role in hemostasis, fibrin acts as a scaffold for tissue repair and provides important cues for directing cell phenotype following injury. Because of these properties and the ease of polymerization of the material, fibrin has been widely utilized as a biomaterial for over a century. Modifying the macroscopic properties of fibrin, such as elasticity and porosity, has been somewhat elusive until recently, yet with a molecular-level rational design approach can now be somewhat easily modified through alterations of molecular interactions key to the protein’s polymerization process. This review outlines the biochemistry of fibrin and discusses methods for modification of molecular interactions and their application to fibrin based biomaterials. PMID:24056097

  7. Fibrin-fiber architecture influences cell spreading and differentiation

    PubMed Central

    Bruekers, Stéphanie M. C.; Jaspers, Maarten; Hendriks, José M. A.; Kurniawan, Nicholas A.; Koenderink, Gijsje H.; Kouwer, Paul H. J.; Rowan, Alan E.; T. S. Huck, Wilhelm

    2016-01-01

    ABSTRACT The mechanical and structural properties of the extracellular matrix (ECM) play an important role in regulating cell fate. The natural ECM has a complex fibrillar structure and shows nonlinear mechanical properties, which are both difficult to mimic synthetically. Therefore, systematically testing the influence of ECM properties on cellular behavior is very challenging. In this work we show two different approaches to tune the fibrillar structure and mechanical properties of fibrin hydrogels. Addition of extra thrombin before gelation increases the protein density within the fibrin fibers without significantly altering the mechanical properties of the resulting hydrogel. On the other hand, by forming a composite hydrogel with a synthetic biomimetic polyisocyanide network the protein density within the fibrin fibers decreases, and the mechanics of the composite material can be tuned by the PIC/fibrin mass ratio. The effect of the changes in gel structure and mechanics on cellular behavior are investigated, by studying human mesenchymal stem cell (hMSC) spreading and differentiation on these gels. We find that the trends observed in cell spreading and differentiation cannot be explained by the bulk mechanics of the gels, but correlate to the density of the fibrin fibers the gels are composed of. These findings strongly suggest that the microscopic properties of individual fibers in fibrous networks play an essential role in determining cell behavior. PMID:26910190

  8. Fibrin-fiber architecture influences cell spreading and differentiation.

    PubMed

    Bruekers, Stéphanie M C; Jaspers, Maarten; Hendriks, José M A; Kurniawan, Nicholas A; Koenderink, Gijsje H; Kouwer, Paul H J; Rowan, Alan E; T S Huck, Wilhelm

    2016-09-02

    The mechanical and structural properties of the extracellular matrix (ECM) play an important role in regulating cell fate. The natural ECM has a complex fibrillar structure and shows nonlinear mechanical properties, which are both difficult to mimic synthetically. Therefore, systematically testing the influence of ECM properties on cellular behavior is very challenging. In this work we show two different approaches to tune the fibrillar structure and mechanical properties of fibrin hydrogels. Addition of extra thrombin before gelation increases the protein density within the fibrin fibers without significantly altering the mechanical properties of the resulting hydrogel. On the other hand, by forming a composite hydrogel with a synthetic biomimetic polyisocyanide network the protein density within the fibrin fibers decreases, and the mechanics of the composite material can be tuned by the PIC/fibrin mass ratio. The effect of the changes in gel structure and mechanics on cellular behavior are investigated, by studying human mesenchymal stem cell (hMSC) spreading and differentiation on these gels. We find that the trends observed in cell spreading and differentiation cannot be explained by the bulk mechanics of the gels, but correlate to the density of the fibrin fibers the gels are composed of. These findings strongly suggest that the microscopic properties of individual fibers in fibrous networks play an essential role in determining cell behavior.

  9. 3D Printed Bionic Ears

    PubMed Central

    Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

    2013-01-01

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  10. 3D printed bionic ears.

    PubMed

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

  11. 3D Audio System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  12. Twin Peaks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. 3D glasses are necessary to identify surface detail. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.

    The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  13. 3D and beyond

    NASA Astrophysics Data System (ADS)

    Fung, Y. C.

    1995-05-01

    This conference on physiology and function covers a wide range of subjects, including the vasculature and blood flow, the flow of gas, water, and blood in the lung, the neurological structure and function, the modeling, and the motion and mechanics of organs. Many technologies are discussed. I believe that the list would include a robotic photographer, to hold the optical equipment in a precisely controlled way to obtain the images for the user. Why are 3D images needed? They are to achieve certain objectives through measurements of some objects. For example, in order to improve performance in sports or beauty of a person, we measure the form, dimensions, appearance, and movements.

  14. Novel enzymatically cross-linked hyaluronan hydrogels support the formation of 3D neuronal networks.

    PubMed

    Broguiere, Nicolas; Isenmann, Luca; Zenobi-Wong, Marcy

    2016-08-01

    Hyaluronan (HA) is an essential component of the central nervous system's extracellular matrix and its high molecular weight (MW) form has anti-inflammatory and anti-fibrotic properties relevant for regenerative medicine. Here, we introduce a new hydrogel based on high MW HA which is cross-linked using the transglutaminase (TG) activity of the activated blood coagulation factor XIII (FXIIIa). These HA-TG gels have significant advantages for neural tissue engineering compared to previous HA gels. Due to their chemical inertness in the absence of FXIIIa, the material can be stored long-term, is stable in solution, and shows no cytotoxicity. The gelation is completely cell-friendly due to the specificity of the enzyme and the gelation rate can be tuned from seconds to hours at physiological pH and independently of stiffness. The gels are injectable, and attach covalently to fibrinogen and fibrin, two common bioactive components in in vitro tissue engineering, as well as proteins present in vivo, allowing the gels to covalently bind to brain or spinal cord defects. These optimal chemical and bioactive properties of HA-TG gels enabled the formation of 3D neuronal cultures of unprecedented performance, showing fast neurite outgrowth, axonal and dendritic speciation, strong synaptic connectivity in 3D networks, and rapidly-occurring and long-lasting coordinated electrical activity.

  15. In vitro characterization and in vivo behavior of human nucleus pulposus and annulus fibrosus cells in clinical-grade fibrin and collagen-enriched fibrin gels.

    PubMed

    Colombini, Alessandra; Lopa, Silvia; Ceriani, Cristina; Lovati, Arianna B; Croiset, Samantha J; Di Giancamillo, Alessia; Lombardi, Giovanni; Banfi, Giuseppe; Moretti, Matteo

    2015-02-01

    The intervertebral disc (IVD) presents a limited self-repair ability and cell-based therapies have been suggested to prevent or treat IVD lesions. Fibrin-based scaffolds as cell carriers are promising candidates in IVD tissue engineering, thanks to their ability to be easily delivered into the defect and to adapt to the lesion shape, to support/retain the injected cells into the implantation site and to favor the production of a suitable extracellular matrix (ECM). We evaluated the in vitro and in vivo behavior of human nucleus pulposus (NP) and annulus fibrosus (AF) cells in a clinical-grade collagen-enriched fibrin that has never been tested before for orthopedic applications, comparing it with clinical-grade fibrin. The survival of IVD cells seeded within fibrin or collagen-enriched fibrin and the ECM synthesis were evaluated by biochemical, immunohistochemical, and transcriptional analyses, prior and after subcutaneous implantation of the gels in nude mice. After 28 days of implantation, NP and AF cells were still detectable within explants, produced tissue-specific ECM, and showed a higher content of glycosaminoglycans (GAGs) and type I and II collagen compared to gels before implantation. Both the fibrin gels, enriched or not with collagen, seemed to be suitable for the culture of AF cells, being able to support the homogeneous synthesis of type I collagen, characteristic of the native fibrocartilaginous AF tissue. Differently, fibrin alone was a more suitable matrix for NP culture, supporting the homogeneous deposition of GAGs and type II collagen. In conclusion, our results suggest to combine AF cells with fibrin, enriched or not with collagen, and NP cells with fibrin alone to maintain the typical features of these cell populations, indicating these clinical-grade materials as viable options in cell-based treatments for IVD lesions.

  16. 3D Surgical Simulation

    PubMed Central

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  17. Martian terrain - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    An area of rocky terrain near the landing site of the Sagan Memorial Station can be seen in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  18. Martian terrain - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    An area of rocky terrain near the landing site of the Sagan Memorial Station can be seen in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  19. Fibrin acts as biomimetic niche inducing both differentiation and stem cell marker expression of early human endothelial progenitor cells.

    PubMed

    Barsotti, M C; Magera, A; Armani, C; Chiellini, F; Felice, F; Dinucci, D; Piras, A M; Minnocci, A; Solaro, R; Soldani, G; Balbarini, A; Di Stefano, R

    2011-02-01

    Transplantation of endothelial progenitor cells (EPCs) is a promising approach for revascularization of tissue. We have used a natural and biocompatible biopolymer, fibrin, to induce cell population growth, differentiation and functional activity of EPCs. Peripheral blood mononuclear cells were cultured for 1 week to obtain early EPCs. Fibrin was characterized for stiffness and capability to sustain cell population expansion at different fibrinogen-thrombin ratios. Viability, differentiation and angiogenic properties of EPCs were evaluated and compared to those of EPCs grown on fibronectin. Fibrin had a nanometric fibrous structure forming a porous network. Fibrinogen concentration significantly influenced fibrin stiffness and cell growth: 9 mg/ml fibrinogen and 25 U/ml thrombin was the best ratio for enhanced cell viability. Moreover, cell viability was significantly higher on fibrin compared to being on fibronectin. Even though no significant difference was observed in expression of endothelial markers, culture on fibrin elicited marked induction of stem cell markers OCT 3/4 and NANOG. In vitro angiogenesis assay on Matrigel showed that EPCs grown on fibrin retain angiogenetic capability as EPCs grown on fibronectin, but significantly better release of cytokines involved in cell recruitment was produced by EPC grown on fibrin. Fibrin is a suitable matrix for EPC growth, differentiation and angiogenesis capability, suggesting that fibrin gel may be very useful for regenerative medicine. © 2010 Blackwell Publishing Ltd.

  20. 3D Ultrafast Ultrasound Imaging In Vivo

    PubMed Central

    Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-01-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative real-time imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in three dimensions based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32×32 matrix-array probe. Its capability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3-D Shear-Wave Imaging, 3-D Ultrafast Doppler Imaging and finally 3D Ultrafast combined Tissue and Flow Doppler. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3-D Ultrafast Doppler was used to obtain 3-D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, for the first time, the complex 3-D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, and the 3-D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3-D Ultrafast Ultrasound Imaging for the 3-D real-time mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra- and inter-observer variability. PMID:25207828

  1. Effect of microgravity, temperature, and concentration on fibrin and collagen assembly.

    PubMed

    Nunes, C R; Roedersheimer, M T; Simske, S J; Luttges, M W

    1995-08-01

    In purified form collagen and fibrin can be processed into gel-like matrices of interconnecting fibers. The microscopic structure of materials produced from these macromolecules is critical to their utility as biomaterials. Varying the conditions of the assembly environment allows for the production of a wide range of morphologies. In this study, changes in gravity, temperature, and concentration were examined. Contrary to protein crystal growth studies which indicate substantial increases in organization and size in microgravity, the gravitational environment had no repeatable effect on collagen and fibrin fiber diameters and matrix porosity. However, fibrin gels formed in microgravity appeared more homogeneous than ground samples. Changes in temperature and concentration of both protein and buffer had substantial effects on fiber diameters and material porosity for both collagen and fibrin. Temperature experiments were performed over the range 23.8 to 39 degrees C for fibrin and 22 to 33 degrees C for collagen. Thrombin concentration was varied from 0.02 to 0.10 units/ml for fibrin experiments and buffer concentration was varied by means of a dialysis membrane for collagen experiments. Consequently, the temperature and concentration controls developed for flight experiments are being considered for their potential in developing fibrin and collagen based materials with well-defined microscopic structures. The increased homogeneity of fibrin gels produced in microgravity suggests the possibility of using this environment for the production of optimal biomaterials.

  2. Quantum dot based 3D photonic devices

    NASA Astrophysics Data System (ADS)

    Sakellari, Ioanna; Kabouraki, Elmina; Gray, David; Vamvakaki, Maria; Farsari, Maria

    2017-02-01

    In this work, we present our most recent results on the fabrication of 3D high-resolution woodpile photonic crystals containing an organic-inorganic silicon-zirconium (Si-Zr) composite and cadmium sulfide (CdS) quantum dots (QDs). The structures are fabricated by combining 3D Direct Laser Writing by two-photon absorption and in-situ synthesis of CdS nanoparticles inside the 3D photonic matrix. The CdS-Zr-Si composite material exhibits a high nonlinear refractive index value measured by means of Z-scan method. 3D woodpile photonic structures with varying inlayer periodicity from 600nm to 500nm show clear photonic stop bands in the wavelength region between 1000nm to 450nm.

  3. Enhanced Viability of Endothelial Colony Forming Cells in Fibrin Microbeads for Sensor Vascularization.

    PubMed

    Gandhi, Jarel K; Zivkovic, Lada; Fisher, John P; Yoder, Mervin C; Brey, Eric M

    2015-09-18

    Enhanced vascularization at sensor interfaces can improve long-term function. Fibrin, a natural polymer, has shown promise as a biomaterial for sensor coating due to its ability to sustain endothelial cell growth and promote local vascularization. However, the culture of cells, particularly endothelial cells (EC), within 3D scaffolds for more than a few days is challenging due to rapid loss of EC viability. In this manuscript, a robust method for developing fibrin microbead scaffolds for long-term culture of encapsulated ECs is described. Fibrin microbeads are formed using sodium alginate as a structural template. The size, swelling and structural properties of the microbeads were varied with needle gauge and composition and concentration of the pre-gel solution. Endothelial colony-forming cells (ECFCs) were suspended in the fibrin beads and cultured within a perfusion bioreactor system. The perfusion bioreactor enhanced ECFCs viability and genome stability in fibrin beads relative to static culture. Perfusion bioreactors enable 3D culture of ECs within fibrin beads for potential application as a sensor coating.

  4. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  5. A microfluidic device for 2D to 3D and 3D to 3D cell navigation

    NASA Astrophysics Data System (ADS)

    Shamloo, Amir; Amirifar, Leyla

    2016-01-01

    Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduced a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor concentration gradients, adult human dermal microvascular endothelial cells also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient were required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies.

  6. Characterization of Fibrin and Collagen Gels for Engineering Wound Healing Models

    PubMed Central

    Moreno-Arotzena, Oihana; Meier, Johann G.; del Amo, Cristina; García-Aznar, José Manuel

    2015-01-01

    Hydrogels are used for 3D in vitro assays and tissue engineering and regeneration purposes. For a thorough interpretation of this technology, an integral biomechanical characterization of the materials is required. In this work, we characterize the mechanical and functional behavior of two specific hydrogels that play critical roles in wound healing, collagen and fibrin. A coherent and complementary characterization was performed using a generalized and standard composition of each hydrogel and a combination of techniques. Microstructural analysis was performed by scanning electron microscopy and confocal reflection imaging. Permeability was measured using a microfluidic-based experimental set-up, and mechanical responses were analyzed by rheology. We measured a pore size of 2.84 and 1.69 μm for collagen and fibrin, respectively. Correspondingly, the permeability of the gels was 1.00·10−12 and 5.73·10−13 m2. The shear modulus in the linear viscoelastic regime was 15 Pa for collagen and 300 Pa for fibrin. The gels exhibited strain-hardening behavior at ca. 10% and 50% strain for fibrin and collagen, respectively. This consistent biomechanical characterization provides a detailed and robust starting point for different 3D in vitro bioapplications, such as collagen and/or fibrin gels. These features may have major implications for 3D cellular behavior by inducing divergent microenvironmental cues. PMID:26290683

  7. Prominent rocks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  8. Pluto in 3-D

    NASA Image and Video Library

    2015-10-23

    Global stereo mapping of Pluto surface is now possible, as images taken from multiple directions are downlinked from NASA New Horizons spacecraft. Stereo images will eventually provide an accurate topographic map of most of the hemisphere of Pluto seen by New Horizons during the July 14 flyby, which will be key to understanding Pluto's geological history. This example, which requires red/blue stereo glasses for viewing, shows a region 180 miles (300 kilometers) across, centered near longitude 130 E, latitude 20 N (the red square in the global context image). North is to the upper left. The image shows an ancient, heavily cratered region of Pluto, dotted with low hills and cut by deep fractures, which indicate extension of Pluto's crust. Analysis of these stereo images shows that the steep fracture in the upper left of the image is about 1 mile (1.6 kilometers) deep, and the craters in the lower right part of the image are up to 1.3 miles (2.1 km) deep. Smallest visible details are about 0.4 miles (0.6 kilometers) across. You will need 3D glasses to view this image showing an ancient, heavily cratered region of Pluto. http://photojournal.jpl.nasa.gov/catalog/PIA20032

  9. Intraoral 3D scanner

    NASA Astrophysics Data System (ADS)

    Kühmstedt, Peter; Bräuer-Burchardt, Christian; Munkelt, Christoph; Heinze, Matthias; Palme, Martin; Schmidt, Ingo; Hintersehr, Josef; Notni, Gunther

    2007-09-01

    Here a new set-up of a 3D-scanning system for CAD/CAM in dental industry is proposed. The system is designed for direct scanning of the dental preparations within the mouth. The measuring process is based on phase correlation technique in combination with fast fringe projection in a stereo arrangement. The novelty in the approach is characterized by the following features: A phase correlation between the phase values of the images of two cameras is used for the co-ordinate calculation. This works contrary to the usage of only phase values (phasogrammetry) or classical triangulation (phase values and camera image co-ordinate values) for the determination of the co-ordinates. The main advantage of the method is that the absolute value of the phase at each point does not directly determine the coordinate. Thus errors in the determination of the co-ordinates are prevented. Furthermore, using the epipolar geometry of the stereo-like arrangement the phase unwrapping problem of fringe analysis can be solved. The endoscope like measurement system contains one projection and two camera channels for illumination and observation of the object, respectively. The new system has a measurement field of nearly 25mm × 15mm. The user can measure two or three teeth at one time. So the system can by used for scanning of single tooth up to bridges preparations. In the paper the first realization of the intraoral scanner is described.

