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Sample records for cell adhesion properties

  1. Adhesion defective BHK cell mutant has cell surface heparan sulfate proteoglycan of altered properties

    DEFF Research Database (Denmark)

    Couchman, J R; Austria, R; Woods, A; Hughes, R C

    1988-01-01

    In the light of accumulating data that implicate cell surface heparan sulfate proteoglycans (HSPGs) with a role in cell interactions with extracellular matrix molecules such as fibronectin, we have compared the properties of these molecules in wild-type BHK cells and an adhesion-defective ricin......-resistant mutant (RicR14). Our results showed that the mutant, unlike BHK cells, cannot form focal adhesions when adherent to planar substrates in the presence of serum. Furthermore, while both cell lines possess similar amounts of cell surface HSPG with hydrophobic properties, that of RicR14 cells had decreased...... sulfation, reduced affinity for fibronectin and decreased half-life on the cell surface when compared to the normal counterpart. Our conclusions based on this data are that these altered properties may, in part, account for the adhesion defect in the ricin-resistant mutant. Whether this results from the...

  2. Combinational Effect of Cell Adhesion Biomolecules and Their Immobilized Polymer Property to Enhance Cell-Selective Adhesion

    Directory of Open Access Journals (Sweden)

    Rio Kurimoto

    2016-01-01

    Full Text Available Although surface immobilization of medical devices with bioactive molecules is one of the most widely used strategies to improve biocompatibility, the physicochemical properties of the biomaterials significantly impact the activity of the immobilized molecules. Herein we investigate the combinational effects of cell-selective biomolecules and the hydrophobicity/hydrophilicity of the polymeric substrate on selective adhesion of endothelial cells (ECs, fibroblasts (FBs, and smooth muscle cells (SMCs. To control the polymeric substrate, biomolecules are immobilized on thermoresponsive poly(N-isopropylacrylamide-co-2-carboxyisopropylacrylamide (poly(NIPAAm-co-CIPAAm-grafted glass surfaces. By switching the molecular conformation of the biomolecule-immobilized polymers, the cell-selective adhesion performances are evaluated. In case of RGDS (Arg-Gly-Asp-Ser peptide-immobilized surfaces, all cell types adhere well regardless of the surface hydrophobicity. On the other hand, a tri-Arg-immobilized surface exhibits FB-selectivity when the surface is hydrophilic. Additionally, a tri-Ile-immobilized surface exhibits EC-selective cell adhesion when the surface is hydrophobic. We believe that the proposed concept, which is used to investigate the biomolecule-immobilized surface combination, is important to produce new biomaterials, which are highly demanded for medical implants and tissue engineering.

  3. Cell adhesion property affected by cyclooxygenase and lipoxygenase: Opto-electric approach.

    Science.gov (United States)

    Choi, Chang Kyoung; Sukhthankar, Mugdha; Kim, Chul-Ho; Lee, Seong-Ho; English, Anthony; Kihm, Kenneth D; Baek, Seung Joon

    2010-01-15

    Expression of cyclooxygenases (COX) and lipoxygenases (LOX) has been linked to many pathophysiological phenotypes, including cell adhesion. However, many current approaches to measure cellular changes are performed only in a fixed-time point. Since cells dynamically move in conjunction with the cell matrix, there is a pressing need for dynamic or time-dependent methods for the investigation of cell properties. In the presented study, we used stable human colorectal cancer cell lines ectopically expressing COX-1, COX-2, and 15LOX-1, to investigate whether expression of COX-1, COX-2, or 15LOX-1 would affect cell adhesion using our opto-electric methodology. In a fixed-time point experiment, only COX-1- and COX-2-expressing cells enhanced phosphorylation of focal adhesion kinase, but all the transfected cells showed invasion activity. However, in a real-time experiment using opto-electric approaches, transmitted cellular morphology was much different with tight adhesion being shown in COX-2 expressing cells, as imaged by differential interference contrast microscopy (DICM) and interference reflection contrast microscopy (IRCM). Furthermore, micro-impedance measurements showed a continued increase in both resistance and reactance of COX- and LOX-transfected cells, consistent with the imaging data. Our data indicate that both COX- and LOX-expressing cells have strong cell-to-cell and cell-to-substrate adhesions, and that cell imaging analysis with cell impedance data generates fully reliable results on cell adhesion measurement. PMID:20026301

  4. Tailoring Novel PTFE Surface Properties: Promoting Cell Adhesion and Antifouling Properties via a Wet Chemical Approach.

    Science.gov (United States)

    Gabriel, Matthias; Niederer, Kerstin; Becker, Marc; Raynaud, Christophe Michel; Vahl, Christian-Friedrich; Frey, Holger

    2016-05-18

    Many biomaterials used for tissue engineering applications lack cell-adhesiveness and, in addition, are prone to nonspecific adsorption of proteins. This is especially important for blood-contacting devices such as vascular grafts and valves where appropriate surface properties should inhibit the initial attachment of platelets and promote endothelial cell colonization. As a consequence, the long-term outcome of the implants would be improved and the need for anticoagulation therapy could be reduced or even abolished. Polytetrafluoroethylene (PTFE), a frequently used polymer for various medical applications, was wet-chemically activated and subsequently modified by grafting the endothelial cell (EC) specific peptide arginine-glutamic acid-aspartic acid-valine (REDV) using a bifunctional polyethylene glycol (PEG)-spacer (known to reduce platelet and nonspecific protein adhesion). Modified and control surfaces were both evaluated in terms of EC adhesion, colonization, and the attachment of platelets. In addition, samples underwent bacterial challenges. The results strongly suggested that PEG-mediated peptide immobilization renders PTFE an excellent substrate for cellular growth while simultaneously endowing the material with antifouling properties. PMID:27041509

  5. Cell adhesion property affected by cyclooxygenase and lipoxygenase: Opto-electric approach

    OpenAIRE

    Choi, Chang Kyoung; Sukhthankar, Mugdha; Kim, Chul-Ho; Lee, Seong-Ho; English, Anthony; Kenneth D. Kihm; Baek, Seung Joon

    2009-01-01

    Expression of cyclooxygenases (COX) and lipoxygenases (LOX) has been linked to many pathophysiological phenotypes, including cell adhesion. However, many current approaches to measure cellular changes are performed only in a fixed time point. Since cells dynamically move in conjunction with the cell matrix, there is a pressing need for dynamic or time-dependent methods for the investigation of cell properties. In the presented study, we used stable human colorectal cancer cell lines ectopical...

  6. Spring constants and adhesive properties of native bacterial biofilm cells measured by atomic force microscopy.

    Science.gov (United States)

    Volle, C B; Ferguson, M A; Aidala, K E; Spain, E M; Núñez, M E

    2008-11-15

    Bacterial biofilms were imaged by atomic force microscopy (AFM), and their elasticity and adhesion to the AFM tip were determined from a series of tip extension and retraction cycles. Though the five bacterial strains studied included both Gram-negative and -positive bacteria and both environmental and laboratory strains, all formed simple biofilms on glass surfaces. Cellular spring constants, determined from the extension portion of the force cycle, varied between 0.16+/-0.01 and 0.41+/-0.01 N/m, where larger spring constants were measured for Gram-positive cells than for Gram-negative cells. The nonlinear regime in the extension curve depended upon the biomolecules on the cell surface: the extension curves for the smooth Gram-negative bacterial strains with the longest lipopolysaccharides on their surface had a larger nonlinear region than the rough bacterial strain with shorter lipopolysaccharides on the surface. Adhesive forces between the retracting silicon nitride tip and the cells varied between cell types in terms of the force components, the distance components, and the number of adhesion events. The Gram-negative cells' adhesion to the tip showed the longest distance components, sometimes more than 1 microm, whereas the shortest distance adhesion events were measured between the two Gram-positive cell types and the tip. Fixation of free-swimming planktonic cells by NHS and EDC perturbed both the elasticity and the adhesive properties of the cells. Here we consider the biochemical meaning of the measured physical properties of simple biofilms and implications to the colonization of surfaces in the first stages of biofilm formation. PMID:18815013

  7. Migratory and adhesive properties of Xenopus laevis primordial germ cells in vitro

    Directory of Open Access Journals (Sweden)

    Aliaksandr Dzementsei

    2013-11-01

    The directional migration of primordial germ cells (PGCs to the site of gonad formation is an advantageous model system to study cell motility. The embryonic development of PGCs has been investigated in different animal species, including mice, zebrafish, Xenopus and Drosophila. In this study we focus on the physical properties of Xenopus laevis PGCs during their transition from the passive to the active migratory state. Pre-migratory PGCs from Xenopus laevis embryos at developmental stages 17–19 to be compared with migratory PGCs from stages 28–30 were isolated and characterized in respect to motility and adhesive properties. Using single-cell force spectroscopy, we observed a decline in adhesiveness of PGCs upon reaching the migratory state, as defined by decreased attachment to extracellular matrix components like fibronectin, and a reduced adhesion to somatic endodermal cells. Data obtained from qPCR analysis with isolated PGCs reveal that down-regulation of E-cadherin might contribute to this weakening of cell-cell adhesion. Interestingly, however, using an in vitro migration assay, we found that movement of X. laevis PGCs can also occur independently of specific interactions with their neighboring cells. The reduction of cellular adhesion during PGC development is accompanied by enhanced cellular motility, as reflected in increased formation of bleb-like protrusions and inferred from electric cell-substrate impedance sensing (ECIS as well as time-lapse image analysis. Temporal alterations in cell shape, including contraction and expansion of the cellular body, reveal a higher degree of cellular dynamics for the migratory PGCs in vitro.

  8. Irradiation effect of carbon negative-ion implantation on polytetrafluoroethylene for controlling cell-adhesion property

    Science.gov (United States)

    Sommani, Piyanuch; Tsuji, Hiroshi; Kojima, Hiroyuki; Sato, Hiroko; Gotoh, Yasuhito; Ishikawa, Junzo; Takaoka, Gikan H.

    2010-10-01

    We have investigated the irradiation effect of negative-ion implantation on the changes of physical surface property of polytetrafluoroethylene (PTFE) for controlling the adhesion property of stem cells. Carbon negative ions were implanted into PTFE sheets at fluences of 1 × 10 14-1 × 10 16 ions/cm 2 and energies of 5-20 keV. Wettability and atomic bonding state including the ion-induced functional groups on the modified surfaces were investigated by water contact angle measurement and XPS analysis, respectively. An initial value of water contact angles on PTFE decreased from 104° to 88° with an increase in ion influence to 1 × 10 16 ions/cm 2, corresponding to the peak shifting of XPS C1s spectra from 292.5 eV to 285 eV with long tail on the left peak-side. The change of peak position was due to decrease of C-F 2 bonds and increase of C-C bonds with the formation of hydrophilic oxygen functional groups of OH and C dbnd O bonds after the ion implantation. After culturing rat mesenchymal stem cells (MSC) for 4 days, the cell-adhesion properties on the C --patterned PTFE were observed by fluorescent microscopy with staining the cell nuclei and their actin filament (F-actin). The clear adhesion patterning of MSCs on the PTFE was obtained at energies of 5-10 keV and a fluence of 1 × 10 15 ions/cm 2. While the sparse patterns and the uncontrollable patterns were found at a low fluence of 3 × 10 14 ions/cm 2 and a high fluence of 3 × 10 15 ions/cm 2, respectively. As a result, we could improve the surface wettability of PTFE to control the cell-adhesion property by carbon negative-ion implantation.

  9. Impacts of Hematite Nanoparticle Exposure on Biomechanical, Adhesive, and Surface Electrical Properties of Escherichia coli Cells

    OpenAIRE

    Zhang, Wen; Hughes, Joseph; Chen, Yongsheng

    2012-01-01

    Despite a wealth of studies examining the toxicity of engineered nanomaterials, current knowledge on their cytotoxic mechanisms (particularly from a physical perspective) remains limited. In this work, we imaged and quantitatively characterized the biomechanical (hardness and elasticity), adhesive, and surface electrical properties of Escherichia coli cells with and without exposure to hematite nanoparticles (NPs) in an effort to advance our understanding of the cytotoxic impacts of nanomater...

  10. Structural and cell adhesion properties of zebrafish syndecan-4 are shared with higher vertebrates

    DEFF Research Database (Denmark)

    Whiteford, James; Ko, Sunggeon; Lee, Weontae;

    2008-01-01

    The syndecan proteoglycans are an ancient class of receptor, bearing heparan sulfate chains that interact with numerous potential ligands including growth factors, morphogens, and extracellular matrix molecules. The single syndecan of invertebrates appears not to have cell adhesion roles, but the...... properties of syndecan-4 are consistent across the vertebrate spectrum and reflect an early acquisition of specialization after syndecan gene duplication events at the invertebrate/early chordate boundary....

  11. Elasticity, biodegradability and cell adhesive properties of chitosan/hyaluronan multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Aurore; Richert, Ludovic; Francius, Gregory; Voegel, Jean-Claude; Picart, Catherine [Present address: Universite de Montpellier II, CNRS-UMR 5539, cc107, Place Eugene Bataillon, 34 095 Montpellier Cedex 5 (France)

    2007-03-01

    In the bioengineering field, a recent and promising approach to modifying biomaterial surfaces is the layer-by-layer (LbL) technique used to build thin polyelectrolyte multilayer films. In this work, we focused on polyelectrolyte multilayer films made of two polysaccharides, chitosan (CHI) and hyaluronan (HA), and on the control of their physico-chemical and cell adhesive properties by chemical cross-linking. CHI/HA films were cross-linked using a water soluble carbodiimide and observed by confocal laser scanning microscopy (CLSM) with a fluorescently labeled CHI. Film thicknesses were similar for native and cross-linked films. The film nanometer roughness was measured by atomic force microscopy and was found to be higher for cross-linked films. Cross-linking the films also leads to a drastic change in film stiffness. The elastic modulus of the films (Young's modulus) as measured by AFM nano-indentation was about tenfold increased for cross-linked films as compared to native ones. From a biological point of view, cross-liked films are more resistant to enzymatic degradation by hyaluronidase. Furthermore, the increase in film stiffness has a favorable effect on the adhesion and spreading of chondrosarcoma cells. Thus, the CHI/HA cross-linked films could be used for various applications due to their adhesive properties and to their mechanical properties (including stability in enzymatic media)

  12. Elasticity, biodegradability and cell adhesive properties of chitosan/hyaluronan multilayer films

    Science.gov (United States)

    Schneider, Aurore; Richert, Ludovic; Francius, Gregory; Voegel, Jean-Claude; Picart, Catherine

    2007-03-01

    In the bioengineering field, a recent and promising approach to modifying biomaterial surfaces is the layer-by-layer (LbL) technique used to build thin polyelectrolyte multilayer films. In this work, we focused on polyelectrolyte multilayer films made of two polysaccharides, chitosan (CHI) and hyaluronan (HA), and on the control of their physico-chemical and cell adhesive properties by chemical cross-linking. CHI/HA films were cross-linked using a water soluble carbodiimide and observed by confocal laser scanning microscopy (CLSM) with a fluorescently labeled CHI. Film thicknesses were similar for native and cross-linked films. The film nanometer roughness was measured by atomic force microscopy and was found to be higher for cross-linked films. Cross-linking the films also leads to a drastic change in film stiffness. The elastic modulus of the films (Young's modulus) as measured by AFM nano-indentation was about tenfold increased for cross-linked films as compared to native ones. From a biological point of view, cross-liked films are more resistant to enzymatic degradation by hyaluronidase. Furthermore, the increase in film stiffness has a favorable effect on the adhesion and spreading of chondrosarcoma cells. Thus, the CHI/HA cross-linked films could be used for various applications due to their adhesive properties and to their mechanical properties (including stability in enzymatic media).

  13. Morphology and interdiffusion control to improve adhesion and cohesion properties in inverted polymer solar cells

    KAUST Repository

    Dupont, Stephanie R.

    2015-01-01

    © 2014 Elsevier B.V. All rights reserved. The role of pre-electrode deposition annealing on the morphology and the fracture properties of polymer solar cells is discussed. We found an increase in adhesion at the weak P3HT:PCBM/PEDOT:PSS interface with annealing temperature, caused by increased interdiffusion between the organic layers. The formation of micrometer sized PCBM crystallites, which occurs with annealing above the crystallization temperature of PCBM, initially weakened the P3HT:PCBM layer itself. Further annealing improved the cohesion, due to a pull-out toughening mechanism of the growing PCBM clusters. Understanding how the morphology, tuned by annealing, affects the adhesive and cohesive properties in these organic films is essential for the mechanical integrity of OPV devices.

  14. Polyampholyte- and nanosilicate-based soft bionanocomposites with tailorable mechanical and cell adhesion properties.

    Science.gov (United States)

    Jain, Minkle; Matsumura, Kazuaki

    2016-06-01

    Engineered tissues are excellent substitutes for treating organ failure associated with disease, injury, and degeneration. Designing new biomaterials with controlled release profiles, good mechanical properties, and cell adhesion characteristics can be useful for the formation of specific functional tissues. Here, we report the formulation of nanocomposite hydrogels based on carboxylated poly-l-lysine and synthetic clay laponite XLG in which four-arm polyethylene glycol with N-hydroxy succinimide ester (PEG-NHS) was used as the chemical crosslinker. Interestingly, the degradation of this gel could be adjusted from a few days to a few months. Incorporation of laponite XLG resulted in the formation of mechanically tough hydrogels and conferred cytocompatibility. The mechanical properties of the nanocomposite could be modulated by changing the crosslinking density and laponite concentration. The feasibility of using this system for cellular therapies was investigated by evaluating cell adhesion on the nanocomposite surface. Thus, these nanocomposites can serve as scaffolds with tunable mechanical and degradation properties that also provide structural integrity to tissue constructs. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1379-1386, 2016. PMID:26833827

  15. A conserved NXIP motif is required for cell adhesion properties of the syndecan-4 ectodomain

    DEFF Research Database (Denmark)

    Whiteford, James R; Couchman, John R

    2006-01-01

    Syndecans are cell surface proteoglycans involved in cell adhesion and motility. Syndecan-4 is an important component of focal adhesions and is involved in cytoskeletal reorganization. Previous work has shown that the syndecan-4 ectodomain can support cell attachment. Here, three vertebrate...... syndecan-4 ectodomains were compared, including that of the zebrafish, and we have demonstrated that the cell binding activity of the syndecan-4 ectodomain is conserved. Cell adhesion to the syndecan-4 ectodomain appears to be a characteristic of mesenchymal cells. Comparison of syndecan-4 ectodomain...... sequences led to the identification of three conserved regions of sequence, of which the NXIP motif is important for cell binding activity. We have shown that cell adhesion to the syndecan-4 ectodomain involves beta1 integrins in several cell types....

  16. Cell adhesion over two distinct surfaces varied with chemical and mechanical properties

    International Nuclear Information System (INIS)

    Chitosan is widely recognized as a natural and proper scaffold material; however, as a base substrate, it shows little promotion effect for the growth of cultured fibroblast cells. In this study, chitosan in a film form was prepared and used as a cell-culturing matrix, followed by patterning the evaporated Au upon it. Micro-scale Au clusters of ∼ 150 μm in diameter and ∼ 20 nm in thickness were then patterned and adhered upon the chitosan matrix. Physical and chemical properties of Au/chitosan were characterized. In particular, nano-indentation with dynamic contact module was applied to measure the nano-hardness of the tailored surfaces on Au/chitosan. Fibroblast cells were thereafter cultured on Au/chitosan. Experimental results demonstrated that as compared with the chitosan matrix, Au clusters and their boundary area exhibited favorable to promote cell adhesion, spreading, and growth. As well, nano-hardness on the boundary area of Au/chitosan significantly enhanced, while the cultured fibroblast cells aggregated upon Au clusters and the boundary area. In combination with the possible chemical and mechanical changes resulted by the evaporation of Au clusters upon the chitosan matrix, a selectively-enhanced Au/chitosan to promote fibroblast cells proliferation was created. Such design is anticipated for enabling a surface for scaffold materials with the cell-guidable function.

  17. Impacts of hematite nanoparticle exposure on biomechanical, adhesive, and surface electrical properties of Escherichia coli cells.

    Science.gov (United States)

    Zhang, Wen; Hughes, Joseph; Chen, Yongsheng

    2012-06-01

    Despite a wealth of studies examining the toxicity of engineered nanomaterials, current knowledge on their cytotoxic mechanisms (particularly from a physical perspective) remains limited. In this work, we imaged and quantitatively characterized the biomechanical (hardness and elasticity), adhesive, and surface electrical properties of Escherichia coli cells with and without exposure to hematite nanoparticles (NPs) in an effort to advance our understanding of the cytotoxic impacts of nanomaterials. Both scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that E. coli cells had noticeable deformation with hematite treatment for 45 min with a statistical significance. The hematite-treated cells became significantly harder or stiffer than untreated ones, as evidenced by indentation and spring constant measurements. The average indentation of the hematite-treated E. coli cells was 120 nm, which is significantly lower (P hematite-treated E. coli cells (0.28 ± 0.11 nN/nm) was about 20 times higher than that of untreated ones (0.01 ± 0.01 nN/nm). The zeta potential of E. coli cells, measured by dynamic light scattering (DLS), was shown to shift from -4 ± 2 mV to -27 ± 8 mV with progressive surface adsorption of hematite NPs, a finding which is consistent with the local surface potential measured by Kelvin probe force microscopy (KPFM). Overall, the reported findings quantitatively revealed the adverse impacts of nanomaterial exposure on physical properties of bacterial cells and should provide insight into the toxicity mechanisms of nanomaterials. PMID:22467500

  18. Adhesive properties of Enterobacter sakazakii to human epithelial and brain microvascular endothelial cells

    Directory of Open Access Journals (Sweden)

    Pospischil Andreas

    2006-06-01

    Full Text Available Abstract Background Enterobacter sakazakii is an opportunistic pathogen that has been associated with sporadic cases and outbreaks causing meningitis, necrotizing enterocolitis and sepsis especially in neonates. However, up to now little is known about the mechanisms of pathogenicity in E. sakazakii. A necessary state in the successful colonization, establishment and ultimately production of disease by microbial pathogens is the ability to adhere to host surfaces such as mucous membranes, gastric and intestinal epithelial or endothelial tissue. This study examined for the first time the adherence ability of 50 E. sakazakii strains to the two epithelial cell lines HEp-2 and Caco-2, as well as the brain microvascular endothelial cell line HBMEC. Furthermore, the effects of bacterial culture conditions on the adherence behaviour were investigated. An attempt was made to characterize the factors involved in adherence. Results Two distinctive adherence patterns, a diffuse adhesion and the formation of localized clusters of bacteria on the cell surface could be distinguished on all three cell lines. In some strains, a mixture of both patterns was observed. Adherence was maximal during late exponential phase, and increased with higher MOI. The adhesion capacity of E. sakazakii to HBMEC cells was affected by the addition of blood to the bacteria growth medium. Mannose, hemagglutination, trypsin digestion experiments and transmission electron microscopy suggested that the adhesion of E. sakazakii to the epithelial and endothelial cells is mainly non-fimbrial based. Conclusion Adherence experiments show heterogeneity within different E. sakazakii strains. In agreement with studies on E. cloacae, we found no relationship between the adhesive capacities in E. sakazakii and the eventual production of specific fimbriae. Further studies will have to be carried out in order to determine the adhesin(s involved in the interaction of E. sakazakii with cells and to

  19. Syndecans and cell adhesion

    DEFF Research Database (Denmark)

    Couchman, J R; Chen, L; Woods, A

    2001-01-01

    Now that transmembrane signaling through primary cell-matrix receptors, integrins, is being elucidated, attention is turning to how integrin-ligand interactions can be modulated. Syndecans are transmembrane proteoglycans implicated as coreceptors in a variety of physiological processes, including...... cell adhesion, migration, response to growth factors, development, and tumorigenesis. This review will describe this family of proteoglycans in terms of their structures and functions and their signaling in conjunction with integrins, and indicate areas for future research....

  20. Synthesis and Cell Adhesive Properties of Linear and Cyclic RGD Functionalized Polynorbornene Thin Films

    OpenAIRE

    Patel, Paresma R.; Kiser, Rosemary Conrad; Lu, Ying Y.; Fong, Eileen; Ho, Wilson C.; Tirrell, David A.; Grubbs, Robert H.

    2012-01-01

    Described herein is the efficient synthesis and evaluation of bioactive arginine-glycine-aspartic acid (RGD) functionalized polynorbornene-based materials for cell adhesion and spreading. Polynorbornenes containing either linear or cyclic RGD peptides were synthesized by ring-opening metathesis polymerization (ROMP) using the well-defined ruthenium initiator [(H_(2)IMes)(pyr)_(2)(Cl)_(2)Ru═CHPh]. The random copolymerization of three separate norbornene monomers allowed for the incorporation o...

  1. Tuning the mechanical properties of bioreducible multilayer films for improved cell adhesion and transfection activity

    OpenAIRE

    Blacklock, Jenifer; Vetter, Andreas; Lankenau, Andreas; Oupický, David; Möhwald, Helmuth

    2010-01-01

    A simple approach to the mechanical modulation of layer-by-layer (LbL) films is through manipulation of the film assembly. Here, we report results based on altering the salt concentration during film assembly and its effect on film rigidity. Based on changes in film rigidity, cell adhesion characteristics and transfection activity were investigated in vitro. LbL films consisting of reducible hyperbranched poly(amide amine) (RHB) have been implemented along with DNA for investigating fibroblas...

  2. Preparation of S-sulfo albumin film and its cell adhesive property

    International Nuclear Information System (INIS)

    Recently, large-scale production of the pharmaceutical grade recombinant human serum albumin was achieved, and several clinical trials have proved its safety and efficacy. Albumin is thought to be a candidate for a safe biopolymer sources for application to biomaterials. In this study, we treated albumin with sodium sulfite and sodium tetrathionate to give S-sulfo albumin, which was found to loose native albumin structure by CD spectra analysis and dye-binding assay. A water-insoluble S-sulfo albumin films were prepared by drying S-sulfo albumin solution and subsequent reformation of disulfide bonds by the oxidation with iodine. Ultimate strength, ultimate elongation and Young's modulus of S-sulfo albumin film prepared at room temperature were 3.3 ± 0.4 MPa, 30.8 ± 3.2% and 40.8 ± 3.3 MPa before oxidative treatment and changed to 13.8 ± 4.2 MPa, 5.6 ± 2.8% and 401.7 ± 15.3 MPa after oxidative treatment. When the film was prepared at 60 deg. C, similar tendency was observed. Thus, the disulfide bonds formation between albumin molecules by oxidative treatment converted the film stronger and stiffer. Cell adhesion and proliferation on the films were evaluated using mouse L929 fibroblast cells. Cell adhesion largely depended on the albumin structure; that is, cells did not attach to native albumin coated surfaces, while cell adhesion and proliferation occurred on the S-sulfo albumin films which lost their native albumin structure. Eighty percent of seeded cells were adhered on S-sulfo albumin films and proliferated well in a similar manner to those on the conventional culture dish. Our results indicate that S-sulfo albumin is a favorable cell culture substrate.

  3. Effect of fibril shape on adhesive properties

    Science.gov (United States)

    Soto, Daniel; Hill, Ginel; Parness, Aaron; Esparza, Noé; Cutkosky, Mark; Kenny, Tom

    2010-08-01

    Research into the gecko's adhesive system revealed a unique architecture for adhesives using tiny hairs. By using a stiff material (β-keratin) to create a highly structured adhesive, the gecko's system demonstrates properties not seen in traditional pressure-sensitive adhesives which use a soft, unstructured planar layer. In contrast to pressure sensitive adhesives, the gecko adhesive displays frictional adhesion, in which increased shear force allows it to withstand higher normal loads. Synthetic fibrillar adhesives have been fabricated but not all demonstrate this frictional adhesion property. Here we report the dual-axis force testing of single silicone rubber pillars from synthetic adhesive arrays. We find that the shape of the adhesive pillar dictates whether frictional adhesion or pressure-sensitive behavior is observed. This work suggests that both types of behavior can be achieved with structures much larger than gecko terminal structures. It also indicates that subtle differences in the shape of these pillars can significantly influence their properties.

  4. The neural cell adhesion molecule

    DEFF Research Database (Denmark)

    Berezin, V; Bock, E; Poulsen, F M

    2000-01-01

    During the past year, the understanding of the structure and function of neural cell adhesion has advanced considerably. The three-dimensional structures of several of the individual modules of the neural cell adhesion molecule (NCAM) have been determined, as well as the structure of the complex...... between two identical fragments of the NCAM. Also during the past year, a link between homophilic cell adhesion and several signal transduction pathways has been proposed, connecting the event of cell surface adhesion to cellular responses such as neurite outgrowth. Finally, the stimulation of neurite...

  5. Syndecan proteoglycans and cell adhesion

    DEFF Research Database (Denmark)

    Woods, A; Oh, E S; Couchman, J R

    1998-01-01

    It is now becoming clear that a family of transmembrane proteoglycans, the syndecans, have important roles in cell adhesion. They participate through binding of matrix ligand to their glycosaminoglycan chains, clustering, and the induction of signaling cascades to modify the internal microfilament...... organization. Syndecans can modulate the type of adhesive responses induced by other matrix ligand-receptor interactions, such as those involving the integrins, and so contribute to the control of cell morphology, adhesion and migration....

  6. PRL-3 engages the focal adhesion pathway in triple-negative breast cancer cells to alter actin structure and substrate adhesion properties critical for cell migration and invasion.

    Science.gov (United States)

    Gari, Hamid H; DeGala, Gregory D; Ray, Rahul; Lucia, M Scott; Lambert, James R

    2016-10-01

    Triple-negative breast cancers (TNBCs) are among the most aggressive cancers characterized by a high propensity to invade, metastasize and relapse. We previously reported that the TNBC-specific inhibitor, AMPI-109, significantly impairs the ability of TNBC cells to migrate and invade by reducing levels of the metastasis-promoting phosphatase, PRL-3. Here, we examined the mechanisms by which AMPI-109 and loss of PRL-3 impede cell migration and invasion. AMPI-109 treatment or knock down of PRL-3 expression were associated with deactivation of Src and ERK signaling and concomitant downregulation of RhoA and Rac1/2/3 GTPase protein levels. These cellular changes led to rearranged filamentous actin networks necessary for cell migration and invasion. Conversely, overexpression of PRL-3 promoted TNBC cell invasion by upregulating matrix metalloproteinase 10, which resulted in increased TNBC cell adherence to, and degradation of, the major basement membrane component laminin. Our data demonstrate that PRL-3 engages the focal adhesion pathway in TNBC cells as a key mechanism for promoting TNBC cell migration and invasion. Collectively, these data suggest that blocking PRL-3 activity may be an effective method for reducing the metastatic potential of TNBC cells. PMID:27452906

  7. Characterization of adhesively bonded joints using bulk adhesive properties

    OpenAIRE

    Kon, Haruhiko

    1991-01-01

    Though using bulk adhesive properties to predict adhesively bonded joint response has yet to be proven infallible, based upon the success of previous works, this effort attempts to shed some light on the stresses present in a typical automotive bonded joint. Adhesive material properties obtained in previous works were used in a finite element analysis of a simulated automotive joint to predict the stresses in that joint. The automotive joint analyzed was a simplified repr...

  8. DDB2 (damaged-DNA binding 2) protein: a new modulator of nanomechanical properties and cell adhesion of breast cancer cells

    Science.gov (United States)

    Barbieux, Claire; Bacharouche, Jalal; Soussen, Charles; Hupont, Sébastien; Razafitianamaharavo, Angélina; Klotz, Rémi; Pannequin, Rémi; Brie, David; Bécuwe, Philippe; Francius, Grégory; Grandemange, Stéphanie

    2016-02-01

    DDB2, known for its role in DNA repair, was recently shown to reduce mammary tumor invasiveness by inducing the transcription of IκBα, an inhibitor of NF-κB activity. Since cellular adhesion is a key event during the epithelial to mesenchymal transition (EMT) leading to the invasive capacities of breast tumor cells, the aim of this study was to investigate the role of DDB2 in this process. Thus, using low and high DDB2-expressing MDA-MB231 and MCF7 cells, respectively, in which DDB2 expression was modulated experimentally, we showed that DDB2 overexpression was associated with a decrease of adhesion abilities on glass and plastic areas of breast cancer cells. Then, we investigated cell nanomechanical properties by atomic force microscopy (AFM). Our results revealed significant changes in the Young's Modulus value and the adhesion force in MDA-MB231 and MCF7 cells, whether DDB2 was expressed or not. The cell stiffness decrease observed in MDA-MB231 and MCF7 expressing DDB2 was correlated with a loss of the cortical actin-cytoskeleton staining. To understand how DDB2 regulates these processes, an adhesion-related gene PCR-Array was performed. Several adhesion-related genes were differentially expressed according to DDB2 expression, indicating that important changes are occurring at the molecular level. Thus, this work demonstrates that AFM technology is an important tool to follow cellular changes during tumorigenesis. Moreover, our data revealed that DDB2 is involved in early events occurring during metastatic progression of breast cancer cells and will contribute to define this protein as a new marker of metastatic progression in this type of cancer.

  9. Syndecans, signaling, and cell adhesion

    DEFF Research Database (Denmark)

    Couchman, J R; Woods, A

    1996-01-01

    structures within the heparan sulfate chains, leaving the roles of chondroitin sulfate chains and extracellular portion of the core proteins to be elucidated. Evidence that syndecans are a class of receptor involved in cell adhesion is mounting, and their small cytoplasmic domains may link with the...... transmembrane signaling from matrix to cytoskeleton, as proposed for other classes of adhesion receptors....

  10. Cell surface properties of rhizobial isolated from soils contaminated with hydrocarbons: hydrophobicity and adhesion to sandy soil

    Energy Technology Data Exchange (ETDEWEB)

    Mehmannavaz, R. [INRS-Institut Armand-Frappier, Centre de microbiologie et biotechnologie, Pointe-Claire, Quebec (Canada); McGill Univ., Ste-Anne-de-Bellevue, Quebec (Canada); Prasher, S.O. [McGill Univ., Ste-Anne-de-Bellevue, Quebec (Canada); Ahmad, D. [INRS-Institut Armand-Frappier, Centre de microbiologie et biotechnologie, Pointe-Claire, Quebec (Canada)

    2001-02-01

    Ten strains of Rhizobium meliloti and two non-rhizobial strains, Escherichia coli JM105 and Comomonas testosteroni B-356, were studied for their behaviour in soil and water matrices by determining their hydrophobicity, as measured by bacterial adherence to n-octane, and adhesion, as measured by their retention on sandy soil particles. The hydrophobicity values for the rhizobial strains were similar to that for E. coli (around 15%), whereas C. testosteroni, which belongs to the Pseudomonads group, showed a significantly higher level (33%). Both non-rhizobial strains, however, showed higher levels of adhesion, (85% and 78%, respectively) than did the rhizobial strains ({approx}55%). The cell surface properties of the rhizobial strains were influenced by the composition of the growth media used, being significantly higher with nutrient-rich media. The nature or level of contaminants in the soil from which these strains were originally isolated did not, however, influence these properties. These characteristics are important in determining the fate of bacteria in the unsaturated subsurface soil environment because of their influence on the vertical transport, distribution and survival. Information about these characteristics will be particularly useful in choosing stains for agricultural applications (e.g., as biofertilizers or biocontrol agents) or in situ soil environment operations (e.g., bioaugmentation for bioremediation of pollutants). (Author)

  11. Notch-Mediated Cell Adhesion

    OpenAIRE

    Akihiko Murata; Shin-Ichi Hayashi

    2016-01-01

    Notch family members are generally recognized as signaling molecules that control various cellular responses in metazoan organisms. Early fly studies and our mammalian studies demonstrated that Notch family members are also cell adhesion molecules; however, information on the physiological roles of this function and its origin is limited. In this review, we discuss the potential present and ancestral roles of Notch-mediated cell adhesion in order to explore its origin and the initial roles of...

  12. The effect of anneal, solar irradiation and humidity on the adhesion/cohesion properties of P3HT:PCBM based inverted polymer solar cells

    KAUST Repository

    Dupont, Stephanie R.

    2012-06-01

    We use a thin-film adhesion technique that enables us to precisely measure the energy required to separate adjacent layers in OPV cells. We demonstrate the presence of weak interfaces in prototypical inverted polymer solar cells, either prepared by spin, spray or slot-die coating, including flexible and non flexible solar cells. In all cases, we observed adhesive failure at P3HT:PCBM/PEDOT:PSS interface, indicating the intrinsic material dependence of this mechanism. The impact of temperature, solar irradiation and humidity on the adhesion and cohesion properties of this particular interface is discussed. First, we have found that post-deposition annealing increases the adhesion significantly. Annealing changes the morphology in the photoactive layer and consequently alters the chemical properties at the interface. Second, solar irradiation on fully encapsulated solar cells has no damaging but in contrast an enhancing effect on the adhesion properties, due to the heat generated from IR radiation. Finally, the synergetic effect of stress and an environmental species like moisture greatly accelerates the decohesion rate in the weak hygroscopic PEDOT:PSS layer. This results in a loss of mechanical integrity and device performance. The insight into the mechanisms of delamination and decohesion yields general guidelines for the design of more reliable organic electronic devices. © 2012 IEEE.

  13. Physicochemical Cell Surface and Adhesive Properties of Coryneform Bacteria Related to the Presence and Chain Length of Mycolic Acids

    OpenAIRE

    1993-01-01

    The presence and chain length of mycolic acids of bacteria of the genera Corynebacterium, Rhodococcus, Gordona, Mycobacterium, and Arthrobacter and of coryneform bacteria containing a type B peptidoglycan were related to the cell surface hydrophobicity of the bacteria, which in turn was related to adhesion of the cells to defined surfaces such as Teflon and glass. The origin of the overall negative charge of these bacteria is discussed.

  14. Film adhesion in amorphous silicon solar cells

    Indian Academy of Sciences (India)

    A R M Yusoff; M N Syahrul; K Henkel

    2007-08-01

    A major issue encountered during fabrication of triple junction -Si solar cells on polyimide substrates is the adhesion of the solar cell thin films to the substrates. Here, we present our study of film adhesion in amorphous silicon solar cells made on different polyimide substrates (Kapton VN, Upilex-S and Gouldflex), and the effect of tie coats on film adhesion.

  15. Synthetic Biodegradable Hydrogels with Excellent Mechanical Properties and Good Cell Adhesion Characteristics Obtained by the Combinatorial Synthesis of Photo-Cross-Linked Networks.

    Science.gov (United States)

    Zant, Erwin; Grijpma, Dirk W

    2016-05-01

    Major drawbacks of synthetic hydrogels are their poor mechanical properties and their limited ability to allow cell attachment and proliferation. By photo-cross-linking mixtures of dimethacrylate-functionalized oligomers (macromers) in a combinatorial manner in solution, synthetic hydrogels with high water uptake and the remarkable ability to promote cell adhesion and proliferation were prepared. A total of 255 different networks based on poly(trimethylene carbonate) (PTMC)-, poly(d,l-lactide) (PDLLA)-, poly(ε-caprolactone) (PCL)- and poly(ethylene glycol) (PEG) macromers were synthesized simultaneously and screened for their ability to allow the adhesion of human mesenchymal stem cells (hMSCs) in a high throughput-like manner. Of these networks, several hydrogels could be identified that were able to take up large amounts of water while at the same time allowed the adhesion of cells. By synthesizing these hydrogel networks anew and analyzing the cell adhesion and proliferation behavior of human mesenchymal stem cells to these synthetic hydrogels in more detail, it was confirmed that mixed-macromer hydrogel networks prepared from equal amounts of PTMC-dMA 4k, PDLLA-dMA 4k, PCL-dMA 4k, PEG-dMA 4k, and PEG-dMA 10k and hydrogel networks prepared from PTMC-dMA 4k, PDLLA 4k, PEG-dMA 4k, PTMC-dMA 10k and PEG-dMA 10k were highly hydrophilic (water uptake was respectively 181 ± 2 and 197 ± 18 wt % water) and allowed very good cell adhesion and proliferation. Furthermore, these networks were extremely resilient in the hydrated state, with tearing energies of respectively 0.64 ± 0.34 and 0.27 ± 0.04 kJ/m(2). This is much higher than other synthetic hydrogels described in literature and close to articular cartilage (1 kJ/m(2)). PMID:27077699

  16. N-methylformamide induces changes on adhesive properties and lung-colonizing potential of M14 melanoma cells.

    OpenAIRE

    Del Bufalo, D; C. Leonetti; Bucci, B.; Amedeo, C.; Falcioni, R.; Biroccio, A; Zupi, G.

    1998-01-01

    We have studied whether N-methylformamide can affect the expression pattern of adhesion molecules and the attachment behaviour of M14 human melanoma cells. The role of N-methylformamide on experimental and spontaneous pulmonary metastases from M14 cells in nude mice was also investigated. We demonstrate that N-methylformamide in vitro pretreatment of M14 cells, although inducing a significant increase in the expression of alpha2beta1, alpha6beta1 and alpha(v)beta3 integrin receptors, slightly...

  17. Strategies to prepare TiO2 thin films, doped with transition metal ions, that exhibit specific physicochemical properties to support osteoblast cell adhesion and proliferation

    International Nuclear Information System (INIS)

    Metal ion doped titanium oxide (TiO2) thin films, as bioactive coatings on metal or other implantable materials, can be used as surfaces for studying the cell biological properties of osteogenic and other cell types. Bulk crystallite phase distribution and surface carbon–oxygen constitution of thin films, play an important role in determining the biological responses of cells that come in their contact. Here we present a strategy to control the polarity of atomic interactions between the dopant metal and TiO2 molecules and obtain surfaces with smaller crystallite phases and optimal surface carbon–oxygen composition to support the maximum proliferation and adhesion of osteoblast cells. Our results suggest that surfaces, in which atomic interactions between the dopant metals and TiO2 were less polar, could support better adhesion, spreading and proliferation of cells. - Highlights: • Electrochemical properties of dopants control the nature of TiO2 thin films. • A model explains the correlation of dopant properties and behaviour of TiO2 films. • Dopants with less polar interaction with TiO2 exhibit better biological activity

  18. Plasma polymerization for cell adhesive/anti-adhesive implant coating

    Science.gov (United States)

    Meichsner, Juergen; Testrich, Holger; Rebl, Henrike; Nebe, Barbara

    2015-09-01

    Plasma polymerization of ethylenediamine (C2H8N2, EDA) and perfluoropropane (C3F8, PFP) with admixture of argon and hydrogen, respectively, was studied using an asymmetric 13.56 MHz CCP. The analysis of the plasma chemical gas phase processes for stable molecules revealed consecutive reactions: C2H8N2 consumption, intermediate product NH3, and main final product HCN. In C3F8- H2 plasma the precursor molecule C3F8 and molecular hydrogen are consumed and HF as well as CF4 and C2F6 are found as main gaseous reaction products. The deposited plasma polymer films on the powered electrode are strongly cross-linked due to ion bombardment. The stable plasma polymerized films from EDA are characterized by high content of nitrogen with N/C ratio of about 0.35. The plasma polymerized fluorocarbon film exhibit a reduced F/C ratio of about 1.2. Adhesion tests with human osteoblast cell line MG-63 on coated Ti6Al4V samples (polished) compared with uncoated reference sample yielded both, the enhanced cell adhesion for plasma polymerized EDA and significantly reduced cell adhesion for fluorocarbon coating, respectively. Aging of the plasma polymerized EDA film, in particular due to the reactions with oxygen from air, showed no significant change in the cell adhesion. The fluorocarbon coating with low cell adhesion is of interest for temporary implants. Funded by the Campus PlasmaMed.

  19. Cell adhesion on cellulose nanofibrils

    OpenAIRE

    Liljeström, Anna

    2016-01-01

    Cellulose nanofibrils (CNF) is an emerging biomaterial suitable for medical research. CNF hydrogel has been used as a three dimensional platforms for cell culture. This thesis aims to understand how human liver carcinoma (HepG2) cells interact with CNF. Measurements were performed with Quartz crystal microbalance with dissipation in order to quantify cell adsorption on CNF. Furthermore, the effect of the cell medium on the viscoelastic properties of CNF and on cell-CNF interactions were ...

  20. Synaptic Cell Adhesion Molecules in Alzheimer's Disease

    Science.gov (United States)

    Leshchyns'ka, Iryna

    2016-01-01

    Alzheimer's disease (AD) is a neurodegenerative brain disorder associated with the loss of synapses between neurons in the brain. Synaptic cell adhesion molecules are cell surface glycoproteins which are expressed at the synaptic plasma membranes of neurons. These proteins play key roles in formation and maintenance of synapses and regulation of synaptic plasticity. Genetic studies and biochemical analysis of the human brain tissue, cerebrospinal fluid, and sera from AD patients indicate that levels and function of synaptic cell adhesion molecules are affected in AD. Synaptic cell adhesion molecules interact with Aβ, a peptide accumulating in AD brains, which affects their expression and synaptic localization. Synaptic cell adhesion molecules also regulate the production of Aβ via interaction with the key enzymes involved in Aβ formation. Aβ-dependent changes in synaptic adhesion affect the function and integrity of synapses suggesting that alterations in synaptic adhesion play key roles in the disruption of neuronal networks in AD. PMID:27242933

  1. Hydrogen peroxide regulates cell adhesion through the redox sensor RPSA.

    Science.gov (United States)

    Vilas-Boas, Filipe; Bagulho, Ana; Tenente, Rita; Teixeira, Vitor H; Martins, Gabriel; da Costa, Gonçalo; Jerónimo, Ana; Cordeiro, Carlos; Machuqueiro, Miguel; Real, Carla

    2016-01-01

    To become metastatic, a tumor cell must acquire new adhesion properties that allow migration into the surrounding connective tissue, transmigration across endothelial cells to reach the blood stream and, at the site of metastasis, adhesion to endothelial cells and transmigration to colonize a new tissue. Hydrogen peroxide (H2O2) is a redox signaling molecule produced in tumor cell microenvironment with high relevance for tumor development. However, the molecular mechanisms regulated by H2O2 in tumor cells are still poorly known. The identification of H2O2-target proteins in tumor cells and the understanding of their role in tumor cell adhesion are essential for the development of novel redox-based therapies for cancer. In this paper, we identified Ribosomal Protein SA (RPSA) as a target of H2O2 and showed that RPSA in the oxidized state accumulates in clusters that contain specific adhesion molecules. Furthermore, we showed that RPSA oxidation improves cell adhesion efficiency to laminin in vitro and promotes cell extravasation in vivo. Our results unravel a new mechanism for H2O2-dependent modulation of cell adhesion properties and identify RPSA as the H2O2 sensor in this process. This work indicates that high levels of RPSA expression might confer a selective advantage to tumor cells in an oxidative environment. PMID:26603095

  2. Cell adhesion strength from cortical tension - an integration of concepts.

    Science.gov (United States)

    Winklbauer, Rudolf

    2015-10-15

    Morphogenetic mechanisms such as cell movement or tissue separation depend on cell attachment and detachment processes, which involve adhesion receptors as well as the cortical cytoskeleton. The interplay between the two components is of stunning complexity. Most strikingly, the binding energy of adhesion molecules is usually too small for substantial cell-cell attachment, pointing to a main deficit in our present understanding of adhesion. In this Opinion article, I integrate recent findings and conceptual advances in the field into a coherent framework for cell adhesion. I argue that active cortical tension is best viewed as an integral part of adhesion, and propose on this basis a non-arbitrary measure of adhesion strength - the tissue surface tension of cell aggregates. This concept of adhesion integrates heterogeneous molecular inputs into a single mechanical property and simplifies the analysis of attachment-detachment processes. It draws attention to the enormous variation of adhesion strengths among tissues, whose origin and function is little understood. PMID:26471994

  3. Amygdalin influences bladder cancer cell adhesion and invasion in vitro.

    Directory of Open Access Journals (Sweden)

    Jasmina Makarević

    Full Text Available The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as well as tumor cell migration was examined. Effects of drug treatment on integrin α and β subtypes, on integrin-linked kinase (ILK and total and activated focal adhesion kinase (FAK were also determined. Integrin knock-down was carried out to evaluate integrin influence on migration and adhesion. A 24 h or 2 week amygdalin application distinctly reduced tumor cell adhesion and migration of UMUC-3 and RT112 cells. TCCSUP adhesion was also reduced, but migration was elevated under amygdalin. Integrin subtype expression was significantly and specifically altered by amygdalin depending on the cell line. ILK was moderately, and activated FAK strongly, lost in all tumor cell lines in the presence of amygdalin. Knock down of β1 integrin caused a significant decrease in both adhesion and migration of UMUC-3 cells, but a significant increase in TCCSUP adhesion. Knock down of β4 integrin caused a significant decrease in migration of RT112 cells. Since the different actions of amygdalin on the different cell lines was mirrored by β1 or β4 knock down, it is postulated that amygdalin influences adhesion and migratory properties of bladder cancer cells by modulating β1 or β4 integrin expression. The amygdalin induced increase in TCCSUP migratory behavior indicates that any anti-tumor benefits from amygdalin (seen with the other two cell lines may depend upon the cancer cell type.

  4. Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns

    International Nuclear Information System (INIS)

    cancer cells while favoring the adhesion of normal cells. - Highlights: • Si platforms with cytophobic/philic patterns were developed to program cell growth. • Both nanotopography and chemistry contributed to the cytophobic property. • Cytophobic zones efficiently repel and drive HeLa cells to migrate to adhesive sites. • The approach enables cell patterning, directionality, channelling, and trapping. • This approach paves the way for developing anti-cancer platforms

  5. Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns

    Energy Technology Data Exchange (ETDEWEB)

    Premnath, Priyatha, E-mail: priyatha.premnath@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Tavangar, Amirhossein, E-mail: atavanga@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Tan, Bo, E-mail: tanbo@ryerson.ca [Nanocharacterization Laboratory, Department of Aerospace Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Venkatakrishnan, Krishnan, E-mail: venkat@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada)

    2015-09-10

    cancer cells while favoring the adhesion of normal cells. - Highlights: • Si platforms with cytophobic/philic patterns were developed to program cell growth. • Both nanotopography and chemistry contributed to the cytophobic property. • Cytophobic zones efficiently repel and drive HeLa cells to migrate to adhesive sites. • The approach enables cell patterning, directionality, channelling, and trapping. • This approach paves the way for developing anti-cancer platforms.

  6. Focal adhesions and cell-matrix interactions

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    1988-01-01

    Focal adhesions are areas of cell surfaces where specializations of cytoskeletal, membrane and extracellular components combine to produce stable cell-matrix interactions. The morphology of these adhesions and the components identified in them are discussed together with possible mechanisms of...

  7. Syndecans: synergistic activators of cell adhesion

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    1998-01-01

    Cell-surface proteoglycans participate in cell adhesion, growth-factor signalling, lipase activity and anticoagulation. Until recently, only the roles of the glycosaminoglycan chains were investigated. Now, with molecular characterization of several core proteins, the roles of each individual...... molecules modulating integrin-based adhesion....

  8. Homozygous mutation of focal adhesion kinase in embryonic stem cell derived neurons: normal electrophysiological and morphological properties in vitro

    Directory of Open Access Journals (Sweden)

    Komiyama NH

    2006-06-01

    Full Text Available Abstract Background Genetically manipulated embryonic stem (ES cell derived neurons (ESNs provide a powerful system with which to study the consequences of gene manipulation in mature, synaptically connected neurons in vitro. Here we report a study of focal adhesion kinase (FAK, which has been implicated in synapse formation and regulation of ion channels, using the ESN system to circumvent the embryonic lethality of homozygous FAK mutant mice. Results Mouse ES cells carrying homozygous null mutations (FAK-/- were generated and differentiated in vitro into neurons. FAK-/- ESNs extended axons and dendrites and formed morphologically and electrophysiologically intact synapses. A detailed study of NMDA receptor gated currents and voltage sensitive calcium currents revealed no difference in their magnitude, or modulation by tyrosine kinases. Conclusion FAK does not have an obligatory role in neuronal differentiation, synapse formation or the expression of NMDA receptor or voltage-gated calcium currents under the conditions used in this study. The use of genetically modified ESNs has great potential for rapidly and effectively examining the consequences of neuronal gene manipulation and is complementary to mouse studies.

  9. The effect of terminal sterilization on structural and biophysical properties of a decellularized collagen-based scaffold; implications for stem cell adhesion.

    Science.gov (United States)

    Matuska, Andrea M; McFetridge, Peter S

    2015-02-01

    Terminal sterilization induces physical and chemical changes in the extracellular matrix (ECM) of ex vivo-derived biomaterials due to their aggressive mechanism of action. Prior studies have focused on how sterilization affects the mechanical integrity of tissue-based biomaterials but have rarely characterized effects on early cellular interaction, which is indicative of the biological response. Using a model fibrocartilage disc scaffold, these investigations compare the effect of three common sterilization methods [peracetic acid (PAA), gamma irradiation (GI), and ethylene oxide (EtO)] on a range of material properties and characterized early cellular interactions. GI and EtO produced unfavorable structural damage that contributed to inferior cell adhesion. Conversely, exposure to PAA resulted in limited structural alterations while inducing chemical modifications that favored cell attachment. Results suggest that the sterilization approach can be selected to modulate biomaterial properties to favor cellular adhesion and has relevance in tissue engineering and regenerative medicine applications. Furthermore, the study of cellular interactions with modified biomaterials in vitro provides information of how materials may react in subsequent clinical applications. PMID:24895116

  10. A Review of Cell Adhesion Studies for Biomedical and Biological Applications

    Science.gov (United States)

    Ahmad Khalili, Amelia; Ahmad, Mohd Ridzuan

    2015-01-01

    Cell adhesion is essential in cell communication and regulation, and is of fundamental importance in the development and maintenance of tissues. The mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. The essential function of cell adhesion has created tremendous interests in developing methods for measuring and studying cell adhesion properties. The study of cell adhesion could be categorized into cell adhesion attachment and detachment events. The study of cell adhesion has been widely explored via both events for many important purposes in cellular biology, biomedical, and engineering fields. Cell adhesion attachment and detachment events could be further grouped into the cell population and single cell approach. Various techniques to measure cell adhesion have been applied to many fields of study in order to gain understanding of cell signaling pathways, biomaterial studies for implantable sensors, artificial bone and tooth replacement, the development of tissue-on-a-chip and organ-on-a-chip in tissue engineering, the effects of biochemical treatments and environmental stimuli to the cell adhesion, the potential of drug treatments, cancer metastasis study, and the determination of the adhesion properties of normal and cancerous cells. This review discussed the overview of the available methods to study cell adhesion through attachment and detachment events. PMID:26251901

  11. Physics of cell adhesion: some lessons from cell-mimetic systems

    OpenAIRE

    Sackmann, Erich; Smith, Ana-Sunčana

    2014-01-01

    Cell adhesion is a paradigm of the ubiquitous interplay of cell signalling, modulation of material properties and biological functions of cells. It is controlled by competition of short range attractive forces, medium range repellant forces and the elastic stresses associated with local and global deformation of the composite cell envelopes. We review the basic physical rules governing the physics of cell adhesion learned by studying cell-mimetic systems and demonstrate the importance of thes...

  12. Single-cell force spectroscopy of pili-mediated adhesion

    Science.gov (United States)

    Sullan, Ruby May A.; Beaussart, Audrey; Tripathi, Prachi; Derclaye, Sylvie; El-Kirat-Chatel, Sofiane; Li, James K.; Schneider, Yves-Jacques; Vanderleyden, Jos; Lebeer, Sarah; Dufrêne, Yves F.

    2013-12-01

    Although bacterial pili are known to mediate cell adhesion to a variety of substrates, the molecular interactions behind this process are poorly understood. We report the direct measurement of the forces guiding pili-mediated adhesion, focusing on the medically important probiotic bacterium Lactobacillus rhamnosus GG (LGG). Using non-invasive single-cell force spectroscopy (SCFS), we quantify the adhesion forces between individual bacteria and biotic (mucin, intestinal cells) or abiotic (hydrophobic monolayers) surfaces. On hydrophobic surfaces, bacterial pili strengthen adhesion through remarkable nanospring properties, which - presumably - enable the bacteria to resist high shear forces under physiological conditions. On mucin, nanosprings are more frequent and adhesion forces larger, reflecting the influence of specific pili-mucin bonds. Interestingly, these mechanical responses are no longer observed on human intestinal Caco-2 cells. Rather, force curves exhibit constant force plateaus with extended ruptures reflecting the extraction of membrane nanotethers. These single-cell analyses provide novel insights into the molecular mechanisms by which piliated bacteria colonize surfaces (nanosprings, nanotethers), and offer exciting avenues in nanomedicine for understanding and controlling the adhesion of microbial cells (probiotics, pathogens).

  13. Hierarchical Nanopatterns for Cell Adhesion Studies

    OpenAIRE

    Schwieder, Marco

    2008-01-01

    Hierarchical nanopatterned interfaces are an intriguing tool to study clustering processes of proteins like for example integrins that mediate cell adhesion. The aim of this work is the development of innovative methods for the fabrication of hierarchical micro-nanopatterned surfaces and the use of such systems as platforms to study cell adhesion. In the first part of this work different approaches are presented which are suitable for preparing micro-nanopatterned interfaces at a large scale ...

  14. The FRIABLE1 gene product affects cell adhesion in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Lutz Neumetzler

    Full Text Available Cell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1, was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic defects in organ separation. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246. Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion.

  15. Micropatterning cell adhesion on polyacrylamide hydrogels.

    Science.gov (United States)

    Zhang, Jian; Guo, Wei-Hui; Rape, Andrew; Wang, Yu-Li

    2013-01-01

    Cell shape and substrate rigidity play critical roles in regulating cell behaviors and fate. Controlling cell shape on elastic adhesive materials holds great promise for creating a physiologically relevant culture environment for basic and translational research and clinical applications. However, it has been technically challenging to create high-quality adhesive patterns on compliant substrates. We have developed an efficient and economical method to create precise micron-scaled adhesive patterns on the surface of a hydrogel (Rape et al., Biomaterials 32:2043-2051, 2011). This method will facilitate the research on traction force generation, cellular mechanotransduction, and tissue engineering, where precise controls of both materials rigidity and adhesive patterns are important. PMID:23955741

  16. Properties of Nano SiO2 Modified PVF Adhesive

    Institute of Scientific and Technical Information of China (English)

    CHEN He-sheng; SUN Zhen-ya; XUE Li-hui

    2004-01-01

    Some properties of nano SiO2 modified PVF adhesive were studied. The experimental results show that nano SiO2 can improve the properties of PVF adhesive very well. Meanwhile the modification mechanism of nano SiO2 to PVF adhesive and the applications of this adhesive in paper-plastic composite, concrete and fireproof paint were discussed by using IR and XRD determination.

  17. Cell adhesion molecules: detection with univalent second antibody

    OpenAIRE

    1980-01-01

    Identification of cell surface molecules that play a role in cell-cell adhesion (here called cell adhesion molecules) has been achieved by demonstrating the inhibitory effect of univalent antibodies that bind these molecules in an in vitro assay of cell-cell adhesion. A more convenient reagent, intact (divalent) antibody, has been avoided because it might agglutinate the cells rather than blocking cell-cell adhesion. In this report, we show that intact rabbit immunoglobulin directed against c...

  18. Structural basis of cell-cell adhesion by NCAM

    DEFF Research Database (Denmark)

    Kasper, C; Rasmussen, H; Kastrup, Jette Sandholm Jensen; Ikemizu, S; Jones, E Y; Berezin, V; Bock, E; Larsen, I K

    2000-01-01

    The neural cell adhesion molecule NCAM, a member of the immunoglobulin superfamily, mediates cell-cell recognition and adhesion via a homophilic interaction. NCAM plays a key role during development and regeneration of the nervous system and is involved in synaptic plasticity associated with memory...

  19. Amygdalin Influences Bladder Cancer Cell Adhesion and Invasion In Vitro

    OpenAIRE

    Jasmina Makarević; Jochen Rutz; Eva Juengel; Silke Kaulfuss; Igor Tsaur; Karen Nelson; Jesco Pfitzenmaier; Axel Haferkamp; Blaheta, Roman A.

    2014-01-01

    The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml) was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as...

  20. Anisotropic Adhesion Properties of Triangular-Tip-Shaped Micropillars

    KAUST Repository

    Kwak, Moon Kyu

    2011-06-01

    Directional dry adhesive microstructures consisting of high-density triangular-tip-shaped micropillars are described. The wide-tip structures allow for unique directional shear adhesion properties with respect to the peeling direction, along with relatively high normal adhesion. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The adhesion modulating properties of tenascin-W.

    Science.gov (United States)

    Brellier, Florence; Martina, Enrico; Chiquet, Matthias; Ferralli, Jacqueline; van der Heyden, Michael; Orend, Gertraud; Schittny, Johannes C; Chiquet-Ehrismann, Ruth; Tucker, Richard P

    2012-01-01

    Tenascins are extracellular matrix glycoproteins associated with cell motility, proliferation and differentiation. Tenascin-C inhibits cell spreading by binding to fibronectin; tenascin-R and tenascin-X also have anti-adhesive properties in vitro. Here we have studied the adhesion modulating properties of the most recently characterized tenascin, tenascin-W. C2C12 cells, a murine myoblast cell line, will form broad lamellipodia with stress fibers and focal adhesion complexes after culture on fibronectin. In contrast, C2C12 cells cultured on tenascin-W fail to spread and form stress fibers or focal adhesion complexes, and instead acquire a multipolar shape with short, actin-tipped pseudopodia. The same stellate morphology is observed when C2C12 cells are cultured on a mixture of fibronectin and tenascin-W, or on fibronectin in the presence of soluble tenascin-W. Tenascin-W combined with fibronectin also inhibits the spreading of mouse embryo fibroblasts when compared with cells cultured on fibronectin alone. The similarity between the adhesion modulating effects of tenascin-W and tenascin-C in vitro led us to study the possibility of tenascin-W compensating for tenascin-C in tenascin-C knockout mice, especially during epidermal wound healing. Dermal fibroblasts harvested from a tenascin-C knockout mouse express tenascin-W, but dermal fibroblasts taken from a wild type mouse do not. However, there is no upregulation of tenascin-W in the dermis of tenascin-C knockout mice, or in the granulation tissue of skin wounds in tenascin-C knockout animals. Similarly, tenascin-X is not upregulated in early wound granulation tissue in the tenascin-C knockout mice. Thus, tenascin-W is able to inhibit cell spreading in vitro and it is upregulated in dermal fibroblasts taken from the tenascin-C knockout mouse, but neither it nor tenascin-X are likely to compensate for missing tenascin-C during wound healing. PMID:22211116

  2. The Adhesion Modulating Properties of Tenascin-W

    Directory of Open Access Journals (Sweden)

    Florence Brellier, Enrico Martina, Matthias Chiquet, Jacqueline Ferralli, Michael van der Heyden, Gertraud Orend, Johannes C. Schittny, Ruth Chiquet-Ehrismann, Richard P. Tucker

    2012-01-01

    Full Text Available Tenascins are extracellular matrix glycoproteins associated with cell motility, proliferation and differentiation. Tenascin-C inhibits cell spreading by binding to fibronectin; tenascin-R and tenascin-X also have anti-adhesive properties in vitro. Here we have studied the adhesion modulating properties of the most recently characterized tenascin, tenascin-W. C2C12 cells, a murine myoblast cell line, will form broad lamellipodia with stress fibers and focal adhesion complexes after culture on fibronectin. In contrast, C2C12 cells cultured on tenascin-W fail to spread and form stress fibers or focal adhesion complexes, and instead acquire a multipolar shape with short, actin-tipped pseudopodia. The same stellate morphology is observed when C2C12 cells are cultured on a mixture of fibronectin and tenascin-W, or on fibronectin in the presence of soluble tenascin-W. Tenascin-W combined with fibronectin also inhibits the spreading of mouse embryo fibroblasts when compared with cells cultured on fibronectin alone. The similarity between the adhesion modulating effects of tenascin-W and tenascin-C in vitro led us to study the possibility of tenascin-W compensating for tenascin-C in tenascin-C knockout mice, especially during epidermal wound healing. Dermal fibroblasts harvested from a tenascin-C knockout mouse express tenascin-W, but dermal fibroblasts taken from a wild type mouse do not. However, there is no upregulation of tenascin-W in the dermis of tenascin-C knockout mice, or in the granulation tissue of skin wounds in tenascin-C knockout animals. Similarly, tenascin-X is not upregulated in early wound granulation tissue in the tenascin-C knockout mice. Thus, tenascin-W is able to inhibit cell spreading in vitro and it is upregulated in dermal fibroblasts taken from the tenascin-C knockout mouse, but neither it nor tenascin-X are likely to compensate for missing tenascin-C during wound healing.

  3. The Adhesion Modulating Properties of Tenascin-W

    Science.gov (United States)

    Brellier, Florence; Martina, Enrico; Chiquet, Matthias; Ferralli, Jacqueline; van der Heyden, Michael; Orend, Gertraud; Schittny, Johannes C.; Chiquet-Ehrismann, Ruth; Tucker, Richard P.