  10. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  11. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  12. 3D Printing and 3D Bioprinting in Pediatrics

    PubMed Central

    Vijayavenkataraman, Sanjairaj; Fuh, Jerry Y H; Lu, Wen Feng

    2017-01-01

    Additive manufacturing, commonly referred to as 3D printing, is a technology that builds three-dimensional structures and components layer by layer. Bioprinting is the use of 3D printing technology to fabricate tissue constructs for regenerative medicine from cell-laden bio-inks. 3D printing and bioprinting have huge potential in revolutionizing the field of tissue engineering and regenerative medicine. This paper reviews the application of 3D printing and bioprinting in the field of pediatrics. PMID:28952542

  13. 3D Printing and 3D Bioprinting in Pediatrics.

    PubMed

    Vijayavenkataraman, Sanjairaj; Fuh, Jerry Y H; Lu, Wen Feng

    2017-07-13

    Additive manufacturing, commonly referred to as 3D printing, is a technology that builds three-dimensional structures and components layer by layer. Bioprinting is the use of 3D printing technology to fabricate tissue constructs for regenerative medicine from cell-laden bio-inks. 3D printing and bioprinting have huge potential in revolutionizing the field of tissue engineering and regenerative medicine. This paper reviews the application of 3D printing and bioprinting in the field of pediatrics.

  14. Customizable engineered blood vessels using 3D printed inserts.

    PubMed

    Pinnock, Cameron B; Meier, Elizabeth M; Joshi, Neeraj N; Wu, Bin; Lam, Mai T

    2016-04-15

    Current techniques for tissue engineering blood vessels are not customizable for vascular size variation and vessel wall thickness. These critical parameters vary widely between the different arteries in the human body, and the ability to engineer vessels of varying sizes could increase capabilities for disease modeling and treatment options. We present an innovative method for producing customizable, tissue engineered, self-organizing vascular constructs by replicating a major structural component of blood vessels - the smooth muscle layer, or tunica media. We utilize a unique system combining 3D printed plate inserts to control construct size and shape, and cell sheets supported by a temporary fibrin hydrogel to encourage cellular self-organization into a tubular form resembling a natural artery. To form the vascular construct, 3D printed inserts are adhered to tissue culture plates, fibrin hydrogel is deposited around the inserts, and human aortic smooth muscle cells are then seeded atop the fibrin hydrogel. The gel, aided by the innate contractile properties of the smooth muscle cells, aggregates towards the center post insert, creating a tissue ring of smooth muscle cells. These rings are then stacked into the final tubular construct. Our methodology is robust, easily repeatable and allows for customization of cellular composition, vessel wall thickness, and length of the vessel construct merely by varying the size of the 3D printed inserts. This platform has potential for facilitating more accurate modeling of vascular pathology, serving as a drug discovery tool, or for vessel repair in disease treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Bone repair with a form of BMP-2 engineered for incorporation into fibrin cell ingrowth matrices.

    PubMed

    Schmoekel, Hugo G; Weber, Franz E; Schense, Jason C; Grätz, Klaus W; Schawalder, Peter; Hubbell, Jeffrey A

    2005-02-05

    Most growth factors naturally involved in development and regeneration demonstrate strong binding to the extracellular matrix and are retained there until being locally mobilized by cells. In spite of this feedback between cell activity and growth factor mobilization in the extracellular matrix, this approach has not been extensively explored in therapeutic situations. We present an engineered bone morphogenetic protein-2 (BMP-2) fusion protein that mimics such function in a surgically relevant matrix, fibrin, incorporated into the matrix until it is locally liberated by cell surface-associated proteases. A tripartite fusion protein, denoted TG-pl-BMP-2, was designed and produced recombinantly. An N-terminal transglutaminase substrate (TG) domain provides covalent attachment to fibrin during coagulation under the influence of the blood transglutaminase factor XIIIa. A central plasmin substrate (pl) domain provides a cleavage site for local release of the attached growth factor from the fibrin matrix under the influence of cell-activated plasmin. A C-terminal human BMP-2 domain provides osteogenic activity. TG-pl-BMP-2 in fibrin was evaluated in vivo in critical-size craniotomy defects in rats, where it induced 76% more defect healing with bone at 3 weeks with a dose of 1 mug/defect than wildtype BMP-2 in fibrin. After a dosing study in rabbits, the engineered growth factor in fibrin was evaluated in a prospective clinical study for pancarpal fusion in dogs, where it induced statistically faster and more extensive bone bridging than equivalent treatment with cancellous bone autograft. The strong healing response shown by fibrin including a bound BMP-2 variant suggests that with the combination of bound growth factor and ingrowth matrix, it may be possible to improve upon the natural growth factor and even upon tissue autograft.

  16. The safety of fibrin sealants.

    PubMed

    Joch, Christine

    2003-08-01

    Fibrin sealants are prepared from fibrinogen, thrombin and sometimes also factor XIII that have been purified from human plasma. Bovine aprotinin is also included in some preparations. Each of these components has the potential to carry blood-borne pathogens, albeit at a very low frequency. In order to minimize the risk of viral transmission from commercial fibrin sealants, plasma donations undergo a series of procedures that contribute to avoiding, inactivating and eliminating potential contaminants. The procedures for selection and screening of plasma donors, and the testing of donated plasma, incorporates highly sensitive molecular techniques (e.g. PCR testing) and contributes significantly to reducing the theoretical possibility of viral transmission. The starting material for bovine aprotinin is also carefully selected, and the manufacturing process rigorously assessed, to minimize the putative risk of transmission of bovine spongiform encephalopathies. The manufacturing process for commercial fibrin sealants comprises a range of procedures, including heat treatment (e.g. pasteurization, dry or vapor heating), filtration, solvent/detergent treatment, precipitation, pH treatment and chromatography. Some steps are an inherent part of the purification process and others (e.g. pasteurization, nanofiltration) are deliberately introduced to inactivate/eliminate potential pathogens. Current manufacturing processes provide a very high degree of safety for fibrin sealants. In 20 years of worldwide use, there have been no known cases of hepatitis or HIV transmission associated with the use of commercial fibrin sealants.

  17. Calcium and fibrin gel structure.

    PubMed

    Okada, M; Blombäck, B

    1983-02-01

    Calcium ions (Ca), when present in the gel forming system, were shown to influence liquid permeation of the gels formed, as judged from the Ks-values (permeability coefficients) of the final gels. On increasing Ca concentration, the Ks-values for Fibrin I and Fibrin II gels increase and a maximum is reached at about 10-20 mM for gels formed at ionic strengths between 0.18 and 0.24. For both gels, clotting times (Ct) were shortened on increasing Ca concentration and the shortening was accompanied by increase in Ks. Magnesium also shortened Ct but had no appreciable effect on Ks. The rate of activation of fibrinogen (release of FPA and FPB) was not much affected by Ca, but the activation required for gelation at Ct, decreased with increasing Ca concentration. After the gels were formed, the removal of Ca by EDTA did not change the flow properties. Our results showed that Ca is of importance for formation of the fibrin gel structure, but it may be of minor importance for preservation of the gel structure after its formation. There is a difference between Fibrin I and Fibrin II gels with regard to Ca dependence. The role of calcium in gelation as well as its physiological implications is discussed.

  18. Recent EFIT Developments and 3D Extension

    NASA Astrophysics Data System (ADS)

    Lao, L. L.; Chu, M. S.; St. John, H. E.; Strait, E. J.; Montgomery, A. L.; Perkins, F. W.

    2006-10-01

    Recent developments of the equilibrium reconstruction code EFIT and its 3D extension to model toroidally asymmetric effects due to error and externally applied perturbation magnetic fields are presented. These include a new more complete uncertainty matrix for magnetic diagnostics based on detailed knowledge about their fabrication, installation, calibration, and operation. A new algorithm to efficiently compute high bootstrap-fraction equilibria that explicitly separates out the Pfirsch-Schluter and bootstrap contributions to the poloidal current stream function is also being developed. Other on-going and planned developments include a new computational structure based on Fortran 90/95 with a unified interface that can conveniently accommodate different tokamak devices and grid sizes, as well as a computational link that allows easy integration with transport and stability physics modules for integrated modeling. EFIT reconstruction capability is also being extended to 3D based on perturbation solutions to the 3D Grad-Shafranov equilibrium equation.

  19. Fibrinolysis inhibitors adversely affect remodeling of tissues sealed with fibrin glue.

    PubMed

    Krishnan, Lissy K; Vijayan Lal, Arthur; Uma Shankar, P R; Mohanty, Mira

    2003-01-01

    Experiments have been carried out to determine if aprotinin and epsilon -amino caproic acid increases the quality of Fibrin glue. A rat model was used for tissues such as liver and skin while rabbits were used for application of glue in dura mater. Apposition of all the tissues, glued with fibrin was found to be good and remnants of the polymerized fibrin were seen even on the seventh day of application, though inhibitors were not incorporated with the glue. In skin, excessive amounts of fibrin remained as a result of addition of aprotinin and epsilon -amino caproic acid, as compared to the glue applied without any inhibitor. After dural sealing, the wound repair and new bone formation at craniotomy site progressed well in the fibrin glue applied area as compared to the commercially available glue that contained aprotinin. The adhesive strength of the glue without or with fibrinolysis inhibitors was found to be similar, after 1h grafts on rat back. The observations from this study suggests that the use of aprotinin with fibrin glue may not be required because, even liver tissue that is known to have high fibrinolytic activity was sealed and repaired well in the absence of plasminogen inhibitors. On the other hand, it was found that if inhibitors were added, nondegraded matrix remained in the tissue even after 15 days and affected migration of repair cells. Thus, the inhibition of fibrinolysis after fibrin glue application is found detrimental to wound healing.

  20. Cell culture in autologous fibrin scaffolds for applications in tissue engineering.

    PubMed

    de la Puente, Pilar; Ludeña, Dolores

    2014-03-10

    In tissue engineering techniques, three-dimensional scaffolds are needed to adjust and guide cell growth and to allow tissue regeneration. The scaffold must be biocompatible, biodegradable and must benefit the interactions between cells and biomaterial. Some natural biomaterials such as fibrin provide a structure similar to the native extracellular matrix containing the cells. Fibrin was first used as a sealant based on pools of commercial fibrinogen. However, the high risk of viral transmission of these pools led to the development of techniques of viral inactivation and elimination and the use of autologous fibrins. In recent decades, fibrin has been used as a release system and three-dimensional scaffold for cell culture. Fibrin scaffolds have been widely used for the culture of different types of cells, and have found several applications in tissue engineering. The structure and development of scaffolds is a key point for cell culture because scaffolds of autologous fibrin offer an important alternative due to their low fibrinogen concentrations, which are more suitable for cell growth. With this review our aim is to follow methods of development, analyze the commercial and autologous fibrins available and assess the possible applications of cell culture in tissue engineering in these three-dimensional structures.

  1. Reproducibility of 3D chromatin configuration reconstructions

    PubMed Central

    Segal, Mark R.; Xiong, Hao; Capurso, Daniel; Vazquez, Mariel; Arsuaga, Javier

    2014-01-01

    It is widely recognized that the three-dimensional (3D) architecture of eukaryotic chromatin plays an important role in processes such as gene regulation and cancer-driving gene fusions. Observing or inferring this 3D structure at even modest resolutions had been problematic, since genomes are highly condensed and traditional assays are coarse. However, recently devised high-throughput molecular techniques have changed this situation. Notably, the development of a suite of chromatin conformation capture (CCC) assays has enabled elicitation of contacts—spatially close chromosomal loci—which have provided insights into chromatin architecture. Most analysis of CCC data has focused on the contact level, with less effort directed toward obtaining 3D reconstructions and evaluating the accuracy and reproducibility thereof. While questions of accuracy must be addressed experimentally, questions of reproducibility can be addressed statistically—the purpose of this paper. We use a constrained optimization technique to reconstruct chromatin configurations for a number of closely related yeast datasets and assess reproducibility using four metrics that measure the distance between 3D configurations. The first of these, Procrustes fitting, measures configuration closeness after applying reflection, rotation, translation, and scaling-based alignment of the structures. The others base comparisons on the within-configuration inter-point distance matrix. Inferential results for these metrics rely on suitable permutation approaches. Results indicate that distance matrix-based approaches are preferable to Procrustes analysis, not because of the metrics per se but rather on account of the ability to customize permutation schemes to handle within-chromosome contiguity. It has recently been emphasized that the use of constrained optimization approaches to 3D architecture reconstruction are prone to being trapped in local minima. Our methods of reproducibility assessment provide a

  2. EFIT 3D Reconstruction and Recent Developments

    NASA Astrophysics Data System (ADS)

    Lao, L. L.; Chu, M. S.; St. John, H. E.; Strait, E. J.; Turnbull, A. D.; Ren, Q.; Jeon, Y. M.; Flannagan, D.

    2007-11-01

    Recent 3D extension of the EFIT equilibrium reconstruction code to model toroidally asymmetric effects due to error and externally applied perturbation magnetic fields and other developments are presented. The 3D extension is based on an expansion of the MHD equations. Other developments include a new computational structure based on Fortran 90/95 with a unified interface that can conveniently accommodate different tokamak devices and grid sizes, as well as a Python-based GUI. New computational links that allow easy integration with transport and stability physics modules to facilitate kinetic reconstruction and stability analysis are also being developed. A new more complete uncertainty matrix for magnetic diagnostics based on knowledge about their fabrication, installation, calibration, and operation has also been implemented into EFIT and tested. Reconstructions with the new magnetic uncertainty matrix yield results similar to those using the existing one but with more realistic fitting merit figures.

  3. Matrix viscoplasticity and its shielding by active mechanics in microtissue models: experiments and mathematical modeling

    NASA Astrophysics Data System (ADS)

    Liu, Alan S.; Wang, Hailong; Copeland, Craig R.; Chen, Christopher S.; Shenoy, Vivek B.; Reich, Daniel H.

    2016-09-01

    The biomechanical behavior of tissues under mechanical stimulation is critically important to physiological function. We report a combined experimental and modeling study of bioengineered 3D smooth muscle microtissues that reveals a previously unappreciated interaction between active cell mechanics and the viscoplastic properties of the extracellular matrix. The microtissues’ response to stretch/unstretch actuations, as probed by microcantilever force sensors, was dominated by cellular actomyosin dynamics. However, cell lysis revealed a viscoplastic response of the underlying model collagen/fibrin matrix. A model coupling Hill-type actomyosin dynamics with a plastic perfectly viscoplastic description of the matrix quantitatively accounts for the microtissue dynamics, including notably the cells’ shielding of the matrix plasticity. Stretch measurements of single cells confirmed the active cell dynamics, and were well described by a single-cell version of our model. These results reveal the need for new focus on matrix plasticity and its interactions with active cell mechanics in describing tissue dynamics.

  4. Matrix viscoplasticity and its shielding by active mechanics in microtissue models: experiments and mathematical modeling

    PubMed Central

    Liu, Alan S.; Wang, Hailong; Copeland, Craig R.; Chen, Christopher S.; Shenoy, Vivek B.; Reich, Daniel H.