    2012-01-01

    Tenascins are extracellular matrix glycoproteins associated with cell motility, proliferation and differentiation. Tenascin-C inhibits cell spreading by binding to fibronectin; tenascin-R and tenascin-X also have anti-adhesive properties in vitro. Here we have studied the adhesion modulating properties of the most recently characterized tenascin, tenascin-W. C2C12 cells, a murine myoblast cell line, will form broad lamellipodia with stress fibers and focal adhesion complexes after culture on fibronectin. In contrast, C2C12 cells cultured on tenascin-W fail to spread and form stress fibers or focal adhesion complexes, and instead acquire a multipolar shape with short, actin-tipped pseudopodia. The same stellate morphology is observed when C2C12 cells are cultured on a mixture of fibronectin and tenascin-W, or on fibronectin in the presence of soluble tenascin-W. Tenascin-W combined with fibronectin also inhibits the spreading of mouse embryo fibroblasts when compared with cells cultured on fibronectin alone. The similarity between the adhesion modulating effects of tenascin-W and tenascin-C in vitro led us to study the possibility of tenascin-W compensating for tenascin-C in tenascin-C knockout mice, especially during epidermal wound healing. Dermal fibroblasts harvested from a tenascin-C knockout mouse express tenascin-W, but dermal fibroblasts taken from a wild type mouse do not. However, there is no upregulation of tenascin-W in the dermis of tenascin-C knockout mice, or in the granulation tissue of skin wounds in tenascin-C knockout animals. Similarly, tenascin-X is not upregulated in early wound granulation tissue in the tenascin-C knockout mice. Thus, tenascin-W is able to inhibit cell spreading in vitro and it is upregulated in dermal fibroblasts taken from the tenascin-C knockout mouse, but neither it nor tenascin-X are likely to compensate for missing tenascin-C during wound healing. PMID:22211116

  4. Cell adhesion behavior on the silicone rubber surface modified by using ion beam irradiation

    International Nuclear Information System (INIS)

    In this study we studied cell adhesion and proliferation on the surface of a silicone rubber modified by ion beam irradiation. The surface property of the irradiated silicone rubber was characterized by water contact angle and FT-IR analyses. It was observed that human (HEK293) fibroblast cells exhibit strong adhesion to the irradiated silicone surface. This enhanced adhesion of mammalian cells can be attributed to the increase in the hydrophilicity of the silicone surface by ion beam irradiation

  5. Physics of cell adhesion: some lessons from cell-mimetic systems

    Science.gov (United States)

    Sackmann, Erich; Smith, Ana-Sunčana

    2014-01-01

    Cell adhesion is a paradigm of the ubiquitous interplay of cell signalling, modulation of material properties and biological functions of cells. It is controlled by competition of short range attractive forces, medium range repellant forces and the elastic stresses associated with local and global deformation of the composite cell envelopes. We review the basic physical rules governing the physics of cell adhesion learned by studying cell-mimetic systems and demonstrate the importance of these rules in the context of cellular systems. We review how adhesion induced micro-domains couple to the intracellular actin and microtubule networks allowing cells to generate strong forces with a minimum of attractive cell adhesion molecules (CAMs) and to manipulate other cells through filopodia over micrometer distances. The adhesion strength can be adapted to external force fluctuations within seconds by varying the density of attractive and repellant CAMs through exocytosis and endocytosis or protease-mediated dismantling of the CAM–cytoskeleton link. Adhesion domains form local end global biochemical reaction centres enabling the control of enzymes. Actin–microtubule crosstalk at adhesion foci facilitates the mechanical stabilization of polarized cell shapes. Axon growth in tissue is guided by attractive and repulsive clues controlled by antagonistic signalling pathways. PMID:24651316

  6. Adhesion property of epoxidized natural rubber (ENR-based adhesives containing calcium carbonate

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The adhesion property (i.e. viscosity, loop tack and peel strength of epoxidized natural rubber (ENR 25 and ENR 50 grade-based pressure-sensitive adhesive was studied in the presence of calcium carbonate. The range of calcium carbonate loaded was from 10 to 50 parts per hundred parts of rubber (phr. Coumarone-indene resin was used as the tackifier and its concentration was fixed at 80 phr. Toluene was chosen as the solvent throughout the investigation. The substrates (PET film/paper were coated with the adhesive using a SHEEN hand coater at a coating thickness of 60 µm. Viscosity of the adhesive was measured by a HAAKE Rotary Viscometer whereas loop tack and peel strength were determined by a Llyod Adhesion Tester operating at 30 cm/min. Results show that viscosity of ENR-based adhesives increases gradually with increase in calcium carbonate loading due to the concentration effect of the filler. However, for loop tack and peel strength, it passes through a maximum at 30 phr calcium carbonate, an observation which is attributed to the optimum wettability of adhesive on the substrate at this adhesive composition. ENR 25-based adhesive consistently exhibits higher adhesion property than ENR 50 for all calcium carbonate loadings studied.

  7. Single Cell Adhesion Assay Using Computer Controlled Micropipette

    OpenAIRE

    Rita Salánki; Csaba Hős; Norbert Orgovan; Beatrix Péter; Noémi Sándor; Zsuzsa Bajtay; Anna Erdei; Robert Horvath; Bálint Szabó

    2014-01-01

    Cell adhesion is a fundamental phenomenon vital for all multicellular organisms. Recognition of and adhesion to specific macromolecules is a crucial task of leukocytes to initiate the immune response. To gain statistically reliable information of cell adhesion, large numbers of cells should be measured. However, direct measurement of the adhesion force of single cells is still challenging and today's techniques typically have an extremely low throughput (5-10 cells per day). Here, we introduc...

  8. Effects of DNP on the cell surface properties of marine bacteria and its implication for adhesion to surfaces

    Digital Repository Service at National Institute of Oceanography (India)

    Jain, A.; Nishad, K.K.; Bhosle, N.B.

    The effect of 2, 4-dinitrophenol (DNP) on extracelluar polysaccharides (EPS), cell surface charge, and hydrophobicity of six marine bacterial cultures was studied, and its influence on attachment of these bacteria to glass and polystyrene...

  9. Mutant p53 in cell adhesion and motility.

    Science.gov (United States)

    Yeudall, W Andrew; Wrighton, Katharine H; Deb, Sumitra

    2013-01-01

    Pro-oncogenic properties of mutant p53 were investigated with the aid of migration assays, adhesion assays, and soft agar growth assays using cells stably expressing gain-of-function p53 mutants. To determine cell migration, "wound-healing" (scratch) assays and haptotactic (chamber) assays were used. H1299 cells expressing mutant p53 were found to migrate more rapidly than cells transfected with empty vector alone. Results from both types of migration assay were broadly similar. Migratory ability differed for different p53 mutants, suggesting allele-specific effects. Cells expressing p53 mutants also showed enhanced adhesion to extracellular matrix compare to controls. Furthermore, stable transfection of mutant p53-H179L into NIH3T3 fibroblasts was sufficient to allow anchorage-independent growth in soft agar. PMID:23150443

  10. The Rheological Property of Potato Starch Adhesives

    Directory of Open Access Journals (Sweden)

    Junjun Liu

    2014-02-01

    Full Text Available The main goal of this study was to use potato starch in the production of environmentally sound adhesives. ‘Three-formaldehyde glue’ pollutes the environment and harms to human health strongly, which widely used for wood-based panels preparation. Environment-friendly potato starch adhesives were prepared using method of oxidation-gelatinization, insteading of the three formaldehyde glue. The effects of the quality ratio of starch and water, temperature and shear rate on the apparent viscosity of the adhesive were studied. The rheological eigenvalue of apparent viscosity was studied through nonlinear regression. The results showed that the apparent viscosity of potato starch adhesives decreased with the increasing of temperature; the apparent viscosity decreased slowly with the increasing of rotor speed; the phenomenon of shear thinning appeared within potato starch adhesives which was pseudo-plastic fluids. Potato starch adhesives with characteristics of non-toxic, no smell and pollution could be applied in interior and upscale packaging.

  11. Cytoskeletal and Focal Adhesion Influences on Mesenchymal Stem Cell Shape, Mechanical Properties, and Differentiation Down Osteogenic, Adipogenic, and Chondrogenic Pathways

    OpenAIRE

    Mathieu, Pattie S.; Loboa, Elizabeth G

    2012-01-01

    Mesenchymal stem cells (MSCs) hold great potential for regenerative medicine and tissue-engineering applications. They have multipotent differentiation capabilities and have been shown to differentiate down various lineages, including osteoblasts, adipocytes, chondrocytes, myocytes, and possibly neurons. The majority of approaches to control the MSC fate have been via the use of chemical factors in the form of growth factors within the culture medium. More recently, it has been understood tha...

  12. Optical biosensors for cell adhesion.

    Science.gov (United States)

    Ramsden, Jeremy J; Horvath, Robert

    2009-01-01

    Planar optical waveguides offer an ideal substratum for cells on which to reside. The materials from which the waveguides are made--high refractive index transparent dielectrics--correspond to the coatings of medical implants (e.g., the oxides of niobium, tantalum, and titanium) or the high molecular weight polymers used for culture flasks (e.g., polystyrene). The waveguides can furthermore be modified both chemically and morphologically while retaining their full capability for generating an evanescent optical field that has its greatest strength at the interface between the solid substratum and the liquid phase with which it is invariably in contact (i.e., the culture medium bathing the cells), decaying exponentially perpendicular to the interface at a rate controllable by varying the material parameters of the waveguide. Analysis of the perturbation of the evanescent field by the presence of living cells within it enables their size, number density, shape, refractive index (linked to their constitution) and so forth to be determined, the number of parameters depending on the number of waveguide lightmodes analyzed. No labeling of any kind is necessary, and convenient measurement setups are fully compatible with maintaining the cells in their usual environment. If the temporal evolution of the perturbation is analyzed, even more information can be obtained, such as the amount of material (microexudate) secreted by the cell while residing on the surface. Separation of parallel effects simultaneously contributing to the perturbation of the evanescent field can be accomplished by analysis of coupling peak shape when a grating coupler is used to measure the propagation constants of the waveguide lightmodes. PMID:19635032

  13. Cell adhesion in regulation of asymmetric stem cell division

    OpenAIRE

    Yamashita, Yukiko M

    2010-01-01

    Adult stem cells inevitably communicate with their cellular neighbors within the tissues they sustain. Indeed, such communication, particularly with components of the stem cell niche, is essential for many aspects of stem cell behavior, including the maintenance of stem cell identity and asymmetric cell division. Cell adhesion mediates this communication by placing stem cells in close proximity to the signaling source and by providing a polarity cue that orients stem cells. Here, I review the...

  14. Adhesion of cells to polystyrene surfaces

    OpenAIRE

    1983-01-01

    The surface treatment of polystyrene, which is required to make polystyrene suitable for cell adhesion and spreading, was investigated. Examination of surfaces treated with sulfuric acid or various oxidizing agents using (a) x-ray photoelectron and attenuated total reflection spectroscopy and (b) measurement of surface carboxyl-, hydroxyl-, and sulfur-containing groups by various radiochemical methods showed that sulfuric acid produces an insignificant number of sulfonic acid groups on polyst...

  15. Caspr2 : possible synaptogenic cell adhesion molecule

    OpenAIRE

    Do, Trinh Thuy

    2011-01-01

    Synapses are crucial for communication among neurons in the central nervous system. Contactin-associated protein- like 2 (Caspr2) is a neuronal protein that is a member of the neurexin superfamily and is found in the juxtaparanodal regions of myelinated axons. Caspr2 has also been found in synapses and therefore is also thought to function as a cell adhesion molecule. As such, it should also induce synaptogenesis in vitro similar to the interaction between neurexins (located presynaptically) ...

  16. Cell adhesion and proliferation on modified polyethylene

    Czech Academy of Sciences Publication Activity Database

    Kasálková, N.; Kolářová, K.; Bačáková, Lucie; Pařízek, Martin; Macková, Anna; Švorčík, V.

    ZURICH: TRANS TECH PUBLICATIONS LTD, 2008 - (Sandera, P.), s. 269-272. (MATERIALS SCIENCE FORUM. 567-568). ISSN 0255-5476. [5th International Conference on Materials Structure & Micromechanics of Fracture. Brno (CZ), 27.06.2007-29.06.2007] Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z50110509 Keywords : polyethylene * plasma modification * cell adhesion and proliferation Subject RIV: BO - Biophysics

  17. An adhesion-dependent switch between mechanisms that determine motile cell shape.

    Directory of Open Access Journals (Sweden)

    Erin L Barnhart

    2011-05-01

    Full Text Available Keratocytes are fast-moving cells in which adhesion dynamics are tightly coupled to the actin polymerization motor that drives migration, resulting in highly coordinated cell movement. We have found that modifying the adhesive properties of the underlying substrate has a dramatic effect on keratocyte morphology. Cells crawling at intermediate adhesion strengths resembled stereotypical keratocytes, characterized by a broad, fan-shaped lamellipodium, clearly defined leading and trailing edges, and persistent rates of protrusion and retraction. Cells at low adhesion strength were small and round with highly variable protrusion and retraction rates, and cells at high adhesion strength were large and asymmetrical and, strikingly, exhibited traveling waves of protrusion. To elucidate the mechanisms by which adhesion strength determines cell behavior, we examined the organization of adhesions, myosin II, and the actin network in keratocytes migrating on substrates with different adhesion strengths. On the whole, our results are consistent with a quantitative physical model in which keratocyte shape and migratory behavior emerge from the self-organization of actin, adhesions, and myosin, and quantitative changes in either adhesion strength or myosin contraction can switch keratocytes among qualitatively distinct migration regimes.

  18. Characterization of adhesive interactions between human endothelial cells and megakaryocytes.

    OpenAIRE

    Avraham, H; Cowley, S; Chi, S. Y.; Jiang, S.; Groopman, J E

    1993-01-01

    Cell-cell adhesion is essential for many immunological functions and is believed to be important in the regulation of hematopoiesis. Adhesive interactions between human endothelial cells and megakaryocytes were characterized in vitro using the CMK megakaryocytic cell line as well as marrow megakaryocytes. Although there was no adhesion between unactivated human umbilical vein endothelial cells (HUVEC) and megakaryocytes, treatment of HUVEC with inflammatory cytokines such as IL-1 beta, tumor ...

  19. Preparation and Properties of Cornstarch Adhesives

    Directory of Open Access Journals (Sweden)

    Li Yang

    2013-08-01

    Full Text Available The main goal of this study was to use cornstarch in the production of environmentally sound adhesives. ‘Three-formaldehyde glue’ pollutes the environment and harms to human health strongly, which widely used for wood-based panels preparation. Environment-friendly cornstarch adhesives were prepared using method of oxidation-gelatinization, insteading of the three formaldehyde glue. The effects of the quality ratio of starch and water, temperature and shear rate on the apparent viscosity of the adhesive were studied. The rheological eigenvalue of apparent viscosity was studied through nonlinear regression. The results showed that the apparent viscosity of cornstarch adhesives increased and then decreased with the increasing of temperature and the maximum value was obtained at 10oC; the apparent viscosity decreased slowly with the increasing of rotor speed; the phenomenon of shear thinning appeared wither cornstarch adhesives which was pseudo-plastic fluids. Cornstarch adhesives with characteristics of non-toxic, no smell and pollution could be applied in interior and upscale packaging.

  20. Maspin Regulates Endothelial Cell Adhesion and Migration through an Integrin Signaling Pathway*

    OpenAIRE

    Qin, Li; Zhang, Ming

    2010-01-01

    Maspin has been identified as a potent angiogenesis inhibitor. However, the molecular mechanism responsible for its anti-angiogenic property is unclear. In this study, we examined the effect of maspin on endothelial cell (EC) adhesion and migration in a cell culture system. We found that maspin was expressed in blood vessels ECs and human umbilical vein endothelial cells (HUVECs). Maspin significantly enhanced HUVEC cell adhesion to various matrix proteins. This effect was dependent on the ac...

  1. Cell Adhesion on Surface-Functionalized Magnesium.

    Science.gov (United States)

    Wagener, Victoria; Schilling, Achim; Mainka, Astrid; Hennig, Diana; Gerum, Richard; Kelch, Marie-Luise; Keim, Simon; Fabry, Ben; Virtanen, Sannakaisa

    2016-05-18

    The biocompatibility of commercially pure magnesium-based (cp Mg) biodegradable implants is compromised of strong hydrogen evolution and surface alkalization due to high initial corrosion rates of cp Mg in the physiological environment. To mitigate this problem, the addition of corrosion-retarding alloying elements or coating of implant surfaces has been suggested. In the following work, we explored the effect of organic coatings on long-term cell growth. cp Mg was coated with aminopropyltriehtoxysilane + vitamin C (AV), carbonyldiimidazole (CDI), or stearic acid (SA). All three coatings have been previously suggested to reduce initial corrosion and to enhance protein adsorption and hence cell adhesion on magnesium surfaces. Endothelial cells (DH1+/+) and osteosarcoma cells (MG63) were cultured on coated samples for up to 20 days. To quantify Mg corrosion, electrochemical impedance spectroscopy (EIS) was measured after 1, 3, and 5 days of cell culture. We also investigated the speed of initial cell spreading after seeding using fluorescently labeled fibroblasts (NIH/3T3). Hydrogen evolution after contact with cell culture medium was markedly decreased on AV- and SA-coated Mg compared to uncoated Mg. These coatings also showed improved cell adhesion and spreading after 24 h of culture comparable to tissue-treated plastic surfaces. On AV-coated cp Mg, a confluent layer of endothelial cells formed after 5 days and remained intact for up to 20 days. Together, these data demonstrate that surface coating with AV is a viable strategy for improving long-term biocompatibility of cp Mg-based implants. EIS measurements confirmed that the presence of a confluent cell layer increased the corrosion resistance. PMID:27089250

  2. Cooperative inhibitory effects of antisense oligonucleotide of cell adhesion molecules and cimetidine on cancer cell adhesion

    Institute of Scientific and Technical Information of China (English)

    Nan-Hong Tang; Yan-Ling Chen; Xiao-Qian Wang; Xiu-Jin Li; Feng-Zhi Yin; Xiao-Zhong Wang

    2004-01-01

    AIM: To explore the cooperative effects of antisense oligonucleotide (ASON) of cell adhesion molecules and cimetidine on the expression of E-selectin and ICAM-1 in endothelial cells and their adhesion to tumor cells.METHODS: After treatment of endothelial cells with ASON and/or cimetidine and induction with TNF-α, the protein and mRNA changes of E-selectin and ICAM-1 in endothelial cells were examined by flow cytometry and RT-PCR,respectively. The adhesion rates of endothelial cells to tumor cells were measured by cell adhesion experiment.RESULTS: In comparison with TNF-α inducing group, lipoASON and lipo-ASON/cimetidine could significantly decrease the protein and mRNA levels of E-selectin and ICAM-1 in endothelial cells, and lipo-ASON/cimetidine had most significant inhibitory effect on E-selectin expression (from 36.37±1.56% to 14.23±1.07%, P<0.001). Meanwhile,cimetidine alone could inhibit the expression of E-selectin (36.37±1.56% vs 27.2±1.31%, P<0.001), but not ICAM-1 (69.34±2.50% vs68.07±2.10%,P>O.05)and the two kinds of mRNA, either. Compared with TNF-αα inducing group, the rate of adhesion was markedly decreased in lipo-E-selectin ASON and lipo-E-selectin ASON/cimetidine treated groups(P<0.05),and Jipo-E-selectin ASON/cimetidine worked better than lipo-E-selectin ASON alone except for HepG2/ECV304 group(P<0.05). However, the decrease of adhesion was not significant in lipo-ICAM-1 ASON and lipo-ICAM-1 ASON/cimetidine treated groups except for HepG2/ECV304 group (P >0.05).CONCLUSION: These data demonstrate that ASON in combination with cimetidine in vitro can significantly reduce the adhesion between endothelial cells and hepatic or colorectal cancer cells, which is stronger than ASON or cimetidine alone. This study provides some useful proofs for gene therapy of antiadhesion.

  3. Soy protein isolate molecular level contributions to bulk adhesive properties

    Science.gov (United States)

    Shera, Jeanne Norton

    Increasing environmental awareness and the recognized health hazards of formaldehyde-based resins has prompted a strong demand for environmentally-responsible adhesives for wood composites. Soy protein-based adhesives have been shown to be commercially viable with 90-day shelf stability and composite physical properties comparable to those of commercial formaldehyde-based particleboards. The main research focus is to isolate and characterize the molecular level features in soy protein isolate responsible for providing mechanical properties, storage stability, and water resistance during adhesive formulation, processing, and wood composite fabrication. Commercial composite board will be reviewed to enhance our understanding of the individual components and processes required for particleboard production. The levels of protein structure will be defined and an overview of current bio-based technology will be presented. In the process, the logic for utilizing soy protein as a sole binder in the adhesive will be reinforced. Variables such as adhesive components, pH, divalent ions, blend aging, protein molecular weight, formulation solids content, and soy protein functionalization will relate the bulk properties of soy protein adhesives to the molecular configuration of the soybean protein. This work has demonstrated that when intermolecular beta-sheet interactions and protein long-range order is disrupted, viscosity and mechanical properties decrease. Storage stability can be maintained through the stabilization of intermolecular beta-sheet interactions. When molecular weight is reduced through enzymatic digestion, long-range order is disrupted and viscosity and mechanical properties decrease accordingly. Processibility and physical properties must be balanced to increase solids while maintaining low viscosity, desirable mechanical properties, and adequate storage stability. The structure of the soybean protein must be related to the particleboard bulk mechanical

  4. Cell-matrix adhesion characterization using multiple shear stress zones in single stepwise microchannel

    Science.gov (United States)

    Kim, Min-Ji; Doh, Il; Bae, Gab-Yong; Cha, Hyuk-Jin; Cho, Young-Ho

    2014-08-01

    This paper presents a cell chip capable to characterize cell-matrix adhesion by monitoring cell detachment rate. The proposed cell chip can supply multiple levels of shear stress in single stepwise microchannel. As epithelial-mesenchymal transition (EMT), one of hallmarks of cancer metastasis is closely associated to the interaction with extracelluar matrix (ECM), we took advantage of two lung cancer cell models with different adhesion properties to ECM depending their epithelial or mesenchymal properties, including the pair of lung cancer cells with (A549sh) or without E-cadherin expression (A549sh-Ecad), which would be optimal model to examine the alteration of adhesion properties after EMT induction. The cell-matrix adhesion resisting to shear stress appeared to be remarkably differed between lung cancer cells. The detachment rate of epithelial-like H358 and mesenchymal-like H460 cells was 53%-80% and 25%-66% in the shear stress range of 34-60 dyn/cm2, respectively. A549sh-Ecad cells exhibits lower detachment rate (5%-9%) compared to A549sh cells (14%-40%). By direct comparison of adhesion between A549sh and A549sh-Ecad, we demonstrated that A549shE-cad to mimic EMT were more favorable to the ECM attachment under the various levels of shear stress. The present method can be applied to quantitative analysis of tumor cell-ECM adhesion.

  5. Improved adhesive properties of recombinant bifidobacteria expressing the Bifidobacterium bifidum-specific lipoprotein BopA

    Directory of Open Access Journals (Sweden)

    Gleinser Marita

    2012-06-01

    Full Text Available Abstract Background Bifidobacteria belong to one of the predominant bacterial groups in the intestinal microbiota of infants and adults. Several beneficial effects on the health status of their human hosts have been demonstrated making bifidobacteria interesting candidates for probiotic applications. Adhesion of probiotics to the intestinal epithelium is discussed as a prerequisite for colonisation of and persistence in the gastrointestinal tract. Results In the present study, 15 different strains of bifidobacteria were tested for adhesion. B. bifidum was identified as the species showing highest adhesion to all tested intestinal epithelial cell (IEC lines. Adhesion of B. bifidum S17 to IECs was strongly reduced after treatment of bacteria with pronase. These results strongly indicate that a proteinaceous cell surface component mediates adhesion of B. bifidum S17 to IECs. In silico analysis of the currently accessible Bifidobacterium genomes identified bopA encoding a lipoprotein as a B. bifidum-specific gene previously shown to function as an adhesin of B. bifidum MIMBb75. The in silico results were confirmed by Southern Blot analysis. Furthermore, Northern Blot analysis demonstrated that bopA is expressed in all B. bifidum strains tested under conditions used to cultivate bacteria for adhesion assays. The BopA gene was successfully expressed in E. coli and purified by Ni-NTA affinity chromatography as a C-terminal His6-fusion. Purified BopA had an inhibitory effect on adhesion of B. bifidum S17 to IECs. Moreover, bopA was successfully expressed in B. bifidum S17 and B. longum/infantis E18. Strains overexpressing bopA showed enhanced adhesion to IECs, clearly demonstrating a role of BopA in adhesion of B. bifidum strains. Conclusions BopA was identified as a B. bifidum-specific protein involved in adhesion to IECs. Bifidobacterium strains expressing bopA show enhanced adhesion. Our results represent the first report on recombinant

  6. 肾小管上皮细胞与基底膜的粘附力学特性%The adhesive mechanical properties of renal tubular epithelial cells on matrigel

    Institute of Scientific and Technical Information of China (English)

    宋关斌; 俞为群; 王东; 吴雄飞

    2000-01-01

    purpose: to investigate the adhesive properties of renal tubular epithelial cells on matrigel and compared with the following three cases: ischemia、hypoxia and ischemia & hypoxia(I/H).materials and methods: A micropipette aspiration technique was adopted to determine the adhesive mechanics of renal tubular epithelial cells on matrige. results: it showed that the adhesion of renal tubular epithelial cells on matrigel was higher than that of those three model, further more, a different factor was followed by different adhesive mechanic. conclusion: the adhesion of I/H is lower, the ischemia is higher, but all were lower compared with control. It suggested that effect of hypoxia on adhesive properties of renal tubular epithelial cells on matrigel is bigger than that of ichemia.%目的:研究模拟缺血、缺氧、缺血缺氧三种条件下肾小管上皮细胞与基底膜的粘附力学特性。材料与方法:利用微管吸吮技术测定肾小管上皮细胞与人工基底膜的粘附力。结果:模拟缺血、缺氧、缺血缺氧三种模型中肾小管上皮细胞与基底膜的粘附力均较正常情况明显降低。结论:不同模拟损伤因素对粘附力的影响不同,其中缺血缺氧组粘附力最小,单纯缺血组的影响较小。这些结果提示,在一定条件下,氧缺乏比缺血情况更能影响肾小管上皮细胞与基底膜的粘附作用。

  7. Adhesion of Aeromonas sp. to cell lines used as models for intestinal adhesion.

    OpenAIRE

    Kirov, S M; Hayward, L. J.; Nerrie, M. A.

    1995-01-01

    Adhesion to HEp-2 cells has been shown to correlate with enteropathogenicity for Aeromonas species. Such adhesion is thought to reflect the ability of strains to adhere to human intestinal enterocytes, although HEp-2 cells are not of intestinal origin. In this study strains of Aeromonas veronii biotype sobria isolated from various sources were investigated in parallel assays for their ability to adhere to HEp-2 cells and to an intestinal cell line (Caco-2). Quantitative assays showed identica...

  8. Anti-adhesive properties of fish tropomyosins

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Bernbom, Nete; Gram, Lone;

    2008-01-01

    Aims: We have recently found that preconditioning of stainless steel surfaces with an aqueous fish muscle extract can significantly impede bacterial adhesion. The purpose of this study was to identify and characterize the primary components associated with this bacteria-repelling effect. Methods...

  9. Wet-chemical approach for the cell-adhesive modification of polytetrafluoroethylene

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, Matthias; Dahm, Manfred; Vahl, Christian-F, E-mail: mgabriel@uni-mainz.de [Department of Cardiothoracic and Vascular Surgery, Johannes Gutenberg-University School of Medicine, Mainz (Germany)

    2011-06-15

    Polytetrafluoroethylene (PTFE), a frequently utilized polymer for the fabrication of synthetic vascular grafts, was surface-modified by means of a wet-chemical process. The inherently non-cell-adhesive polymer does not support cellular attachment, a prerequisite for the endothelialization of luminal surface grafts in small diameter applications. To impart the material with cell-adhesive properties a treatment with sodium-naphthalene provided a basis for the subsequent immobilization of the adhesion promoting RGD-peptide using a hydroxy- and amine-reactive crosslinker. Successful conjugation was shown with cell culture experiments which demonstrated excellent endothelial cell growth on the modified surfaces.

  10. Fulvic Acid Attenuates Resistin-Induced Adhesion of HCT-116 Colorectal Cancer Cells to Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Wen-Shih Huang

    2015-12-01

    Full Text Available A high level of serum resistin has recently been found in patients with a number of cancers, including colorectal cancer (CRC. Hence, resistin may play a role in CRC development. Fulvic acid (FA, a class of humic substances, possesses pharmacological properties. However, the effect of FA on cancer pathophysiology remains unclear. The aim of this study was to investigate the effect of resistin on the endothelial adhesion of CRC and to determine whether FA elicits an antagonistic mechanism to neutralize this resistin effect. Human HCT-116 (p53-negative and SW-48 (p53-positive CRC cells and human umbilical vein endothelial cells (HUVECs were used in the experiments. Treatment of both HCT-116 and SW-48 cells with resistin increases the adhesion of both cells to HUVECs. This result indicated that p53 may not regulate this resistin effect. A mechanistic study in HCT-116 cells further showed that this resistin effect occurs via the activation of NF-κB and the expression of intercellular adhesion molecule-1 (ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1. Co-treating cells with both FA and resistin revealed that FA significantly attenuated the resistin-increased NF-κB activation and ICAM-1/VCAM-1 expression and the consequent adhesion of HCT-116 cells to HUVECs. These results demonstrate the role of resistin in promoting HCT-116 cell adhesion to HUVECs and indicate that FA might be a potential candidate for the inhibition of the endothelial adhesion of CRC in response to resistin.

  11. Detecting cell-adhesive sites in extracellular matrix using force spectroscopy mapping

    International Nuclear Information System (INIS)

    The cell microenvironment is composed of extracellular matrix (ECM), which contains specific binding sites that allow the cell to adhere to its surroundings. Cells employ focal adhesion proteins, which must be able to resist a variety of forces to bind to ECM. Current techniques for detecting the spatial arrangement of these adhesions, however, have limited resolution and those that detect adhesive forces lack sufficient spatial characterization or resolution. Using a unique application of force spectroscopy, we demonstrate here the ability to determine local changes in the adhesive property of a fibronectin substrate down to the resolution of the fibronectin antibody-functionalized tip diameter, ∼ 20 nm. To verify the detection capabilities of force spectroscopy mapping (FSM), changes in loading rate and temperature were used to alter the bond dynamics and change the adhesion force. Microcontact printing was also used to pattern fluorescein isothiocyanate-conjugated fibronectin in order to mimic the discontinuous adhesion domains of native ECM. Fluorescent detection was used to identify the pattern while FSM was used to map cell adhesion sites in registry with the initial fluorescent image. The results show that FSM can be used to detect the adhesion domains at high resolution and may subsequently be applied to native ECM with randomly distributed cell adhesion sites.

  12. Dynamic force spectroscopy to probe adhesion strength of living cells

    OpenAIRE

    Prechtel, K.; Bausch, A. R.; Marchi-Artzner, V.; Kantlehner, M.; Kessler, H; Merkel, R

    2002-01-01

    We studied the mechanical strength of the adhesion of living cells to model membranes. The latter contained a RGD lipopeptide which is a high affinity binding site for a cell adhesion molecule (integrin alpha(V)beta(3)). Cells adhered specifically to the vesicles. We used micropipette aspiration for breaking this adhesion with well defined forces. Systematic variation of the rate of force application revealed pronounced kinetic effects. The dependence of the detachment forces on the loading r...

  13. Adhesive properties of Staphylococcus epidermidis probed by atomic force microscopy

    DEFF Research Database (Denmark)

    Hu, Yifan; Ulstrup, Jens; Zhang, Jingdong;

    2011-01-01

    (biofilm positive and biofilm negative strains) were analyzed using in situ atomic force microscopy (AFM). Force measurements performed using bare hydrophilic silicon nitride tips disclosed similar adhesive properties for each strain. However, use of hydrophobic tips showed that hydrophobic forces are not......Mapping of the surface properties of Staphylococcus epidermidis and of biofilm forming bacteria in general is a key to understand their functions, particularly their adhesive properties. To gain a comprehensive view of the structural and chemical properties of S. epidermidis, four different strains...

  14. Relationship between the adhesive properties of bacteria and their transport and colonization in the subsurface environment. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, M.

    1997-03-13

    The adhesion of bacteria to sediment particle or rock surfaces considerably effects their transport in subsurface environments. This research focuses on the macromolecular properties of bacteria that determine their adhesiveness and on the significance of adhesion in transport of subsurface bacteria. Specific objectives include (1) to obtain adhesion mutants of subsurface Pseudomonas species altered in surface adhesives; (2) to determine alterations in adhesives in selected mutants; (3) to evaluate the effect of adhesiveness on transport and long-term distribution and colonization of bacteria in porous media. Primary methods will be tranposon mutagenesis to generate adhesion mutants, biochemical analyses of cell surface polymers, and the use of laboratory columns containing subsurface materials to study the distribution and transport of bacteria along flow paths over time.

  15. Adhesive properties of PTFE modified by DC discharge

    International Nuclear Information System (INIS)

    It is shown that low-pressure DC discharge treatment of PTFE films at both the anode and cathode leads to substantial enhancement of the contact properties of the polymer surface and alters considerably the adhesion properties of PTFE film surface. A procedure is developed for determination the adhesion characteristics of the modified surface of plasma treated thin polymer films using Scotch® 810 adhesive tape. The procedure comprises of a study of the surface coating created by means of physical vapor deposition of an aluminum layer with thickness of the order of 100 nm, an adhesive joint of the film with Scotch® 810 tape, and T-peel testing of the specimen. Using this procedure, the peel resistance of the initial and the modified PTFE film on both the anode and the cathode in DC discharge is measured.

  16. A cell cycle and nutritional checkpoint controlling bacterial surface adhesion.

    Directory of Open Access Journals (Sweden)

    Aretha Fiebig

    2014-01-01

    Full Text Available In natural environments, bacteria often adhere to surfaces where they form complex multicellular communities. Surface adherence is determined by the biochemical composition of the cell envelope. We describe a novel regulatory mechanism by which the bacterium, Caulobacter crescentus, integrates cell cycle and nutritional signals to control development of an adhesive envelope structure known as the holdfast. Specifically, we have discovered a 68-residue protein inhibitor of holdfast development (HfiA that directly targets a conserved glycolipid glycosyltransferase required for holdfast production (HfsJ. Multiple cell cycle regulators associate with the hfiA and hfsJ promoters and control their expression, temporally constraining holdfast development to the late stages of G1. HfiA further functions as part of a 'nutritional override' system that decouples holdfast development from the cell cycle in response to nutritional cues. This control mechanism can limit surface adhesion in nutritionally sub-optimal environments without affecting cell cycle progression. We conclude that post-translational regulation of cell envelope enzymes by small proteins like HfiA may provide a general means to modulate the surface properties of bacterial cells.

  17. Membrane Surface Nanostructures and Adhesion Property of T Lymphocytes Exploited by AFM

    Directory of Open Access Journals (Sweden)

    Lu Hongsong

    2009-01-01

    Full Text Available Abstract The activation of T lymphocytes plays a very important role in T-cell-mediated immune response. Though there are many related literatures, the changes of membrane surface nanostructures and adhesion property of T lymphocytes at different activation stages have not been reported yet. However, these investigations will help us further understand the biophysical and immunologic function of T lymphocytes in the context of activation. In the present study, the membrane architectures of peripheral blood T lymphocytes were obtained by AFM, and adhesion force of the cell membrane were measured by acquiring force–distance curves. The results indicated that the cell volume increased with the increases of activation time, whereas membrane surface adhesion force decreased, even though the local stiffness for resting and activated cells is similar. The results provided complementary and important data to further understand the variation of biophysical properties of T lymphocytes in the context of in vitro activation.

  18. Dynamic Regulation of Activated Leukocyte Cell Adhesion Molecule–mediated Homotypic Cell Adhesion through the Actin CytoskeletonV⃞

    OpenAIRE

    Nelissen, Judith M. D. T.; Peters, Inge M.; de Grooth, Bart G.; Van Kooyk, Yvette; Figdor, Carl G.

    2000-01-01

    Restricted expression of activated leukocyte cell adhesion molecule (ALCAM) by hematopoietic cells suggests an important role in the immune system and hematopoiesis. To get insight into the mechanisms that control ALCAM-mediated adhesion we have investigated homotypic ALCAM–ALCAM interactions. Here, we demonstrate that the cytoskeleton regulates ALCAM-mediated cell adhesion because inhibition of actin polymerization by cytochalasin D (CytD) strongly induces homotypic ALCAM–ALCAM interactions....

  19. Adhesion of different cell cycle human hepatoma cells to endothelial cells and roles of integrin β1

    Institute of Scientific and Technical Information of China (English)

    Guan-Bin Song; Jian Qin; Qing Luo; Xiao-Dong Shen; Run-Bin Yan; Shao-Xi Cai

    2005-01-01

    AIM: To investigate the adhesive mechanical properties of different cell cycle human hepatoma cells (SMMC-7721)to human umbilical vein endothelial cells (ECV-304),expression of adhesive molecule integrinβ1 in SMMC-7721cells and its contribution to this adhesive course.METHODS: Adhesive force of SMMC-7721 cells to endothelialcells was measured using micropipette aspiration technique.Synchronous G1 and S phase SMMC-7721 cells wereachieved by thymine-2-deoxyriboside and colchicinessequential blockage method and double thymine-2-deoxyriboside blockage method, respectively. Synchronousrates of SMMC-7721 cells and expression of integrinβ1 inSMMC-7721 cells were detected by flow cytometer.RESULTS: The percentage of cell cycle phases of generalSMMC-7721 cells was 11.01% in G2/M phases, 53.51% inG0/G1 phase, and 35.48% in S phase. The synchronous ratesof G1 and S phase SMMC-7721 cells amounted to 74.09%and 98.29%, respectively. The adhesive force of SMMC-7721cells to endothelial cells changed with the variations ofadhesive time and presented behavior characteristics ofadhesion and de-adhesion. S phase SMMC-7721 cells had higheradhesive forces than G1 phase cells [(307.65±92.10)× 10-10Nvs (195.42±60.72)×10-10N, P<0.01]. The expressivefluorescent intensity of integrinβ1 in G1 phase SMMC-7721cells was depressed more significantly than the values ofS phase and general SMMC-7721cells. The contribution ofadhesive integrinβ1 was about 53% in this adhesive course.CONCLUSION: SMMC-7721 cells can be synchronizedpreferably in G1 and S phases with thymine-2-deoxyribosideand colchicines. The adhesive molecule integrinβ1 expressesa high level in SMMC-7721 cells and shows differences invarious cell cycles, suggesting integrin β1 plays an importantrole in adhesion to endothelial cells. The change of adhesiveforces in different cell cycle SMMC-7721 cells indicatesthat S phase cells play predominant roles possibly whilethey interact with endothelial cells.

  20. Dynamic monitoring of changes in endothelial cell-substrate adhesiveness during leukocyte adhesion by microelectrical impedance assay

    Institute of Scientific and Technical Information of China (English)

    Yakun Ge; Tongle Deng; Xiaoxiang Zheng

    2009-01-01

    Adhesion of leukocytes to endothelial cells in inflammation processes leads to changes of endothelial cell-substrate adhesiveness, and understanding of such changes will provide us with important information of inflammation processes. In this study, we used a non-invasive biosensor system referred to as real-time cell electronic sensor (RT-CES) system to monitor the changes in endothelial cell-substrate adhesiveness induced by human monoblastic cell line U937 cell adhesion in a dynamic and quantitative manner. This assay, which is based on cell-substrate impedance readout, is able to monitor transient changes in cell-substrate adhesiveness as a result of U937 cell adhesion. The U937 cell adhesion to endothelial cells was induced by lipopolysaccharide (LPS) in a dose-dependent manner. Although the number of adherent U937 cells to the endothelial cells was verified by a standard assay, the adhesiveness of endothelial cells after addition of U937 cells was monitored by the RT-CES system. Furthermore, focal adhesion kinase protein decrease and F-actin rearrangement in endothelial cells were observed after addition of U937 cells. Our results indicated that the adhesion of U937 cells to LPS-treated endothelial cells reduced the cell adhesiveness to the substrate, and such reduction might facilitate infiltration of leukocytes.

  1. IL-1β enhances cell adhesion to degraded fibronectin

    OpenAIRE

    Rajshankar, Dhaarmini; Downey, Gregory P.; McCulloch, Christopher A.

    2012-01-01

    IL-1β is a prominent proinflammatory cytokine that mediates degradation of extracellular matrix proteins through increased expression of matrix metalloproteinases, which involves a signaling pathway in adherent cells that is restricted by focal adhesions. Currently, the mechanism by which IL-1β affects cell adhesion to matrix proteins is not defined, and it is not known whether degraded matrix proteins affect IL-1β signaling. We examined adhesion-related IL-1β signaling in fibroblasts attachi...

  2. Design of Xylose-Based Semisynthetic Polyurethane Tissue Adhesives with Enhanced Bioactivity Properties.

    Science.gov (United States)

    Balcioglu, Sevgi; Parlakpinar, Hakan; Vardi, Nigar; Denkbas, Emir Baki; Karaaslan, Merve Goksin; Gulgen, Selam; Taslidere, Elif; Koytepe, Suleyman; Ates, Burhan

    2016-02-24

    Developing biocompatible tissue adhesives with high adhesion properties is a highly desired goal of the tissue engineering due to adverse effects of the sutures. Therefore, our work involves synthesis, characterization, adhesion properties, protein adsorption, in vitro biodegradation, in vitro and in vivo biocompatibility properties of xylose-based semisynthetic polyurethane (NPU-PEG-X) bioadhesives. Xylose-based semisynthetic polyurethanes were developed by the reaction among 4,4'-methylenebis(cyclohexyl isocyanate) (MCI), xylose and polyethylene glycol 200 (PEG). Synthesized polyurethanes (PUs) showed good thermal stability and high adhesion strength. The highest values in adhesion strength were measured as 415.0 ± 48.8 and 94.0 ± 2.8 kPa for aluminum substrate and muscle tissue in 15% xylose containing PUs (NPU-PEG-X-15%), respectively. The biodegradation of NPU-PEG-X-15% was also determined as 19.96 ± 1.04% after 8 weeks of incubation. Relative cell viability of xylose containing PU was above 86%. Moreover, 10% xylose containing NPU-PEG-X (NPU-PEG-X-10%) sample has favorable tissue response, and inflammatory reaction between 1 and 6 weeks implantation period. With high adhesiveness and biocompatibility properties, NPU-PEG-X can be used in the medical field as supporting materials for preventing the fluid leakage after abdominal surgery or wound closure. PMID:26824739

  3. Modified Surface Having Low Adhesion Properties to Mitigate Insect Residue Adhesion

    Science.gov (United States)

    Wohl, Christopher J., Jr. (Inventor); Smith, Joseph G., Jr. (Inventor); Siochi, Emilie J. (Inventor); Penner, Ronald K. (Inventor)

    2016-01-01

    A process to modify a surface to provide reduced adhesion surface properties to mitigate insect residue adhesion. The surface may include the surface of an article including an aircraft, an automobile, a marine vessel, all-terrain vehicle, wind turbine, helmet, etc. The process includes topographically and chemically modifying the surface by applying a coating comprising a particulate matter, or by applying a coating and also topographically modifying the surface by various methods, including but not limited to, lithographic patterning, laser ablation and chemical etching, physical vapor phase deposition, chemical vapor phase deposition, crystal growth, electrochemical deposition, spin casting, and film casting.

  4. Influence of fermentation conditions on the surface properties and adhesion of Lactobacillus rhamnosus GG

    Directory of Open Access Journals (Sweden)

    Deepika Gurjot

    2012-08-01

    Full Text Available Abstract Background The surface properties of probiotic bacteria influence to a large extent their interactions within the gut ecosystem. There is limited amount of information on the effect of the production process on the surface properties of probiotic lactobacilli in relation to the mechanisms of their adhesion to the gastrointestinal mucosa. The aim of this work was to investigate the effect of the fermentation pH and temperature on the surface properties and adhesion ability to Caco-2 cells of the probiotic strain Lactobacillus rhamnosus GG. Results The cells were grown at pH 5, 5.5, 6 (temperature 37°C and at pH 6.5 (temperature 25°C, 30°C and 37°C, and their surfaces analysed by X-ray photoelectron spectrometry (XPS, Fourier transform infrared spectroscopy (FT-IR and gel-based proteomics. The results indicated that for all the fermentation conditions, with the exception of pH 5, a higher nitrogen to carbon ratio and a lower phosphate content was observed at the surface of the bacteria, which resulted in a lower surface hydrophobicity and reduced adhesion levels to Caco-2 cells as compared to the control fermentation (pH 6.5, 37°C. A number of adhesive proteins, which have been suggested in previous published works to take part in the adhesion of bacteria to the human gastrointestinal tract, were identified by proteomic analysis, with no significant differences between samples however. Conclusions The temperature and the pH of the fermentation influenced the surface composition, hydrophobicity and the levels of adhesion of L. rhamnosus GG to Caco-2 cells. It was deduced from the data that a protein rich surface reduced the adhesion ability of the cells.

  5. Cell adhesion molecules in the central nervous system

    OpenAIRE

    Togashi, Hideru; Sakisaka, Toshiaki; Takai, Yoshimi

    2009-01-01

    Cell-cell adhesion molecules play key roles at the intercellular junctions of a wide variety of cells, including interneuronal synapses and neuron-glia contacts. Functional studies suggest that adhesion molecules are implicated in many aspects of neural network formation, such as axon-guidance, synapse formation, regulation of synaptic structure and astrocyte-synapse contacts. Some basic cell biological aspects of the assembly of junctional complexes of neurons and glial cells resemble those ...

  6. Probing bacterial adhesion at the single-cell level

    DEFF Research Database (Denmark)

    Zeng, Guanghong; Müller, Torsten; Meyer, Rikke Louise

    cantilever coated with the commercial cell adhesive CellTakTM. We applied the method to study adhesion of living cells to abiotic surfaces at the single-cell level. Immobilisation of single bacterial cells to the cantilever was stable for several hours, and viability was confirmed by Live/Dead staining and......Bacteria initiate attachment to surfaces with the aid of different extracellular proteins and polymeric adhesins. To quantitatively analyse the cell-cell and cell-surface interactions provided by bacterial adhesins, it is essential to go down to single cell level where cell-to-cell variation can be...... considered. We have developed a simple and versatile method to make single-cell bacterial probes for measuring single cell adhesion by force spectroscopy using atomic force microscopy (AFM). A single-cell probe was readily made by picking up a bacterial cell from a glass surface by approaching a tipless AFM...

  7. Inducible adhesion of mesenchymal cells to elastic fibers: elastonectin.

    OpenAIRE

    Hornebeck, W; Tixier, J M; L. Robert

    1986-01-01

    The addition of highly purified elastic fibers to confluent human skin fibroblast or porcine aorta smooth muscle cell cultures resulted in a time-dependent, strong adhesion of the fibrils to the cell surface. The kinetics of adhesion was studied by video/time-lapse cinematography. After a 0.5-1 hr lag period, adhesion progressed to a maximum amount in 3-6 hr in the described conditions. Adhesion is strongly accelerated by the prior addition of soluble elastin peptides (kappa-elastin) to the c...

  8. Cell Adhesion to Plasma-Coated PVC

    Directory of Open Access Journals (Sweden)

    Elidiane C. Rangel

    2014-01-01

    Full Text Available To produce environments suitable for cell culture, thin polymer films were deposited onto commercial PVC plates from radiofrequency acetylene-argon plasmas. The proportion of argon in the plasmas, PAr, was varied from 5.3 to 65.8%. The adhesion and growth of Vero cells on the coated surfaces were examined for different incubation times. Cytotoxicity tests were performed using spectroscopic methods. Carbon, O, and N were detected in all the samples using XPS. Roughness remained almost unchanged in the samples prepared with 5.3 and 28.9% but tended to increase for the films deposited with PAr between 28.9 and 55.3%. Surface free energy increased with increasing PAr, except for the sample prepared at 28.9% of Ar, which presented the least reactive surface. Cells proliferated on all the samples, including the bare PVC. Independently of the deposition condition there was no evidence of cytotoxicity, indicating the viability of such coatings for designing biocompatible devices.

  9. Photocrosslinked nanocomposite hydrogels from PEG and silica nanospheres: Structural, mechanical and cell adhesion characteristics

    International Nuclear Information System (INIS)

    Photopolymerized hydrogels are extensively investigated for various tissue engineering applications, primarily due to their ability to form hydrogels in a minimally invasive manner. Although photocrosslinkable hydrogels provide necessary biological and chemical characteristics to mimic cellular microenvironments, they often lack sufficient mechanical properties. Recently, nanocomposite approaches have demonstrated potential to overcome these deficits by reinforcing the hydrogel network with. In this study, we investigate some physical, chemical, and biological properties of photocrosslinked poly(ethylene glycol) (PEG)-silica hydrogels. The addition of silica nanospheres significantly suppresses the hydration degree of the PEG hydrogels, indicating surface interactions between the silica nanospheres and the polymer chains. No significant change in hydrogel microstructure or average pore size due to the addition of silica nanospheres was observed. However, addition of silica nanospheres significantly increases both the mechanical strength and the toughness of the hydrogel networks. The biological properties of these nanocomposite hydrogels were evaluated by seeding fibroblast cells on the hydrogel surface. While the PEG hydrogels showed minimum cell adhesion, spreading and proliferation, the addition of silica nanospheres enhanced initial cell adhesion, promoted cell spreading and increased the metabolic activity of the cells. Overall, results indicate that the addition of silica nanospheres improves the mechanical stiffness and cell adhesion properties of PEG hydrogels and can be used for biomedical applications that required controlled cell adhesion. - Graphical abstract: Structural, mechanical and biological properties of photocrosslinked nanocomposite hydrogels from silica and poly(ethylene oxide) are investigated. Silica reinforce the hydrogel network and improved mechanical strength. Addition of induces cell adhesion characteristic properties for various

  10. Photocrosslinked nanocomposite hydrogels from PEG and silica nanospheres: Structural, mechanical and cell adhesion characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Gaharwar, Akhilesh K., E-mail: agaharwa@purdue.edu; Rivera, Christian; Wu, Chia-Jung; Chan, Burke K.; Schmidt, Gudrun

    2013-04-01

    Photopolymerized hydrogels are extensively investigated for various tissue engineering applications, primarily due to their ability to form hydrogels in a minimally invasive manner. Although photocrosslinkable hydrogels provide necessary biological and chemical characteristics to mimic cellular microenvironments, they often lack sufficient mechanical properties. Recently, nanocomposite approaches have demonstrated potential to overcome these deficits by reinforcing the hydrogel network with. In this study, we investigate some physical, chemical, and biological properties of photocrosslinked poly(ethylene glycol) (PEG)-silica hydrogels. The addition of silica nanospheres significantly suppresses the hydration degree of the PEG hydrogels, indicating surface interactions between the silica nanospheres and the polymer chains. No significant change in hydrogel microstructure or average pore size due to the addition of silica nanospheres was observed. However, addition of silica nanospheres significantly increases both the mechanical strength and the toughness of the hydrogel networks. The biological properties of these nanocomposite hydrogels were evaluated by seeding fibroblast cells on the hydrogel surface. While the PEG hydrogels showed minimum cell adhesion, spreading and proliferation, the addition of silica nanospheres enhanced initial cell adhesion, promoted cell spreading and increased the metabolic activity of the cells. Overall, results indicate that the addition of silica nanospheres improves the mechanical stiffness and cell adhesion properties of PEG hydrogels and can be used for biomedical applications that required controlled cell adhesion. - Graphical abstract: Structural, mechanical and biological properties of photocrosslinked nanocomposite hydrogels from silica and poly(ethylene oxide) are investigated. Silica reinforce the hydrogel network and improved mechanical strength. Addition of induces cell adhesion characteristic properties for various

  11. Differential adhesion of tumor cells to capillary endothelial cells in vitro.

    OpenAIRE

    Alby, L; Auerbach, R

    1984-01-01

    Adhesion studies were carried out to determine the relative ability of glioma cells and ovary-derived teratoma cells to adhere to endothelial cells obtained from mouse brain capillaries (designated MBE cell line) or mouse ovaries (designated MOE cell line). The teratoma cells showed preferential adhesion to MOE cells, whereas the glioma cells showed preferential adhesion to the MBE cell line. In contrast, the glioma and teratoma cells adhered equally to L929 and 3T3 fibroblasts. A testicular ...

  12. Crystal violet staining to quantity Candida adhesion to epithelial cells

    OpenAIRE

    Negri, M.; Gonçalves, Vera M.; Silva, Sónia Carina; Henriques, Mariana; Azeredo, Joana; Oliveira, Rosário

    2010-01-01

    In vitro studies of adhesion capability are essential to characterise the virulence of Candida species. However, the assessment of adhesion by traditional methods is timeconsuming. The aim of the present study is the development of a simple methodology using crystal violet staining to quantify in vitro adhesion of different Candida species to epithelial cells. The experiments are performed using Candida albicans (ATCC 90028), C. glabrata (ATCC 2001), C. parapsilosis (ATCC 22019) and C. tropic...

  13. Nanofibers and nanoparticles from the insect-capturing adhesive of the Sundew (Drosera for cell attachment

    Directory of Open Access Journals (Sweden)

    Zhang Mingjun

    2010-08-01

    Full Text Available Abstract Background The search for naturally occurring nanocomposites with diverse properties for tissue engineering has been a major interest for biomaterial research. In this study, we investigated a nanofiber and nanoparticle based nanocomposite secreted from an insect-capturing plant, the Sundew, for cell attachment. The adhesive nanocomposite has demonstrated high biocompatibility and is ready to be used with minimal preparation. Results Atomic force microscopy (AFM conducted on the adhesive from three species of Sundew found that a network of nanofibers and nanoparticles with various sizes existed independent of the coated surface. AFM and light microscopy confirmed that the pattern of nanofibers corresponded to Alcian Blue staining for polysaccharide. Transmission electron microscopy identified a low abundance of nanoparticles in different pattern form AFM observations. In addition, energy-dispersive X-ray spectroscopy revealed the presence of Ca, Mg, and Cl, common components of biological salts. Study of the material properties of the adhesive yielded high viscoelasticity from the liquid adhesive, with reduced elasticity observed in the dried adhesive. The ability of PC12 neuron-like cells to attach and grow on the network of nanofibers created from the dried adhesive demonstrated the potential of this network to be used in tissue engineering, and other biomedical applications. Conclusions This discovery demonstrates how a naturally occurring nanofiber and nanoparticle based nanocomposite from the adhesive of Sundew can be used for tissue engineering, and opens the possibility for further examination of natural plant adhesives for biomedical applications.

  14. Single cell adhesion assay using computer controlled micropipette.

    Directory of Open Access Journals (Sweden)

    Rita Salánki

    Full Text Available Cell adhesion is a fundamental phenomenon vital for all multicellular organisms. Recognition of and adhesion to specific macromolecules is a crucial task of leukocytes to initiate the immune response. To gain statistically reliable information of cell adhesion, large numbers of cells should be measured. However, direct measurement of the adhesion force of single cells is still challenging and today's techniques typically have an extremely low throughput (5-10 cells per day. Here, we introduce a computer controlled micropipette mounted onto a normal inverted microscope for probing single cell interactions with specific macromolecules. We calculated the estimated hydrodynamic lifting force acting on target cells by the numerical simulation of the flow at the micropipette tip. The adhesion force of surface attached cells could be accurately probed by repeating the pick-up process with increasing vacuum applied in the pipette positioned above the cell under investigation. Using the introduced methodology hundreds of cells adhered to specific macromolecules were measured one by one in a relatively short period of time (∼30 min. We blocked nonspecific cell adhesion by the protein non-adhesive PLL-g-PEG polymer. We found that human primary monocytes are less adherent to fibrinogen than their in vitro differentiated descendants: macrophages and dendritic cells, the latter producing the highest average adhesion force. Validation of the here introduced method was achieved by the hydrostatic step-pressure micropipette manipulation technique. Additionally the result was reinforced in standard microfluidic shear stress channels. Nevertheless, automated micropipette gave higher sensitivity and less side-effect than the shear stress channel. Using our technique, the probed single cells can be easily picked up and further investigated by other techniques; a definite advantage of the computer controlled micropipette. Our experiments revealed the existence of a

  15. Simulation of Cell Adhesion using a Particle Transport Model

    Science.gov (United States)

    Chesnutt, Jennifer

    2005-11-01

    An efficient computational method for simulation of cell adhesion through protein binding forces is discussed. In this method, the cells are represented by deformable elastic particles, and the protein binding is represented by a rate equation. The method is first developed for collision and adhesion of two similar cells impacting on each other from opposite directions. The computational method is then applied in a particle-transport model for a cloud of interacting and colliding cells, each of which are represented by particles of finite size. One application might include red blood cells adhering together to form rouleaux, which are chains of red blood cells that are found in different parts of the circulatory system. Other potential applications include adhesion of platelets to a blood vessel wall or mechanical heart valve, which is a precursor of thrombosis formation, or adhesion of cancer cells to organ walls in the lymphatic, circulatory, digestive or pulmonary systems.

  16. Extracellular Membrane-proximal Domain of HAb18G/CD147 Binds to Metal Ion-dependent Adhesion Site (MIDAS) Motif of Integrin β1 to Modulate Malignant Properties of Hepatoma Cells*

    Science.gov (United States)

    Li, Yong; Wu, Jiao; Song, Fei; Tang, Juan; Wang, Shi-Jie; Yu, Xiao-Ling; Chen, Zhi-Nan; Jiang, Jian-Li

    2012-01-01

    Several lines of evidence suggest that HAb18G/CD147 interacts with the integrin variants α3β1 and α6β1. However, the mechanism of the interaction remains largely unknown. In this study, mammalian protein-protein interaction trap (MAPPIT), a mammalian two-hybrid method, was used to study the CD147-integrin β1 subunit interaction. CD147 in human hepatocellular carcinoma (HCC) cells was interfered with by small hairpin RNA. Nude mouse xenograft model and metastatic model of HCC were used to detect the role of CD147 in carcinogenesis and metastasis. We found that the extracellular membrane-proximal domain of HAb18G/CD147 (I-type domain) binds at the metal ion-dependent adhesion site in the βA domain of the integrin β1 subunit, and Asp179 in the I-type domain of HAb18G/CD147 plays an important role in the interaction. The levels of the proteins that act downstream of integrin, including focal adhesion kinase (FAK) and phospho-FAK, were decreased, and the cytoskeletal structures of HCC cells were rearranged bearing the HAb18G/CD147 deletion. Simultaneously, the migration and invasion capacities, secretion of matrix metalloproteinases, colony formation rate in vitro, and tumor growth and metastatic potential in vivo were decreased. These results indicate that the interaction of HAb18G/CD147 extracellular I-type domain with the integrin β1 metal ion-dependent adhesion site motif activates the downstream FAK signaling pathway, subsequently enhancing the malignant properties of HCC cells. PMID:22130661

  17. Extracellular membrane-proximal domain of HAb18G/CD147 binds to metal ion-dependent adhesion site (MIDAS) motif of integrin β1 to modulate malignant properties of hepatoma cells.

    Science.gov (United States)

    Li, Yong; Wu, Jiao; Song, Fei; Tang, Juan; Wang, Shi-Jie; Yu, Xiao-Ling; Chen, Zhi-Nan; Jiang, Jian-Li

    2012-02-10

    Several lines of evidence suggest that HAb18G/CD147 interacts with the integrin variants α3β1 and α6β1. However, the mechanism of the interaction remains largely unknown. In this study, mammalian protein-protein interaction trap (MAPPIT), a mammalian two-hybrid method, was used to study the CD147-integrin β1 subunit interaction. CD147 in human hepatocellular carcinoma (HCC) cells was interfered with by small hairpin RNA. Nude mouse xenograft model and metastatic model of HCC were used to detect the role of CD147 in carcinogenesis and metastasis. We found that the extracellular membrane-proximal domain of HAb18G/CD147 (I-type domain) binds at the metal ion-dependent adhesion site in the βA domain of the integrin β1 subunit, and Asp(179) in the I-type domain of HAb18G/CD147 plays an important role in the interaction. The levels of the proteins that act downstream of integrin, including focal adhesion kinase (FAK) and phospho-FAK, were decreased, and the cytoskeletal structures of HCC cells were rearranged bearing the HAb18G/CD147 deletion. Simultaneously, the migration and invasion capacities, secretion of matrix metalloproteinases, colony formation rate in vitro, and tumor growth and metastatic potential in vivo were decreased. These results indicate that the interaction of HAb18G/CD147 extracellular I-type domain with the integrin β1 metal ion-dependent adhesion site motif activates the downstream FAK signaling pathway, subsequently enhancing the malignant properties of HCC cells. PMID:22130661

  18. Simple and Biocompatible Ion Beam Micropatterning of a Cell-Repellent Polymer on Cell-Adhesive Surfaces to Manipulate Cell Adhesion.

    Science.gov (United States)

    Hwang, In-Tae; Jung, Chan-Hee; Jung, Chang-Hee; Choi, Jae-Hak; Shin, Kwanwoo; Yoo, Young-Do

    2016-02-01

    In this paper, the simple and biocompatible micropatterning of cell-repellent poly(N-isopropylacrylamide) (PNIPAAm) on a cell-adhesive substrate by ion beam micropatterning to control cell adhesion is described. Cell-repellent PNIPAAm films spin-coated on cell-adhesive tissue culture polystyrene (TCPS) substrates were selectively irradiated by energetic proton ions at various fluences through a pattern mask, and subsequently developed to create the micropatterns of PNIPAAm. Well-defined negative-type PNIPAAm micropatterns were successfully created on the TCPS substrates at fluences higher than 5 x 10¹⁴ ions/cm², and their chemical properties were dependent on the fluence. Moreover, based on the results of the protein adsorption and in-vitro cell culture tests, 200 µm well-defined micropatterns of mammalian cells were clearly formed on the PNIPAAm-micropatterned TCPS substrates though the preferential adsorption and growth of cells on the TCPS regions due to the strong cell-repellency of PNIPAAm. PMID:27305772

  19. The role of focal adhesion kinase in the regulation of cellular mechanical properties

    Science.gov (United States)

    Mierke, Claudia Tanja

    2013-12-01

    The regulation of mechanical properties is necessary for cell invasion into connective tissue or intra- and extravasation through the endothelium of blood or lymph vessels. Cell invasion is important for the regulation of many healthy processes such as immune response reactions and wound healing. In addition, cell invasion plays a role in disease-related processes such as tumor metastasis and autoimmune responses. Until now the role of focal adhesion kinase (FAK) in regulating mechanical properties of cells and its impact on cell invasion efficiency is still not well known. Thus, this review focuses on mechanical properties regulated by FAK in comparison to the mechano-regulating protein vinculin. Moreover, it points out the connection between cancer cell invasion and metastasis and FAK by showing that FAK regulates cellular mechanical properties required for cellular motility. Furthermore, it sheds light on the indirect interaction of FAK with vinculin by binding to paxillin, which then impairs the binding of paxillin to vinculin. In addition, this review emphasizes whether FAK fulfills regulatory functions similar to vinculin. In particular, it discusses the differences and the similarities between FAK and vinculin in regulating the biomechanical properties of cells. Finally, this paper highlights that both focal adhesion proteins, vinculin and FAK, synergize their functions to regulate the mechanical properties of cells such as stiffness and contractile forces. Subsequently, these mechanical properties determine cellular invasiveness into tissues and provide a source sink for future drug developments to inhibit excessive cell invasion and hence, metastases formation.

  20. The role of focal adhesion kinase in the regulation of cellular mechanical properties

    International Nuclear Information System (INIS)

    The regulation of mechanical properties is necessary for cell invasion into connective tissue or intra- and extravasation through the endothelium of blood or lymph vessels. Cell invasion is important for the regulation of many healthy processes such as immune response reactions and wound healing. In addition, cell invasion plays a role in disease-related processes such as tumor metastasis and autoimmune responses. Until now the role of focal adhesion kinase (FAK) in regulating mechanical properties of cells and its impact on cell invasion efficiency is still not well known. Thus, this review focuses on mechanical properties regulated by FAK in comparison to the mechano-regulating protein vinculin. Moreover, it points out the connection between cancer cell invasion and metastasis and FAK by showing that FAK regulates cellular mechanical properties required for cellular motility. Furthermore, it sheds light on the indirect interaction of FAK with vinculin by binding to paxillin, which then impairs the binding of paxillin to vinculin. In addition, this review emphasizes whether FAK fulfills regulatory functions similar to vinculin. In particular, it discusses the differences and the similarities between FAK and vinculin in regulating the biomechanical properties of cells. Finally, this paper highlights that both focal adhesion proteins, vinculin and FAK, synergize their functions to regulate the mechanical properties of cells such as stiffness and contractile forces. Subsequently, these mechanical properties determine cellular invasiveness into tissues and provide a source sink for future drug developments to inhibit excessive cell invasion and hence, metastases formation. (paper)

  1. Adhesive Micropatterns for Cells: A Microcontact Printing Protocol

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Manuel Théry and Matthieu Piel Corresponding authors ([](); []()) ### INTRODUCTION This protocol describes a simple, fast, and efficient method for making adhesive micropatterns that can be used to control individual cell shape and adhesion patterns. It is based on the use of an elastomeric stamp containing microfeatures to print proteins on the substrate of choice. The process can be subdiv...

  2. Effect of Surface Pretreatment on Adhesive Properties of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Jinsheng ZHANG; Xuhui ZHAO; Yu ZUO; Jinping XIONG; Xiaofeng ZHANG

    2008-01-01

    The lap-shear strength and durability of adhesive bonded AI alloy joints with different pretreatments were studied by the lap-shear test and wedge test. The results indicate that the maximum lap-shear strength and durability of the bonding joints pretreated by different processes are influenced by the grade of abrasive papers and can be obviously improved by phosphoric acid anodizing. Alkali etching can obviously improve the durability of bonding joints although it slightly influences the maximum lap-shear strength. The process which is composed of grit-finishing, acetone degreasing, alkali etching and phosphoric acid anodizing, provides a better adhesive bonding property of AI alloy.

  3. Cell adhesion molecules during odontogenesis and tooth-related diseases

    OpenAIRE

    Heymann, Robert

    2002-01-01

    Cell adhesion molecules play essential roles in the development and disease of tooth and oral structures, as well as in the maintenance of adult tissue structure/function. It has been shown that different types of cell adhesion molecules (CAMs) play an important part in craniofacial development when ectomesenchymal cells migrate from the neural list to the primitive oral cavity, giving rise to the palatal processes and tooth germs. The role of CAMs in craniofacial developmen...

  4. Evidence for heterophilic adhesion of embryonic retinal cells and neuroblastoma cells to substratum-adsorbed NCAM

    OpenAIRE

    1992-01-01

    The adhesion of embryonic chicken retinal cells and mouse N2A neuroblastoma cells to purified embryonic chicken retinal NCAM adsorbed on a solid substratum was examined using a quantitative centrifugal adhesion assay. Both cell types adhered to NCAM and the adhesion was specifically inhibited by monovalent anti-NCAM antibody fragments. N2A cell adhesion depended on the amount of NCAM applied to the substratum, was cation independent, and was insensitive to treatment with the cytoskeletal pert...

  5. Amine-functionalized polypyrrole: Inherently cell adhesive conducting polymer.

    Science.gov (United States)

    Lee, Jae Y; Schmidt, Christine E

    2015-06-01

    Electrically conducting polymers (CPs) have been recognized as novel biomaterials that can electrically communicate with biological systems. For their tissue engineering applications, CPs have been modified to promote cell adhesion for improved interactions between biomaterials and cells/tissues. Conventional approaches to improve cell adhesion involve the surface modification of CPs with biomolecules, such as physical adsorption of cell adhesive proteins and polycationic polymers, or their chemical immobilization; however, these approaches require additional multiple modification steps with expensive biomolecules. In this study, as a simple and effective alternative to such additional biomolecule treatment, we synthesized amine-functionalized polypyrrole (APPy) that inherently presents cell adhesion-supporting positive charges under physiological conditions. The synthesized APPy provides electrical activity in a moderate range and a hydrophilic surface compared to regular polypyrrole (PPy) homopolymers. Under both serum and serum-free conditions, APPy exhibited superior attachment of human dermal fibroblasts and Schwann cells compared to PPy homopolymer controls. Moreover, Schwann cell adhesion onto the APPy copolymer was at least similar to that on poly-l-lysine treated PPy controls. Our results indicate that amine-functionalized CP substrates will be useful to achieve good cell adhesion and potentially electrically stimulate various cells. In addition, amine functionality present on CPs can further serve as a novel and flexible platform to chemically tether various bioactive molecules, such as growth factors, antibodies, and chemical drugs. PMID:25294089

  6. Cells adhesion and growth on gold nanoparticle grafted glass

    International Nuclear Information System (INIS)

    The surface of glass substrate was plasma treated, coated by gold nano-structures and subsequently grafted with nanoparticles. The samples were plasma treated, sputtered with Au nanostructures which was followed by grafting with biphenyl-4,4′-dithiol (BPD) and then gold nanoparticles. The wettability, optical and chemical properties and surface morphology were studied. The adhesion and proliferation of vascular smooth muscle cells (VSMCs) on the samples were investigated in-vitro as well. Grafting of gold nanoparticles with the dithiol increases the UV–vis absorbance, the surface becomes more hydrophobic, rougher and more rugged compared to pristine, sputtered and only dithiol treated surface. Gold nano-particles bound over dithiol and Au nanostructures cause better cell proliferation than purely BPD treated or pristine glass.