    2016-01-01

    The biomechanical behavior of tissues under mechanical stimulation is critically important to physiological function. We report a combined experimental and modeling study of bioengineered 3D smooth muscle microtissues that reveals a previously unappreciated interaction between active cell mechanics and the viscoplastic properties of the extracellular matrix. The microtissues’ response to stretch/unstretch actuations, as probed by microcantilever force sensors, was dominated by cellular actomyosin dynamics. However, cell lysis revealed a viscoplastic response of the underlying model collagen/fibrin matrix. A model coupling Hill-type actomyosin dynamics with a plastic perfectly viscoplastic description of the matrix quantitatively accounts for the microtissue dynamics, including notably the cells’ shielding of the matrix plasticity. Stretch measurements of single cells confirmed the active cell dynamics, and were well described by a single-cell version of our model. These results reveal the need for new focus on matrix plasticity and its interactions with active cell mechanics in describing tissue dynamics. PMID:27671239

  5. Magnetic Properties of 3D Printed Toroids

    NASA Astrophysics Data System (ADS)

    Bollig, Lindsey; Otto, Austin; Hilpisch, Peter; Mowry, Greg; Nelson-Cheeseman, Brittany; Renewable Energy; Alternatives Lab (REAL) Team

    Transformers are ubiquitous in electronics today. Although toroidal geometries perform most efficiently, transformers are traditionally made with rectangular cross-sections due to the lower manufacturing costs. Additive manufacturing techniques (3D printing) can easily achieve toroidal geometries by building up a part through a series of 2D layers. To get strong magnetic properties in a 3D printed transformer, a composite filament is used containing Fe dispersed in a polymer matrix. How the resulting 3D printed toroid responds to a magnetic field depends on two structural factors of the printed 2D layers: fill factor (planar density) and fill pattern. In this work, we investigate how the fill factor and fill pattern affect the magnetic properties of 3D printed toroids. The magnetic properties of the printed toroids are measured by a custom circuit that produces a hysteresis loop for each toroid. Toroids with various fill factors and fill patterns are compared to determine how these two factors can affect the magnetic field the toroid can produce. These 3D printed toroids can be used for numerous applications in order to increase the efficiency of transformers by making it possible for manufacturers to make a toroidal geometry.

  6. Ultra-Rapid 2-D and 3-D Laser Microprinting of Proteins

    NASA Astrophysics Data System (ADS)

    Scott, Mark Andrew

    When viewed under the microscope, biological tissues reveal an exquisite microarchitecture. These complex patterns arise during development, as cells interact with a multitude of chemical and mechanical cues in the surrounding extracellular matrix. Tissue engineers have sought for decades to repair or replace damaged tissue, often relying on porous scaffolds as an artificial extracellular matrix to support cell development. However, these grafts are unable to recapitulate the complexity of the in vivo environment, limiting our ability to regenerate functional tissue. Biomedical engineers have developed several methods for printing two- and three-dimensional patterns of proteins for studying and directing cell development. Of these methods, laser microprinting of proteins has shown the most promise for printing sub-cellular resolution gradients of cues, but the photochemistry remains too slow to enable large-scale applications for screening and therapeutics In this work, we demonstrate a novel high-speed photochemistry based on multi-photon photobleaching of fluorescein, and we build the fastest 2-D and 3-D laser microprinter for proteins to date. First, we show that multiphoton photobleaching of a deoxygenated solution of biotin-4-fluorescein onto a PEG monolayer with acrylate end-group can enable print speeds of almost 20 million pixels per second at 600 nanometer resolution. We discovered that the mechanism of fluorescein photobleaching evolves from a 2-photon to 3- and 4-photon regime at higher laser intensities, unlocking faster printing kinetics. Using this 2-D printing system, we develop a novel triangle-ratchet method for directing the polarization of single hippocampal neurons. This ability to determine which neurite becomes an axon, and which neuritis become dendrites is an essential step for developing defined in vitro neural networks. Next, we modify our multiphoton photobleaching system to print in three dimensions. For the first time, we demonstrate 3

  7. NGT-3D: a simple nematode cultivation system to study Caenorhabditis elegans biology in 3D.

    PubMed

    Lee, Tong Young; Yoon, Kyoung-Hye; Lee, Jin Il

    2016-04-15

    The nematodeCaenorhabditiselegansis one of the premier experimental model organisms today. In the laboratory, they display characteristic development, fertility, and behaviors in a two dimensional habitat. In nature, however,C. elegansis found in three dimensional environments such as rotting fruit. To investigate the biology ofC. elegansin a 3D controlled environment we designed a nematode cultivation habitat which we term the nematode growth tube or NGT-3D. NGT-3D allows for the growth of both nematodes and the bacteria they consume. Worms show comparable rates of growth, reproduction and lifespan when bacterial colonies in the 3D matrix are abundant. However, when bacteria are sparse, growth and brood size fail to reach levels observed in standard 2D plates. Using NGT-3D we observe drastic deficits in fertility in a sensory mutant in 3D compared to 2D, and this defect was likely due to an inability to locate bacteria. Overall, NGT-3D will sharpen our understanding of nematode biology and allow scientists to investigate questions of nematode ecology and evolutionary fitness in the laboratory.

  8. NGT-3D: a simple nematode cultivation system to study Caenorhabditis elegans biology in 3D

    PubMed Central

    Lee, Tong Young; Yoon, Kyoung-hye; Lee, Jin Il

    2016-01-01

    ABSTRACT The nematode Caenorhabditis elegans is one of the premier experimental model organisms today. In the laboratory, they display characteristic development, fertility, and behaviors in a two dimensional habitat. In nature, however, C. elegans is found in three dimensional environments such as rotting fruit. To investigate the biology of C. elegans in a 3D controlled environment we designed a nematode cultivation habitat which we term the nematode growth tube or NGT-3D. NGT-3D allows for the growth of both nematodes and the bacteria they consume. Worms show comparable rates of growth, reproduction and lifespan when bacterial colonies in the 3D matrix are abundant. However, when bacteria are sparse, growth and brood size fail to reach levels observed in standard 2D plates. Using NGT-3D we observe drastic deficits in fertility in a sensory mutant in 3D compared to 2D, and this defect was likely due to an inability to locate bacteria. Overall, NGT-3D will sharpen our understanding of nematode biology and allow scientists to investigate questions of nematode ecology and evolutionary fitness in the laboratory. PMID:26962047

  9. 3D Spectroscopy in Astronomy

    NASA Astrophysics Data System (ADS)

    Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

    2011-09-01

    Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

  10. Spherical 3D isotropic wavelets

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2012-04-01

    Context. Future cosmological surveys will provide 3D large scale structure maps with large sky coverage, for which a 3D spherical Fourier-Bessel (SFB) analysis in spherical coordinates is natural. Wavelets are particularly well-suited to the analysis and denoising of cosmological data, but a spherical 3D isotropic wavelet transform does not currently exist to analyse spherical 3D data. Aims: The aim of this paper is to present a new formalism for a spherical 3D isotropic wavelet, i.e. one based on the SFB decomposition of a 3D field and accompany the formalism with a public code to perform wavelet transforms. Methods: We describe a new 3D isotropic spherical wavelet decomposition based on the undecimated wavelet transform (UWT) described in Starck et al. (2006). We also present a new fast discrete spherical Fourier-Bessel transform (DSFBT) based on both a discrete Bessel transform and the HEALPIX angular pixelisation scheme. We test the 3D wavelet transform and as a toy-application, apply a denoising algorithm in wavelet space to the Virgo large box cosmological simulations and find we can successfully remove noise without much loss to the large scale structure. Results: We have described a new spherical 3D isotropic wavelet transform, ideally suited to analyse and denoise future 3D spherical cosmological surveys, which uses a novel DSFBT. We illustrate its potential use for denoising using a toy model. All the algorithms presented in this paper are available for download as a public code called MRS3D at http://jstarck.free.fr/mrs3d.html

  11. 3D Elevation Program—Virtual USA in 3D

    USGS Publications Warehouse

    Lukas, Vicki; Stoker, J.M.

    2016-04-14

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  12. Dynamic 3D cell culture via a chemoselective photoactuated ligand.

    PubMed

    Westcott, Nathan P; Luo, Wei; Goldstein, Jeffrey; Yousaf, Muhammad N

    2014-09-01

    A new strategy to create a dynamic scaffold for three-dimensional (3D) cell experiments based on a photo-activated cell adhesive peptide ligand is described. After polymerization, the inert matrix becomes cell adhesive by chemoselective modification through the conjugation of oxyamine-terminated ligands. Furthermore, spatial and temporal control of cell culture within the 3D matrix was achieved by the use of a biospecific photoprotected peptide and visualized by confocal microscopy.

  13. Parallel CARLOS-3D code development

    SciTech Connect

    Putnam, J.M.; Kotulski, J.D.

    1996-02-01

    CARLOS-3D is a three-dimensional scattering code which was developed under the sponsorship of the Electromagnetic Code Consortium, and is currently used by over 80 aerospace companies and government agencies. The code has been extensively validated and runs on both serial workstations and parallel super computers such as the Intel Paragon. CARLOS-3D is a three-dimensional surface integral equation scattering code based on a Galerkin method of moments formulation employing Rao- Wilton-Glisson roof-top basis for triangular faceted surfaces. Fully arbitrary 3D geometries composed of multiple conducting and homogeneous bulk dielectric materials can be modeled. This presentation describes some of the extensions to the CARLOS-3D code, and how the operator structure of the code facilitated these improvements. Body of revolution (BOR) and two-dimensional geometries were incorporated by simply including new input routines, and the appropriate Galerkin matrix operator routines. Some additional modifications were required in the combined field integral equation matrix generation routine due to the symmetric nature of the BOR and 2D operators. Quadrilateral patched surfaces with linear roof-top basis functions were also implemented in the same manner. Quadrilateral facets and triangular facets can be used in combination to more efficiently model geometries with both large smooth surfaces and surfaces with fine detail such as gaps and cracks. Since the parallel implementation in CARLOS-3D is at high level, these changes were independent of the computer platform being used. This approach minimizes code maintenance, while providing capabilities with little additional effort. Results are presented showing the performance and accuracy of the code for some large scattering problems. Comparisons between triangular faceted and quadrilateral faceted geometry representations will be shown for some complex scatterers.

  14. Perception of 3D spatial relations for 3D displays

    NASA Astrophysics Data System (ADS)

    Rosen, Paul; Pizlo, Zygmunt; Hoffmann, Christoph; Popescu, Voicu S.

    2004-05-01

    We test perception of 3D spatial relations in 3D images rendered by a 3D display (Perspecta from Actuality Systems) and compare it to that of a high-resolution flat panel display. 3D images provide the observer with such depth cues as motion parallax and binocular disparity. Our 3D display is a device that renders a 3D image by displaying, in rapid succession, radial slices through the scene on a rotating screen. The image is contained in a glass globe and can be viewed from virtually any direction. In the psychophysical experiment several families of 3D objects are used as stimuli: primitive shapes (cylinders and cuboids), and complex objects (multi-story buildings, cars, and pieces of furniture). Each object has at least one plane of symmetry. On each trial an object or its "distorted" version is shown at an arbitrary orientation. The distortion is produced by stretching an object in a random direction by 40%. This distortion must eliminate the symmetry of an object. The subject's task is to decide whether or not the presented object is distorted under several viewing conditions (monocular/binocular, with/without motion parallax, and near/far). The subject's performance is measured by the discriminability d', which is a conventional dependent variable in signal detection experiments.

  15. LLNL-Earth3D

    SciTech Connect

    2013-10-01

    Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.

  16. 3D World Building System

    ScienceCinema

    None

    2016-07-12

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  17. Market study: 3-D eyetracker

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.

  18. 3D Buckligami: Digital Matter

    NASA Astrophysics Data System (ADS)

    van Hecke, Martin; de Reus, Koen; Florijn, Bastiaan; Coulais, Corentin

    2014-03-01

    We present a class of elastic structures which exhibit collective buckling in 3D, and create these by a 3D printing/moulding technique. Our structures consist of cubic lattice of anisotropic unit cells, and we show that their mechanical properties are programmable via the orientation of these unit cells.

  19. 3D World Building System

    SciTech Connect

    2013-10-30

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  20. Euro3D Science Conference

    NASA Astrophysics Data System (ADS)

    Walsh, J. R.

    2004-02-01

    The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly

  1. 3D printing in dentistry.

    PubMed

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.

  2. 3D vision system assessment

    NASA Astrophysics Data System (ADS)

    Pezzaniti, J. Larry; Edmondson, Richard; Vaden, Justin; Hyatt, Bryan; Chenault, David B.; Kingston, David; Geulen, Vanilynmae; Newell, Scott; Pettijohn, Brad

    2009-02-01

    In this paper, we report on the development of a 3D vision system consisting of a flat panel stereoscopic display and auto-converging stereo camera and an assessment of the system's use for robotic driving, manipulation, and surveillance operations. The 3D vision system was integrated onto a Talon Robot and Operator Control Unit (OCU) such that direct comparisons of the performance of a number of test subjects using 2D and 3D vision systems were possible. A number of representative scenarios were developed to determine which tasks benefited most from the added depth perception and to understand when the 3D vision system hindered understanding of the scene. Two tests were conducted at Fort Leonard Wood, MO with noncommissioned officers ranked Staff Sergeant and Sergeant First Class. The scenarios; the test planning, approach and protocols; the data analysis; and the resulting performance assessment of the 3D vision system are reported.

  3. PLOT3D user's manual

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  4. The mechanics of fibrin networks and their alterations by platelets

    NASA Astrophysics Data System (ADS)

    Jawerth, Louise Marie

    Fibrin is a biopolymer that assembles into a network during blood coagulation to become the structural scaffold of a blood clot. The precise mechanics of this network are crucial for a blood clot to properly stem the flow of blood at the site of vascular injury while still remaining pliable enough to avoid dislocation. A hallmark of fibrin's mechanical response is strain-stiffening: at small strains, its response is low and linear; while at high strains, its stiffness increases non-linearly with increasing strain. The physical origins of strain-stiffening have been studied for other biopolymer systems but have remained elusive for biopolymer networks composed of stiff filaments, such as fibrin. To understand the origins of this intriguing behavior, we directly observe and quantify the motion of all of the fibers in the fibrin networks as they undergo shear in 3D using confocal microscopy. We show that the strain-stiffening response of a clot is a result of the full network deformation rather than an intrinsic strain-stiffening response of the individual fibers. We observe a distinct transition from a linear, low-strain regime, where all fibers avoid any internal stretching, to a non-linear, high-strain regime, where an increasing number of fibers become stretched. This transition is characterized by a high degree of non-affine motion. Moreover, we are able to precisely calculate the non-linear stress-strain response of the network by using the strains on each fiber measured directly with confocal microscopy and by assuming the fibers behave like linearly elastic beams. This result confirms that it is the network deformation that causes the strain-stiffening behavior of fibrin clots. These data are consistent with predictions for low-connectivity networks with soft, bending, or floppy modes. Moreover, we show that the addition of small contractile cells, platelets, increases the low-strain stiffness of the network while the high-strain stiffness is independent of

  5. Microporous nanofibrous fibrin-based scaffolds for craniofacial bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Osathanon, Thanaphum

    The fibrotic response of the body to synthetic polymers limits their success in tissue engineering and other applications. Though porous polymers have demonstrated improved healing, difficulty in controlling their pore sizes and pore interconnections has clouded the understanding of this phenomenon. In this study, a novel method to fabricate natural polymer/calcium phosphate composite scaffolds and immobilized alkaline phosphatase fibrin scaffolds with tightly controllable pore size, pore interconnection has been investigated. Microporous, nanofibrous fibrin scaffolds (FS) were fabricated using sphere-templating method. Calcium phosphate/fibrin composite scaffolds were created by solution deposition of calcium phosphate on fibrin surfaces or by direct incorporation of nanocrystalline hydroxyapatite (nHA). The SEM results showed that fibrin scaffolds exhibited a highly porous and interconnected structure. Osteoblast-like cells, obtained from murine calvaria, attached, spread and showed a polygonal morphology on the surface of the biomaterial. Multiple cell layers and fibrillar matrix deposition were observed. Moreover, cells seeded on mineralized fibrin scaffolds (MFS) exhibited significantly higher alkaline phosphatase activity as well as osteoblast marker gene expression compared to FS and nHA incorporated fibrin scaffolds (nHA/FS). These fibrin-based scaffolds were degraded both in vitro and in vivo. Furthermore, these scaffolds promoted bone formation in a mouse calvarial defect model and the bone formation was enhanced by addition of rhBMP-2. The second approach was to immobilize alkaline phosphatase (ALP) on fibrin scaffolds. ALP enzyme was covalently immobilized on the microporous nanofibrous fibrin scaffolds using 1-ethyl-3-(dimethylaminopropyl)carbodiimide hydrochloride (EDC). The SEM results demonstrated mineral deposition on immobilized ALP fibrin scaffolds (ALP/FS) when incubated in medium supplemented with beta-glycerophosphate, suggesting that the

  6. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  7. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  8. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  9. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  10. Fibrin Targeted Block Copolymers for the Prevention of Postsurgical Adhesions

    PubMed Central

    Medley, John M.; Kaplan, Eugene; Oz, Helieh S.; Sundararaj, Sharath C.; Puleo, David A.; Dziubla, Thomas D.

    2015-01-01

    Despite advances in surgical methods, postsurgical adhesions (PSA) remain a significant clinical challenge affecting millions of patients each year. These permanent fibrous connections between tissues result from the bridging of wounded internal surfaces by an extended fibrin gel matrix (FGM). Adhesion formation is a result of a systems level convergence of wound healing pathways, complicating the design of materials that could inhibit their occurrence. In this study, a systematic approach that identifies key material properties required for functional performance optimization was used to design a new fibrin-targeted PSA prevention material. A series of multifunctional polymers with varied molecular architectures was synthesized to investigate the effect of changing polymer structural parameters on the ability to disrupt the formation of an extended FGM. Initial studies in a murine adhesion model demonstrated a statistically significant reduction in the degree of PSA formation, demonstrating the potential value of this systematic approach. PMID:21695779

  11. 3D Cell Culture in Alginate Hydrogels

    PubMed Central

    Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael

    2015-01-01

    This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue. PMID:27600217

  12. Rubber Impact on 3D Textile Composites

    NASA Astrophysics Data System (ADS)

    Heimbs, Sebastian; Van Den Broucke, Björn; Duplessis Kergomard, Yann; Dau, Frederic; Malherbe, Benoit

    2012-06-01

    A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools.

  13. Unassisted 3D camera calibration

    NASA Astrophysics Data System (ADS)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  14. Bioprinting of 3D hydrogels.

    PubMed

    Stanton, M M; Samitier, J; Sánchez, S

    2015-08-07

    Three-dimensional (3D) bioprinting has recently emerged as an extension of 3D material printing, by using biocompatible or cellular components to build structures in an additive, layer-by-layer methodology for encapsulation and culture of cells. These 3D systems allow for cell culture in a suspension for formation of highly organized tissue or controlled spatial orientation of cell environments. The in vitro 3D cellular environments simulate the complexity of an in vivo environment and natural extracellular matrices (ECM). This paper will focus on bioprinting utilizing hydrogels as 3D scaffolds. Hydrogels are advantageous for cell culture as they are highly permeable to cell culture media, nutrients, and waste products generated during metabolic cell processes. They have the ability to be fabricated in customized shapes with various material properties with dimensions at the micron scale. 3D hydrogels are a reliable method for biocompatible 3D printing and have applications in tissue engineering, drug screening, and organ on a chip models.

  15. Acute fibrinous and organising pneumonia.

    PubMed

    Guimarães, Catarina; Sanches, Inês; Ferreira, Catarina

    2012-03-20

    Acute fibrinous and organising pneumonia (AFOP) was recently described as an unusual pattern of diffuse lung disease. Particular characteristics make the differential diagnosis with the well recognised clinical patterns of diffuse alveolar damage, cryptogenic organising pneumonia or eosinophilic pneumonia. The lack of hyaline membranes, the presence of intra-alveolar fibrin, absence of noticeable eosinophils and patchy distribution suggests that AFOP define a distinct histological pattern. The authors describe the case of a woman diagnosed with AFOP after surgical lung biopsy, in association with primary biliary cirrhosis. The patient presented dyspnoea, fatigue, dry cough and thoracic pain. The CT scan showed bilateral patchy infiltrates predominantly in the lower lobes. Flexible bronchoscopy and subsidiary techniques were inconclusive and biopsy through video-assisted thoracoscopic surgery led to anatomopathological diagnosis of AFOP. The patient is having a good clinical response to prednisone.

  16. Acute fibrinous and organising pneumonia

    PubMed Central

    Guimarães, Catarina; Sanches, Inês; Ferreira, Catarina

    2012-01-01

    Acute fibrinous and organising pneumonia (AFOP) was recently described as an unusual pattern of diffuse lung disease. Particular characteristics make the differential diagnosis with the well recognised clinical patterns of diffuse alveolar damage, cryptogenic organising pneumonia or eosinophilic pneumonia. The lack of hyaline membranes, the presence of intra-alveolar fibrin, absence of noticeable eosinophils and patchy distribution suggests that AFOP define a distinct histological pattern. The authors describe the case of a woman diagnosed with AFOP after surgical lung biopsy, in association with primary biliary cirrhosis. The patient presented dyspnoea, fatigue, dry cough and thoracic pain. The CT scan showed bilateral patchy infiltrates predominantly in the lower lobes. Flexible bronchoscopy and subsidiary techniques were inconclusive and biopsy through video-assisted thoracoscopic surgery led to anatomopathological diagnosis of AFOP. The patient is having a good clinical response to prednisone. PMID:22605688

  17. 3D Scan Systems Integration

    DTIC Science & Technology

    2007-11-02

    AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 5 Feb 98 4. TITLE AND SUBTITLE 3D Scan Systems Integration REPORT TYPE AND DATES COVERED...2-89) Prescribed by ANSI Std. Z39-1 298-102 [ EDO QUALITY W3PECTEDI DLA-ARN Final Report for US Defense Logistics Agency on DDFG-T2/P3: 3D...SCAN SYSTEMS INTEGRATION Contract Number SPO100-95-D-1014 Contractor Ohio University Delivery Order # 0001 Delivery Order Title 3D Scan Systems

  18. Recent Development in 3D Food Printing.

    PubMed

    Yang, Fan; Zhang, Min; Bhandari, Bhesh

    2015-10-19

    Robots and softwares have been significantly improving our daily lives by rendering us much convenience. And 3D printing is a typical example, for it is going to usher in a new era of localized manufacturing that is actually based on digital fabrication by layer-by-layer deposition in three dimensional space. In terms of food industry, the revolution that three-dimensional printing technologies is bringing to food manufacturing is convenience of low-cost customized fabrication and even precise nutrition control. This paper is aimed to give a brief introduction of recent development of food printing and material property of food ingredients that can be used to design the 3D food matrix and investigate the relationship between process parameters and resulting printed food properties in order to establish a food manufacturing process with this new food production approach.

  19. ASI/MET - 3-D

    NASA Image and Video Library

    1997-07-13

    The Atmospheric Structure Instrument/Meteorology Package ASI/MET is the mast and windsocks at the center of this stereo image from NASA Mars Pathfinder. 3D glasses are necessary to identify surface detail.

  20. 3D Models of Immunotherapy

    Cancer.gov

    This collaborative grant is developing 3D models of both mouse and human biology to investigate aspects of therapeutic vaccination in order to answer key questions relevant to human cancer immunotherapy.

  1. 3D polymer scaffold arrays.

    PubMed

    Simon, Carl G; Yang, Yanyin; Dorsey, Shauna M; Ramalingam, Murugan; Chatterjee, Kaushik

    2011-01-01

    We have developed a combinatorial platform for fabricating tissue scaffold arrays that can be used for screening cell-material interactions. Traditional research involves preparing samples one at a time for characterization and testing. Combinatorial and high-throughput (CHT) methods lower the cost of research by reducing the amount of time and material required for experiments by combining many samples into miniaturized specimens. In order to help accelerate biomaterials research, many new CHT methods have been developed for screening cell-material interactions where materials are presented to cells as a 2D film or surface. However, biomaterials are frequently used to fabricate 3D scaffolds, cells exist in vivo in a 3D environment and cells cultured in a 3D environment in vitro typically behave more physiologically than those cultured on a 2D surface. Thus, we have developed a platform for fabricating tissue scaffold libraries where biomaterials can be presented to cells in a 3D format.

  2. Accepting the T3D

    SciTech Connect

    Rich, D.O.; Pope, S.C.; DeLapp, J.G.

    1994-10-01

    In April, a 128 PE Cray T3D was installed at Los Alamos National Laboratory`s Advanced Computing Laboratory as part of the DOE`s High-Performance Parallel Processor Program (H4P). In conjunction with CRI, the authors implemented a 30 day acceptance test. The test was constructed in part to help them understand the strengths and weaknesses of the T3D. In this paper, they briefly describe the H4P and its goals. They discuss the design and implementation of the T3D acceptance test and detail issues that arose during the test. They conclude with a set of system requirements that must be addressed as the T3D system evolves.

  3. [Tridimensional (3D) endoscopic ultrasonography].

    PubMed

    Varas Lorenzo, M J; Muñoz Agel, F; Abad Belando, R

    2007-01-01

    A review and update on 3D endoscopic ultrasonography is included regarding all of this technique s aspects, technical details, and current indications. Images from our own clinical experience are presented.

  4. Heterodyne 3D ghost imaging

    NASA Astrophysics Data System (ADS)

    Yang, Xu; Zhang, Yong; Yang, Chenghua; Xu, Lu; Wang, Qiang; Zhao, Yuan

    2016-06-01

    Conventional three dimensional (3D) ghost imaging measures range of target based on pulse fight time measurement method. Due to the limit of data acquisition system sampling rate, range resolution of the conventional 3D ghost imaging is usually low. In order to take off the effect of sampling rate to range resolution of 3D ghost imaging, a heterodyne 3D ghost imaging (HGI) system is presented in this study. The source of HGI is a continuous wave laser instead of pulse laser. Temporal correlation and spatial correlation of light are both utilized to obtain the range image of target. Through theory analysis and numerical simulations, it is demonstrated that HGI can obtain high range resolution image with low sampling rate.

  5. Combinatorial 3D Mechanical Metamaterials

    NASA Astrophysics Data System (ADS)

    Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin

    2015-03-01

    We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.

  6. Breast cancer metastasis suppressor 1 (BRMS1) suppresses attachment and spreading of breast cancer cells on 2D and 3D extracellular matrix components by altering focal adhesion-associated signaling

    USDA-ARS?s Scientific Manuscript database

    Metastatic dissemination of cancer cells from primary tumor to secondary sites is a multi-step process that depends heavily on the ability of cancer cells to respond to the microenvironmental cues, such as changes in composition of surrounding extracellular matrix (ECM), by adapting their adhesion a...

  7. 3D Electromagnetic inversion using conjugate gradients

    SciTech Connect

    Newman, G.A.; Alumbaugh, D.L.

    1997-06-01

    In large scale 3D EM inverse problems it may not be possible to directly invert a full least-squares system matrix involving model sensitivity elements. Thus iterative methods must be employed. For the inverse problem, we favor either a linear or non-linear (NL) CG scheme, depending on the application. In a NL CG scheme, the gradient of the objective function is required at each relaxation step along with a univariate line search needed to determine the optimum model update. Solution examples based on both approaches will be presented.

  8. LASTRAC.3d: Transition Prediction in 3D Boundary Layers

    NASA Technical Reports Server (NTRS)

    Chang, Chau-Lyan

    2004-01-01

    Langley Stability and Transition Analysis Code (LASTRAC) is a general-purpose, physics-based transition prediction code released by NASA for laminar flow control studies and transition research. This paper describes the LASTRAC extension to general three-dimensional (3D) boundary layers such as finite swept wings, cones, or bodies at an angle of attack. The stability problem is formulated by using a body-fitted nonorthogonal curvilinear coordinate system constructed on the body surface. The nonorthogonal coordinate system offers a variety of marching paths and spanwise waveforms. In the extreme case of an infinite swept wing boundary layer, marching with a nonorthogonal coordinate produces identical solutions to those obtained with an orthogonal coordinate system using the earlier release of LASTRAC. Several methods to formulate the 3D parabolized stability equations (PSE) are discussed. A surface-marching procedure akin to that for 3D boundary layer equations may be used to solve the 3D parabolized disturbance equations. On the other hand, the local line-marching PSE method, formulated as an easy extension from its 2D counterpart and capable of handling the spanwise mean flow and disturbance variation, offers an alternative. A linear stability theory or parabolized stability equations based N-factor analysis carried out along the streamline direction with a fixed wavelength and downstream-varying spanwise direction constitutes an efficient engineering approach to study instability wave evolution in a 3D boundary layer. The surface-marching PSE method enables a consistent treatment of the disturbance evolution along both streamwise and spanwise directions but requires more stringent initial conditions. Both PSE methods and the traditional LST approach are implemented in the LASTRAC.3d code. Several test cases for tapered or finite swept wings and cones at an angle of attack are discussed.

  9. 3-D threat image projection

    NASA Astrophysics Data System (ADS)

    Yildiz, Yesna O.; Abraham, Douglas Q.; Agaian, Sos; Panetta, Karen

    2008-02-01

    Automated Explosive Detection Systems utilizing Computed Tomography perform a series X-ray scans of passenger bags being checked in at the airport, and produce various 2-D projection images and 3-D volumetric images of the bag. The determination as to whether the passenger bag contains an explosive and needs to be searched manually is performed through trained Transportation Security Administration screeners following an approved protocol. In order to keep the screeners vigilant with regards to screening quality, the Transportation Security Administration has mandated the use of Threat Image Projection on 2-D projection X-ray screening equipment used at all US airports. These algorithms insert visual artificial threats into images of the normal passenger bags in order to test the screeners with regards to their screening efficiency and their screening quality at determining threats. This technology for 2-D X-ray system is proven and is widespread amongst multiple manufacturers of X-ray projection systems. Until now, Threat Image Projection has been unsuccessful at being introduced into 3-D Automated Explosive Detection Systems for numerous reasons. The failure of these prior attempts are mainly due to imaging queues that the screeners pickup on, and therefore make it easy for the screeners to discern the presence of the threat image and thus defeating the intended purpose. This paper presents a novel approach for 3-D Threat Image Projection for 3-D Automated Explosive Detection Systems. The method presented here is a projection based approach where both the threat object and the bag remain in projection sinogram space. Novel approaches have been developed for projection based object segmentation, projection based streak reduction used for threat object isolation along with scan orientation independence and projection based streak generation for an overall realistic 3-D image. The algorithms are prototyped in MatLab and C++ and demonstrate non discernible 3-D threat

  10. From 3D view to 3D print

    NASA Astrophysics Data System (ADS)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  11. Thermal effusivity measurement based on analysis of 3D heat flow by modulated spot heating using a phase lag matrix with a combination of thermal effusivity and volumetric heat capacity

    NASA Astrophysics Data System (ADS)

    Ohta, Hiromichi; Hatori, Kimihito; Matsui, Genzou; Yagi, Takashi; Miyake, Shugo; Okamura, Takeo; Endoh, Ryo; Okada, Ryo; Morishita, Keisuke; Yokoyama, Shinichiro; Taguchi, Kohei; Kato, Hideyuki

    2016-11-01

    The study goal was to establish a standard industrial procedure for the measurement of thermal effusivity by a thermal microscope (TM), using a periodic heating method with a thermoreflectance (TR) technique. To accomplish this goal, a working group was organized that included four research institutes. Each institute followed the same procedure: a molybdenum (Mo) film was sputtered on the surface of Pyrex, yttria-stabilized zirconia (YSZ), alumina (Al2O3), Germanium (Ge), and silicon (Si) samples, and then the phase lag of the laser intensity modulation was measured by the resultant surface temperature. A procedure was proposed to calibrate the effect of 3D heat flow, based on the analytical solution of the heat conduction equation, and thermal effusivity was measured. The derived values show good agreement with literature values. As a result, the TM calibration procedure can be recommended for practical use in measuring the thermal effusivity in a small region of the materials.

  12. Fibrin-mediated integrin signaling plays a critical role in hepatic regeneration after partial hepatectomy in mice

    PubMed Central

    Beier, Juliane I.; Guo, Luping; Joshi-Barve, Swati; Ritzenthaler, Jeffrey D.; Roman, Jesse; Arteel, Gavin E.