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

    Science.gov (United States)

    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.

  8. Amplified effect of surface charge on cell adhesion by nanostructures

    Science.gov (United States)

    Xu, Li-Ping; Meng, Jingxin; Zhang, Shuaitao; Ma, Xinlei; Wang, Shutao

    2016-06-01

    Nano-biointerfaces with varied surface charge can be readily fabricated by integrating a template-based process with maleimide-thiol coupling chemistry. Significantly, nanostructures are employed for amplifying the effect of surface charge on cell adhesion, as revealed by the cell-adhesion performance, cell morphology and corresponding cytoskeletal organization. This study may provide a promising strategy for developing new biomedical materials with tailored cell adhesion for tissue implantation and regeneration.Nano-biointerfaces with varied surface charge can be readily fabricated by integrating a template-based process with maleimide-thiol coupling chemistry. Significantly, nanostructures are employed for amplifying the effect of surface charge on cell adhesion, as revealed by the cell-adhesion performance, cell morphology and corresponding cytoskeletal organization. This study may provide a promising strategy for developing new biomedical materials with tailored cell adhesion for tissue implantation and regeneration. Electronic supplementary information (ESI) available: Experimental details, SEM, KFM AFM, chemical modification and characterization. See DOI: 10.1039/c6nr00649c

  9. Comparing In Situ and Bulk Constitutive Properties of a Structural Adhesive

    OpenAIRE

    Grohs, Joshua Walter

    2007-01-01

    In the continuing quest for more efficient designs, structural adhesives are being used in place of, or with, traditional fastening methods; however designing with adhesives is refined as traditional methods. To obtain the adhesive design properties, tests are often performed on bulk tensile and bonded shear specimens. Questions remain about the relationship between properties obtained from in situ adhesive joints and bulk adhesive specimens. As a result, an experimental plan was developed...

  10. Running with neighbors: coordinating cell migration and cell-cell adhesion.

    Science.gov (United States)

    Collins, Caitlin; Nelson, W James

    2015-10-01

    Coordinated movement of large groups of cells is required for many biological processes, such as gastrulation and wound healing. During collective cell migration, cell-cell and cell-extracellular matrix (ECM) adhesions must be integrated so that cells maintain strong interactions with neighboring cells and the underlying substratum. Initiation and maintenance of cadherin adhesions at cell-cell junctions and integrin-based cell-ECM adhesions require integration of mechanical cues, dynamic regulation of the actin cytoskeleton, and input from specific signaling cascades, including Rho family GTPases. Here, we summarize recent advances made in understanding the interplay between these pathways at cadherin-based and integrin-based adhesions during collective cell migration and highlight outstanding questions that remain in the field. PMID:26201843

  11. Cell adhesion and proliferation on polyethylene grafted with Au nanoparticles

    Science.gov (United States)

    Kasálková, N. Slepičková; Slepička, P.; Kolská, Z.; Sajdl, P.; Bačáková, L.; Rimpelová, S.; Švorčík, V.

    2012-02-01

    Plasma treatment and subsequent Au nano-particles grafting of polyethylene (PE) lead to changes in surface morphology, roughness and wettability, significantly increasing the attractiveness of the material for cells. The PE samples were exposed to argon plasma. Plasma modified PE was chemically grafted by immersion to biphenyldithiol and consequently into solution of Au nano-particles. Changes in chemical structure of the modified PE were studied using X-ray Photoelectron Spectroscopy (XPS) and electrokinetic analysis ( ζ-potential). The surface wettability of the modified PE samples was examined by measurement of the contact angle by standard goniometry. The surface morphology of the plasma modified PE and that grafted with Au nano-particles was studied by Atomic Force Microscopy (AFM). The modified PE samples were seeded with rat vascular smooth muscle cells (VSMCs) and their adhesion and proliferation were studied. Chemically bounded biphenyldithiol increases the number of the incorporated gold nano-particles and changes sample surface properties. The presence of the biphenyldithiol and the gold nano-particles on the PE surface influences dramatically adhesion and proliferation of VSMCs.

  12. Extracellular matrix heparin induces alteration of the cell adhesion during brain development

    NARCIS (Netherlands)

    Ushakova, GA; Nikonenko, IR; Nikonenko, AG; Skibo, GG

    2002-01-01

    The studies of neuronal cell-glycosaminoglycan interactions indicate an increasing interest in the question of how heparin can mediate adhesion properties of the cell. We have found that high levels of both N-CAM concentration and heparin-binding activity were noticed in the early stages of brain fo

  13. Microtubule Disruption in Keratinocytes Induces Cell-Cell Adhesion through Activation of Endogenous E-Cadherin

    OpenAIRE

    Kee, Sun-Ho; Steinert, Peter M.

    2001-01-01

    The association of the cytoskeleton with the cadherin–catenin complex is essential for strong cell-cell adhesion in epithelial cells. In this study, we have investigated the effect of microtubule organization on cell-cell adhesion in differentiating keratinocytes. When microtubules of normal human epidermal keratinocytes (NHEKs) grown in low calcium media (0.05 mM) were disrupted with nocodazole or colcemid, cell-cell adhesion was induced through relocalization of the ...

  14. The interplay of cell–cell and cell–substrate adhesion in collective cell migration

    OpenAIRE

    Wang, Chenlu; Chowdhury, Sagar; Driscoll, Meghan; Parent, Carole A.; Gupta, S.K.; Losert, Wolfgang

    2014-01-01

    Collective cell migration often involves notable cell–cell and cell–substrate adhesions and highly coordinated motion of touching cells. We focus on the interplay between cell–substrate adhesion and cell–cell adhesion. We show that the loss of cell-surface contact does not significantly alter the dynamic pattern of protrusions and retractions of fast migrating amoeboid cells (Dictyostelium discoideum), but significantly changes their ability to adhere to other cells. Analysis of the dynamics ...

  15. Higher-Order Architecture of Cell Adhesion Mediated by Polymorphic Synaptic Adhesion Molecules Neurexin and Neuroligin

    Directory of Open Access Journals (Sweden)

    Hiroki Tanaka

    2012-07-01

    Full Text Available Polymorphic adhesion molecules neurexin and neuroligin (NL mediate asymmetric trans-synaptic adhesion, which is crucial for synapse development and function. It is not known whether or how individual synapse function is controlled by the interactions between variants and isoforms of these molecules with differing ectodomain regions. At a physiological concentration of Ca2+, the ectodomain complex of neurexin-1 β isoform (Nrx1β and NL1 spontaneously assembled into crystals of a lateral sheet-like superstructure topologically compatible with transcellular adhesion. Correlative light-electron microscopy confirmed extracellular sheet formation at the junctions between Nrx1β- and NL1-expressing non-neuronal cells, mimicking the close, parallel synaptic membrane apposition. The same NL1-expressing cells, however, did not form this higher-order architecture with cells expressing the much longer neurexin-1 α isoform, suggesting a functional discrimination mechanism between synaptic contacts made by different isoforms of neurexin variants.

  16. Adhesive properties of a symbolic bacterium from a wood-boreing marine shipworm

    International Nuclear Information System (INIS)

    Adhesive properties of cellulolytic, nitrogen-fixing bacterium isolated from a marine shipworm are described. 35S-labeled cells of the shipworm bacterium bound preferentially Whatman no.1 cellulose filter paper, compared with its binding to other cellulose substrata or substrata lacking cellulose. The ability of the bacteria to bind to Whatman no. 1 filter paper was significantly reduced by glutaraldehyde or heat treatment of cells. Pretreatment of cells with azide, valinomycin, gramicidin-D, bis-hexafluoroacetylacetone (1799), or carbonyl cyanide-p-trifluoromethoxyphenylhydrazone inhibited adhesion activity. Cells pretreated with pronase or trypsin also exhibited reduced binding activity, but chymotrypsin and peptidase had no effect on adhesion activity. Cellodextrins and methyl cellulose 15 inhibited the adhesion of the shipworm bacteria to filter paper, whereas glucose, cellobiose, and soluble carboxymethyl cellulose had no significant effect. The divalent cation chelators EDTA and EGTA [ethylene hlycol-bis(β-aminoethyl ether)-N,N,N'N'-tetraacetic acid] had little or no effect on adhesive properties of shipworm bacteria. Also, preabsorbing the substratum with extracellular endoglucanase isolated from the ship worm bacterium or 1% bovine serum albumin had no apparent effect on bacterial binding. Low concentration (0.01%) of sodium dodecyl sulfate solubilized a fraction from whole cells, which appeared to be involved in cellular binding activity. After removal of sodium dodecyl, sulfate, several proteins in this fraction associated with intact cells. These cells exhibited up to 50% enhanced binding to filter paper in comparison to cells which had not been exposed to the sodium dodecyl sulfate-solubilized fraction

  17. Cell adhesion and growth on ion-implanted polymer surface

    International Nuclear Information System (INIS)

    The adhesion and growth of endothelial cells on ion-implanted polystyrene and segmented polyurethane surface were investigated. Ions of Na+, N2+, O2+, Ar+ and Kr+ were implanted to the polymer surface with ion fluences between 1 x 1015 and 3 x 1017 ions/cm2 at energy of 150 KeV at room temperature. Ion-implanted polymers were characterized by FT-IR-ATR an Raman spectroscopies. The adhesion and proliferation of bovine aorta endothelial cells on ion-implanted polymer surface were observed by an optical microscope. The rate of growth of BAECs on ion-implanted PSt was faster than that on non-implanted PSt. Complete cell adhesion and growth were observed on ion-implanted SPU, whereas the adhesion and growth of BAECs on the non-implanted SPU was not observed. It was attempted to control the cell culture on the ion-implanted domain fabricated using a mask. (author)

  18. Dynamic cell adhesion and migration on nanoscale grooved substrates

    Directory of Open Access Journals (Sweden)

    E Lamers

    2012-03-01

    Full Text Available Organised nanotopography mimicking the natural extracellular matrix can be used to control morphology, cell motility, and differentiation. However, it is still unknown how specific cell types react with specific patterns. Both initial adhesion and preferential cell migration may be important to initiate and increase cell locomotion and coverage with cells, and thus achieve an enhanced wound healing response around an implantable material. Therefore, the aim of this study was to evaluate how MC3T3-E1 osteoblast initial adhesion and directional migration are influenced by nanogrooves with pitches ranging from 150 nm up to 1000 nm. In this study, we used a multi-patterned substrate with five different groove patterns and a smooth area with either a concentric or radial orientation. Initial cell adhesion measurements after 10 s were performed using atomic force spectroscopy-assisted single-cell force spectroscopy, and demonstrated that nascent cell adhesion was highly induced by a 600 nm pitch and reduced by a 150 nm pitch. Addition of RGD peptide significantly reduced adhesion, indicating that integrins and cell adhesive proteins (e.g. fibronectin or vitronectin are key factors in specific cell adhesion on nanogrooved substrates. Also, cell migration was highly dependent on the groove pitch; the highest directional migration parallel to the grooves was observed on a 600 nm pitch, whereas a 150 nm pitch restrained directional cell migration. From this study, we conclude that grooves with a pitch of 600 nm may be favourable to enhance fast wound closure, thereby promoting tissue regeneration.

  19. Cell Adhesion on Polycaprolactone Modified by Plasma Treatment

    OpenAIRE

    Nina Recek; Matic Resnik; Helena Motaln; Tamara Lah-Turnšek; Robin Augustine; Nandakumar Kalarikkal; Sabu Thomas; Miran Mozetič

    2016-01-01

    We have investigated the influence of various plasma treatments of electrospun polycaprolactone (PCL) scaffolds on the adhesion and proliferation of human umbilical endothelial cells (HUVEC). The PCL scaffolds were treated in plasmas created in O2, NH3 or SO2 gas at identical conditions. Surface functionalization of plasma-treated samples was determined using X-ray photoelectron spectroscopy. Cell adhesion and morphology were investigated by scanning electron microscopy and the influence of p...

  20. Adhesion of Actinobacillus actinomycetemcomitans to a human oral cell line.

    OpenAIRE

    Mintz, K. P.; Fives-Taylor, P M

    1994-01-01

    Two quantitative, rapid assays were developed to study the adhesion of Actinobacillus actinomycetemcomitans, an oral bacterium associated with periodontal disease, to human epithelial cells. The human oral carcinoma cell line KB was grown in microtiter plates, and adherent bacteria were detected by an enzyme-linked immunosorbent assay with purified anti-A. actinomycetemcomitans serum and horseradish peroxidase-conjugated secondary antibody or [3H]thymidine-labeled bacteria. Adhesion was found...

  1. Material- and feature-dependent effects on cell adhesion to micro injection moulded medical polymers.

    Science.gov (United States)

    Choi, Seong Ying; Habimana, Olivier; Flood, Peter; Reynaud, Emmanuel G; Rodriguez, Brian J; Zhang, Nan; Casey, Eoin; Gilchrist, Michael D

    2016-09-01

    Two polymers, polymethylmethacrylate (PMMA) and cyclic olefin copolymer (COC), containing a range of nano- to micron- roughness surfaces (Ra 0.01, 0.1, 0.4, 1.0, 2.0, 3.2 and 5.0μm) were fabricated using electrical discharge machining (EDM) and replicated using micro injection moulding (μIM). Polymer samples were characterized using optical profilometry, atomic force microscopy (AFM) and water surface contact angle. Cell adhesion tests were carried out using bacterial Pseudomonas fluorescens and mammalian Madin-Darby Canine Kidney (MDCK) cells to determine the effect of surface hydrophobicity, surface roughness and stiffness. It is found that there are features which gave insignificant differences (feature-dependent effect) in cell adhesion, albeit a significant difference in the physicochemical properties (material-dependent effect) of substrata. In bacterial cell adhesion, the strongest feature-dependence is found at Ra 0.4μm surfaces, with material-dependent effects strongest at Ra 0.01μm. Ra 0.1μm surfaces exhibited strongest feature-dependent effects and Ra 5.0μm has strongest material-dependent effects on mammalian cell adhesion. Bacterial cell adhesion is found to be favourable to hydrophobic surfaces (COC), with the lowest adhesion at Ra 0.4μm for both materials. Mammalian cell adhesion is lowest in Ra 0.1μm and highest in Ra 1.0μm, and generally favours hydrophilic surfaces (PMMA). These findings can be used as a basis for developing medical implants or microfluidic devices using micro injection moulding for diagnostic purposes, by tuning the cell adhesion on different areas containing different surface roughnesses on the diagnostic microfluidic devices or medical implants. PMID:27137802

  2. Adhesion properties of inverted polymer solarcells: Processing and film structure parameters

    KAUST Repository

    Dupont, Stephanie R.

    2013-05-01

    We report on the adhesion of weak interfaces in inverted P3HT:PCBM-based polymer solar cells (OPV) with either a conductive polymer, PEDOT:PSS, or a metal oxide, molybdenum trioxide (MoO3), as the hole transport layer. The PEDOT:PSS OPVs were prepared by spin or spray coating on glass substrates, or slot-die coating on flexible PET substrates. In all cases, we observed adhesive failure at the interface between the P3HT:PCBM with PEDOT:PSS layer. The adhesion energy measured for the solar cells made on glass substrates was about 1.8 J/m2, but only 0.5 J/m2 for the roll-to-roll processed flexible solar cells. The adhesion energy was insensitive to the PEDOT:PSS layer thickness in the range of 10-40 nm. A marginal increase in adhesion energy was measured with increased O2 plasma power. Compared to solution processed PEDOT:PSS, we found that thermally evaporated MoO 3 adheres less to the P3HT:PCBM layer, which we attributed to the reduced mixing at the MoO3/P3HT:PCBM interface during the thermal evaporation process. Insights into the mechanisms of delamination and the effect of different material properties and processing parameters yield general guidelines for the design of more reliable organic photovoltaic devices.© 2013 Elsevier B.V. All rights reserved.

  3. Photocrosslinked nanocomposite hydrogels from PEG and silica nanospheres: structural, mechanical and cell adhesion characteristics.

    Science.gov (United States)

    Gaharwar, Akhilesh K; Rivera, Christian; Wu, Chia-Jung; Chan, Burke K; Schmidt, Gudrun

    2013-04-01

    Photopolymerized hydrogels are extensively investigated for various tissue engineering applications, primarily due to their ability to form hydrogels in a minimally invasive manner. Although photocrosslinkable hydrogels provide necessary biological and chemical characteristics to mimic cellular microenvironments, they often lack sufficient mechanical properties. Recently, nanocomposite approaches have demonstrated potential to overcome these deficits by reinforcing the hydrogel network with. In this study, we investigate some physical, chemical, and biological properties of photocrosslinked poly(ethylene glycol) (PEG)-silica hydrogels. The addition of silica nanospheres significantly suppresses the hydration degree of the PEG hydrogels, indicating surface interactions between the silica nanospheres and the polymer chains. No significant change in hydrogel microstructure or average pore size due to the addition of silica nanospheres was observed. However, addition of silica nanospheres significantly increases both the mechanical strength and the toughness of the hydrogel networks. The biological properties of these nanocomposite hydrogels were evaluated by seeding fibroblast cells on the hydrogel surface. While the PEG hydrogels showed minimum cell adhesion, spreading and proliferation, the addition of silica nanospheres enhanced initial cell adhesion, promoted cell spreading and increased the metabolic activity of the cells. Overall, results indicate that the addition of silica nanospheres improves the mechanical stiffness and cell adhesion properties of PEG hydrogels and can be used for biomedical applications that required controlled cell adhesion. PMID:23827639

  4. Effects of mechanical properties of adhesive resin cements on stress distribution in fiber-reinforced composite adhesive fixed partial dentures.

    Science.gov (United States)

    Yokoyama, Daiichiro; Shinya, Akikazu; Gomi, Harunori; Vallittu, Pekka K; Shinya, Akiyoshi

    2012-01-01

    Using finite element analysis (FEA), this study investigated the effects of the mechanical properties of adhesive resin cements on stress distributions in fiber-reinforced resin composite (FRC) adhesive fixed partial dentures (AFPDs). Two adhesive resin cements were compared: Super-Bond C&B and Panavia Fluoro Cement. The AFPD consisted of a pontic to replace a maxillary right lateral incisor and retainers on a maxillary central incisor and canine. FRC framework was made of isotropic, continuous, unidirectional E-glass fibers. Maximum principal stresses were calculated using finite element method (FEM). Test results revealed that differences in the mechanical properties of adhesive resin cements led to different stress distributions at the cement interfaces between AFPD and abutment teeth. Clinical implication of these findings suggested that the safety and longevity of an AFPD depended on choosing an adhesive resin cement with the appropriate mechanical properties. PMID:22447051

  5. Sundew-Inspired Adhesive Hydrogels Combined with Adipose-Derived Stem Cells for Wound Healing.

    Science.gov (United States)

    Sun, Leming; Huang, Yujian; Bian, Zehua; Petrosino, Jennifer; Fan, Zhen; Wang, Yongzhong; Park, Ki Ho; Yue, Tao; Schmidt, Michael; Galster, Scott; Ma, Jianjie; Zhu, Hua; Zhang, Mingjun

    2016-01-27

    The potential to harness the unique physical, chemical, and biological properties of the sundew (Drosera) plant's adhesive hydrogels has long intrigued researchers searching for novel wound-healing applications. However, the ability to collect sufficient quantities of the sundew plant's adhesive hydrogels is problematic and has eclipsed their therapeutic promise. Inspired by these natural hydrogels, we asked if sundew-inspired adhesive hydrogels could overcome the drawbacks associated with natural sundew hydrogels and be used in combination with stem-cell-based therapy to enhance wound-healing therapeutics. Using a bioinspired approach, we synthesized adhesive hydrogels comprised of sodium alginate, gum arabic, and calcium ions to mimic the properties of the natural sundew-derived adhesive hydrogels. We then characterized and showed that these sundew-inspired hydrogels promote wound healing through their superior adhesive strength, nanostructure, and resistance to shearing when compared to other hydrogels in vitro. In vivo, sundew-inspired hydrogels promoted a "suturing" effect to wound sites, which was demonstrated by enhanced wound closure following topical application of the hydrogels. In combination with mouse adipose-derived stem cells (ADSCs) and compared to other therapeutic biomaterials, the sundew-inspired hydrogels demonstrated superior wound-healing capabilities. Collectively, our studies show that sundew-inspired hydrogels contain ideal properties that promote wound healing and suggest that sundew-inspired-ADSCs combination therapy is an efficacious approach for treating wounds without eliciting noticeable toxicity or inflammation. PMID:26731614

  6. An evidence for adhesion-mediated acquisition of acute myeloid leukemic stem cell-like immaturities

    Energy Technology Data Exchange (ETDEWEB)

    Funayama, Keiji; Shimane, Miyuki; Nomura, Hitoshi [Department of Integrative Bioscience and Biomedical Engineering, Waseda University, 4-3-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Asano, Shigetaka, E-mail: asgtkmd@waseda.jp [Department of Integrative Bioscience and Biomedical Engineering, Waseda University, 4-3-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2010-02-12

    For long-term survival in vitro and in vivo of acute myeloid leukemia cells, their adhesion to bone marrow stromal cells is indispensable. However, it is still unknown if these events are uniquely induced by the leukemic stem cells. Here we show that TF-1 human leukemia cells, once they have formed a cobblestone area by adhering to mouse bone marrow-derived MS-5 cells, can acquire some leukemic stem cell like properties in association with a change in the CD44 isoform-expression pattern and with an increase in a set of related microRNAs. These findings strongly suggest that at least some leukemia cells can acquire leukemic stem cell like properties in an adhesion-mediated stochastic fashion.

  7. Heparanase facilitates cell adhesion and spreading by clustering of cell surface heparan sulfate proteoglycans.

    Directory of Open Access Journals (Sweden)

    Flonia Levy-Adam

    Full Text Available Heparanase is a heparan sulfate (HS degrading endoglycosidase participating in extracellular matrix degradation and remodeling. Apart of its well characterized enzymatic activity, heparanase was noted to exert also enzymatic-independent functions. Non-enzymatic activities of heparanase include enhanced adhesion of tumor-derived cells and primary T-cells. Attempting to identify functional domains of heparanase that would serve as targets for drug development, we have identified heparin binding domains of heparanase. A corresponding peptide (residues Lys(158-Asp(171, termed KKDC was demonstrated to physically associate with heparin and HS, and to inhibit heparanase enzymatic activity. We hypothesized that the pro-adhesive properties of heparanase are mediated by its interaction with cell surface HS proteoglycans, and utilized the KKDC peptide to examine this possibility. We provide evidence that the KKDC peptide interacts with cell membrane HS, resulting in clustering of syndecan-1 and syndecan-4. We applied classical analysis of cell morphology, fluorescent and time-lapse microscopy and demonstrated that the KKDC peptide efficiently stimulates the adhesion and spreading of various cell types, mediated by PKC, Src, and the small GTPase Rac1. These results support, and further substantiate the notion that heparanase function is not limited to its enzymatic activity.

  8. Characterization of bifidobacterial adhesion to intestinal epithelial cells

    OpenAIRE

    Gleinser, Marita

    2012-01-01

    Adhesion of probiotics is discussed as a prerequisite for the persistence and the colonization of the gut. Based on previous studies of our group, the strain B. bifidum S17 could be identified as promising candidate to investigate adhesion properties (Riedel et al., 2006a; Preising et al., 2010). Several E. coli-Bifidobacterium shuttle vectors with different antibiotic resistances were generated. Using a gusA reporter assay the promoter Pgap was shown to have detectable transcriptional activi...

  9. Dynamic Cell Adhesion and Migration on Nanoscale Grooved Substrates

    NARCIS (Netherlands)

    Lamers, E.; Riet, te J.; Domanski, M.; Luttge, R.; Figdor, C.G.; Gardeniers, J.G.E.; Walboomers, X.F.; Jansen, J.A.

    2012-01-01

    Organised nanotopography mimicking the natural extracellular matrix can be used to control morphology, cell motility, and differentiation. However, it is still unknown how specific cell types react with specific patterns. Both initial adhesion and preferential cell migration may be important to init

  10. Dynamic cell adhesion and migration on nanoscale grooved substrates.

    NARCIS (Netherlands)

    Lamers, E.; Riet, J. te; Domanski, M.; Luttge, R.; Figdor, C.G.; Gardeniers, J.G.E.; Walboomers, X.F.; Jansen, J.B.M.J.

    2012-01-01

    Organised nanotopography mimicking the natural extracellular matrix can be used to control morphology, cell motility, and differentiation. However, it is still unknown how specific cell types react with specific patterns. Both initial adhesion and preferential cell migration may be important to init

  11. Nanoporous Monolithic Microsphere Arrays Have Anti-Adhesive Properties Independent of Humidity

    Science.gov (United States)

    Eichler-Volf, Anna; Xue, Longjian; Kovalev, Alexander; Gorb, Elena; Gorb, Stanislav; Steinhart, Martin

    2016-05-01

    Bioinspired artificial surfaces with tailored adhesive properties have attracted significant interest. While fibrillar adhesive pads mimicking gecko feet are optimized for strong reversible adhesion, monolithic microsphere arrays mimicking the slippery zone of the pitchers of carnivorous plants of the genus Nepenthes show anti-adhesive properties even against tacky counterpart surfaces. In contrast to the influence of topography, the influence of relative humidity (RH) on adhesion has been widely neglected. Some previous works deal with the influence of RH on the adhesive performance of fibrillar adhesive pads. Commonly, humidity-induced softening of the fibrils enhances adhesion. However, little is known on the influence of RH on solid anti-adhesive surfaces. We prepared polymeric nanoporous monolithic microsphere arrays (NMMAs) with microsphere diameters of a few 10 {\\mu}m to test their anti-adhesive properties at RHs of 2 % and 90 %. Despite the presence of continuous nanopore systems through which the inner nanopore walls were accessible to humid air, the topography-induced anti-adhesive properties of NMMAs on tacky counterpart surfaces were retained even at RH = 90 %. This RH-independent robustness of the anti-adhesive properties of NMMAs significantly contrasts the adhesion enhancement by humidity-induced softening on nanoporous fibrillar adhesive pads made of the same material.

  12. Nanoporous Monolithic Microsphere Arrays Have Anti-Adhesive Properties Independent of Humidity

    Directory of Open Access Journals (Sweden)

    Anna Eichler-Volf

    2016-05-01

    Full Text Available Bioinspired artificial surfaces with tailored adhesive properties have attracted significant interest. While fibrillar adhesive pads mimicking gecko feet are optimized for strong reversible adhesion, monolithic microsphere arrays mimicking the slippery zone of the pitchers of carnivorous plants of the genus Nepenthes show anti-adhesive properties even against tacky counterpart surfaces. In contrast to the influence of topography, the influence of relative humidity (RH on adhesion has been widely neglected. Some previous works deal with the influence of RH on the adhesive performance of fibrillar adhesive pads. Commonly, humidity-induced softening of the fibrils enhances adhesion. However, little is known on the influence of RH on solid anti-adhesive surfaces. We prepared polymeric nanoporous monolithic microsphere arrays (NMMAs with microsphere diameters of a few 10 µm to test their anti-adhesive properties at RHs of 2% and 90%. Despite the presence of continuous nanopore systems through which the inner nanopore walls were accessible to humid air, the topography-induced anti-adhesive properties of NMMAs on tacky counterpart surfaces were retained even at RH = 90%. This RH-independent robustness of the anti-adhesive properties of NMMAs significantly contrasts the adhesion enhancement by humidity-induced softening on nanoporous fibrillar adhesive pads made of the same material.

  13. The role of adhesion strength in human mesenchymal stem cell osteoblastic differentiation on biodegradable polymers

    Science.gov (United States)

    Krizan, Sylva Jana

    Human mesenchymal stem cells (hMSC) are promising candidates for promoting bone growth on biodegradable polymer scaffolds however little is known about early hMSC-polymer interactions. Adhesion is highly dynamic and during adhesive reinforcement, numerous proteins form adhesion plaques linking the cell's cytoskeleton with the extracellular environment. These proteins are known to affect cellular function but their role in hMSC differentiation is less clear. Adhesion plaques are associated with adhesive force, still a detachment force of hMSC on polycaprolactone (PCL), poly-lactide-co-glycolide (PLGA) or alginate has never been described or shown to affect downstream function. We demonstrate that hMSC attached to PCL, PLGA and alginate exhibit different adhesion strengths (tau50) as determined by both fluid shear and spinning disk systems, with PLGA demonstrating the greatest tau 50. Elastic modulus and hydrophobicity were characterized for these surfaces and correlated positively with tau50 to an optimum. Attachment studies of hMSC showed that adhesion plateau timespans were independent of cell line and surface but both morphology and focal adhesion expression varied by polymer type. Differentiation studies of hMSC on PLGA and PCL showed a strong association between markers of differentiation (alkaline phosphatase activity and mineral content) and tau50 within polymer groups, but a poor relationship was found between tau50 and differentiation across polymer groups, suggesting that other polymer properties may be important for differentiation. Subsequently, we examined the role of focal adhesion kinase (FAK) and Rho-GTPase (RhoA) on hMSC adhesion and differentiation when plated onto PLGA. hMSC were retrovirally transduced with mutant constructs of FAK and RhoA cDNA. Alternatively, hMSC were treated with Rho-kinase inhibitor, Y27632. Both cells transduced with mutant RhoA or FAK constructs, or those treated with Y27632 displayed aberrant cell morphology and changes

  14. Cell Adhesion and Proliferation on the "Living" Surface of a Polyelectrolyte Multilayer.

    Science.gov (United States)

    Arias, Carlos J; Surmaitis, Richard L; Schlenoff, Joseph B

    2016-05-31

    The adhesion of living eukaryotic cells to a substrate, one of the most complex problems in surface science, requires adsorption of extracellular proteins such as fibronectin. Thin films of polyelectrolyte complex made layer-by-layer (polyelectrolyte multilayers or PEMUs) offer a high degree of control of surface charge and composition-interconnected and essential variables for protein adhesion. Fibroblasts grown on multilayers of poly(styrenesulfonate), PSS, and poly(diallyldimethylammonium), PDADMA, with increasing thickness exhibit good adhesion until the 12th layer of polyelectrolyte has been added, whereupon there is a sudden transition to nonadhesive behavior. This sharp change is due to the migration of excess positive charge to the surface-a previously unrecognized property of PEMUs. Precise radiotracer assays of adsorbed (125)I-albumin show how protein adsorption is related to multilayer surface charge. With more negative surface charge density from the sulfonates of PSS, more albumin adsorbs to the surface. However, a loosely held or "soft corona" exchanges with serum protein under the Vroman effect, which is correlated with poor cell adhesion. A comprehensive view of cell adhesion highlights the central role of robust protein adhesion, which is required before any secondary effects of matrix stiffness on cell fate can come into play. PMID:27191244

  15. Quantification of Depletion-Induced Adhesion of Red Blood Cells

    Science.gov (United States)

    Steffen, P.; Verdier, C.; Wagner, C.

    2013-01-01

    Red blood cells (RBCs) are known to form aggregates in the form of rouleaux due to the presence of plasma proteins under physiological conditions. The formation of rouleaux can also be induced in vitro by the addition of macromolecules to the RBC suspension. Current data on the adhesion strength between red blood cells in their natural discocyte shapes mostly originate from indirect measurements such as flow chamber experiments, but data is lacking at the single cell level. Here, we present measurements on the dextran-induced aggregation of red blood cells using atomic force microscopy-based single cell force spectroscopy. The effects of dextran concentration and molecular weight on the interaction energy of adhering RBCs were determined. The results on adhesion energy are in excellent agreement with a model based on the depletion effect and previous experimental studies. Furthermore, our method allowed to determine the adhesion force, a quantity that is needed in theoretical investigations on blood flow.

  16. Cell Adhesion Selectivity of Stent Material to improve Bio-functionality by Ion Beam Modification

    International Nuclear Information System (INIS)

    In this study, ion implantation into collagen coated Co-Cr alloy, which is a cheaper material of the artificial stent product comparing with Ti alloy, has been studied to develop small diameter artificial stent by the cell adhesion control. The size of stent was 1.6mm of the diameter and 18mm of the length. The life-time of artificial stent depends on adhesion property of endothelial-cells. We successfully controlled cell adhesion selectivity between endothelial cell and muscle cell by using collagen coated and He+ ion beam irradiated Co-Cr-alloy to apply to artificial stent. But, we did not achieve the inhibition of platelet adhesion, yet by using collagen coating and He+ ion beam irradiation. Based on this study, we have plan to research about separation between collagen coating effect and ion beam effect. Also, we will have more detail analysis of the mechanism of cell attachment. In recent years, ion implantation has been applied to the surface modification of prosthesis to improve blood compatibility and tissue compatibility in field of biomedical application. As well known, bio compatibility was concerned with the cell adhesion selectivity for bio-functionality. The biomedical application of ion beam technology would be used more widely in the future such as catheter and artificial graft

  17. Cell Adhesion Selectivity of Stent Material to improve Bio-functionality by Ion Beam Modification

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaesang; Park, JUngchan; Jung, Myunghwan; Kim, Yongki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Junkyu [Bio alpha., Co. Ltd., Gimhae (Korea, Republic of)

    2014-05-15

    In this study, ion implantation into collagen coated Co-Cr alloy, which is a cheaper material of the artificial stent product comparing with Ti alloy, has been studied to develop small diameter artificial stent by the cell adhesion control. The size of stent was 1.6mm of the diameter and 18mm of the length. The life-time of artificial stent depends on adhesion property of endothelial-cells. We successfully controlled cell adhesion selectivity between endothelial cell and muscle cell by using collagen coated and He{sup +} ion beam irradiated Co-Cr-alloy to apply to artificial stent. But, we did not achieve the inhibition of platelet adhesion, yet by using collagen coating and He{sup +} ion beam irradiation. Based on this study, we have plan to research about separation between collagen coating effect and ion beam effect. Also, we will have more detail analysis of the mechanism of cell attachment. In recent years, ion implantation has been applied to the surface modification of prosthesis to improve blood compatibility and tissue compatibility in field of biomedical application. As well known, bio compatibility was concerned with the cell adhesion selectivity for bio-functionality. The biomedical application of ion beam technology would be used more widely in the future such as catheter and artificial graft.