    2016-01-01

    Background The regenerative capacity of the liver is critical for proper responses to injury. Fibrin extracellular matrix (ECM) deposition is a common response to insult and contributes to inflammatory liver injury. However, the role of this matrix in hepatic regeneration has not been determined. Objective The purpose of this study was first to determine the role of fibrin ECM in hepatic regeneration followed by the role of the fibrin-binding αvβ3 integrin in mediating this effect. Material and methods C57BI/6J (WT) or PAI-1 knockout (KO) mice underwent 70% partial hepatectomy (PHx); plasma and histologic indices of regeneration were determined, as well as expression of key genes involved in hepatic regeneration. Results PHx promoted transient fibrin deposition by activating coagulation and concomitantly decreasing fibrinolysis. Inhibiting fibrin deposition, either by blocking thrombin (hirudin) in WT mice or by knocking out PAI-1, was associated with a decrease in hepatocyte proliferation after PHx. This strongly suggested a role for fibrin ECM in liver regeneration. To investigate if αvβ3 integrin mediates this action, we tested the effects of the anti-αvβ3 cyclic peptide RGDfV in animals after PHx. As was observed with inhibition of fibrin deposition, competitive inhibition of αvβ3 integrin delayed regeneration after PHx, while not affecting fibrin deposition. These effects of RGDfV correlated with impaired angiogenesis and STAT3 signaling, as well as transient endothelial dysfunction. In conclusion, these data suggest that αvβ3 integrin plays an important role in coordinating hepatocyte division during liver regeneration after PHx via crosstalk with fibrin ECM. PMID:27493116

  13. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

    NASA Astrophysics Data System (ADS)

    Schild, Jonas; Seele, Sven; Masuch, Maic

    2012-03-01

    Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

  14. Generation of strip-format fibrin-based engineered heart tissue (EHT).

    PubMed

    Schaaf, Sebastian; Eder, Alexandra; Vollert, Ingra; Stöhr, Andrea; Hansen, Arne; Eschenhagen, Thomas

    2014-01-01

    This protocol describes a method for casting fibrin-based engineered heart tissue (EHT) in standard 24-well culture dishes. In principle, a hydrogel tissue engineering method requires cardiomyocytes, a liquid matrix that forms a gel, a casting mold, and a device that keeps the developing tissue in place. This protocol refers to neonatal rat heart cells as the cell source; the matrix of choice is fibrin, and the tissues are generated in rectangular agarose-casting molds (12 × 3 × 3 mm) prepared in standard 24-well cell culture dishes, in which a pair of flexible silicone posts is suspended from above. A master mix of freshly isolated cells, medium, fibrinogen, and thrombin is pipetted into the casting mold and, over a period of 2 h, polymerizes and forms a fibrin cell block around two silicone posts. Silicone racks holding four pairs of silicone posts each are used to transfer the fresh fibrin cell blocks into new 24-well dishes with culture medium. Without further handling, the cells start to remodel the fibrin gel, form contacts with each other, elongate, and condense the gel to approximately ¼ of the initial volume. Spontaneous and rhythmic contractions start after 1 week. EHTs are viable and relatively stable for several weeks in this format and can be subjected to repeated measurements of contractile function and final morphological and molecular analyses.

  15. Speaking Volumes About 3-D

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In 1999, Genex submitted a proposal to Stennis Space Center for a volumetric 3-D display technique that would provide multiple users with a 360-degree perspective to simultaneously view and analyze 3-D data. The futuristic capabilities of the VolumeViewer(R) have offered tremendous benefits to commercial users in the fields of medicine and surgery, air traffic control, pilot training and education, computer-aided design/computer-aided manufacturing, and military/battlefield management. The technology has also helped NASA to better analyze and assess the various data collected by its satellite and spacecraft sensors. Genex capitalized on its success with Stennis by introducing two separate products to the commercial market that incorporate key elements of the 3-D display technology designed under an SBIR contract. The company Rainbow 3D(R) imaging camera is a novel, three-dimensional surface profile measurement system that can obtain a full-frame 3-D image in less than 1 second. The third product is the 360-degree OmniEye(R) video system. Ideal for intrusion detection, surveillance, and situation management, this unique camera system offers a continuous, panoramic view of a scene in real time.

  16. 3D Printed Bionic Nanodevices.

    PubMed

    Kong, Yong Lin; Gupta, Maneesh K; Johnson, Blake N; McAlpine, Michael C

    2016-06-01

    The ability to three-dimensionally interweave biological and functional materials could enable the creation of bionic devices possessing unique and compelling geometries, properties, and functionalities. Indeed, interfacing high performance active devices with biology could impact a variety of fields, including regenerative bioelectronic medicines, smart prosthetics, medical robotics, and human-machine interfaces. Biology, from the molecular scale of DNA and proteins, to the macroscopic scale of tissues and organs, is three-dimensional, often soft and stretchable, and temperature sensitive. This renders most biological platforms incompatible with the fabrication and materials processing methods that have been developed and optimized for functional electronics, which are typically planar, rigid and brittle. A number of strategies have been developed to overcome these dichotomies. One particularly novel approach is the use of extrusion-based multi-material 3D printing, which is an additive manufacturing technology that offers a freeform fabrication strategy. This approach addresses the dichotomies presented above by (1) using 3D printing and imaging for customized, hierarchical, and interwoven device architectures; (2) employing nanotechnology as an enabling route for introducing high performance materials, with the potential for exhibiting properties not found in the bulk; and (3) 3D printing a range of soft and nanoscale materials to enable the integration of a diverse palette of high quality functional nanomaterials with biology. Further, 3D printing is a multi-scale platform, allowing for the incorporation of functional nanoscale inks, the printing of microscale features, and ultimately the creation of macroscale devices. This blending of 3D printing, novel nanomaterial properties, and 'living' platforms may enable next-generation bionic systems. In this review, we highlight this synergistic integration of the unique properties of nanomaterials with the

  17. 3D Printed Bionic Nanodevices

    PubMed Central

    Kong, Yong Lin; Gupta, Maneesh K.; Johnson, Blake N.; McAlpine, Michael C.

    2016-01-01

    Summary The ability to three-dimensionally interweave biological and functional materials could enable the creation of bionic devices possessing unique and compelling geometries, properties, and functionalities. Indeed, interfacing high performance active devices with biology could impact a variety of fields, including regenerative bioelectronic medicines, smart prosthetics, medical robotics, and human-machine interfaces. Biology, from the molecular scale of DNA and proteins, to the macroscopic scale of tissues and organs, is three-dimensional, often soft and stretchable, and temperature sensitive. This renders most biological platforms incompatible with the fabrication and materials processing methods that have been developed and optimized for functional electronics, which are typically planar, rigid and brittle. A number of strategies have been developed to overcome these dichotomies. One particularly novel approach is the use of extrusion-based multi-material 3D printing, which is an additive manufacturing technology that offers a freeform fabrication strategy. This approach addresses the dichotomies presented above by (1) using 3D printing and imaging for customized, hierarchical, and interwoven device architectures; (2) employing nanotechnology as an enabling route for introducing high performance materials, with the potential for exhibiting properties not found in the bulk; and (3) 3D printing a range of soft and nanoscale materials to enable the integration of a diverse palette of high quality functional nanomaterials with biology. Further, 3D printing is a multi-scale platform, allowing for the incorporation of functional nanoscale inks, the printing of microscale features, and ultimately the creation of macroscale devices. This blending of 3D printing, novel nanomaterial properties, and ‘living’ platforms may enable next-generation bionic systems. In this review, we highlight this synergistic integration of the unique properties of nanomaterials with

  18. 3D Computations and Experiments

    SciTech Connect

    Couch, R; Faux, D; Goto, D; Nikkel, D

    2004-04-05

    This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.

  19. Petal, terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at the lower area of this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. The metallic object at lower right is part of the lander's low-gain antenna. This image is part of a 3D 'monster

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  20. Petal, terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at the lower area of this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. The metallic object at lower right is part of the lander's low-gain antenna. This image is part of a 3D 'monster

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  1. Mesenchymal stem cells and myoblast differentiation under HGF and IGF-1 stimulation for 3D skeletal muscle tissue engineering.

    PubMed

    Witt, R; Weigand, A; Boos, A M; Cai, A; Dippold, D; Boccaccini, A R; Schubert, D W; Hardt, M; Lange, C; Arkudas, A; Horch, R E; Beier, J P

    2017-02-28

    Volumetric muscle loss caused by trauma or after tumour surgery exceeds the natural regeneration capacity of skeletal muscle. Hence, the future goal of tissue engineering (TE) is the replacement and repair of lost muscle tissue by newly generating skeletal muscle combining different cell sources, such as myoblasts and mesenchymal stem cells (MSCs), within a three-dimensional matrix. Latest research showed that seeding skeletal muscle cells on aligned constructs enhance the formation of myotubes as well as cell alignment and may provide a further step towards the clinical application of engineered skeletal muscle. In this study the myogenic differentiation potential of MSCs upon co-cultivation with myoblasts and under stimulation with hepatocyte growth factor (HGF) and insulin-like growth factor-1 (IGF-1) was evaluated. We further analysed the behaviour of MSC-myoblast co-cultures in different 3D matrices. Primary rat myoblasts and rat MSCs were mono- and co-cultivated for 2, 7 or 14 days. The effect of different concentrations of HGF and IGF-1 alone, as well as in combination, on myogenic differentiation was analysed using microscopy, multicolour flow cytometry and real-time PCR. Furthermore, the influence of different three-dimensional culture models, such as fibrin, fibrin-collagen-I gels and parallel aligned electrospun poly-ε-caprolacton collagen-I nanofibers, on myogenic differentiation was analysed. MSCs could be successfully differentiated into the myogenic lineage both in mono- and in co-cultures independent of HGF and IGF-1 stimulation by expressing desmin, myocyte enhancer factor 2, myosin heavy chain 2 and alpha-sarcomeric actinin. An increased expression of different myogenic key markers could be observed under HGF and IGF-1 stimulation. Even though, stimulation with HGF/IGF-1 does not seem essential for sufficient myogenic differentiation. Three-dimensional cultivation in fibrin-collagen-I gels induced higher levels of myogenic differentiation

  2. Optimization of acidic fibroblast growth factor (FGF-1) and its delivery through a modified degradable fibrin scaffold

    NASA Astrophysics Data System (ADS)

    Pandit, Abhay Smashikant

    The aim of this investigation was to develop a degradable fibrin wound dressing that can deliver an optimized dose of acidic fibroblast growth factor (FGF-1). This aim led to three distinct phases of study. In the first phase, a structurally modified fibrin degradable scaffold was developed and tested in a rabbit ear ulcer model. A significant increase in the angiogenic and fibroblastic response with a corresponding decrease in healing time was seen in the modified fibrin-treated ulcers as compared with untreated ulcers and ulcers treated with non-modified fibrin systems. In the second phase of the study, a biochemical factor, FGF-1, was added to this scaffold. An optimal dose of 8 mug of FGF-1 was determined to be required to initiate a desired wound-healing response in a rabbit ear ulcer model, based on an enhanced angiogenic and fibroblastic response and an increased epithelialization rate. The objective of the last phase was to investigate the efficacy of a modified scaffold as a vehicle for FGF-1. In vivo testing was conducted in a full-thickness defect model in a rabbit. Improvements were seen in the angiogenic and fibroblastic responses in the FGF-1/modified fibrin treatment group and, hence, FGF-1/modified fibrin was the preferred treatment. In conclusion, the modified fibrin/FGF-1 matrix served as a suitable vehicle for the growth factor, providing a desired healing response and a desirable release rate and, thus, was determined to be an effective scaffold.

  3. 3D Printing: Exploring Capabilities

    ERIC Educational Resources Information Center

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  4. Baghdad Sulcus in 3-D

    NASA Image and Video Library

    2010-02-23

    This anaglyph from images captured by NASA Cassini spacecraft shows a dramatic, 3-D view of one of the deep fractures nicknamed tiger stripes on Saturn moon Enceladus which are located near the moon south pole, spray jets of water ice.

  5. 3D Printing: Exploring Capabilities

    ERIC Educational Resources Information Center

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  6. Making Inexpensive 3-D Models

    ERIC Educational Resources Information Center

    Manos, Harry

    2016-01-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…

  7. Ganges Chasma in 3-D

    NASA Image and Video Library

    1999-06-25

    Ganges Chasma is part of the Valles Marineris trough system that stretches nearly 5,000 kilometers 3,000 miles across the western equatorial region of Mars. This stereo anaglyph is from NASA Mars Global Surveyor. 3D glasses are necessary.

  8. Opportunity Stretches Out 3-D

    NASA Image and Video Library

    2004-02-02

    This is a three-dimensional stereo anaglyph of an image taken by the front hazard-identification camera onboard NASA Mars Exploration Rover Opportunity, showing the rover arm in its extended position. 3D glasses are necessary to view this image.

  9. Making Inexpensive 3-D Models

    ERIC Educational Resources Information Center

    Manos, Harry

    2016-01-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…

  10. The World of 3-D.

    ERIC Educational Resources Information Center

    Mayshark, Robin K.

    1991-01-01

    Students explore three-dimensional properties by creating red and green wall decorations related to Christmas. Students examine why images seem to vibrate when red and green pieces are small and close together. Instructions to conduct the activity and construct 3-D glasses are given. (MDH)

  11. Rosetta Comet in 3-D

    NASA Image and Video Library

    2014-11-21

    A 3D image shows what it would look like to fly over the surface of comet 67P/Churyumov-Gerasimenko. The image was generated by data collected by ESA Philae spacecraft during the decent to the spacecraft initial touchdown on the comet Nov. 12, 2014.

  12. SNL3dFace

    SciTech Connect

    Russ, Trina; Koch, Mark; Koudelka, Melissa; Peters, Ralph; Little, Charles; Boehnen, Chris; Peters, Tanya

    2007-07-20

    This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial features of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.

  13. TACO3D. 3-D Finite Element Heat Transfer Code

    SciTech Connect

    Mason, W.E.

    1992-03-04

    TACO3D is a three-dimensional, finite-element program for heat transfer analysis. An extension of the two-dimensional TACO program, it can perform linear and nonlinear analyses and can be used to solve either transient or steady-state problems. The program accepts time-dependent or temperature-dependent material properties, and materials may be isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions and loadings are available including temperature, flux, convection, and radiation boundary conditions and internal heat generation. Additional specialized features treat enclosure radiation, bulk nodes, and master/slave internal surface conditions (e.g., contact resistance). Data input via a free-field format is provided. A user subprogram feature allows for any type of functional representation of any independent variable. A profile (bandwidth) minimization option is available. The code is limited to implicit time integration for transient solutions. TACO3D has no general mesh generation capability. Rows of evenly-spaced nodes and rows of sequential elements may be generated, but the program relies on separate mesh generators for complex zoning. TACO3D does not have the ability to calculate view factors internally. Graphical representation of data in the form of time history and spatial plots is provided through links to the POSTACO and GRAPE postprocessor codes.

  14. Feasibility of Bioprinting with a Modified Desktop 3D Printer.

    PubMed

    Goldstein, Todd A; Epstein, Casey J; Schwartz, John; Krush, Alex; Lagalante, Dan J; Mercadante, Kevin P; Zeltsman, David; Smith, Lee P; Grande, Daniel A

    2016-12-01

    Numerous studies have shown the capabilities of three-dimensional (3D) printing for use in the medical industry. At the time of this publication, basic home desktop 3D printer kits can cost as little as $300, whereas medical-specific 3D bioprinters can cost more than $300,000. The purpose of this study is to show how a commercially available desktop 3D printer could be modified to bioprint an engineered poly-l-lactic acid scaffold containing viable chondrocytes in a bioink. Our bioprinter was used to create a living 3D functional tissue-engineered cartilage scaffold. In this article, we detail the design, production, and calibration of this bioprinter. In addition, the bioprinted cells were tested for viability, proliferation, biochemistry, and gene expression; these tests showed that the cells survived the printing process, were able to continue dividing, and produce the extracellular matrix expected of chondrocytes.

  15. Color correction using 3D multi-view geometry

    NASA Astrophysics Data System (ADS)

    Shin, Dong-Won; Ho, Yo-Sung

    2015-01-01

    Recently, many 3D contents production tools using multi-view system has been introduced: e.g., depth estimation, 3D reconstruction and so forth. However, there is color mismatch problem in multiview system and it can cause big differences for the final result. In this paper we propose a color correction method using 3D multi-view geometry. The propose method finds correspondences between source and target viewpoint and calculates a translation matrix by using a polynomial regression technique. An experiment is performed in CIELab color space which is designed to approximate an human visual system and proposed method properly corrected the color compare to conventional methods. Moreover, we applied the proposed color correction method to 3D object reconstruction and we acquired a consistent 3D model in terms of color.