  18. Sliced Magnetic Polyacrylamide Hydrogel with Cell-Adhesive Microarray Interface: A Novel Multicellular Spheroid Culturing Platform.

    Science.gov (United States)

    Hu, Ke; Zhou, Naizhen; Li, Yang; Ma, Siyu; Guo, Zhaobin; Cao, Meng; Zhang, Qiying; Sun, Jianfei; Zhang, Tianzhu; Gu, Ning

    2016-06-22

    Cell-adhesive properties are of great significance to materials serving as extracellular matrix mimics. Appropriate cell-adhesive property of material interface can balance the cell-matrix interaction and cell-cell interaction and can promote cells to form 3D structures. Herein, a novel magnetic polyacrylamide (PAM) hydrogel fabricated via combining magnetostatic field induced magnetic nanoparticles assembly and hydrogel gelation was applied as a multicellular spheroids culturing platform. When cultured on the cell-adhesive microarray interface of sliced magnetic hydrogel, normal and tumor cells from different cell lines could rapidly form multicellular spheroids spontaneously. Furthermore, cells which could only form loose cell aggregates in a classic 3D cell culture model (such as hanging drop system) were able to be promoted to form multicellular spheroids on this platform. In the light of its simplicity in fabricating as well as its effectiveness in promoting formation of multicellular spheroids which was considered as a prevailing tool in the study of the microenvironmental regulation of tumor cell physiology and therapeutic problems, this composite material holds promise in anticancer drugs or hyperthermia therapy evaluation in vitro in the future. PMID:27258682

  19. Monitoring cell adhesion on tantalum and oxidised polystyrene using a quartz crystal microbalance with dissipation.

    Science.gov (United States)

    Lord, Megan Susan; Modin, Charlotte; Foss, Morten; Duch, Mogens; Simmons, Anne; Pedersen, Finn S; Milthorpe, Bruce K; Besenbacher, Flemming

    2006-09-01

    The quartz crystal microbalance with dissipation (QCM-D) (Q-Sense AB, Sweden) has been established as a useful tool for evaluating interactions between various biological and non-biological systems, and there has been increasing interest in using the QCM-D technique for cell monitoring applications. This study investigated the potential of the QCM-D to characterise the initial adhesion and spreading of cells in contact with protein precoated biocompatible surfaces. The QCM-D technique is attractive for monitoring cell adhesion and spreading as it allows in situ real-time measurements. The adhesion of NIH3T3 (EGFP) fibroblasts to tantalum (Ta) and oxidised polystyrene (PS(ox)) surfaces precoated with serum proteins was examined using the QCM-D for a period of either 2 or 4 h. Time-lapse photography was performed at 30 min intervals to visually examine cell adhesion and spreading in order to relate cell morphology to the QCM-D response. Following adsorption of albumin, fibronectin or newborn calf serum onto the surfaces, QCM-D measurements showed that cells adhered and spread on the fibronectin and serum coated surfaces, while few cells adhered to the albumin coated surfaces. Cells adhered to albumin coated surfaces had a rounded morphology. The responses to fibronectin and serum precoated surfaces were quite different for each of the underlying substrates indicating that the process of cell adhesion and spreading elicits different responses depending on both the protein coating composition and the influence of the underlying substrate. The different response may be due to extracellular matrix remodelling as well as cytoskeletal changes. Frequency (f) and dissipation (D) changes associated with cell adhesion were less than would be expected from the Sauerbrey relation due to the viscoelastic properties of the cells. PMID:16716396

  20. Intercellular Cell Adhesion Molecule-1, Vascular Cell Adhesion Molecule-1, and Regulated on Activation Normal T Cell Expressed and Secreted Are Expressed by Human Breast Carcinoma Cells and Support Eosinophil Adhesion and Activation

    OpenAIRE

    Ali, Shahina; Kaur, Jaswinder; Patel, Kamala D.

    2000-01-01

    Eosinophils are usually associated with parasitic and allergic diseases; however, eosinophilia is also observed in several types of human tumors, including breast carcinomas. In this study we examined several human breast carcinoma cell lines for adhesion molecule expression and the ability to bind and activate eosinophils. MDA-MB-435S and MDA-MB-468 cells constitutively expressed both intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and this expressio...

  1. Prostaglandins in Cancer Cell Adhesion, Migration, and Invasion

    Directory of Open Access Journals (Sweden)

    David G. Menter

    2012-01-01

    Full Text Available Prostaglandins exert a profound influence over the adhesive, migratory, and invasive behavior of cells during the development and progression of cancer. Cyclooxygenase-2 (COX-2 and microsomal prostaglandin E2 synthase-1 (mPGES-1 are upregulated in inflammation and cancer. This results in the production of prostaglandin E2 (PGE2, which binds to and activates G-protein-coupled prostaglandin E1-4 receptors (EP1-4. Selectively targeting the COX-2/mPGES-1/PGE2/EP1-4 axis of the prostaglandin pathway can reduce the adhesion, migration, invasion, and angiogenesis. Once stimulated by prostaglandins, cadherin adhesive connections between epithelial or endothelial cells are lost. This enables cells to invade through the underlying basement membrane and extracellular matrix (ECM. Interactions with the ECM are mediated by cell surface integrins by “outside-in signaling” through Src and focal adhesion kinase (FAK and/or “inside-out signaling” through talins and kindlins. Combining the use of COX-2/mPGES-1/PGE2/EP1-4 axis-targeted molecules with those targeting cell surface adhesion receptors or their downstream signaling molecules may enhance cancer therapy.

  2. Apicobasal Polarity Controls Lymphocyte Adhesion to Hepatic Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Natalia Reglero-Real

    2014-09-01

    Full Text Available Loss of apicobasal polarity is a hallmark of epithelial pathologies. Leukocyte infiltration and crosstalk with dysfunctional epithelial barriers are crucial for the inflammatory response. Here, we show that apicobasal architecture regulates the adhesion between hepatic epithelial cells and lymphocytes. Polarized hepatocytes and epithelium from bile ducts segregate the intercellular adhesion molecule 1 (ICAM-1 adhesion receptor onto their apical, microvilli-rich membranes, which are less accessible by circulating immune cells. Upon cell depolarization, hepatic ICAM-1 becomes exposed and increases lymphocyte binding. Polarized hepatic cells prevent ICAM-1 exposure to lymphocytes by redirecting basolateral ICAM-1 to apical domains. Loss of ICAM-1 polarity occurs in human inflammatory liver diseases and can be induced by the inflammatory cytokine tumor necrosis factor alpha (TNF-α. We propose that adhesion receptor polarization is a parenchymal immune checkpoint that allows functional epithelium to hamper leukocyte binding. This contributes to the haptotactic guidance of leukocytes toward neighboring damaged or chronically inflamed epithelial cells that expose their adhesion machinery.

  3. Osteoblast Adhesion of Breast Cancer Cells with Scanning Acoustic Microscopy

    Science.gov (United States)

    Miyasaka, C.; Mercer, R. R.; Mastro, A. M.

    Conditioned medium was collected from a bone-metastatic breast cancer cell line, MDA-MB-231, and cultured with an immature osteoblast cell line, MC3T3-E1. Under these conditions the osteoblasts acquired a changed morphology and appeared to adhere in a different way to the substrate and to each other. To characterize cellular adhesion, MC3T3-E1 osteoblasts were cultured with or without MDA-MB-231 conditioned medium for two days. With mechanical scanning acoustic reflection microscopy, we were able to detect a change in the adhesive condition of the interface between the cell and the substrate, but not with optical microscopy

  4. Mimicking the inflammatory cell adhesion cascade by nucleic acid aptamer programmed cell-cell interactions

    OpenAIRE

    Zhao, Weian; Loh, Weili; Droujinine, Ilia A.; Teo, Weisuong; Kumar, Namit; Schafer, Sebastian; Cui, Cheryl H.; Zhang, Liang; Sarkar, Debanjan; Karnik, Rohit; Karp, Jeffrey M.

    2011-01-01

    Nature has evolved effective cell adhesion mechanisms to deliver inflammatory cells to inflamed tissue; however, many culture-expanded therapeutic cells are incapable of targeting diseased tissues following systemic infusion, which represents a great challenge in cell therapy. Our aim was to develop simple approaches to program cell-cell interactions that would otherwise not exist toward cell targeting and understanding the complex biology of cell-cell interactions. We employed a chemistry ap...

  5. CHARACTERISTICS OF ADHESIVE PROPERTIES OF LACTOBACILLUS - CLINICAL ISOLATES AND COMPONENTS OF BIOLOGICAL PRODUCTS

    Directory of Open Access Journals (Sweden)

    Lavryk G.

    2015-05-01

    Full Text Available Lactobacilli detected in all biotopes of digestive tract, starting from the mouth and ending with the colon, is the dominant flora of vaginal biotope. Their adhesiveness to epithelial cells leads to survive in conditions of microorganism biotopes and to form biofilm, thus mediating passive antagonism against conditionally pathogenic bacteria. Colonization resistance provides a set of mechanisms that provide individual anatomical stability and normal microflora. It is experimentally confirmed that lactobacilli provide biotopes colonization resistance of the human body due to competitive inhibition and coagregation of allochthonous microorganisms. It is important to consider the fact that probiotics should not compete with autochthonous microflora, which is always more physiological for each individual than most valuable exogenous bacteria, even with the greatest potential beneficial properties. The probiotic activity should be directed to the main target bacterial therapy, which is to restore physiological ecological community. The aim of research was to compare the adhesive properties of lactobacilli - clinical isolates of probiotic preparations and ingredients to the buccal epithelium cells and erythrocytes 0 (1 of the blood group system AB0 person. Materials and methods. The object of the research were clinical strains of Lactobacillus spp. selected from the mouth, intestines, vagina healthy people. At the the species identification of lactic acid bacteria were taken into account morphological and cultural properties, aerotolerance. The carbohydrate profile was determined using the test system API-50SN L (Bio-Merieux, lack of catalase activity. The ability of allocated bacteria to adhesion were observed in erythrocytes 0 (1 blood and buccal epithelium cells by human Brilis VI and oth. For comparison were used probiotic strains L. rlantarum 8PA3, L.acidophilus KS 400, Lactobacillus reuteri DSM 17938. The effectiveness of adhesion was assessed

  6. Dynamic mechanical and thermal properties of seven polyurethane adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.M.

    1981-03-01

    Seven polyurethane adhesives have been developed at Lawrence Livermore National Laboratory (LLNL). These adhesives, designated Halthanes were synthesized because of OSHA restrictions on the use of the curing agent methylene bis(2-chloroaniline). Four of the Halthanes were made from LLNL-developed 4,4'-methylene bis(phenylisocyanate) terminated prepolymers cured with a blend of polyols; three were made from an LLNL-developed prepolymer terminated with Hylene W and cured with aromatic diamines. In this paper the dynamic mechanical and thermal behavior of these seven segmented polyurethanes are discussed. The chemical structure of the hard and soft segments, the concentrations of each block, and the presence of tetrafunctional crosslinker determined the dynamic mechanical and thermal properties of the three types of polyurethane adhesives, 73-, 87-, and 88-series Halthanes studied. Aromatic-aliphatic MDI- butanediol urethane hard segments produce lower modulus (10/sup 6/ Pa) materials in the rubbery region than cyclic unsaturated-aromatic urea hard segments. Incorporation of chemical crosslinks in the hard segments extended the rubbery plateau beyond the hard segment transitions up to temperatures where the polymer begins to degrade. Concentration of hard and soft segments can also be used to control the modulus between the glass transition temperatures of the two blocks.

  7. Adhesion in the stem cell niche: biological roles and regulation

    OpenAIRE

    Chen, Shuyi; Lewallen, Michelle; Xie, Ting

    2013-01-01

    Stem cell self-renewal is tightly controlled by the concerted action of stem cell-intrinsic factors and signals within the niche. Niche signals often function within a short range, allowing cells in the niche to self-renew while their daughters outside the niche differentiate. Thus, in order for stem cells to continuously self-renew, they are often anchored in the niche via adhesion molecules. In addition to niche anchoring, however, recent studies have revealed other important roles for adhe...

  8. How to let go: pectin and plant cell adhesion

    OpenAIRE

    Daher, Firas Bou; Braybrook, Siobhan A.

    2015-01-01

    Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbors, intimately linked through growth and differentiation. The mediator of this connection, the pectin-rich middle lamella, is deposited during cell division and maintained throughout the cell’s life to protect tissue integrity. The maintenance of adhesion requires cell wall modification and is dependent on the actin cytoskeleton. There are developmental processes that require cell separation, such...

  9. Adhesion between peptides/antibodies and breast cancer cells

    Science.gov (United States)

    Meng, J.; Paetzell, E.; Bogorad, A.; Soboyejo, W. O.

    2010-06-01

    Atomic force microscopy (AFM) techniques were used to measure the adhesion forces between the receptors on breast cancer cells specific to human luteinizing hormone-releasing hormone (LHRH) peptides and antibodies specific to the EphA2 receptor. The adhesion forces between LHRH-coated AFM tips and human MDA-MB-231 cells (breast cancer cells) were shown to be about five times greater than those between LHRH-coated AFM tips and normal Hs578Bst breast cells. Similarly, those between EphA2 antibody-coated AFM tips and breast cancer cells were over five times greater than those between EphA2 antibody-coated AFM tips and normal breast cells. The results suggest that AFM can be used for the detection of breast cancer cells in biopsies. The implications of the results are also discussed for the early detection and localized treatment of cancer.

  10. Impact of electrospun nanofibres orientation on mesenchymal stem cell adhesion and morphology

    International Nuclear Information System (INIS)

    Electrospun nanofibrous materials mimicking the architecture of native extracellular matrix (ECM) hold great promise as scaffolds in tissue engineering. In order to optimize the properties of nanofibrous scaffolds it is important to understand the impact of fibres’ organization on cell behaviour. Herein, we investigated the effect of nanofibres (NFs) alignment on human adipose-derived mesenchymal stem cells (hAD-MSCs) adhesion and morphology. Electrospun composite fibrinogen/poly-lactic acid (FNG/PLA) NF scaffolds with same composition and comparable fibre size were fabricated into randomly oriented and aligned configuration and stem cells adhesion was characterized by the meaning of overall cell morphology, actin cytoskeleton organization and expression of molecules, involved in the development of focal adhesion complexes. We found that hAD-MSCs altered their morphology, actin cytoskeleton and cell attachment in accordance with nanofibre orientation while cell spreading, focal adhesions and expression of β1 and αN integrin receptors were not influenced significantly by fibre orientation. These results confirmed that fibre alignment of scaffold guide cellular arrangement and could be beneficial for stem differentiation and therefore for the successful scaffolds development if its contact guidance coincided with the cell shape and cytoskeletal tension. Key words: electrospinning, human adipose-derived stem cells, fibrinogen/polylactic acid hybrid nanofibres

  11. Cell Adhesion on Polycaprolactone Modified by Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Nina Recek

    2016-01-01

    Full Text Available We have investigated the influence of various plasma treatments of electrospun polycaprolactone (PCL scaffolds on the adhesion and proliferation of human umbilical endothelial cells (HUVEC. The PCL scaffolds were treated in plasmas created in O2, NH3 or SO2 gas at identical conditions. Surface functionalization of plasma-treated samples was determined using X-ray photoelectron spectroscopy. Cell adhesion and morphology were investigated by scanning electron microscopy and the influence of plasma treatment on cell adhesion and viability was evaluated with cell viability assay (MTT assay. The results showed the highest metabolic activity of HUVEC on PCL samples treated with O2 and NH3 plasma. Accordingly, the cells reflected the best adhesion and morphology on O2 and NH3 plasma-treated PCL samples already at 3 h. Moreover, treatment with O2 and NH3 plasma even stimulated endothelial cell proliferation on PCL surfaces by 60% as measured at 24 h, showing significant improvement in endothelialization of this material. Contrarily, SO2 plasma appeared to be less promising in comparison with O2 and NH3 plasma; however, it was still better than without any plasma treatment. Thus, our results importantly contribute to the biocompatibility improvement of the PCL polymer, commonly used for scaffolds in tissue engineering.

  12. Pathogenic Actions of Cell Adhesion Molecule 1 in Pulmonary Emphysema and Atopic Dermatitis

    OpenAIRE

    Yoneshige, Azusa; Hagiyama, Man; Fujita, Mitsugu; Ito, Akihiko

    2015-01-01

    Cell adhesion mediated by adhesion molecules is of central importance in the maintenance of tissue homeostasis. Therefore, altered expression of adhesion molecules leads to the development of various tissue disorders involving cell activation, degeneration, and apoptosis. Nevertheless, it still remains unclear what initiates the altered expression of adhesion molecules and how the subsequent pathological cascades proceed. In this regard, cell adhesion molecule 1 (CADM1) is one of the candidat...

  13. Tumour-stromal interactions: Integrins and cell adhesions as modulators of mammary cell survival and transformation

    International Nuclear Information System (INIS)

    Stromal–epithelial interactions modulate mammary epithelial cell (MEC) growth and apoptosis by influencing cell adhesion and tissue organization. Perturbations in the mammary stroma and cell adhesion characterize breast tumors and underlie the altered tissue organization, disrupted tissue homeostasis and enhanced survival phenotype of the disease. Apoptosis resistance likely arises during malignant transformation via genetic and epigenetic modification of cell adhesion pathways induced by a changing tissue microenvironment. Acquisition of adhesion-linked survival networks that enhance MEC viability in the absence of basement membrane interactions probably promote malignant transformation, and may render breast tumors sufficiently resistant to exogenous apoptotic stimuli to generate multidrug resistance

  14. From flexibility to cooperativity: multiscale modeling of cadherin-mediated cell adhesion

    Science.gov (United States)

    Wu, Yinghao

    2013-03-01

    Cadherins constitute a large family of Ca2 +-dependent adhesion molecules in the Inter-cellular junctions that play a pivotal role in the assembly of cells into specific three-dimensional tissues. Although the molecular mechanisms underlying cadherin-mediated cell adhesion are still not fully understood, it seems likely that both cis dimers that are formed by binding of extracellular domains of two cadherins on the same cell surface, and trans-dimers formed between cadherins on opposing cell surfaces, are critical to trigger the junction formation. Here we present a new multiscale computational strategy to model the process of junction formation based on the knowledge of cadherin molecular structures and its 3D binding affinities. The cell interfacial region is defined by a simplified system where each of two interacting membrane surfaces is represented as a two-dimensional lattice with each cadherin molecule treated as a randomly diffusing unit. The binding energy for a pair of interacting cadherins in this two-dimensional discrete system is obtained from 3D binding affinities through a renormalization process derived from statistical thermodynamics. The properties of individual cadherins used in the lattice model are based on molecular level simulations. Our results show that within the range of experimentally-measured binding affinities, cadherins condense into junctions driven by the coupling of cis and trans interactions. The key factor appears to be a loss of molecular flexibility during trans dimerization that increases the magnitude of lateral cis interactions. We have also developed stochastic dynamics to study the adhesion of multiple cells. Each cell in the system is described as a mechanical entity and adhesive properties between two cells are derived from the lattice model. The cellular simulations are used to study the specific problems of tissue morphogenesis and tumor metastasis. The consequent question and upcoming challenge is to understand the

  15. How to let go: pectin and plant cell adhesion.

    Science.gov (United States)

    Daher, Firas Bou; Braybrook, Siobhan A

    2015-01-01

    Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbors, intimately linked through growth and differentiation. The mediator of this connection, the pectin-rich middle lamella, is deposited during cell division and maintained throughout the cell's life to protect tissue integrity. The maintenance of adhesion requires cell wall modification and is dependent on the actin cytoskeleton. There are developmental processes that require cell separation, such as organ abscission, dehiscence, and ripening. In these instances, the pectin-rich middle lamella must be actively altered to allow cell separation, a process which also requires cell wall modification. In this review, we will focus on the role of pectin and its modification in cell adhesion and separation. Recent insights gained in pectin gel mechanics will be discussed in relation to existing knowledge of pectin chemistry as it relates to cell adhesion. As a whole, we hope to begin defining the physical mechanisms behind a cells' ability to hang on, and how it lets go. PMID:26236321

  16. Quantification of depletion-induced adhesion of Red Blood Cells

    OpenAIRE

    Steffen, Patrick; Verdier, Claude; Wagner, Christian

    2013-01-01

    Red blood cells (RBC) are known to form aggregates in the forms of rouleaux due to the presence of plasma proteins under physiological conditions. Rouleaux formation can be also induced in vitro by the addition of macromolecules to the RBC solution. Current data on the adhesion strength between red blood cells in their natural discocyte shapes mostly rely on indirect measurements like flow chamber experiments, but on the single cell level data is lacking. Here we present measurements on the d...

  17. Adhesion of human basophils, eosinophils, and neutrophils to interleukin 1-activated human vascular endothelial cells: contributions of endothelial cell adhesion molecules

    OpenAIRE

    1991-01-01

    Cytokines such as interleukin 1 (IL-1) promote adhesiveness in human umbilical vein endothelial cells for leukocytes including basophils, eosinophils, and neutrophils, and induce expression of adherence molecules including ICAM-1 (intercellular adhesion molecule-1), ELAM-1 (endothelial-leukocyte adhesion molecule-1), and VCAM-1 (vascular cell adhesion molecule-1). In the present study, blocking monoclonal antibodies (mAb) recognizing ICAM-1, ELAM-1, and VCAM-1 have been used to compare their ...

  18. Biomimetic emulsions reveal the effect of homeostatic pressure on cell-cell adhesion

    CERN Document Server

    Pontani, Lea-Laetitia; Viasnoff, Virgile; Brujic, Jasna

    2012-01-01

    Cell-cell contacts in tissues are continuously subject to mechanical forces due to homeostatic pressure and active cytoskeleton dynamics. While much is known about the molecular pathways of adhesion, the role of mechanics is less well understood. To isolate the role of pressure we present a dense packing of functionalized emulsion droplets in which surface interactions are tuned to mimic those of real cells. By visualizing the microstructure in 3D we find that a threshold compression force is necessary to overcome electrostatic repulsion and surface elasticity and establish protein-mediated adhesion. Varying the droplet interaction potential maps out a phase diagram for adhesion as a function of force and salt concentration. Remarkably, fitting the data with our theoretical model predicts binder concentrations in the adhesion areas that are similar to those found in real cells. Moreover, we quantify the adhesion size dependence on the applied force and thus reveal adhesion strengthening with increasing homeos...

  19. Regulation of cell–cell adhesion by the cadherin–catenin complex

    OpenAIRE

    Nelson, W. James

    2008-01-01

    Ca2+-dependent cell–cell adhesion is regulated by the cadherin family of cell adhesion proteins. Cadherins form trans-interactions on opposing cell surfaces which result in weak cell–cell adhesion. Stronger cell–cell adhesion occurs by clustering of cadherins and through changes in the organization of the actin cytoskeleton. Although cadherins were thought to bind directly to the actin cytoskeleton through cytoplasmic proteins, termed α- and β-catenin, recent studies with purified proteins in...

  20. Reinforcing endothelial junctions prevents microvessel permeability increase and tumor cell adhesion in microvessels in vivo

    OpenAIRE

    Bingmei M Fu; Jinlin Yang; Bin Cai; Jie Fan; Lin Zhang; Min Zeng

    2015-01-01

    Tumor cell adhesion to the microvessel wall is a critical step during tumor metastasis. Vascular endothelial growth factor (VEGF), a secretion of tumor cells, can increase microvessel permeability and tumor cell adhesion in the microvessel. To test the hypothesis that inhibiting permeability increase can reduce tumor cell adhesion, we used in vivo fluorescence microscopy to measure both microvessel permeability and adhesion rates of human mammary carcinoma MDA-MB-231 cells in post-capillary v...

  1. Biodegradable copolymers carrying cell-adhesion peptide sequences

    Czech Academy of Sciences Publication Activity Database

    Proks, Vladimír; Machová, Luďka; Popelka, Štěpán; Rypáček, František

    Antalya : Ankara University, Tissue Engineering and Biomaterials Laboratory, 2002. s. P-35. [International Symposium on Biomedical Science and Technology BIOMED /9./. 19.09.2002-22.09.2002, Antalya ] R&D Projects: GA AV ČR IAA4050202; GA MŠk LN00A065 Keywords : amphiphilic block copolymers * cell adhesion * biodegradable Subject RIV: CD - Macromolecular Chemistry

  2. 3D porous biomimetically modified hydrogels supporting stem cells adhesion

    Czech Academy of Sciences Publication Activity Database

    Studenovská, Hana; Vodička, Petr; Proks, Vladimír; Juhásová, Jana; Motlík, Jan; Rypáček, František

    Dublin : National University of Ireland , 2011. s. 119, psiii-630. [Annual Conference of the European Society for Biomaterials /24./. 04.09.2011-08.09.2011, Dublin] R&D Projects: GA MŠk 1M0538 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50450515 Keywords : porous hydrogel * cell adhesion * polypeptide Subject RIV: FH - Neurology

  3. Pharmacology of cell adhesion molecules of the nervous system

    DEFF Research Database (Denmark)

    Kiryushko, Darya; Bock, Elisabeth; Berezin, Vladimir

    2007-01-01

    Cell adhesion molecules (CAMs) play a pivotal role in the development and maintenance of the nervous system under normal conditions. They also are involved in numerous pathological processes such as inflammation, degenerative disorders, and cancer, making them attractive targets for drug...

  4. Selective adhesion of intestinal epithelial cells on patterned films with amine functionalities formed by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Control of cell adhesion to surfaces is important to develop analytical tools in the areas of biomedical engineering. To control cell adhesiveness of the surface, we constructed a variety of plasma polymerized hexamethyldisiloxane (PPHMDSO) thin films deposited at the plasma power range of 10-100 W by plasma enhanced chemical vapor deposition (PECVD). The PPHMDSO film that was formed at 10 W was revealed to be resistant to cell adhesion. The resistance to cell adhesion is closely related to physicochemical properties of the film. Atomic force microscopic data show an increase in surface roughness from 0.52 nm to 0.74 nm with increasing plasma power. From Fourier transform infrared (FT-IR) absorption spectroscopy data, it was also determined that the methyl (-CH3) peak intensity increases with increasing plasma power, whereas the hydroxyl (-OH) peak decreases. X-ray photoelectron spectroscopy data reveal an increase in C-O bonding with increasing plasma power. These results suggest that C-O bonding and hydroxyl (-OH) and methyl (-CH3) functional groups play a critical part in cell adhesion. Furthermore, to enhance a diversity of film surface, we accumulated the patterned plasma polymerized ethylenediamine (PPEDA) thin film on the top of the PPHMDSO thin film. The PPEDA film is established to be strongly cell-adherent. This patterned two-layer film stacking method can be used to form the selectively limited cell-adhesive PPEDA spots over the adhesion-resistant surface.

  5. Drug release and adhesive properties of crospovidone-containing matrix patches based on polyisobutene and acrylic adhesives.

    Science.gov (United States)

    Schulz, Martin; Fussnegger, Bernhard; Bodmeier, Roland

    2010-12-23

    Ethinyl estradiol and levonorgestrel were insoluble in blends of high:medium:low molecular weight polyisobutene adhesives (ratio: 1:5:0, 1:5:2 and 1:5:4) but soluble in acrylic adhesives (Durotak 87-202A, Durotak 87-2074 and Durotak 87-2677). The incorporation of drug adsorbates onto crospovidone into the polyisobutene blends yielded crystal-free patches. The drug release from these patches was independent of polyisobutene's molecular weight distribution, probably because the drug release occurred mainly through fluid filled channels. By contrast, the drug release from acrylic adhesives was independent of whether the patches contained pure drugs or drug adsorbates onto crospovidone. A higher degree of saturation (or supersaturation) in these systems resulted in a higher thermodynamic activity of the drugs and hence a higher drug release. The crystal-free acrylic and polyisobutene patches did not show drug recrystallization after 3 months at 25°C/60 RH and 40°C/75 RH. The adhesive properties of polyisobutene patches were investigated in vitro and in vivo. The area under the curve of force-distance curves recorded with the texture analyzer correlated well with the in vivo skin adhesion. The elongation at detachment showed the same trend as the in vivo matrix creep. Crospovidone contents ≤ 30% had no detrimental effect on the adhesive properties of the patches. PMID:20883778

  6. Upregulation of cell adhesion through delta Np63 silencing in human 5637 bladder cancer cells

    Institute of Scientific and Technical Information of China (English)

    Yun-Feng He; Dai-Yin Tian; Zheng-Jin Yi; Zhi-Kang Yin; Chun-Li Luo; Wei Tang; Xiao-Hou Wu

    2012-01-01

    Some researchs have demonstrated that the loss of delta Np63 is associated with aggressive phenotypes and poor prognosis.However,other research indicates that delta Np63 is considered to have oncogenic properties,Delta Np63 overexpression is often observed in association with the oncogenic growth of squamous cell carcinomas and bladder cancer.In this study,we investigated the oocogenic role of delta Np63 in regulating cell adhesion in transitional cell carcinoma of the bladder (TCCB).The Cells were stably transfected with the delta Np63 short hairpin RNA (shRNA) plasmid.Immunocytochemistry was performed to determine the knockdown efficiency.Tumour cells were studied for their ability to adhere to vascular endothelial cells.Confocal microscopy was used to analyse the changes in cytoskeletal F-actin.F-actin expression was measured by flow cytometry.Cell invasion ability was assessed using transwell chambers.fhe delta Np63-silenced tumour cells were shown to adhere more tightly than controls to vascular endothelial cells (P<0.05).The content of F-actin in the delta Np63-silenced cells was enhanced (P<0.05),The Matrigel invasion assays showed that human 5637 bladder cancer cells had a lower degree of motility when transfected with pdetta Np63-shRNA ( P< 0.05).In conclusion,silencing of the delta Np63 expression can enhance the adhesiveness of 5637 cells by inducing F-actin cytoskeleton production,and it will possibly inhibit the TCCB invasion and metastasis.

  7. Effect of molecular weight and testing rate on adhesion property of pressure-sensitive adhesives prepared from epoxidized natural rubber

    International Nuclear Information System (INIS)

    Research highlights: → Elucidation of adhesion property of epoxidized natural rubber (ENR 25). → Correlation of peel and shear strength with molecular weight and rate of testing. → Confirmation of miscibility of tackifier and ENR 25 by DSC and FTIR study. → Applicability of Fox equation in ENR 25/coumarone-indene resin system. -- Abstract: The dependence of peel strength and shear strength of epoxidized natural rubber (ENR 25)-based pressure-sensitive adhesive on molecular weight and rate of testing was investigated using coumarone-indene as the tackifying resin. Toluene and polyethylene terephthalate (PET) were used as the solvent and substrate respectively throughout the study. A SHEEN hand coater was used to coat the adhesive on the substrate at a coating thickness of 120 μm. All the adhesion properties were determined by a Llyod Adhesion Tester operating at different rates of testing. Result shows that peel strength and shear strength increases up to an optimum molecular weight of 6.5 x 104 of ENR 25. For peel strength, the observation is attributed to the combined effects of wettability and mechanical strength of rubber at the optimum molecular weight, whereas for the shear strength, it is ascribed to the increasing amount of adhesive present in the coating layer which enhances the shear resistance of the adhesive. Peel strength and shear strength also increases with increase in rate of testing, an observation which is associated to the viscoeslastic response of the adhesive. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) study confirms the miscibility of tackifier and the ENR 25.

  8. RNA-binding IMPs promote cell adhesion and invadopodia formation

    DEFF Research Database (Denmark)

    Vikesaa, Jonas; Hansen, Thomas V O; Jønson, Lars; Borup, Rehannah; Wewer, Ulla M; Christiansen, Jan; Nielsen, Finn C

    2006-01-01

    Oncofetal RNA-binding IMPs have been implicated in mRNA localization, nuclear export, turnover and translational control. To depict the cellular actions of IMPs, we performed a loss-of-function analysis, which showed that IMPs are necessary for proper cell adhesion, cytoplasmic spreading and...... invadopodia formation. Loss of IMPs was associated with a coordinate downregulation of mRNAs encoding extracellular matrix and adhesion proteins. The transcripts were present in IMP RNP granules, implying that IMPs were directly involved in the post-transcriptional control of the transcripts. In particular......-mediated invadopodia formation. Taken together, our results indicate that RNA-binding proteins exert profound effects on cellular adhesion and invasion during development and cancer formation....

  9. Allogeneic hematopoietic stem-cell transplantation for leukocyte adhesion deficiency

    DEFF Research Database (Denmark)

    Qasim, Waseem; Cavazzana-Calvo, Marina; Davies, E Graham;

    2009-01-01

    of leukocyte adhesion deficiency who underwent hematopoietic stem-cell transplantation between 1993 and 2007 was retrospectively analyzed. Data were collected by the registries of the European Society for Immunodeficiencies/European Group for Blood and Marrow Transplantation, and the Center for International......, with full donor engraftment in 17 cases, mixed multilineage chimerism in 7 patients, and mononuclear cell-restricted chimerism in an additional 3 cases. CONCLUSIONS: Hematopoietic stem-cell transplantation offers long-term benefit in leukocyte adhesion deficiency and should be considered as an early...... therapeutic option if a suitable HLA-matched stem-cell donation is available. Reduced-intensity conditioning was particularly safe, and mixed-donor chimerism seems sufficient to prevent significant symptoms, although careful long-term monitoring will be required for these patients....

  10. The role of physicochemical and structural surface properties in co-adhesion of microbial pairs in a parallel-plate flow chamber

    NARCIS (Netherlands)

    Bos, R; van der Mei, Henderina; de Vries, Jacob; Busscher, HJ

    1996-01-01

    Biofilm formation on solid surfaces involves interactions between planktonic organisms and the substratum as well as between flowing and already adhering organisms (''co-adhesion''). Biochemical studies have yielded information on the structural cell surface properties involved in interspecies bindi

  11. Greater osteoblast and endothelial cell adhesion on nanostructured polyethylene and titanium

    Directory of Open Access Journals (Sweden)

    Theresa Raimondo

    2010-09-01

    Full Text Available Theresa Raimondo, Sabrina Puckett, Thomas J WebsterSchool of Engineering and Department of Orthopedics, Brown University, Providence, RI, USAAbstract: Mostly due to desirable mechanical properties (such as high durability and low wear, certain synthetic polymers (such as polyethylene and metals (such as titanium have found numerous applications in the medical device arena from orthopedics to the vasculature, yet frequently, they do not proactively encourage desirable cell responses. In an effort to improve the efficacy of such traditional materials for various implant applications, this study used electron beam evaporation to create nanostructured surface features that mimic those of natural tissue on polyethylene and titanium. For other materials, it has been shown that the creation of nanorough surfaces increases surface energy leading to greater select protein (such as vitronectin and fibronectin interactions to increase specific cell adhesion. Here, osteoblast (bone forming cells and endothelial cell (cells that line the vasculature adhesion was determined on nanostructured compared to conventional, nano-smooth polyethylene and titanium. Results demonstrated that nanorough surfaces created by electron beam evaporation increased the adhesion of both cells markedly better than conventional smooth surfaces. In summary, this study provided evidence that electron beam evaporation can modify implant surfaces (specifically, polyethylene and titanium to have nanostructured surface features to improve osteoblast and endothelial cell adhesion. Since the adhesion of anchorage dependent cells (such as osteoblasts and endothelial cells is a prerequisite for their long-term functions, this study suggests that electron beam evaporation should be further studied for improving materials for various biomedical applications. Keywords: nanotechnology, polyethylene, osteoblasts, orthopedics, vascular, titanium

  12. Alcohol inhibits cell-cell adhesion mediated by human L1.

    Science.gov (United States)

    Ramanathan, R; Wilkemeyer, M F; Mittal, B; Perides, G; Charness, M E

    1996-04-01

    Mental retardation, hydrocephalus, and agenesis of the corpus callosum are observed both in fetal alcohol syndrome (FAS) and in children with mutations in the gene for the cell adhesion molecule L1. We studied the effects of ethanol on cell-cell adhesion in mouse fibroblasts transfected with human L1. L1-transfected fibroblasts exhibited increased cell-cell adhesion compared with wild-type or vector-transfected controls. Ethanol potently and completely inhibited L1-mediated adhesion both in transfected L cells and NIH/3T3 cells. Half-maximal inhibition was observed at 7 mM ethanol, a concentration achieved in blood and brain after ingesting one alcoholic beverage. In contrast, ethanol did not inhibit the adhesion of fibroblasts transfected with vector alone or with N-CAM-140. L1-mediated cell-cell adhesion was inhibited with increasing potency by n-propanol and n-butanol, but was not inhibited at all by n-alcohols of 5 to 8 carbons, acetaldehyde, or acetate, suggesting that ethanol interacts directly with a small hydrophobic pocket within L1. Phenylalanine, teratogenic anticonvulsants, and high concentrations of glucose did not inhibit L1-mediated cell-cell adhesion. Ethanol also inhibited potently the heterotypic adhesion of rat cerebellar granule cells to a monolayer of L1-transfected NIH/3T3 cells, but had no effect on their adhesion to N-CAM-140 or vector-transfected NIH/3T3 cells. Because L1 plays a role in both neural development and learning, ethanol inhibition of L1-mediated cell-cell interactions could contribute to FAS and ethanol-associated memory disorders. PMID:8609170

  13. The adhesion receptor CD44 promotes atherosclerosis by mediating inflammatory cell recruitment and vascular cell activation

    OpenAIRE

    Cuff, Carolyn A.; Kothapalli, Devashish; Azonobi, Ijeoma; Chun, Sam; Zhang, Yuanming; Belkin, Richard; Yeh, Christine; Secreto, Anthony; Richard K Assoian; Rader, Daniel J; Puré, Ellen

    2001-01-01

    Atherosclerosis causes most acute coronary syndromes and strokes. The pathogenesis of atherosclerosis includes recruitment of inflammatory cells to the vessel wall and activation of vascular cells. CD44 is an adhesion protein expressed on inflammatory and vascular cells. CD44 supports the adhesion of activated lymphocytes to endothelium and smooth muscle cells. Furthermore, ligation of CD44 induces activation of both inflammatory and vascular cells. To assess the potential contribution of CD4...

  14. Surface grafting of carboxylic groups onto thermoplastic polyurethanes to reduce cell adhesion

    International Nuclear Information System (INIS)

    The interaction of polymers with other materials is an important issue, being their surface properties clearly crucial. For some important polymer applications, their surfaces have to be modified. Surface modification aims to tailor the surface characteristics of a material for a specific application without affecting its bulk properties. Materials can be surface modified by using biological, chemical or physical methods. The aim of this work was to improve the reactivity of the thermoplastic polyurethane (TPU) material (Elastollan®) surface and to make its surface cell repellent by grafting carboxylic groups onto its surface. Two TPU materials were studied: a polyether-based TPU and a polyester-based TPU. The grafting efficiency was evaluated by contact angle measurements and by analytical determination of the COOH groups. Scanning electron microscopy (SEM) of the membranes surface was performed as well as cell adhesion tests. It was proved that the surfaces of the TPUs membranes were successfully modified and that cell adhesion was remarkably reduced.

  15. The cell adhesion molecules Echinoid and Friend of Echinoid coordinate cell adhesion and cell signaling to regulate the fidelity of ommatidial rotation in the Drosophila eye

    OpenAIRE

    Fetting, Jennifer L.; Spencer, Susan A; Wolff, Tanya

    2009-01-01

    Directed cellular movements are a universal feature of morphogenesis in multicellular organisms. Differential adhesion between the stationary and motile cells promotes these cellular movements to effect spatial patterning of cells. A prominent feature of Drosophila eye development is the 90° rotational movement of the multicellular ommatidial precursors within a matrix of stationary cells. We demonstrate that the cell adhesion molecules Echinoid (Ed) and Friend of Echi...

  16. Photoinitiator-free synthesis of endothelial cell-adhesive and enzymatically degradable hydrogels.

    Science.gov (United States)

    Jones, Derek R; Marchant, Roger E; von Recum, Horst; Sen Gupta, Anirban; Kottke-Marchant, Kandice

    2015-02-01

    We report on a photoinitiator-free synthetic method of incorporating bioactivity into poly(ethylene glycol) (PEG) hydrogels in order to control physical properties, enzymatic biodegradability and cell-specific adhesiveness of the polymer network, while eliminating the need for UV-mediated photopolymerization. To accomplish this, hydrogel networks were polymerized using Michael addition with four-arm PEG acrylate (10 kDa), using a collagenase-sensitive peptide (CSP) as a crosslinker, and introducing an endothelial cell-adhesive peptide either terminally (RGD) or attached to the crosslinking peptide sequence (CSP-RGD). The efficiency of the Michael addition reactions were determined by nuclear magnetic resonance and Ellman's assay. Successful decoupling of cell adhesivity and physical properties was demonstrated by quantifying and comparing the swelling ratios and Young's moduli of various hydrogel formulations. Degradation profiles were established by incubating functionalized hydrogels in collagenase solutions (0.0-1.0 μg ml(-1)), demonstrating that functionalized hydrogels degraded at a rate dependent upon collagenase concentration. Moreover, it was shown that the degradation rate was independent of CSP-RGD concentration. Cell attachment and proliferation on functionalized hydrogels were compared for various RGD concentrations, providing evidence that cell attachment and proliferation were directly related to relative amounts of the CSP-RGD combination peptide. An increase in cell viability was achieved using Michael addition techniques when compared to UV polymerization, and was assessed by a LIVE/DEAD fluorescence assay. This photoinitiator-free method shows promise in creating hydrogel-based tissue engineering scaffolds allow for decoupled cell adhesivity and physical properties and that render greater cell viability. PMID:25462848

  17. Hypertonic saline impedes tumor cell-endothelial cell interaction by reducing adhesion molecule and laminin expression.

    LENUS (Irish Health Repository)

    Shields, Conor J

    2012-02-03

    BACKGROUND: Hypertonic saline infusion dampens inflammatory responses and suppresses neutrophil-endothelial interaction by reducing adhesion molecule expression. This study tested the hypothesis that hypertonic saline attenuates tumor cell adhesion to the endothelium through a similar mechanism. METHODS: Human colon cancer cells (LS174T) were transfected with green fluorescent protein and exposed to lipopolysaccharide, tumor necrosis factor-alpha, and interleukin-6 under hypertonic and isotonic conditions for 1 and 4 hours. Confluent human umbilical vein endothelial cells were similarly exposed. Cellular apoptosis and expression of adhesion molecules and laminin were measured by flow cytometry. Tumor cell adhesion to endothelium and laminin was assessed with fluorescence microscopy. Data are represented as mean +\\/- standard error of mean, and an ANOVA test was performed to gauge statistical significance, with P <.05 considered significant. RESULTS: Hypertonic exposure significantly reduced tumor cell adhesion despite the presence of the perioperative cell stressors (42 +\\/- 2.9 vs 172.5 +\\/- 12.4, P <.05), attenuated tumor cell beta-1 integrin (14.43 vs 23.84, P <.05), and endothelial cell laminin expression (22.78 +\\/- 2.2 vs 33.74 +\\/- 2.4, P <.05), but did not significantly alter cell viability. CONCLUSION: Hypertonic saline significantly attenuates tumor cell adhesion to endothelium by inhibiting adhesion molecule and laminin expression. This may halt the metastatic behavior of tumor cells shed at surgery.

  18. Polyphosphoinositides suppress the adhesion of Haemophilus influenzae to pharyngeal cells

    Directory of Open Access Journals (Sweden)

    Hwang Shie-Ming

    2004-09-01

    Full Text Available Abstract Background One of the primary causes of otitis media (OM, an inflammation of the middle ear, is the bacterium Haemophilus influenzae (HI. OM often occurs to young children, and is mostly treated with antibiotics. Due to concerns over bacterial resistance toward antibiotics, reliable prophylactic treatments such as administrating anti-adhesion agents are now viewed as viable alternatives. Results The present study tested the feasibilty of using phosphoinositides as anti-adhesion agents against HI cells. Cells of non-typeable HI were radiolabeled with 111- indium-oxine, pre-incubated with various individual phosphoinositides for 15 minutes at 37°C, and incubated with a monolayer of human pharynx carcinoma (DT 562 cells for 20 minutes at 37°C. The result showed that at 0.1 mg/mL dipalmitoylphosphatidylinositol-3,4-diphosphate (PI-3,4-PP had the highest anti-adhesion activity, followed by phosphatidylinositol-3-phosphate (PI-3-P and phosphatidylinositol-4-phosphate (PI-4-P. The anti-adhesion activity of PI-3,4-PP was dose-dependent ranging from 0.006 to 0.1 mg/mL. In addition, results from an in vivo study demonstrated that pre-incubation of HI cells with PI-3,4-PP at 1 mg/mL suppressed the growth of HI in nasopharynx of neonatal rats. Conclusions These findings suggest that PI-3-P and PI-4-P and more so PI-3,4-PP may serve as prophylactic agents against HI adhesion and colonization.

  19. Effect of ionizing radiation on properties of acrylic pressure sensitive adhesives

    International Nuclear Information System (INIS)

    Pressure-sensitive adhesives for technical application are widely produced. The biological properties of adhesives depend on the type of monomers used. The available literature data as experience of the authors of this study in the area of pressure-sensitive acrylic adhesive, polymers used in medicine, polymerisation in aqueous media, radiation sterilization, permit to make an assumption that it is possible to elaborate the technology of production of pressure-sensitive adhesives in aqueous emulsion for medical applications. Identification of phenomena influencing the adhesive properties, especially its adhesion, cohesion, tack and durability is of great importance. The control of polymer structure is performed by means of adequate selection of conditions of synthesis and parameters of radiation processing. The authors investigate the influence on the final products of such factors as the type and amount of monomers used, their mutual ratio, as well as the ratio monomers and the dose of ionising radiation. There is no available literature information concerning the investigation of resistance of acrylic emulsion adhesive to sterilisation by electron beam. It is known from unpublished research that some adhesives are resistant to radiation, while others undergo destruction. It probably depends on the composition of emulsion, specifically on the additives which modify adhesives. Simultaneous achievement of good cohesion and adhesion in the case of such types of pressure sensitive adhesives is very difficult pressure sensitive adhesives is very difficult

  20. Modeling of cell adhesion and deformation mediated by receptor-ligand interactions.

    Science.gov (United States)

    Golestaneh, Amirreza F; Nadler, Ben

    2016-04-01

    The current work is devoted to studying adhesion and deformation of biological cells mediated by receptors and ligands in order to enhance the existing models. Due to the sufficient in-plane continuity and fluidity of the phospholipid molecules, an isotropic continuum fluid membrane is proposed for modeling the cell membrane. The developed constitutive model accounts for the influence of the presence of receptors on the deformation and adhesion of the cell membrane through the introduction of spontaneous area dilation. Motivated by physics, a nonlinear receptor-ligand binding force is introduced based on charge-induced dipole interaction. Diffusion of the receptors on the membrane is governed by the receptor-ligand interaction via Fick's Law and receptor-ligand interaction. The developed model is then applied to study the deformation and adhesion of a biological cell. The proposed model is used to study the role of the material, binding, spontaneous area dilation and environmental properties on the deformation and adhesion of the cell. PMID:26093646

  1. A High-Adhesive Lysine-Cyclic RGD Peptide Designed for Selective Cell Retention Technology.

    Science.gov (United States)

    Luo, Keyu; Mei, Tieniu; Li, Zhiqiang; Deng, Moyuan; Zhang, Zehua; Hou, Tianyong; Dong, Shiwu; Xie, Zhao; Xu, Jianzhong; Luo, Fei

    2016-06-01

    Cell adhesion is an important property of biomaterials used in selective cell retention (SCR) technology, which fabricates bone grafts rapidly in clinical settings. This could be improved by physical and biologic manipulations. To facilitate retention of the cells on the scaffold, especially osteoprogenitors from bone marrow in the convenient SCR procedure, a lysine-cyclic RGD (LcRGD) peptide was here designed to coordinate positively charged amino acids and the RGD sequence to enhance the adhesion performance of the scaffold. Demineralized bone matrix (DBM) is an important therapeutic resource, but its cell adhesion ability and osteoinductive capacity are low because of its processing. These capabilities can be increased to enhance the performance of DBM when used in SCR technology. Here, LcRGD peptide was used to modify DBM and produce a DBM/LcRGD composite. This composite exhibited enhanced adhesion performance on cultured human bone marrow-derived mesenchymal stem cells and retained more osteoprogenitors from bone marrow than other materials did. The DBM/LcRGD composite displayed a preferable osteoinduction in vitro and osteogenic capacity in vivo. Thus, LcRGD peptide as a commendable modifier of DBM applied in SCR technology can improve bone transplantation. PMID:27154386

  2. Magnetorheological Elastomer Films with Tunable Wetting and Adhesion Properties.

    Science.gov (United States)

    Lee, Sanghee; Yim, Changyong; Kim, Wuseok; Jeon, Sangmin

    2015-09-01

    We fabricated magnetorheological elastomer (MRE) films consisting of polydimethylsiloxane and various concentrations of fluorinated carbonyl iron particles. The application of a magnetic field to the MRE film induced changes in the surface morphology due to the alignment of the iron particles along the magnetic field lines. At low concentrations of iron particles and low magnetic field intensities, needle-like microstructures predominated. These structures formed more mountain-like microstructures as the concentration of iron particles or the magnetic field intensity increased. The surface roughness increased the water contact angle from 100° to 160° and decreased the sliding angle from 180° to 10°. The wettability and adhesion properties changed substantially within a few seconds simply upon application of a magnetic field. Cyclical measurements revealed that the transition was completely reversible. PMID:26301942

  3. Chemical properties of tannic extracts from bark of Pinus oocarpa and their use as adhesive

    Directory of Open Access Journals (Sweden)

    Michel Cardoso Vieira

    2014-03-01

    Full Text Available This work evaluated the properties of aqueous extracts obtained from the bark of Pinus oocarpa under addition of sodium sulfite and sodium bisulfite and the possibility of employment of tannins from the bark as an adhesive for bonding wood. After evaluation of the chemical properties of tannic extracts it was decided to employ the extraction with distilled water under addition of / 5% sodium sulfite to prepare for the tannin-formaldehyde adhesive. Adhesive phenol formaldehyde and urea-formaldehyde were modified with 10% tannin Pinus oocarpa and the effect of this addition on the quality of the adhesive was evaluated. The addition from the bark of Pinus oocarpa showed that it is possible to use pure tannin as an adhesive because of its good gluing characteristics. The addition of tannic extract to synthetic adhesives contributed to increase viscosity values. Thus the substitution of synthetic adhesives by tannins is possible only up to 10%.

  4. Modeling keratinocyte wound healing dynamics: Cell-cell adhesion promotes sustained collective migration.

    Science.gov (United States)

    Nardini, John T; Chapnick, Douglas A; Liu, Xuedong; Bortz, David M

    2016-07-01

    The in vitro migration of keratinocyte cell sheets displays behavioral and biochemical similarities to the in vivo wound healing response of keratinocytes in animal model systems. In both cases, ligand-dependent Epidermal Growth Factor Receptor (EGFR) activation is sufficient to elicit collective cell migration into the wound. Previous mathematical modeling studies of in vitro wound healing assays assume that physical connections between cells have a hindering effect on cell migration, but biological literature suggests a more complicated story. By combining mathematical modeling and experimental observations of collectively migrating sheets of keratinocytes, we investigate the role of cell-cell adhesion during in vitro keratinocyte wound healing assays. We develop and compare two nonlinear diffusion models of the wound healing process in which cell-cell adhesion either hinders or promotes migration. Both models can accurately fit the leading edge propagation of cell sheets during wound healing when using a time-dependent rate of cell-cell adhesion strength. The model that assumes a positive role of cell-cell adhesion on migration, however, is robust to changes in the leading edge definition and yields a qualitatively accurate density profile. Using RNAi for the critical adherens junction protein, α-catenin, we demonstrate that cell sheets with wild type cell-cell adhesion expression maintain migration into the wound longer than cell sheets with decreased cell-cell adhesion expression, which fails to exhibit collective migration. Our modeling and experimental data thus suggest that cell-cell adhesion promotes sustained migration as cells pull neighboring cells into the wound during wound healing. PMID:27105673

  5. The Neural Cell Adhesion Molecule NCAM2/OCAM/RNCAM, a Close Relative to NCAM

    DEFF Research Database (Denmark)

    Kulahin, Nikolaj; Walmod, Peter

    2008-01-01

    molecule (NCAM) is a well characterized, ubiquitously expressed CAM that is highly expressed in the nervous system. In addition to mediating cell adhesion, NCAM participates in a multitude of cellular events, including survival, migration, and differentiation of cells, outgrowth of neurites, and formation......Cell adhesion molecules (CAMs) constitute a large class of plasma membrane-anchored proteins that mediate attachment between neighboring cells and between cells and the surrounding extracellular matrix (ECM). However, CAMs are more than simple mediators of cell adhesion. The neural cell adhesion...... and plasticity of synapses. NCAM shares an overall sequence identity of approximately 44% with the neural cell adhesion molecule 2 (NCAM2), a protein also known as olfactory cell adhesion molecule (OCAM) and Rb-8 neural cell adhesion molecule (RNCAM), and the region-for-region sequence homology...

  6. Rapid and Localized Mechanical Stimulation and Adhesion Assay: TRPM7 Involvement in Calcium Signaling and Cell Adhesion.

    Directory of Open Access Journals (Sweden)

    Wagner Shin Nishitani

    Full Text Available A cell mechanical stimulation equipment, based on cell substrate deformation, and a more sensitive method for measuring adhesion of cells were developed. A probe, precisely positioned close to the cell, was capable of a vertical localized mechanical stimulation with a temporal frequency of 207 Hz, and strain magnitude of 50%. This setup was characterized and used to probe the response of Human Umbilical Endothelial Vein Cells (HUVECs in terms of calcium signaling. The intracellular calcium ion concentration was measured by the genetically encoded Cameleon biosensor, with the Transient Receptor Potential cation channel, subfamily M, member 7 (TRPM7 expression inhibited. As TRPM7 expression also regulates adhesion, a relatively simple method for measuring adhesion of cells was also developed, tested and used to study the effect of adhesion alone. Three adhesion conditions of HUVECs on polyacrylamide gel dishes were compared. In the first condition, the substrate is fully treated with Sulfo-SANPAH crosslinking and fibronectin. The other two conditions had increasingly reduced adhesion: partially treated (only coated with fibronectin, with no use of Sulfo-SANPAH, at 5% of the normal amount and non-treated polyacrylamide gels. The cells showed adhesion and calcium response to the mechanical stimulation correlated to the degree of gel treatment: highest for fully treated gels and lowest for non-treated ones. TRPM7 inhibition by siRNA on HUVECs caused an increase in adhesion relative to control (no siRNA treatment and non-targeting siRNA, but a decrease to 80% of calcium response relative to non-targeting siRNA which confirms the important role of TRPM7 in mechanotransduction despite the increase in adhesion.

  7. Adhesion receptors as therapeutic targets for circulating tumor cells

    Directory of Open Access Journals (Sweden)

    MichaelR.King

    2012-07-01

    Full Text Available Metastasis contributes to >90% of cancer-associated mortality. Though primary tumors can be removed by surgical resection or chemo/radiotherapy, metastatic disease is a great challenge to treatment due to its systemic nature. As metastatic “seeds”, circulating tumor cells (CTCs are believed to be responsible for dissemination from a primary tumor to anatomically distant organs. Despite the possibility of physical trapping of CTCs in microvessels, recent advances have provided insights into the involvement of a variety of adhesion molecules on CTCs. Such adhesion molecules facilitate direct interaction with the endothelium in specific tissues or indirectly through leukocytes. Importantly, significant progress has been made in understanding how these receptors confer enhanced invasion and survival advantage during hematogenous circulation of CTCs through recruitment of macrophages, neutrophils, platelets, and other cells. This review highlights the identification of novel adhesion molecules and how blocking their function can compromise successful seeding and colonization of CTCs in new microenvironment. Encouraged by existing diagnostic tools to identify and isolate CTCs, strategic targeting of these adhesion molecules to deliver conventional chemotherapeutics or novel apoptotic signals is discussed for the neutralization of CTCs in the circulation.

  8. On the mechanical properties of bovine serum albumin (BSA) adhesives.

    Science.gov (United States)

    Berchane, N S; Andrews, M J; Kerr, S; Slater, N K H; Jebrail, F F

    2008-04-01

    Biological adhesives, natural and synthetic, are of current active interest. These adhesives offer significant advantages over traditional sealant techniques, in particular, they are easier to use, and can play an integral part in the healing mechanism of tissue. Thus, biological adhesives can play a major role in medical applications if they possess adequate mechanical behavior and stability over time. In this work, we report on the method of preparation of bovine serum albumin (BSA) into a biological adhesive. We present quantitative measurements that show the effect of BSA concentration and cross-linker content on the bonding strength of BSA adhesive to wood. A comparison is then made with synthetic poly(glycidyl methacrylate) (PGMA) adhesive, and a commercial cyanoacrylate glue, which was used as a control adhesive. In addition, BSA samples were prepared and characterized for their water content, tensile strength, and elasticity. We show that on dry surface, BSA adhesive exhibits a high bonding strength that is comparable with non-biological commercial cyanoacrylate glues, and synthetic PGMA adhesive. Tensile testing on wet wood showed a slight increase in the bonding strength of BSA adhesive, a considerable decrease in the bonding strength of cyanoacrylate glue, and negligible adhesion of PGMA. Tests performed on BSA samples demonstrate that initial BSA concentration and final water content have a significant effect on the stress-strain behavior of the samples. PMID:18197367

  9. Differential expression of cell adhesion genes

    DEFF Research Database (Denmark)

    Stein, Wilfred D; Litman, Thomas; Fojo, Tito;

    2005-01-01

    It is well known that tumors arising from tissues such as kidney, pancreas, liver and stomach are particularly refractory to treatment. Searching for new anticancer drugs using cells in culture has yielded some effective therapies, but these refractory tumors remain intractable. Studies that...... survival might, therefore, act through such a matrix-to-cell suppression of apoptosis. Indeed, correlative mining of gene expression and patient survival databases suggests that poor survival in patients with metastatic cancer correlates highly with tumor expression of a common theme: the genes involved in...

  10. Sickle cell disease biochip: a functional red blood cell adhesion assay for monitoring sickle cell disease.

    Science.gov (United States)

    Alapan, Yunus; Kim, Ceonne; Adhikari, Anima; Gray, Kayla E; Gurkan-Cavusoglu, Evren; Little, Jane A; Gurkan, Umut A

    2016-07-01

    Sickle cell disease (SCD) afflicts millions of people worldwide and is associated with considerable morbidity and mortality. Chronic and acute vaso-occlusion are the clinical hallmarks of SCD and can result in pain crisis, widespread organ damage, and early movtality. Even though the molecular underpinnings of SCD were identified more than 60 years ago, there are no molecular or biophysical markers of disease severity that are feasibly measured in the clinic. Abnormal cellular adhesion to vascular endothelium is at the root of vaso-occlusion. However, cellular adhesion is not currently evaluated clinically. Here, we present a clinically applicable microfluidic device (SCD biochip) that allows serial quantitative evaluation of red blood cell (RBC) adhesion to endothelium-associated protein-immobilized microchannels, in a closed and preprocessing-free system. With the SCD biochip, we have analyzed blood samples from more than 100 subjects and have shown associations between the measured RBC adhesion to endothelium-associated proteins (fibronectin and laminin) and individual RBC characteristics, including hemoglobin content, fetal hemoglobin concentration, plasma lactate dehydrogenase level, and reticulocyte count. The SCD biochip is a functional adhesion assay, reflecting quantitative evaluation of RBC adhesion, which could be used at baseline, during crises, relative to various long-term complications, and before and after therapeutic interventions. PMID:27063958

  11. OSTEOBLAST ADHESION OF BREAST CANCER CELLS WITH SCANNING ACOUSTIC MICROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Chiaki Miyasaka; Robyn R. Mercer; Andrea M. Mastro; Ken L. Telschow

    2005-03-01

    Breast cancer frequently metastasizes to the bone. Upon colonizing bone tissue, the cancer cells stimulate osteoclasts (cells that break bone down), resulting in large lesions in the bone. The breast cancer cells also affect osteoblasts (cells that build new bone). Conditioned medium was collected from a bone-metastatic breast cancer cell line, MDA-MB-231, and cultured with an immature osteoblast cell line, MC3T3-E1. Under these conditions the osteoblasts acquired a changed morphology and appeared to adherer in a different way to the substrate and to each other. To characterize cell adhesion, MC3T3-E1 osteoblasts were cultured with or without MDA-MB-231 conditioned medium for two days, and then assayed with a mechanical scanning acoustic reflection microscope (SAM). The SAM indicated that in normal medium the MC3T3-E1 osteoblasts were firmly attached to their plastic substrate. However, MC3T3-E1 cells cultured with MDA-MB-231 conditioned medium displayed both an abnormal shape and poor adhesion at the substrate interface. The cells were fixed and stained to visualize cytoskeletal components using optical microscopic techniques. We were not able to observe these differences until the cells were quite confluent after 7 days of culture. However, using the SAM, we were able to detect these changes within 2 days of culture with MDA-MB-231 conditioned medium

  12. Biological properties of a thermally crosslinked gelatin film as a novel anti-adhesive material: Relationship between the biological properties and the extent of thermal crosslinking.

    Science.gov (United States)

    Tsujimoto, Hiroyuki; Tanzawa, Ayumi; Miyamoto, Hiroe; Horii, Tsunehito; Tsuji, Misaki; Kawasumi, Akari; Tamura, Atsushi; Wang, Zhen; Abe, Rie; Tanaka, Shota; Yamanaka, Kouki; Matoba, Mari; Torii, Hiroko; Ozamoto, Yuki; Takamori, Hideki; Suzuki, Shuko; Morita, Shinichiro; Ikada, Yoshito; Hagiwara, Akeo

    2015-10-01

    In order to prevent postoperative adhesion and the related complications, a thermally crosslinked gelatin (TCG) film was developed and the basic biological properties were examined, paying special attention to the relationship between these properties and the extent of crosslinking of the film. The gelatin films crosslinked thermally for five different time periods (0, 1, 3, 8, and 14 hours) were developed and the following tests were performed. Regarding the material characterization of the films, the water content, the water solubility, and the enzymatic degradation for collagenase were found to be closely related to the duration of thermal crosslinking. In an in vitro study conducted to examine the cell growth of fibroblasts cultured on the films, the degree of cell growth, except no crosslinked film, was less than that observed in the control group, thus suggesting that such effects of the films on fibroblast cell growth may be related with their anti-adhesive effects. In in vivo tests, the films crosslinked for longer time periods (3, 8, and 14 hours) were retained for longer after being implanted into the abdominal cavity in rats and showed a significant anti-adhesive effect in the rat cecum adhesion models, indicating that the biodegradability and anti-adhesive effects of the TCG films depend on the duration of thermal crosslinking. In order to develop useful and effective anti-adhesive gelatin film, it is very important to optimize duration of the thermal crosslinking. PMID:25449656

  13. Ion implantation induced nanotopography on titanium and bone cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Braceras, Iñigo, E-mail: inigo.braceras@tecnalia.com [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (Ciber-BBN) (Spain); Vera, Carolina; Ayerdi-Izquierdo, Ana [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (Ciber-BBN) (Spain); Muñoz, Roberto [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); Lorenzo, Jaione; Alvarez, Noelia [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (Ciber-BBN) (Spain); Maeztu, Miguel Ángel de [Private Practice, P° San Francisco, 43 A-1°, 20400 Tolosa (Spain)

    2014-08-15

    Graphical abstract: Titanium surfaces modified by inert ion implantation affect cell adhesion through modification of the nanotopography in the same dimensional range of that of human bone inorganic phases. - Highlights: • Inert ion implantation on Ti modifies surface nanotopography and bone cell adhesion. • Ion implantation can produce nanostructured surfaces on titanium in the very same range as of those of the mineral phase of the human bone. • Appropriate tool for studying the relevance of nanostructured surfaces on bone mineralization and implant osseointegration. • Ion implantation induced nanotopography have a statistically significant influence on bone cell adhesion. - Abstract: Permanent endo-osseous implants require a fast, reliable and consistent osseointegration, i.e. intimate bonding between bone and implant, so biomechanical loads can be safely transferred. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role. Most surface treatments to improve osseointegration focus on micro-scale features, as few can effectively control the effects of the treatment at nanoscale. On the other hand, ion implantation allows controlling such nanofeatures. This study has investigated the nanotopography of titanium, as induced by different ion implantation surface treatments, its similarity with human bone tissue structure and its effect on human bone cell adhesion, as a first step in the process of osseointegration. The effect of ion implantation treatment parameters such as energy (40–80 keV), fluence (1–2 e17 ion/cm{sup 2}) and ion species (Kr, Ar, Ne and Xe) on the nanotopography of medical grade titanium has been measured and assessed by AFM and contact angle. Then, in vitro tests have been performed to assess the effect of these nanotopographies on osteoblast adhesion. The results have shown that the nanostructure of bone and the studied ion implanted

  14. Ion implantation induced nanotopography on titanium and bone cell adhesion

    International Nuclear Information System (INIS)

    Graphical abstract: Titanium surfaces modified by inert ion implantation affect cell adhesion through modification of the nanotopography in the same dimensional range of that of human bone inorganic phases. - Highlights: • Inert ion implantation on Ti modifies surface nanotopography and bone cell adhesion. • Ion implantation can produce nanostructured surfaces on titanium in the very same range as of those of the mineral phase of the human bone. • Appropriate tool for studying the relevance of nanostructured surfaces on bone mineralization and implant osseointegration. • Ion implantation induced nanotopography have a statistically significant influence on bone cell adhesion. - Abstract: Permanent endo-osseous implants require a fast, reliable and consistent osseointegration, i.e. intimate bonding between bone and implant, so biomechanical loads can be safely transferred. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role. Most surface treatments to improve osseointegration focus on micro-scale features, as few can effectively control the effects of the treatment at nanoscale. On the other hand, ion implantation allows controlling such nanofeatures. This study has investigated the nanotopography of titanium, as induced by different ion implantation surface treatments, its similarity with human bone tissue structure and its effect on human bone cell adhesion, as a first step in the process of osseointegration. The effect of ion implantation treatment parameters such as energy (40–80 keV), fluence (1–2 e17 ion/cm2) and ion species (Kr, Ar, Ne and Xe) on the nanotopography of medical grade titanium has been measured and assessed by AFM and contact angle. Then, in vitro tests have been performed to assess the effect of these nanotopographies on osteoblast adhesion. The results have shown that the nanostructure of bone and the studied ion implanted

  15. Dystrophin Dp71f associates with the beta1-integrin adhesion complex to modulate PC12 cell adhesion

    Science.gov (United States)