  16. Acute fibrinous and organising pneumonia.

    PubMed

    Gonçalves, João Rocha; Marques, Ricardo; Serra, Paula; Cardoso, Leila

    2017-09-07

    Acute fibrinous and organising pneumonia (AFOP) is a rare histological pattern of interstitial lung disease. The authors describe a 60-year-old woman admitted to the hospital for sustained fever, presenting with an alveolar opacity on chest X-ray, with the presumed diagnosis of community-acquired pneumonia and the onset of antibiotics. Since serological results suggested that Legionella pneumophila was the infectious agent, she was discharged on levofloxacin. A week later, she was again admitted with fever. CT scan showed opacities with crescentic morphology and a central ground-glass area suggestive of cryptogenic organising pneumonia. Microbiological, serological and autoimmunity tests were negative. She underwent surgical lung biopsy that revealed inflammatory infiltrate, macrophage desquamation, fibroblasts proliferation and fibrin deposition in the alveolar spaces, consistent with AFOP. She started corticotherapy with good response. Disease relapsed after prednisolone discontinuation, 10 months later. Currently, the patient is on prednisolone 5 mg/day without clinical and radiological recurrence. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  17. N-terminal H3/D3-acetylation for improved high-throughput peptide sequencing by matrix-assisted laser desorption/ionization mass spectrometry with a time-of-flight/time-of-flight analyzer.

    PubMed

    Noga, Marek J; Asperger, Arndt; Silberring, Jerzy

    2006-01-01

    A novel method for peptide sequencing by matrix-assisted laser desorption/ionization mass spectrometry with a time-of-flight/time-of-flight analyzer (MALDI-TOF/TOF) is presented. A stable isotope label introduced in the peptide N-terminus by derivatization, using a 1:1 mixture of acetic anhydride and deuterated acetic anhydride, allows for easy and unambiguous identification of ions belonging either to the N- or the C-terminal ion series in the product ion spectrum, making sequence assignment significantly simplified. The good performance of this technique was shown by successful sequencing of the contents of several peptide maps. A similar approach was recently applied to nanoelectrospray ionization (nanoESI) and nano-liquid chromatography/tandem mass spectrometry (LC/MS/MS). The MALDI-TOF/TOF technique allows for fast, direct sequencing of modified peptides in proteomics samples, and is complementary to the nanoESI and nanoLC/MS/MS approaches.

  18. Multizone Paper Platform for 3D Cell Cultures

    PubMed Central

    Derda, Ratmir; Hong, Estrella; Mwangi, Martin; Mammoto, Akiko; Ingber, Donald E.; Whitesides, George M.

    2011-01-01

    In vitro 3D culture is an important model for tissues in vivo. Cells in different locations of 3D tissues are physiologically different, because they are exposed to different concentrations of oxygen, nutrients, and signaling molecules, and to other environmental factors (temperature, mechanical stress, etc). The majority of high-throughput assays based on 3D cultures, however, can only detect the average behavior of cells in the whole 3D construct. Isolation of cells from specific regions of 3D cultures is possible, but relies on low-throughput techniques such as tissue sectioning and micromanipulation. Based on a procedure reported previously (“cells-in-gels-in-paper” or CiGiP), this paper describes a simple method for culture of arrays of thin planar sections of tissues, either alone or stacked to create more complex 3D tissue structures. This procedure starts with sheets of paper patterned with hydrophobic regions that form 96 hydrophilic zones. Serial spotting of cells suspended in extracellular matrix (ECM) gel onto the patterned paper creates an array of 200 micron-thick slabs of ECM gel (supported mechanically by cellulose fibers) containing cells. Stacking the sheets with zones aligned on top of one another assembles 96 3D multilayer constructs. De-stacking the layers of the 3D culture, by peeling apart the sheets of paper, “sections” all 96 cultures at once. It is, thus, simple to isolate 200-micron-thick cell-containing slabs from each 3D culture in the 96-zone array. Because the 3D cultures are assembled from multiple layers, the number of cells plated initially in each layer determines the spatial distribution of cells in the stacked 3D cultures. This capability made it possible to compare the growth of 3D tumor models of different spatial composition, and to examine the migration of cells in these structures. PMID:21573103

  19. Fibrin functionalization with synthetic adhesive ligands interacting with α6β1 integrin receptor enhance neurite outgrowth of embryonic stem cell-derived neural stem/progenitors.

    PubMed

    Silva, Joana; Bento, Ana R; Barros, Daniela; Laundos, Tiago L; Sousa, Susana R; Quelhas, Pedro; Sousa, Mónica M; Pêgo, Ana P; Amaral, Isabel F

    2017-09-01

    To enhance fibrin hydrogel affinity towards pluripotent stem cell-derived neural stem/progenitor cells (NSPCs) and its capacity to support NSPC migration and neurite extension, we explored the tethering of synthetic peptides engaging integrin α6β1, a cell receptor enriched in NSPCs. Six α6β1 integrin ligands were tested for their ability to support integrin α6β1-mediated adhesion of embryonic stem cell-derived NSPCs (ES-NSPs) and sustain ES-NSPC viability, migration, and neuronal differentiation. Due to their better performance, peptides T1, HYD1, and A5G81 were immobilized into fibrin and functionalized gels characterized in terms of peptide binding efficiency, structure and viscoelastic properties. Tethering of T1 or HYD1 successfully enhanced cell outgrowth from ES-NSPC neurospheres (up to 2.4-fold increase), which exhibited a biphasic response to peptide concentration. Inhibition assays evidenced the involvement of α6β1 and α3β1 integrins in mediating radial outgrowth on T1-/HYD1-functionalized gels. Fibrin functionalization also promoted neurite extension of single ES-NSPCs in fibrin, without affecting cell proliferation and neuronal differentiation. Finally, HYD1-functionalized gels were found to provide a permissive environment for axonal regeneration, leading up to a 2.0-fold increase in neurite extension from rat dorsal root ganglia explants as compared to unmodified fibrin, and to significant improved locomotor function after spinal cord injury (complete transection), along with a trend toward a higher area positive for growth associated protein 43 (marker for axonal growth cone formation). Our results suggest that conjugation of α6β1 integrin-binding motifs is of interest to increase the biofunctionality of hydrogels used in 3D platforms for ES-NSPC culture and potentially, in matrix-assisted ES-NSPC transplantation. Impact statement: The transplantation of NSPCs derived from pluripotent stem cells holds much promise for the treatment of

  20. Three-dimensional structure and cytokine distribution of platelet-rich fibrin

    PubMed Central

    Bai, Meng-Yi; Wang, Ching-Wei; Wang, Jyun-Yi; Lin, Ming-Fang; Chan, Wing P

    2017-01-01

    OBJECTIVES: Previous reports have revealed that several cytokines (including platelet-derived growth factor-BB, transforming growth factors-β1 and insulin-like growth factor-1) can enhance the rate of bone formation and synthesis of extracellular matrix in orthopaedics or periodontology. This study aimed to determine the concentration of cytokines within platelet-rich fibrin microstructures and investigate whether there are differences in the different portions of platelet-rich fibrin, which has implications for proper clinical use of platelet-rich fibrin gel. METHODS: Whole blood was obtained from six New Zealand rabbits (male, 7 to 39 weeks old, weight 2.7-4 kg); it was then centrifuged for preparation of platelet-rich fibrin gels and harvest of plasma. The resultant platelet-rich fibrin gels were used for cytokine determination, histological analyses and scanning electron microscopy. All plasmas obtained were subject to the same cytokine determination assays for the purpose of comparison. RESULTS: Cytokines platelet-derived growth factor-BB and transforming growth factor-β1 formed concentration gradients from high at the red blood cell end of the platelet-rich fibrin gel (p=1.88×10-5) to low at the plasma end (p=0.19). Insulin-like growth factor-1 concentrations were similar at the red blood cell and plasma ends. The porosities of the platelet-rich fibrin samples taken in sequence from the red blood cell end to the plasma end were 6.5% ± 4.9%, 24.8% ± 7.5%, 30.3% ± 8.5%, 41.4% ± 12.3%, and 40.3% ± 11.7%, respectively, showing a gradual decrease in the compactness of the platelet-rich fibrin network. CONCLUSION: Cytokine concentrations are positively associated with platelet-rich fibrin microstructure and portion in a rabbit model. As platelet-rich fibrin is the main entity currently used in regenerative medicine, assessing cytokine concentration and the most valuable portion of PRF gels is essential and recommended to all physicians. PMID:28273236

  1. Bio-printing of collagen and VEGF-releasing fibrin gel scaffolds for neural stem cell culture.

    PubMed

    Lee, Yeong-Bae; Polio, Samuel; Lee, Wonhye; Dai, Guohao; Menon, Lata; Carroll, Rona S; Yoo, Seung-Schik

    2010-06-01

    Time-released delivery of soluble growth factors (GFs) in engineered hydrogel tissue constructs promotes the migration and proliferation of embedded cells, which is an important factor for designing scaffolds that ultimately aim for neural tissue regeneration. We report a tissue engineering technique to print murine neural stem cells (C17.2), collagen hydrogel, and GF (vascular endothelial growth factor: VEGF)-releasing fibrin gel to construct an artificial neural tissue. We examined the morphological changes of the printed C17.2 cells embedded in the collagen and its migration toward the fibrin gel. The cells showed high viability (92.89+/-2.32%) after printing, which was equivalent to that of manually-plated cells. C17.2 cells printed within 1mm from the border of VEGF-releasing fibrin gel showed GF-induced changes in their morphology. The cells printed in this range also migrated toward the fibrin gel, with the total migration distance of 102.4+/-76.1microm over 3days. The cells in the control samples (fibrin without the VEGF or VEGF printed directly in collagen) neither proliferated nor migrated. The results demonstrated that bio-printing of VEGF-containing fibrin gel supported sustained release of the GF in the collagen scaffold. The presented method can be gainfully used in the development of three-dimensional (3D) artificial tissue assays and neural tissue regeneration applications.

  2. Lytic and mechanical stability of clots composed of fibrin and blood vessel wall components.

    PubMed

    Rottenberger, Z; Komorowicz, E; Szabó, L; Bóta, A; Varga, Z; Machovich, R; Longstaff, C; Kolev, K

    2013-03-01

    Proteases expressed in atherosclerotic plaque lesions generate collagen fragments, release glycosaminoglycans (chondroitin sulfate [CS] and dermatan sulfate [DS]) and expose extracellular matrix (ECM) proteins (e.g. decorin) at sites of fibrin formation. Here we address the effect of these vessel wall components on the lysis of fibrin by the tissue plasminogen activator (tPA)/plasminogen system and on the mechanical stability of clots. MMP-8-digested collagen fragments, isolated CS, DS, glycosylated decorin and its core protein were used to prepare mixed matrices with fibrin (additives present at a 50-fold lower mass concentration than fibrinogen). Scanning electron microscopy (SEM) showed that the presence of ECM components resulted in a coarse fibrin structure, most pronounced for glycosylated decorin causing an increase in the median fiber diameter from 85 to 187 nm. Rheological measurements indicated that these structural alterations were coupled to decreased shear resistance (1.8-fold lower shear stress needed for gel/fluid transition of the clots containing glycosylated decorin) and rigidity (reduction of the storage modulus from 54.3 to 33.2 Pa). The lytic susceptibility of the modified fibrin structures was increased. The time to 50% lysis by plasmin was reduced approximately 2-fold for all investigated ECM components (apart from the core protein of decorin which produced a moderate reduction of the lysis time by 25%), whereas fibrin-dependent plasminogen activation by tPA was inhibited by up to 30%. ECM components compromise the chemical and mechanical stability of fibrin as a result of changes in its ultrastructure. © 2012 International Society on Thrombosis and Haemostasis.

  3. The effect of fibrin structure on fibrinolysis.

    PubMed

    Gabriel, D A; Muga, K; Boothroyd, E M

    1992-12-05

    Fibrin structure contributes to the regulation of the fibrinolytic rate. As the fibrin fiber size is decreased, the fibrinolytic rate also decreases. Fibrin structure was altered by either changing the ratio of thrombin to fibrinogen, i.e. altering the assembly rate or by adding a fibrin assembly inhibitor, iopamidol. Changes in the fibrinolytic rate were followed by measuring the time dependence of the decrease in the fiber mass/length ratio during fibrinolysis. A measure of the overall fibrinolytic rate was determined from the decrease in the mass/length ratio versus time. An 8-fold reduction in the fibrinolytic rate was seen on decreasing the mass/length ratio from 2.7 x 10(12) daltons/cm to 0.5 x 10(12) daltons/cm. It is shown that thin fibrin fibers have a decreased rate of conversion of plasminogen to plasmin by tissue plasminogen activator and that thin fibrin fibers are lysed more slowly than thick fibrin fibers.

  4. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part II: platelet-related biologic features.

    PubMed

    Dohan, David M; Choukroun, Joseph; Diss, Antoine; Dohan, Steve L; Dohan, Anthony J J; Mouhyi, Jaafar; Gogly, Bruno

    2006-03-01

    Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates, with simplified processing and without biochemical blood handling. In this second article, we investigate the platelet-associated features of this biomaterial. During PRF processing by centrifugation, platelets are activated and their massive degranulation implies a very significant cytokine release. Concentrated platelet-rich plasma platelet cytokines have already been quantified in many technologic configurations. To carry out a comparative study, we therefore undertook to quantify PDGF-BB, TGFbeta-1, and IGF-I within PPP (platelet-poor plasma) supernatant and PRF clot exudate serum. These initial analyses revealed that slow fibrin polymerization during PRF processing leads to the intrinsic incorporation of platelet cytokines and glycanic chains in the fibrin meshes. This result would imply that PRF, unlike the other platelet concentrates, would be able to progressively release cytokines during fibrin matrix remodeling; such a mechanism might explain the clinically observed healing properties of PRF.

  5. Forensic 3D scene reconstruction

    NASA Astrophysics Data System (ADS)

    Little, Charles Q.; Small, Daniel E.; Peters, Ralph R.; Rigdon, J. B.

    2000-05-01

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a fieldable prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  6. 3D Printed Robotic Hand

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  7. Forensic 3D Scene Reconstruction

    SciTech Connect

    LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

    1999-10-12

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  8. 3-D sprag ratcheting tool

    NASA Technical Reports Server (NTRS)

    Wade, Michael O. (Inventor); Poland, Jr., James W. (Inventor)

    2003-01-01

    A ratcheting device comprising a driver head assembly which includes at least two 3-D sprag elements positioned within a first groove within the driver head assembly such that at least one of the 3-D sprag elements may lockingly engage the driver head assembly and a mating hub assembly to allow for rotation of the hub assembly in one direction with respect to the driver head assembly. This arrangement allows the ratcheting tool to impart torque in either the clockwise or counterclockwise direction without having to first rotate the ratcheting tool in the direction opposite the direction in which the torque is applied. This arrangement also allows the ratcheting tool to impart torque in either the clockwise or counterclockwise direction while in the neutral position.

  9. Comparing swimsuits in 3D.

    PubMed

    van Geer, Erik; Molenbroek, Johan; Schreven, Sander; deVoogd-Claessen, Lenneke; Toussaint, Huib

    2012-01-01

    In competitive swimming, suits have become more important. These suits influence friction, pressure and wave drag. Friction drag is related to the surface properties whereas both pressure and wave drag are greatly influenced by body shape. To find a relationship between the body shape and the drag, the anthropometry of several world class female swimmers wearing different suits was accurately defined using a 3D scanner and traditional measuring methods. The 3D scans delivered more detailed information about the body shape. On the same day the swimmers did performance tests in the water with the tested suits. Afterwards the result of the performance tests and the differences found in body shape was analyzed to determine the deformation caused by a swimsuit and its effect on the swimming performance. Although the amount of data is limited because of the few test subjects, there is an indication that the deformation of the body influences the swimming performance.

  10. 3D-graphite structure

    SciTech Connect

    Belenkov, E. A. Ali-Pasha, V. A.

    2011-01-15

    The structure of clusters of some new carbon 3D-graphite phases have been calculated using the molecular-mechanics methods. It is established that 3D-graphite polytypes {alpha}{sub 1,1}, {alpha}{sub 1,3}, {alpha}{sub 1,5}, {alpha}{sub 2,1}, {alpha}{sub 2,3}, {alpha}{sub 3,1}, {beta}{sub 1,2}, {beta}{sub 1,4}, {beta}{sub 1,6}, {beta}{sub 2,1}, and {beta}{sub 3,2} consist of sp{sup 2}-hybridized atoms, have hexagonal unit cells, and differ in regards to the structure of layers and order of their alternation. A possible way to experimentally synthesize new carbon phases is proposed: the polymerization and carbonization of hydrocarbon molecules.

  11. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  12. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  13. GPU-Accelerated Denoising in 3D (GD3D)

    SciTech Connect

    2013-10-01

    The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer the second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.

  14. GPU-Accelerated Denoising in 3D (GD3D)

    SciTech Connect

    2013-10-01

    The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer the second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.

  15. The application of plastic compression to modulate fibrin hydrogel mechanical properties.

    PubMed

    Haugh, Matthew G; Thorpe, Stephen D; Vinardell, Tatiana; Buckley, Conor T; Kelly, Daniel J

    2012-12-01

    The inherent biocompatibility of fibrin hydrogels makes them an attractive material for use in a wide range of tissue engineering applications. Despite this, their relatively low stiffness and high compliance limits their potential for certain orthopaedic applications. Enhanced mechanical properties are desirable so as to withstand surgical handling and in vivo loading after implantation and additionally, can provide important cues to cells seeded within the hydrogel. Standard methods used to enhance the mechanical properties of biological scaffolds such as chemical or thermal crosslinking cannot be used with fibrin hydrogels as cell seeding and gel formation occurs simultaneously. The objective of this study was to investigate the use of plastic compression as a means to improve the mechanical properties of chondrocyte-seeded fibrin hydrogels and to determine the influence of such compression on cell viability within these constructs. It was found that the application of 80% strain to fibrin hydrogels for 30 min (which resulted in a permanent strain of 47.4%) produced a 2.1-fold increase in the subsequent compressive modulus. Additionally, chondrocyte viability was maintained in the plastically compressed gels with significant cellular proliferation and extracellular matrix accumulation observed over 28 days of culture. In conclusion, plastic compression can be used to modulate the density and mechanical properties of cell-seeded fibrin hydrogels and represents a useful tool for both in theatre and in vitro tissue engineering applications.

  16. A Synthetic Fibrin-Crosslinking Polymer for Modulating Clot Properties and Inducing Hemostasis

    PubMed Central

    Chan, Leslie W.-G.; Wang, Xu; Wei, Hua; Pozzo, Lilo D.; White, Nathan J.; Pun, Suzie H.

    2015-01-01

    Clotting factor replacement is the standard management of acute bleeding in congenital and acquired bleeding disorders. We present a synthetic approach to hemostasis using an engineered hemostatic polymer (PolySTAT) that circulates innocuously in the blood, identifies sites of vascular injury, and promotes clot formation to stop bleeding. PolySTAT induces hemostasis by crosslinking the fibrin matrix within clots, mimicking the function of the transglutaminase Factor XIII. Furthermore, synthetic PolySTAT binds specifically to fibrin monomers and is uniformly integrated into fibrin fibers during fibrin polymerization, resulting in a fortified, hybrid polymer network with enhanced resistance to enzymatic degradation. In vivo hemostatic activity was confirmed in a rat model of trauma and fluid resuscitation in which intravenous administration of PolySTAT improved survival by reducing blood loss and resuscitation fluid requirements. PolySTAT-induced fibrin crosslinking is a novel approach to hemostasis utilizing synthetic polymers for non-invasive modulation of clot architecture with potentially wide-ranging therapeutic applications. PMID:25739763

  17. Fibrin Association at Hybrid Biointerfaces Made of Clot-Binding Peptides and Polythiophene.

    PubMed

    Puiggalí-Jou, A; Del Valle, Luis J; Armelin, Elaine; Alemán, Carlos

    2016-10-01

    The properties as biointerfaces of electroactive conducting polymer-peptide biocomposites formed by poly(3,4-ethylenedioxythiophene) (PEDOT) and CREKA or CR(NMe)EKA peptide sequences (where Glu has been replaced by N-methyl-Glu in the latter) have been compared. CREKA is a linear pentapeptide that recognizes clotted plasma proteins and selectively homes to tumors, while CR(NMe)EKA is an engineer to improve such properties by altering peptide-fibrin interactions. Differences between PEDOT-CREKA and PEDOT-CR(NMe)EKA reflect dissemblance in the organization of the peptides into the polymeric matrix. Both peptides affect fibrinogen thrombin-catalyzed polymerization causing the immediate formation of fibrin, whereas in the absence of thrombin this phenomenon is only observed for CR(NMe)EKA. Consistently, the fibrin-adsorption capacity is higher for PEDOT-CR(NMe)EKA than for PEDOT-CREKA, even though in both cases adsorbed fibrin exhibits round-like morphologies rather than the characteristic fibrous structure. PEDOT-peptide films coated with fibrin are selective in terms of cell adhesion, promoting the attachment of metastatic cells with respect to normal cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Magmatic Systems in 3-D

    NASA Astrophysics Data System (ADS)

    Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.

    2002-12-01

    Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated

  19. In vitro vascularization of a combined system based on a 3D printing technique.

    PubMed

    Zhao, Xinru; Liu, Libiao; Wang, Jiayin; Xu, Yufan; Zhang, Weiming; Khang, Gilson; Wang, Xiaohong

    2016-10-01

    A vital challenge in complex organ manufacturing is to vascularize large combined tissues. The aim of this study is to vascularize in vitro an adipose-derived stem cell (ADSC)/fibrin/collagen incorporated three-dimensional (3D) poly(d,l-lactic-co-glycolic acid) (PLGA) scaffold (10 × 10 × 10 mm(3) ) with interconnected channels. A low-temperature 3D printing technique was employed to build the PLGA scaffold. A step-by-step cocktail procedure was designed to engage or steer the ADSCs in the PLGA channels towards both endothelial and smooth muscle cell lineages. The combined system had sufficient mechanical properties to support the cell/fibrin/collagen hydrogel inside the predefined PLGA channels. The ADSCs encapsulated in the fibrin/collagen hydrogel differentiated to endothelial and smooth muscle cell lineage, respectively, corresponding to their respective locations in the construct and formed vascular-like structures. This technique allows in vitro vascularization of the predefined PLGA channels and provides a choice for complex organ manufacture. Copyright © 2014 John Wiley & Sons, Ltd.

  20. Microbial metabolic exchange in 3D

    PubMed Central

    Watrous, Jeramie D; Phelan, Vanessa V; Hsu, Cheng-Chih; Moree, Wilna J; Duggan, Brendan M; Alexandrov, Theodore; Dorrestein, Pieter C

    2013-01-01

    Mono- and multispecies microbial populations alter the chemistry of their surrounding environments during colony development thereby influencing multicellular behavior and interspecies interactions of neighboring microbes. Here we present a methodology that enables the creation of three-dimensional (3D) models of a microbial chemotype that can be correlated to the colony phenotype through multimodal imaging analysis. These models are generated by performing matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) imaging mass spectrometry (IMS) on serial cross-sections of microbial colonies grown on 8 mm deep agar, registering data sets of each serial section in MATLAB to create a model, and then superimposing the model with a photograph of the colonies themselves. As proof-of-principle, 3D models were used to visualize metabolic exchange during microbial interactions between Bacillus subtilis and Streptomyces coelicolor, as well as, Candida albicans and Pseudomonas aeruginosa. The resulting models were able to capture the depth profile of secreted metabolites within the agar medium and revealed properties of certain mass signals that were previously not observable using two-dimensional MALDI-TOF IMS. Most significantly, the 3D models were capable of mapping previously unobserved chemical distributions within the array of sub-surface hyphae of C. albicans and how this chemistry is altered by the presence of P. aeruginosa, an opportunistic pathogen known to alter virulence of C. albicans. It was determined that the presence of C. albicans triggered increased rhamnolipid production by P. aeruginosa, which in turn was capable of inhibiting embedded hyphal growth produced beneath the C. albicans colony at ambient temperature. PMID:23283018

  1. Migration of keratinocytes through tunnels of digested fibrin

    NASA Astrophysics Data System (ADS)

    Ronfard, Vincent; Barrandon, Yann

    2001-04-01

    We report here a hitherto undescribed form of cell migration. When a suspension of human keratinocytes is plated on a fibrin matrix, single cells invade the matrix and progress through it as rounded cells by dissolving the fibrin and thereby creating tunnels. These tunnels are cylindrical or helical, the latter being the result of constant change in the path of cellular advance around the helical axis. Helical tunnel formation is strongly promoted by epidermal growth factor. The rate of migration of the cell through the track of a helical tunnel (up to 2.1 mm per day) is about 7-fold greater than through a cylindrical tunnel. Pericellular fibrinolysis leading to tunnel formation depends on the presence of plasminogen in the medium and its conversion to plasmin by a cellular activator. Formation of tunnels requires that plasminogen activator be localized on the advancing surface of the keratinocyte; we propose that the tunnel is cylindrical when the site of release of plasmin is located at a fixed point on the cell surface and helical when the site of release precesses.

  2. 3D Printing with Nucleic Acid Adhesives

    PubMed Central

    2015-01-01

    By relying on specific DNA:DNA interactions as a “smart glue”, we have assembled microparticles into a colloidal gel that can hold its shape. This gel can be extruded with a 3D printer to generate centimeter size objects. We show four aspects of this material: (1) The colloidal gel material holds its shape after extrusion. (2) The connectivity among the particles is controlled by the binding behavior between the surface DNA and this mediates some control over the microscale structure. (3) The use of DNA-coated microparticles dramatically reduces the cost of DNA-mediated assembly relative to conventional DNA nanotechnologies and makes this material accessible for macroscale applications. (4) This material can be assembled under biofriendly conditions and can host growing cells within its matrix. The DNA-based control over organization should provide a new means of engineering bioprinted tissues. PMID:25984570

  3. Hybrid 3D Printing of Soft Electronics.

    PubMed

    Valentine, Alexander D; Busbee, Travis A; Boley, John William; Raney, Jordan R; Chortos, Alex; Kotikian, Arda; Berrigan, John Daniel; Durstock, Michael F; Lewis, Jennifer A

    2017-09-06

    Hybrid 3D printing is a new method for producing soft electronics that combines direct ink writing of conductive and dielectric elastomeric materials with automated pick-and-place of surface mount electronic components within an integrated additive manufacturing platform. Using this approach, insulating matrix and conductive electrode inks are directly printed in specific layouts. Passive and active electrical components are then integrated to produce the desired electronic circuitry by using an empty nozzle (in vacuum-on mode) to pick up individual components, place them onto the substrate, and then deposit them (in vacuum-off mode) in the desired location. The components are then interconnected via printed conductive traces to yield soft electronic devices that may find potential application in wearable electronics, soft robotics, and biomedical devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Interactive 3D Mars Visualization

    NASA Technical Reports Server (NTRS)

    Powell, Mark W.

    2012-01-01

    The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.

  5. Evaluating scatterometry 3D capabilities for EUV

    NASA Astrophysics Data System (ADS)

    Li, Jie; Kritsun, Oleg; Dasari, Prasad; Volkman, Catherine; Wallow, Tom; Hu, Jiangtao

    2013-04-01

    Optical critical dimension (OCD) metrology using scatterometry has been demonstrated to be a viable solution for fast and non-destructive in-line process control and monitoring. As extreme ultraviolet lithography (EUVL) is more widely adopted to fabricate smaller and smaller patterns for electronic devices, scatterometry faces new challenges due to several reasons. For 14nm node and beyond, the feature size is nearly an order of magnitude smaller than the shortest wavelength used in scatterometry. In addition, thinner resist layer is used in EUVL compared with conventional lithography, which leads to reduced measurement sensitivity. Despite these difficulties, tolerance has reduced for smaller feature size. In this work we evaluate 3D capability of scatterometry for EUV process using spectroscopic ellipsometry (SE). Three types of structures, contact holes, tip-to-tip, and tip-to-edge, are studied to test CD and end-gap metrology capabilities. The wafer is processed with focus and exposure matrix. Good correlations to CD-SEM results are achieved and good dynamic precision is obtained for all the key parameters. In addition, the fit to process provides an independent method to evaluate data quality from different metrology tools such as OCD and CDSEM. We demonstrate 3D capabilities of scatterometry OCD metrology for EUVL using spectroscopic ellipsometry, which provides valuable in-line metrology for CD and end-gap control in electronic circuit fabrications.

  6. Structural hierarchy governs fibrin gel mechanics.

    PubMed

    Piechocka, Izabela K; Bacabac, Rommel G; Potters, Max; Mackintosh, Fred C; Koenderink, Gijsje H

    2010-05-19

    Fibrin gels are responsible for the mechanical strength of blood clots, which are among the most resilient protein materials in nature. Here we investigate the physical origin of this mechanical behavior by performing rheology measurements on reconstituted fibrin gels. We find that increasing levels of shear strain induce a succession of distinct elastic responses that reflect stretching processes on different length scales. We present a theoretical model that explains these observations in terms of the unique hierarchical architecture of the fibers. The fibers are bundles of semiflexible protofibrils that are loosely connected by flexible linker chains. This architecture makes the fibers 100-fold more flexible to bending than anticipated based on their large diameter. Moreover, in contrast with other biopolymers, fibrin fibers intrinsically stiffen when stretched. The resulting hierarchy of elastic regimes explains the incredible resilience of fibrin clots against large deformations.

  7. Structural Hierarchy Governs Fibrin Gel Mechanics

    PubMed Central

    Piechocka, Izabela K.; Bacabac, Rommel G.; Potters, Max; MacKintosh, Fred C.; Koenderink, Gijsje H.

    2010-01-01

    Abstract Fibrin gels are responsible for the mechanical strength of blood clots, which are among the most resilient protein materials in nature. Here we investigate the physical origin of this mechanical behavior by performing rheology measurements on reconstituted fibrin gels. We find that increasing levels of shear strain induce a succession of distinct elastic responses that reflect stretching processes on different length scales. We present a theoretical model that explains these observations in terms of the unique hierarchical architecture of the fibers. The fibers are bundles of semiflexible protofibrils that are loosely connected by flexible linker chains. This architecture makes the fibers 100-fold more flexible to bending than anticipated based on their large diameter. Moreover, in contrast with other biopolymers, fibrin fibers intrinsically stiffen when stretched. The resulting hierarchy of elastic regimes explains the incredible resilience of fibrin clots against large deformations. PMID:20483337

  8. A Clean Adirondack (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This is a 3-D anaglyph showing a microscopic image taken of an area measuring 3 centimeters (1.2 inches) across on the rock called Adirondack. The image was taken at Gusev Crater on the 33rd day of the Mars Exploration Rover Spirit's journey (Feb. 5, 2004), after the rover used its rock abrasion tool brush to clean the surface of the rock. Dust, which was pushed off to the side during cleaning, can still be seen to the left and in low areas of the rock.

  9. A Clean Adirondack (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This is a 3-D anaglyph showing a microscopic image taken of an area measuring 3 centimeters (1.2 inches) across on the rock called Adirondack. The image was taken at Gusev Crater on the 33rd day of the Mars Exploration Rover Spirit's journey (Feb. 5, 2004), after the rover used its rock abrasion tool brush to clean the surface of the rock. Dust, which was pushed off to the side during cleaning, can still be seen to the left and in low areas of the rock.

  10. Making Inexpensive 3-D Models

    NASA Astrophysics Data System (ADS)

    Manos, Harry

    2016-03-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.

  11. What Lies Ahead (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D cylindrical-perspective mosaic taken by the navigation camera on the Mars Exploration Rover Spirit on sol 82 shows the view south of the large crater dubbed 'Bonneville.' The rover will travel toward the Columbia Hills, seen here at the upper left. The rock dubbed 'Mazatzal' and the hole the rover drilled in to it can be seen at the lower left. The rover's position is referred to as 'Site 22, Position 32.' This image was geometrically corrected to make the horizon appear flat.

  12. What Lies Ahead (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D cylindrical-perspective mosaic taken by the navigation camera on the Mars Exploration Rover Spirit on sol 82 shows the view south of the large crater dubbed 'Bonneville.' The rover will travel toward the Columbia Hills, seen here at the upper left. The rock dubbed 'Mazatzal' and the hole the rover drilled in to it can be seen at the lower left. The rover's position is referred to as 'Site 22, Position 32.' This image was geometrically corrected to make the horizon appear flat.

  13. 3D Printed Shelby Cobra

    SciTech Connect

    Love, Lonnie

    2015-01-09

    ORNL's newly printed 3D Shelby Cobra was showcased at the 2015 NAIAS in Detroit. This "laboratory on wheels" uses the Shelby Cobra design, celebrating the 50th anniversary of this model and honoring the first vehicle to be voted a national monument. The Shelby was printed at the Department of Energy’s Manufacturing Demonstration Facility at ORNL using the BAAM (Big Area Additive Manufacturing) machine and is intended as a “plug-n-play” laboratory on wheels. The Shelby will allow research and development of integrated components to be tested and enhanced in real time, improving the use of sustainable, digital manufacturing solutions in the automotive industry.

  14. Positional Awareness Map 3D (PAM3D)

    NASA Technical Reports Server (NTRS)

    Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise

    2012-01-01

    The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.

  15. 3D print of polymer bonded rare-earth magnets, and 3D magnetic field scanning with an end-user 3D printer

    NASA Astrophysics Data System (ADS)

    Huber, C.; Abert, C.; Bruckner, F.; Groenefeld, M.; Muthsam, O.; Schuschnigg, S.; Sirak, K.; Thanhoffer, R.; Teliban, I.; Vogler, C.; Windl, R.; Suess, D.

    2016-10-01

    3D print is a recently developed technique, for single-unit production, and for structures that have been impossible to build previously. The current work presents a method to 3D print polymer bonded isotropic hard magnets with a low-cost, end-user 3D printer. Commercially available isotropic NdFeB powder inside a PA11 matrix is characterized, and prepared for the printing process. An example of a printed magnet with a complex shape that was designed to generate a specific stray field is presented, and compared with finite element simulation solving the macroscopic Maxwell equations. For magnetic characterization, and comparing 3D printed structures with injection molded parts, hysteresis measurements are performed. To measure the stray field outside the magnet, the printer is upgraded to a 3D magnetic flux density measurement system. To skip an elaborate adjusting of the sensor, a simulation is used to calibrate the angles, sensitivity, and the offset of the sensor. With this setup, a measurement resolution of 0.05 mm along the z-axes is achievable. The effectiveness of our calibration method is shown. With our setup, we are able to print polymer bonded magnetic systems with the freedom of having a specific complex shape with locally tailored magnetic properties. The 3D scanning setup is easy to mount, and with our calibration method we are able to get accurate measuring results of the stray field.

  16. 3D Printable Graphene Composite

    PubMed Central

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-01-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C−1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process. PMID:26153673

  17. 3D Printable Graphene Composite

    NASA Astrophysics Data System (ADS)

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-07-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C-1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.

  18. 3D medical thermography device

    NASA Astrophysics Data System (ADS)

    Moghadam, Peyman

    2015-05-01

    In this paper, a novel handheld 3D medical thermography system is introduced. The proposed system consists of a thermal-infrared camera, a color camera and a depth camera rigidly attached in close proximity and mounted on an ergonomic handle. As a practitioner holding the device smoothly moves it around the human body parts, the proposed system generates and builds up a precise 3D thermogram model by incorporating information from each new measurement in real-time. The data is acquired in motion, thus it provides multiple points of view. When processed, these multiple points of view are adaptively combined by taking into account the reliability of each individual measurement which can vary due to a variety of factors such as angle of incidence, distance between the device and the subject and environmental sensor data or other factors influencing a confidence of the thermal-infrared data when captured. Finally, several case studies are presented to support the usability and performance of the proposed system.

  19. 3D acoustic atmospheric tomography

    NASA Astrophysics Data System (ADS)

    Rogers, Kevin; Finn, Anthony

    2014-10-01

    This paper presents a method for tomographically reconstructing spatially varying 3D atmospheric temperature profiles and wind velocity fields based. Measurements of the acoustic signature measured onboard a small Unmanned Aerial Vehicle (UAV) are compared to ground-based observations of the same signals. The frequency-shifted signal variations are then used to estimate the acoustic propagation delay between the UAV and the ground microphones, which are also affected by atmospheric temperature and wind speed vectors along each sound ray path. The wind and temperature profiles are modelled as the weighted sum of Radial Basis Functions (RBFs), which also allow local meteorological measurements made at the UAV and ground receivers to supplement any acoustic observations. Tomography is used to provide a full 3D reconstruction/visualisation of the observed atmosphere. The technique offers observational mobility under direct user control and the capacity to monitor hazardous atmospheric environments, otherwise not justifiable on the basis of cost or risk. This paper summarises the tomographic technique and reports on the results of simulations and initial field trials. The technique has practical applications for atmospheric research, sound propagation studies, boundary layer meteorology, air pollution measurements, analysis of wind shear, and wind farm surveys.

  20. 3D structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Dougherty, William M.; Goodwin, Paul C.

    2011-03-01

    Three-dimensional structured illumination microscopy achieves double the lateral and axial resolution of wide-field microscopy, using conventional fluorescent dyes, proteins and sample preparation techniques. A three-dimensional interference-fringe pattern excites the fluorescence, filling in the "missing cone" of the wide field optical transfer function, thereby enabling axial (z) discrimination. The pattern acts as a spatial carrier frequency that mixes with the higher spatial frequency components of the image, which usually succumb to the diffraction limit. The fluorescence image encodes the high frequency content as a down-mixed, moiré-like pattern. A series of images is required, wherein the 3D pattern is shifted and rotated, providing down-mixed data for a system of linear equations. Super-resolution is obtained by solving these equations. The speed with which the image series can be obtained can be a problem for the microscopy of living cells. Challenges include pattern-switching speeds, optical efficiency, wavefront quality and fringe contrast, fringe pitch optimization, and polarization issues. We will review some recent developments in 3D-SIM hardware with the goal of super-resolved z-stacks of motile cells.

  1. Martian terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at lower left in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  2. Martian terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at the lower area of this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  3. Martian terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at lower left in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  4. Martian terrain & airbags - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Portions of the lander's deflated airbags and a petal are at the lower area of this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  5. Salmon fibrin glue in rats: antibody studies.

    PubMed

    Laidmäe, Ivo; Belozjorova, Jevgenia; Sawyer, Evelyn S; Janmey, Paul A; Uibo, Raivo

    2012-01-01

    Fibrin sealants and topical thrombin preparations are often used for haemostatic and sealing applications in clinical practice. Some of these preparations contain coagulation factors from bovine sources. To minimize the risk of infection and immunogenicity connected with mammalian blood products, proteins derived from the plasma of farmed Atlantic salmon have been considered as an alternative to these mammalian sources. The purpose of this study is to characterize the immunogenicity of salmon fibrin glue in an animal model focusing on crossreactivity of IgG antibodies to host endogenous counterparts. After two immunizations with salmon fibrin glue, rats developed antibodies of IgG and IgM type to both fibrin glue components. Weak crossreactivity to endogenous fibrinogen and thrombin was seen in a subset of rats after the second application of salmon proteins. Coagulation tests showed that salmon fibrin application has no effect on coagulation profiles in mammalian hosts, consistent with previous reports that found no evidence of significant crossreactivity with host proteins. These studies support the potential suitability of salmon fibrin glue for the development of preparations with clinical impact. Before human use can be considered, however, additional data about safety of this preparation in other animal models, including large animal studies, should be obtained.

  6. LOTT RANCH 3D PROJECT

    SciTech Connect

    Larry Lawrence; Bruce Miller

    2004-09-01

    The Lott Ranch 3D seismic prospect located in Garza County, Texas is a project initiated in September of 1991 by the J.M. Huber Corp., a petroleum exploration and production company. By today's standards the 126 square mile project does not seem monumental, however at the time it was conceived it was the most intensive land 3D project ever attempted. Acquisition began in September of 1991 utilizing GEO-SEISMIC, INC., a seismic data contractor. The field parameters were selected by J.M. Huber, and were of a radical design. The recording instruments used were GeoCor IV amplifiers designed by Geosystems Inc., which record the data in signed bit format. It would not have been practical, if not impossible, to have processed the entire raw volume with the tools available at that time. The end result was a dataset that was thought to have little utility due to difficulties in processing the field data. In 1997, Yates Energy Corp. located in Roswell, New Mexico, formed a partnership to further develop the project. Through discussions and meetings with Pinnacle Seismic, it was determined that the original Lott Ranch 3D volume could be vastly improved upon reprocessing. Pinnacle Seismic had shown the viability of improving field-summed signed bit data on smaller 2D and 3D projects. Yates contracted Pinnacle Seismic Ltd. to perform the reprocessing. This project was initiated with high resolution being a priority. Much of the potential resolution was lost through the initial summing of the field data. Modern computers that are now being utilized have tremendous speed and storage capacities that were cost prohibitive when this data was initially processed. Software updates and capabilities offer a variety of quality control and statics resolution, which are pertinent to the Lott Ranch project. The reprocessing effort was very successful. The resulting processed data-set was then interpreted using modern PC-based interpretation and mapping software. Production data, log data

  7. Generation of 3D Collagen Gels with Controlled Diverse Architectures.

    PubMed

    Doyle, Andrew D

    2016-09-01

    Rat tail collagen solutions have been used as polymerizable in vitro three dimensional (3D) extracellular matrix (ECM) gels for single and collective cell migration assays as well as spheroid formation. Factors such as ECM concentration, pH, ionic concentration, and temperature can alter collagen polymerization and ECM architecture. This unit describes how to generate 3D collagen gels that have distinct architectures ranging from a highly reticular meshwork of short thin fibrils with small pores to a loose matrix consisting of stiff, parallel-bundled long fibrils by changing collagen polymerization temperature. This permits analysis of 3D cell migration in different ECM architectures found in vivo while maintaining a similar ECM concentration. Also included are collagen labeling techniques helpful for ECM visualization during live fluorescence imaging. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

  8. Computerized 3-D reconstruction of complicated anatomical structure

    NASA Astrophysics Data System (ADS)

    Andreasen, Arne; Drewes, Asbjorn M.; Assentoft, Joergen E.

    1992-06-01

    In the study of the rabbit hippocampal region, images of 430 serial sections were aligned by a `parameter-shift' algorithm. The resulting 3-D matrix represents a fixed and stained but `whole' rabbit brain. From this virtual object the slice procedure, displacement, and re- alignment could be computer simulated and the artifacts associated with these procedures estimated.

  9. 3D printed quantum dot light-emitting diodes.

    PubMed

    Kong, Yong Lin; Tamargo, Ian A; Kim, Hyoungsoo; Johnson, Blake N; Gupta, Maneesh K; Koh, Tae-Wook; Chin, Huai-An; Steingart, Daniel A; Rand, Barry P; McAlpine, Michael C

    2014-12-10

    Developing the ability to 3D print various classes of materials possessing distinct properties could enable the freeform generation of active electronics in unique functional, interwoven architectures. Achieving seamless integration of diverse materials with 3D printing is a significant challenge that requires overcoming discrepancies in material properties in addition to ensuring that all the materials are compatible with the 3D printing process. To date, 3D printing has been limited to specific plastics, passive conductors, and a few biological materials. Here, we show that diverse classes of materials can be 3D printed and fully integrated into device components with active properties. Specifically, we demonstrate the seamless interweaving of five different materials, including (1) emissive semiconducting inorganic nanoparticles, (2) an elastomeric matrix, (3) organic polymers as charge transport layers, (4) solid and liquid metal leads, and (5) a UV-adhesive transparent substrate layer. As a proof of concept for demonstrating the integrated functionality of these materials, we 3D printed quantum dot-based light-emitting diodes (QD-LEDs) that exhibit pure and tunable color emission properties. By further incorporating the 3D scanning of surface topologies, we demonstrate the ability to conformally print devices onto curvilinear surfaces, such as contact lenses. Finally, we show that novel architectures that are not easily accessed using standard microfabrication techniques can be constructed, by 3D printing a 2 × 2 × 2 cube of encapsulated LEDs, in which every component of the cube and electronics are 3D printed. Overall, these results suggest that 3D printing is more versatile than has been demonstrated to date and is capable of integrating many distinct classes of materials.

  10. 3D Finite Element Analysis of Particle-Reinforced Aluminum

    NASA Technical Reports Server (NTRS)

    Shen, H.; Lissenden, C. J.

    2002-01-01

    Deformation in particle-reinforced aluminum has been simulated using three distinct types of finite element model: a three-dimensional repeating unit cell, a three-dimensional multi-particle model, and two-dimensional multi-particle models. The repeating unit cell model represents a fictitious periodic cubic array of particles. The 3D multi-particle (3D-MP) model represents randomly placed and oriented particles. The 2D generalized plane strain multi-particle models were obtained from planar sections through the 3D-MP model. These models were used to study the tensile macroscopic stress-strain response and the associated stress and strain distributions in an elastoplastic matrix. The results indicate that the 2D model having a particle area fraction equal to the particle representative volume fraction of the 3D models predicted the same macroscopic stress-strain response as the 3D models. However, there are fluctuations in the particle area fraction in a representative volume element. As expected, predictions from 2D models having different particle area fractions do not agree with predictions from 3D models. More importantly, it was found that the microscopic stress and strain distributions from the 2D models do not agree with those from the 3D-MP model. Specifically, the plastic strain distribution predicted by the 2D model is banded along lines inclined at 45 deg from the loading axis while the 3D model prediction is not. Additionally, the triaxial stress and maximum principal stress distributions predicted by 2D and 3D models do not agree. Thus, it appears necessary to use a multi-particle 3D model to accurately predict material responses that depend on local effects, such as strain-to-failure, fracture toughness, and fatigue life.

  11. Towards Single Cell Traction Microscopy within 3D Collagen Matrices

    PubMed Central

    Hall, Matthew S.; Long, Rong; Feng, Xinzeng; Huang, YuLing; Hui, Chung-Yuen; Wu, Mingming

    2013-01-01

    Mechanical interaction between the cell and its extracellular matrix (ECM) regulates cellular behaviors, including proliferation, differentiation, adhesion, and migration. Cells require the three dimensional (3D) architectural support of the ECM to perform physiologically realistic functions. However, current understanding of cell-ECM and cell-cell mechanical interactions is largely derived from 2D cell traction force microscopy, in which cells are cultured on a flat substrate. 3D cell traction microscopy is emerging for mapping traction fields of single animal cells embedded in either synthetic or natively derived fibrous gels. We discuss here the development of 3D cell traction microscopy, its current limitations, and perspectives on the future of this technology. Emphasis is placed on strategies for applying 3D cell traction microscopy to individual tumor cells migration within collagen gels. PMID:23806281

  12. Autonomous surgical robotics using 3-D ultrasound guidance: feasibility study.

    PubMed

    Whitman, John; Fronheiser, Matthew P; Ivancevich, Nikolas M; Smith, Stephen W

    2007-10-01

    The goal of this study was to test the feasibility of using a real-time 3D (RT3D) ultrasound scanner with a transthoracic matrix array transducer probe to guide an autonomous surgical robot. Employing a fiducial alignment mark on the transducer to orient the robot's frame of reference and using simple thresholding algorithms to segment the 3D images, we tested the accuracy of using the scanner to automatically direct a robot arm that touched two needle tips together within a water tank. RMS measurement error was 3.8% or 1.58 mm for an average path length of 41 mm. Using these same techniques, the autonomous robot also performed simulated needle biopsies of a cyst-like lesion in a tissue phantom. This feasibility study shows the potential for 3D ultrasound guidance of an autonomous surgical robot for simple interventional tasks, including lesion biopsy and foreign body removal.

  13. Toward single cell traction microscopy within 3D collagen matrices.

    PubMed

    Hall, Matthew S; Long, Rong; Feng, Xinzeng; Huang, Yuling; Hui, Chung-Yuen; Wu, Mingming

    2013-10-01

    Mechanical interaction between the cell and its extracellular matrix (ECM) regulates cellular behaviors, including proliferation, differentiation, adhesion, and migration. Cells require the three-dimensional (3D) architectural support of the ECM to perform physiologically realistic functions. However, current understanding of cell-ECM and cell-cell mechanical interactions is largely derived from 2D cell traction force microscopy, in which cells are cultured on a flat substrate. 3D cell traction microscopy is emerging for mapping traction fields of single animal cells embedded in either synthetic or natively derived fibrous gels. We discuss here the development of 3D cell traction microscopy, its current limitations, and perspectives on the future of this technology. Emphasis is placed on strategies for applying 3D cell traction microscopy to individual tumor cell migration within collagen gels. © 2013 Elsevier Inc. All rights reserved.

  14. Sustained (rh)VEGF(165) release from a sprayed fibrin biomatrix induces angiogenesis, up-regulation of endogenous VEGF-R2, and reduces ischemic flap necrosis.

    PubMed

    Mittermayr, Rainer; Morton, Tatjana; Hofmann, Martina; Helgerson, Sam; van Griensven, Martijn; Redl, Heinz

    2008-01-01

    This study investigated (1) the release of recombinant human vascular endothelial growth factor ([rh]VEGF(165)) from an in vitro fibrin matrix, (2) the effects of (rh)VEGF(165) released from an in vivo fibrin matrix on ischemic flap necrosis in the rat dorsal skin flap model, and (3) the effects of (rh)VEGF(165) released from an in vivo fibrin matrix on VEGF-R2 expression in transgenic VEGF-R2/luc mice. In vitro fibrin matrices were spiked with (rh)VEGF(165) and demonstrated (rh)VEGF(165) release over 88 hours with 66% recovery. Ischemic dorsal flaps were treated with a fibrin sealant (FS), FS spiked with (rh)VEGF(165), or left untreated. Flaps treated with FS spiked with (rh)VEGF(165) showed greater viability than controls as measured by planimetric analysis. Immunohistochemical analyses revealed stronger neovascularization than that exhibited by controls. Transgenic mice implanted with FS spiked with (rh)VEGF(165) had significant increases in VEGF-R2 expression relative to controls at days 5-13 after implantation. Conclusions drawn from this work are that (1) (rh)VEGF(165) is released from an in vitr