    Cerna, Joel; Cerecedo, Doris; Ortega, Arturo; García-Sierra, Francisco; Centeno, Federico; Garrido, Efrain; Mornet, Dominique; Cisneros, Bulmaro

    2006-01-01

    Dystrophin Dp71 is the main product of the Duchenne muscular dystrophy gene in the brain; however, its function is unknown. To study the role of Dp71 in neuronal cells, we previously generated by antisense treatment PC12 neuronal cell clones with decreased Dp71 expression (antisense-Dp71 cells). PC12 cells express two different splicing isoforms of Dp71, a cytoplasmic variant called Dp71f and a nuclear isoform called Dp71d. We previously reported that antisense-Dp71 cells display deficient adhesion to substrate and reduced immunostaining of β1-integrin in the cell area contacting the substrate. In this study, we isolated additional antisenseDp71 clones to analyze in detail the potential involvement of Dp71f isoform with the β1-integrin adhesion system of PC12 cells. Immunofluorescence analyses as well as immunoprecipitation assays demonstrated that the PC12 cell β1-integrin adhesion complex is composed of β1-integrin, talin, paxillin, α-actinin, FAK and actin. In addition, our results showed that Dp71f associates with most of the β1-integrin complex components (β1-integrin, FAK, α-actinin, talin and actin). In the antisense-Dp71 cells, the deficiency of Dp71 provokes a significant reduction of the β1-integrin adhesion complex and, consequently, the deficient adhesion of these cells to laminin. In vitro binding experiments confirmed the interaction of Dp71f with FAK and β1-integrin. Our data indicate that Dp71f is a structural component of the β1-integrin adhesion complex of PC12 cells that modulates PC12 cell adhesion by conferring proper complex assembly and/or maintenance. PMID:16935300

  16. Fibronectin adsorption, cell adhesion, and proliferation on nanostructured tantalum surfaces.

    Science.gov (United States)

    Dolatshahi-Pirouz, A; Jensen, T; Kraft, David Christian; Foss, Morten; Kingshott, Peter; Hansen, John Lundsgaard; Larsen, Arne Nylandsted; Chevallier, Jacques; Besenbacher, Flemming

    2010-05-25

    The interaction between dental pulp derived mesenchymal stem cells (DP-MSCs) and three different tantalum nanotopographies with and without a fibronectin coating is examined: sputter-coated tantalum surfaces with low surface roughness tantalum surfaces were examined, as well as cellular attachment, proliferation, and vinculin focal adhesion spot assembly on the respective surfaces. The results showed the highest fibronectin mass uptake on the hut structures, with a slightly higher availability of cell-binding domains and the most pronounced formation of vinculin focal adhesion spots as compared to the other surfaces. The proliferation of DP-MSCs was found to be significantly higher on dome and hut surfaces coated with fibronectin compared to the uncoated flat tantalum surfaces. Consequently, the results presented in this study indicate that fibronectin-coated nanotopographies with a vertical dimension of less than 5 nm influence cell adhesion. This rather interesting behavior is argued to originate from the more available fibronectin cell-binding domains observed on the hut structures. PMID:20443575

  17. Adhesion and invasion of bovine endothelial cells by Neospora caninum.

    Science.gov (United States)

    Hemphill, A; Gottstein, B; Kaufmann, H

    1996-02-01

    Neospora caninum is a recently identified coccidian parasite which was, until 1988, misdiagnosed as Toxoplasma gondii. It causes paralysis and death in dogs and neonatal mortality and abortion in cattle, sheep, goats and horses. The life-cycle of Neospora has not yet been elucidated. The only two stages identified so far are tissue cysts and intracellularly dividing tachyzoites. Very little is known about the biology of this species. We have set up a fluorescence-based adhesion/invasion assay in order to investigate the interaction of N. caninum tachyzoites with bovine aorta endothelial (BAE) cells in vitro. Treatment of both host cells and parasites with metabolic inhibitors determined the metabolic requirements for adhesion and invasion. Chemical and enzymatic modifications of parasite and endothelial cell surfaces were used in order to obtain information on the nature of cell surface components responsible for the interaction between parasite and host. Electron microscopical investigations defined the ultrastructural characteristics of the adhesion and invasion process, and provided information on the intracellular development of the parasites. PMID:8851858

  18. Anandamide inhibits adhesion and migration of breast cancer cells

    International Nuclear Information System (INIS)

    The endocannabinoid system regulates cell proliferation in human breast cancer cells. We reasoned that stimulation of cannabinoid CB1 receptors could induce a non-invasive phenotype in breast mtastatic cells. In a model of metastatic spreading in vivo, the metabolically stable anandamide analogue, 2-methyl-2'-F-anandamide (Met-F-AEA), significantly reduced the number and dimension of metastatic nodes, this effect being antagonized by the selective CB1 antagonist SR141716A. In MDA-MB-231 cells, a highly invasive human breast cancer cell line, and in TSA-E1 cells, a murine breast cancer cell line, Met-F-AEA inhibited adhesion and migration on type IV collagen in vitro without modifying integrin expression: both these effects were antagonized by SR141716A. In order to understand the molecular mechanism involved in these processes, we analyzed the phosphorylation of FAK and Src, two tyrosine kinases involved in migration and adhesion. In Met-F-AEA-treated cells, we observed a decreased tyrosine phosphorylation of both FAK and Src, this effect being attenuated by SR141716A. We propose that CB1 receptor agonists inhibit tumor cell invasion and metastasis by modulating FAK phosphorylation, and that CB1 receptor activation might represent a novel therapeutic strategy to slow down the growth of breast carcinoma and to inhibit its metastatic diffusion in vivo

  19. Changes in materials properties explain the effects of humidity on gecko adhesion.

    Science.gov (United States)

    Puthoff, Jonathan B; Prowse, Michael S; Wilkinson, Matt; Autumn, Kellar

    2010-11-01

    Geckos owe their remarkable stickiness to millions of dry setae on their toes, and the mechanism of adhesion in gecko setae has been the topic of scientific scrutiny for over two centuries. Previously, we demonstrated that van der Waals forces are sufficient for strong adhesion and friction in gecko setae, and that water-based capillary adhesion is not required. However, recent studies demonstrated that adhesion increases with relative humidity (RH) and proposed that surface hydration and capillary water bridge formation is important or even necessary. In this study, we confirmed a significant effect of RH on gecko adhesion, but rejected the capillary adhesion hypothesis. While contact forces of isolated tokay gecko setal arrays increased with humidity, the increase was similar on hydrophobic and hydrophilic surfaces, inconsistent with a capillary mechanism. Contact forces increased with RH even at high shear rates, where capillary bridge formation is too slow to affect adhesion. How then can a humidity-related increase in adhesion and friction be explained? The effect of RH on the mechanical properties of setal β-keratin has escaped consideration until now. We discovered that an increase in RH softens setae and increases viscoelastic damping, which increases adhesion. Changes in setal materials properties, not capillary forces, fully explain humidity-enhanced adhesion, and van der Waals forces remain the only empirically supported mechanism of adhesion in geckos. PMID:20952618

  20. Cell Adhesion and Proliferation on Modified Polyethylene

    Czech Academy of Sciences Publication Activity Database

    Kasálková, N.; Kolářová, K.; Bačáková, Lucie; Pařízek, Martin; Macková, Anna; Švorčík, V.

    567-568, - (2007), s. 269-272. ISSN 0255-5476 R&D Projects: GA ČR GA204/06/0225; GA AV ČR(CZ) KAN400480701; GA AV ČR(CZ) IAA5011301; GA MŠk(CZ) LC06041 Grant ostatní: ICT(CZ) 126080017 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z10480505 Keywords : plasma discharge * aminoacid grafting * vascular smooth muscle cells Subject RIV: EI - Biotechnology ; Bionics Impact factor: 0.399, year: 2005

  1. Growth hormone increases vascular cell adhesion molecule 1 expression

    DEFF Research Database (Denmark)

    Hansen, Troels Krarup; Fisker, Sanne; Dall, Rolf;

    2004-01-01

    We investigated the impact of GH administration on endothelial adhesion molecules, vascular cell adhesion molecule-1 (VCAM-1) and E-selectin, in vivo and in vitro. Soluble VCAM-1, E-selectin, and C-reactive protein concentrations were measured before and after treatment in 25 healthy subjects and...... 25 adult GH-deficient (GHD) patients randomized to GH treatment or placebo. Furthermore, we studied the direct effect of GH and IGF-I and serum from GH-treated subjects on basal and TNF alpha-stimulated expression of VCAM-1 and E-selectin on cultured human umbilical vein endothelial cells. Baseline...... levels of VCAM-1, but not E-selectin, were significantly lower in GHD patients than in healthy subjects (362 +/- 15 microg/liter vs. 516 +/- 21 microg/liter, P < 0.001) and increased in GHD patients during GH treatment, compared with placebo [net difference between groups 151.8 microg/liter (95...

  2. Activation of the canonical Wnt/β-catenin pathway enhances monocyte adhesion to endothelial cells

    International Nuclear Information System (INIS)

    Monocyte adhesion to vascular endothelium has been reported to be one of the early processes in the development of atherosclerosis. In an attempt to develop strategies to prevent or delay atherosclerosis progression, we analyzed effects of the Wnt/β-catenin signaling pathway on monocyte adhesion to various human endothelial cells. Adhesion of fluorescein-labeled monocytes to various human endothelial cells was analyzed under a fluorescent microscope. Unlike sodium chloride, lithium chloride enhanced monocyte adhesion to endothelial cells in a dose-dependent manner. We further demonstrated that inhibitors for glycogen synthase kinase (GSK)-3β or proteosome enhanced monocyte-endothelial cell adhesion. Results of semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) indicated that activation of Wnt/β-catenin pathway did not change expression levels of mRNA for adhesion molecules. In conclusion, the canonical Wnt/β-catenin pathway enhanced monocyte-endothelial cell adhesion without changing expression levels of adhesion molecules

  3. Study on the Rheological Property of Cassava Starch Adhesives

    Directory of Open Access Journals (Sweden)

    Junjun Liu

    2014-03-01

    Full Text Available The main goal of this study was to use cassava starch in the production of environmentally sound adhesives. ‘Three-formaldehyde glue’ pollutes the environment and harms to human health strongly, which widely used for wood-based panels preparation. Environment-friendly cassava starch adhesives were prepared using method of oxidation-gelatinization, insteading of the three formaldehyde glue. The effects of the quality ratio of starch and water, temperature and shear rate on the apparent viscosity of the adhesive were studied. The rheological eigenvalue of apparent viscosity was studied through nonlinear regression. The results showed that the apparent viscosity of cassava starch adhesives decreased with the increasing of temperature; the apparent viscosity decreased slowly with the increasing of rotor speed; the phenomenon of shear thinning appeared within cassava starch adhesives which was pseudo-plastic fluids. Cassava starch adhesives with characteristics of non-toxic, no smell and pollution could be applied in interior and upscale packaging.

  4. Lateral adhesion drives reintegration of misplaced cells into epithelial monolayers.

    Science.gov (United States)

    Bergstralh, Dan T; Lovegrove, Holly E; St Johnston, Daniel

    2015-11-01

    Cells in simple epithelia orient their mitotic spindles in the plane of the epithelium so that both daughter cells are born within the epithelial sheet. This is assumed to be important to maintain epithelial integrity and prevent hyperplasia, because misaligned divisions give rise to cells outside the epithelium. Here we test this assumption in three types of Drosophila epithelium; the cuboidal follicle epithelium, the columnar early embryonic ectoderm, and the pseudostratified neuroepithelium. Ectopic expression of Inscuteable in these tissues reorients mitotic spindles, resulting in one daughter cell being born outside the epithelial layer. Live imaging reveals that these misplaced cells reintegrate into the tissue. Reducing the levels of the lateral homophilic adhesion molecules Neuroglian or Fasciclin 2 disrupts reintegration, giving rise to extra-epithelial cells, whereas disruption of adherens junctions has no effect. Thus, the reinsertion of misplaced cells seems to be driven by lateral adhesion, which pulls cells born outside the epithelial layer back into it. Our findings reveal a robust mechanism that protects epithelia against the consequences of misoriented divisions. PMID:26414404

  5. Photoinitiator-Free Synthesis of Endothelial Cell Adhesive and Enzymatically Degradable Hydrogels

    OpenAIRE

    Jones, Derek R.; Marchant, Roger E.; von Recum, Horst; Gupta, Anirban Sen; Kottke-Marchant, Kandice

    2014-01-01

    We report on a photoinitiator-free synthetic method of incorporating bioactivity into poly(ethylene glycol) (PEG) hydrogels in order to control physical properties, enzymatic biodegradability and cell-specific adhesiveness of the polymer network, while eliminating the need for UV-mediated photopolymerization. To accomplish this, hydrogel networks were polymerized using Michael addition with four-arm PEG acrylate (10 kDa), using a collagenase sensitive peptide (CSP) as a crosslinker, and intro...

  6. Nanofibers and nanoparticles from the insect-capturing adhesive of the Sundew (Drosera) for cell attachment

    OpenAIRE

    Zhang Mingjun; Lenaghan Scott C; Xia Lijin; Dong Lixin; He Wei; Henson William R; Fan Xudong

    2010-01-01

    Abstract Background The search for naturally occurring nanocomposites with diverse properties for tissue engineering has been a major interest for biomaterial research. In this study, we investigated a nanofiber and nanoparticle based nanocomposite secreted from an insect-capturing plant, the Sundew, for cell attachment. The adhesive nanocomposite has demonstrated high biocompatibility and is ready to be used with minimal preparation. Results Atomic force microscopy (AFM) conducted on the adh...

  7. How cells tiptoe on adhesive surfaces before sticking

    CERN Document Server

    Pierres, Anne; Touchard, Dominique; Bongrand, Pierre

    2008-01-01

    Cell membranes are studded with protrusions that were thoroughly analyzed with electron microscopy. However, the nanometer-scale three-dimensional motions generated by cell membranes to fit the topography of foreign surfaces and initiate adhesion remain poorly understood. Here, we describe the dynamics of surface deformations displayed by monocytic cells bumping against fibronectin-coated surfaces. We observed membrane undulations with typically 5 nm amplitude and 5-10 second lifetime. Cell membranes behaved as independent units of micrometer size. Cells detected the presence of foreign surfaces at 50 nm separation, resulting in time-dependent amplification of membrane undulations. Molecular contact then ensued with apparent cell-membrane separation of 30-40 nm, and this distance steadily decreased during the following tens of seconds. Contact maturation was associated with in-plane egress of bulky molecules and robust membrane fluctuations. Thus, membrane undulations may be the major determinant of cell sens...

  8. Wet Chemistry and Peptide Immobilization on Polytetrafluoroethylene for Improved Cell-adhesion.

    Science.gov (United States)

    Gabriel, Matthias; Niederer, Kerstin; Frey, Holger

    2016-01-01

    Endowing materials surface with cell-adhesive properties is a common strategy in biomaterial research and tissue engineering. This is particularly interesting for already approved polymers that have a long standing use in medicine because these materials are well characterized and legal issues associated with the introduction of newly synthesized polymers may be avoided. Polytetrafluoroethylene (PTFE) is one of the most frequently employed materials for the manufacturing of vascular grafts but the polymer lacks cell adhesion promoting features. Endothelialization, i.e., complete coverage of the grafts inner surface with a confluent layer of endothelial cells is regarded key to optimal performance, mainly by reducing thrombogenicity of the artificial interface. This study investigates the growth of endothelial cells on peptide-modified PTFE and compares these results to those obtained on unmodified substrate. Coupling with the endothelial cell adhesive peptide Arg-Glu-Asp-Val (REDV) is performed via activation of the fluorin-containing polymer using the reagent sodium naphthalenide, followed by subsequent conjugation steps. Cell culture is accomplished using Human Umbilical Vein Endothelial Cells (HUVECs) and excellent cellular growth on peptide-immobilized material is demonstrated over a two-week period. PMID:27584937

  9. Nanoscale topographic changes on sterilized glass surfaces affect cell adhesion and spreading.

    Science.gov (United States)

    Wittenburg, Gretel; Lauer, Günter; Oswald, Steffen; Labudde, Dirk; Franz, Clemens M

    2014-08-01

    Producing sterile glass surfaces is of great importance for a wide range of laboratory and medical applications, including in vitro cell culture and tissue engineering. However, sterilization may change the surface properties of glass and thereby affect its use for medical applications, for instance as a substrate for culturing cells. To investigate potential effects of sterilization on glass surface topography, borosilicate glass coverslips were left untreated or subjected to several common sterilization procedures, including low-temperature plasma gas, gamma irradiation and steam. Imaging by atomic force microscopy demonstrated that the surface of untreated borosilicate coverslips features a complex landscape of microislands ranging from 1000 to 3000 nm in diameter and 1 to 3 nm in height. Steam treatment completely removes these microislands, producing a nanosmooth glass surface. In contrast, plasma treatment partially degrades the microisland structure, while gamma irradiation has no effect on microisland topography. To test for possible effects of the nanotopographic structures on cell adhesion, human gingival fibroblasts were seeded on untreated or sterilized glass surfaces. Analyzing fibroblast adhesion 3, 6, and 24 h after cell seeding revealed significant differences in cell attachment and spreading depending on the sterilization method applied. Furthermore, single-cell force spectroscopy revealed a connection between the nanotopographic landscape of glass and the formation of cellular adhesion forces, indicating that fibroblasts generally adhere weakly to nanosmooth but strongly to nanorough glass surfaces. Nanotopographic changes induced by different sterilization methods may therefore need to be considered when preparing sterile glass surfaces for cell culture or biomedical applications. PMID:24027204

  10. Adhesive Properties and Acid-Forming Activity of Lactobacilli and Streptococci Under Inhibitory Substances, Such as Nitrates.

    Science.gov (United States)

    Hakobyan, L; Harutyunyan, K; Harutyunyan, N; Melik-Andreasyan, G; Trchounian, A

    2016-06-01

    One of the main requirements for probiotics is their ability to survive during passage through gastrointestinal tract and to maintain their activity at different adverse conditions. The aim of the study was to look for the strains of lactobacilli and streptococci with high adhesive properties even affected by inhibitory substances, such as nitrates (NO3 (-)). To study the adhesion properties hemagglutination reaction of bacterial cells with red blood cells of different animals and humans was used. The acid formation ability of bacteria was determined by the method of titration after 7 days of incubation in the sterile milk. These properties were investigated at different concentrations of NO3 (-). The high concentration (mostly ≥2.0 %) NO3 (-) inhibited the growth of both lactobacilli and streptococci, but compared with streptococcal cultures lactobacilli, especially Lactobacillus acidophilus Ep 317/402, have shown more stability and higher adhesive properties. In addition, the concentrations of NO3 (-) of 0.5-2.0 % decreased the acid-forming activity of the strains, but even under these conditions they coagulated milk and, in comparison to control, formed low acidity in milk. Thus, the L. acidophilus Ep 317/402 with high adhesive properties has demonstrated a higher activity of NO3 (-) transformation. PMID:26942420

  11. Drosophila Follicle Stem Cells are regulated by proliferation and niche adhesion as well as mitochondria and ROS

    OpenAIRE

    Wang, Zhu A.; Huang, Jianhua; Kalderon, Daniel

    2012-01-01

    The mechanisms underlying adult stem cell behavior are likely to be diverse and have not yet been investigated systematically. Here we conducted an unbiased genetic screen using Drosophila ovarian follicle stem cells (FSCs) to probe essential functions regulating self-renewal of epithelial stem cells. Surprisingly, we find that niche adhesion emerge as the most commonly affected essential stem cell property, and that proliferation is critical for stem cell maintenance. We also find that PI3K ...

  12. Reversing adhesion with light: a general method for functionalized bead release from cells.

    Science.gov (United States)

    Goulet-Hanssens, Alexis; Magdesian, Margaret H; Lopez-Ayon, G Monserratt; Grutter, Peter; Barrett, Christopher J

    2016-07-19

    Coated beads retain great importance in the study of cell adhesion and intracellular communication; we present a generally applicable method permitting spatiotemporal control of bead adhesion from cells. Herein we demonstrate in vitro release of a poly-d-lysine (PDL) layer from anionic polystyrene beads, allowing complete bead release from rat cortical neurons post-adhesion. PMID:27165466

  13. Cadherin-Based Intercellular Adhesions Organize Epithelial Cell-Matrix Traction Forces

    CERN Document Server

    Mertz, Aaron F; Banerjee, Shiladitya; Goldstein, Jill; Rosowski, Kathryn R; Niessen, Carien M; Marchetti, M Cristina; Dufresne, Eric R; Horsley, Valerie

    2012-01-01

    Cell--cell and cell-matrix adhesions play essential roles in the function of tissues. There is growing evidence for the importance of crosstalk between these two adhesion types, yet little is known about the impact of these interactions on the mechanical coupling of cells to the extracellular-matrix (ECM). Here, we combine experiment and theory to reveal how intercellular adhesions modulate forces transmitted to the ECM. In the absence of cadherin-based adhesions, primary mouse keratinocytes within a colony appear to act independently, with significant traction forces extending throughout the colony. In contrast, with strong cadherin-based adhesions, keratinocytes in a cohesive colony localize traction forces to the colony periphery. Through genetic or antibody-mediated loss of cadherin expression or function, we show that cadherin-based adhesions are essential for this mechanical cooperativity. A minimal physical model in which cell--cell adhesions modulate the physical cohesion between contractile cells is ...

  14. Pattern formation of scale cells in Lepidoptera by differential origin-dependent cell adhesion

    OpenAIRE

    Sekimura, T.; Zhu, M.; Cook, J.; Maini, P. K.

    1999-01-01

    We present a model for the formation of parallel rows of scale cells in the developing adult wing of moths and butterflies. Precursors of scale cells differentiate throughout each epithelial monolayer and migrate into rows that are roughly parallel to the body axis. Grafting experiments have revealed what appears to be a gradient of adhesivity along the wing. What is more, cell adhesivity character is maintained after grafting. Thus we suggest that it is a cell’s location prior to migration t...

  15. Polyelectrolytes Multilayers to Modulate Cell Adhesion: A Study of the Influence of Film Composition and Polyelectrolyte Interdigitation on the Adhesion of the A549 Cell Line.

    Science.gov (United States)

    Muzzio, Nicolás E; Pasquale, Miguel A; Gregurec, Danijela; Diamanti, Eleftheria; Kosutic, Marija; Azzaroni, Omar; Moya, Sergio E

    2016-04-01

    Polyelectrolyte multilayers (PEMs) with different polycation/polyanion pairs are fabricated by the layer-by-layer technique employing synthetic, natural, and both types of polyelectrolytes. The impact of the chemical composition of PEMs on cell adhesion is assessed by studying cell shape, spreading area, focal contacts, and cell proliferation for the A549 cell line. Cells exhibit good adhesion on PEMs containing natural polycations and poly(sodium 4-styrenesulfonate) (PSS) as polyanion, but limited adhesion is observed on PEMs fabricated from both natural polyelectrolytes. PEMs are then assembled, depositing a block of natural polyelectrolytes on top of a stiffer block with PSS as polyanion. Cell adhesion is enhanced on top of the diblock PEMs compared to purely natural PEMs. This fact could be explained by the interdigitation between polyelectrolytes from the two blocks. Diblock PEM assembly provides a simple means to tune cell adhesion on biocompatible PEMs. PMID:26663657

  16. Localized Modeling of Biochemical and Flow Interactions during Cancer Cell Adhesion.

    Directory of Open Access Journals (Sweden)

    Julie Behr

    Full Text Available This work focuses on one component of a larger research effort to develop a simulation tool to model populations of flowing cells. Specifically, in this study a local model of the biochemical interactions between circulating melanoma tumor cells (TC and substrate adherent polymorphonuclear neutrophils (PMN is developed. This model provides realistic three-dimensional distributions of bond formation and attendant attraction and repulsion forces that are consistent with the time dependent Computational Fluid Dynamics (CFD framework of the full system model which accounts local pressure, shear and repulsion forces. The resulting full dynamics model enables exploration of TC adhesion to adherent PMNs, which is a known participating mechanism in melanoma cell metastasis. The model defines the adhesion molecules present on the TC and PMN cell surfaces, and calculates their interactions as the melanoma cell flows past the PMN. Biochemical rates of reactions between individual molecules are determined based on their local properties. The melanoma cell in the model expresses ICAM-1 molecules on its surface, and the PMN expresses the β-2 integrins LFA-1 and Mac-1. In this work the PMN is fixed to the substrate and is assumed fully rigid and of a prescribed shear-rate dependent shape obtained from micro-PIV experiments. The melanoma cell is transported with full six-degrees-of-freedom dynamics. Adhesion models, which represent the ability of molecules to bond and adhere the cells to each other, and repulsion models, which represent the various physical mechanisms of cellular repulsion, are incorporated with the CFD solver. All models are general enough to allow for future extensions, including arbitrary adhesion molecule types, and the ability to redefine the values of parameters to represent various cell types. The model presented in this study will be part of a clinical tool for development of personalized medical treatment programs.

  17. Influence of csgD and ompR on Nanomechanics, Adhesion Forces, and Curli Properties of E. coli.

    Science.gov (United States)

    Perni, Stefano; Preedy, Emily Callard; Landini, Paolo; Prokopovich, Polina

    2016-08-01

    Curli are bacterial appendages involved in the adhesion of cells to surfaces; their synthesis is regulated by many genes such as csgD and ompR. The expression of the two curli subunits (CsgA and CsgB) in Escherichia coli (E. coli) is regulated by CsgD; at the same time, csgD transcription is under the control of OmpR. Therefore, both genes are involved in the control of curli production. In this work, we elucidated the role of these genes in the nanomechanical and adhesive properties of E. coli MG1655 (a laboratory strain not expressing significant amount of curli) and its curli-producing mutants overexpressing OmpR and CsgD, employing atomic force microscopy (AFM). Nanomechanical analysis revealed that the expression of these genes gave origin to cells with a lower Young's modulus (E) and turgidity (P0), whereas the adhesion forces were unaffected when genes involved in curli formation were expressed. AFM was also employed to study the primary structure of the curli expressed through the freely jointed chain (FJC) model for polymers. CsgD increased the number of curli on the surface more than OmpR did, and the overexpression of both genes did not result in a greater number of curli. Neither of the genes had an impact on the structure (total length of the polymer and number and length of Kuhn segments) of the curli. Our results further suggest that, despite the widely assumed role of curli in cell adhesion, cell adhesion force is also dictated by surface properties because no relation between the number of curli expressed on the surface and cell adhesion was found. PMID:27434665

  18. Cell Adhesion Modification of Streptococcus viridians in the Presence of Xylitol

    Science.gov (United States)

    Esmacher, Jason; Vidakovich, Blair; Giangrande, Michael; Hoffmann, Peter

    2012-10-01

    There is scientific documentation that those who chew gum sweetened by the sugar alcohol xylitol report a dramatically lower incident of both dental caries and otitis media compared to those who chew conventional gum sweetened by sucrose. An explanation contends that xylitol interferes with the ability of Streptococcus viridian (SV) to form biofilms which is a necessary precursor to the bacteria's ability to damage human tissues. We have used atomic force microscopy to study the cell wall/fimbria properties at the nanonewton level in both the presence and absence of xylitol. The first set of measurements used varying concentrations of xylitol incorporated within the incubation medium. The second used non-xylitol grown bacteria, the xylitol was added externally at various concentrations. Our study suggests that growing SV with xylitol reduces their ability to adhere together. Additionally, externally added xylitol showed grouping of cell adhesion to a relatively narrow nanonewton spread that is concentration dependent. Measurement of the adhesion properties of the bacterial cell wall have found that there is a dramatic increase in the cell wall's firmness which simultaneously accompanied a decrease in its ability to support adhesion, even at very low concentrations of xylitol.

  19. Adhesion Properties between Polyvinyl Acetate Dispersion and Ammonia Modified Oak Wood

    Directory of Open Access Journals (Sweden)

    Darius MINELGA

    2013-05-01

    Full Text Available It is known that PVA dispersion exhibits very good adhesion with natural wood. However, still remains unclear what adhesion-related changes occur, when the outside factor, i. e. ammonia, affects bonding or what the stability of bonding strength is, when the moisture content of ammonia modified wood increases. The aim of this work was to assess adhesive properties of ammonia modified oak wood and the bonding strength of PVA adhesive and modified wood, and to evaluate suitability and boundaries of PVA adhesive for bonding ammonia modified wood. To explore phenomena of adhesive interface of polyvinyl acetate (PVA dispersion and modified wood ammonia treated oak was bonded using PVA dispersions manufactured by JSC “Achema”. Non-water resistant “Lipalas D2” and “Lipalas D3” with enhanced water resistance adhesives comparison allowed examining and comparing gluing performance at variable pH and ammonia content in PVA. In addition bonding strength between PVA adhesive and modified oak wood was evaluated and compared with the adhesive bondline properties for unmodified oak wood. Tests performed in accordance with the standard EN 205:2003 revealed remarkably contrasting effects at dry and wet gluing conditions especially for modified oak. The scanning electron microscope (SEM enabled image confirmation and explanation changes in the PVA adhesive interfaces after contact with modified and untreated oak wood.DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4433

  20. Ion implantation induced nanotopography on titanium and bone cell adhesion

    Science.gov (United States)

    Braceras, Iñigo; Vera, Carolina; Ayerdi-Izquierdo, Ana; Muñoz, Roberto; Lorenzo, Jaione; Alvarez, Noelia; de Maeztu, Miguel Ángel

    2014-08-01

    Permanent endo-osseous implants require a fast, reliable and consistent osseointegration, i.e. intimate bonding between bone and implant, so biomechanical loads can be safely transferred. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role. Most surface treatments to improve osseointegration focus on micro-scale features, as few can effectively control the effects of the treatment at nanoscale. On the other hand, ion implantation allows controlling such nanofeatures. This study has investigated the nanotopography of titanium, as induced by different ion implantation surface treatments, its similarity with human bone tissue structure and its effect on human bone cell adhesion, as a first step in the process of osseointegration. The effect of ion implantation treatment parameters such as energy (40-80 keV), fluence (1-2 e17 ion/cm2) and ion species (Kr, Ar, Ne and Xe) on the nanotopography of medical grade titanium has been measured and assessed by AFM and contact angle. Then, in vitro tests have been performed to assess the effect of these nanotopographies on osteoblast adhesion. The results have shown that the nanostructure of bone and the studied ion implanted surfaces, without surface chemistry modification, are in the same range and that such modifications, in certain conditions, do have a statistically significant effect on bone tissue forming cell adhesion.

  1. Syndecan-1 controls cell migration by activating Rap1 to regulate focal adhesion disassembly

    OpenAIRE

    Altemeier, William A.; Schlesinger, Saundra Y.; Buell, Catherine A.; Parks, William C.; Chen, Peter

    2012-01-01

    After injury, residual epithelial cells coordinate contextual clues from cell–cell and cell–matrix interactions to polarize and migrate over the wound bed. Protrusion formation, cell body translocation and rear retraction is a repetitive process that allows the cell to move across the substratum. Fundamental to this process is the assembly and disassembly of focal adhesions that facilitate cell adhesion and protrusion formation. Here, we identified syndecan-1 as a regulator of focal adhesion ...

  2. Multiple effects of electroporation on the adhesive behaviour of breast cancer cells and fibroblasts

    OpenAIRE

    Pehlivanova Viktoria N; Tsoneva Iana H; Tzoneva Rumiana D

    2012-01-01

    Abstract Background Recently electroporation using biphasic pulses was successfully applied in clinical developments for treating tumours in humans and animals. We evaluated the effects of electrical treatment on cell adhesion behaviour of breast cancer cells and fibroblasts. By applying bipolar electrical pulses we studied short- and long-lived effects on cell adhesion and survival, actin cytoskeleton and cell adhesion contacts in adherent cancer cells and fibroblasts. Methods Two cancer cel...

  3. Osteoblast adhesion to orthopaedic implant alloys: effects of cell adhesion molecules and diamond-like carbon coating.

    Science.gov (United States)

    Kornu, R; Maloney, W J; Kelly, M A; Smith, R L

    1996-11-01

    In total joint arthroplasty, long-term outcomes depend in part on the biocompatibility of implant alloys. This study analyzed effects of surface finish and diamond-like carbon coating on osteoblast cell adhesion to polished titanium-aluminum-vanadium and polished or grit-blasted cobalt-chromium-molybdenum alloys. Osteoblast binding was tested in the presence and absence of the cell adhesion proteins fibronectin, laminin, fibrinogen, and vitronectin and was quantified by measurement of DNA content. Although adherence occurred in serum-free medium, maximal osteoblast binding required serum and was similar for titanium and cobalt alloys at 2 and 12 hours. With the grit-blasted cobalt alloy, cell binding was reduced 48% (p Coating the alloys with diamond-like carbon did not alter osteoblast adhesion, whereas fibronectin pretreatment increased cell binding 2.6-fold (p enhance cell adhesion. These results support the hypothesis that cell adhesion proteins can modify cell binding to orthopaedic alloys. Although osteoblast binding was not affected by the presence of diamond-like carbon, this coating substance may influence other longer term processes, such as bone formation, and deserves further study. PMID:8982128

  4. Hakai reduces cell-substratum adhesion and increases epithelial cell invasion

    International Nuclear Information System (INIS)

    The dynamic regulation of cell-cell adhesions is crucial for developmental processes, including tissue formation, differentiation and motility. Adherens junctions are important components of the junctional complex between cells and are necessary for maintaining cell homeostasis and normal tissue architecture. E-cadherin is the prototype and best-characterized protein member of adherens junctions in mammalian epithelial cells. Regarded as a tumour suppressor, E-cadherin loss is associated with poor prognosis in carcinoma. The E3 ubiquitin-ligase Hakai was the first reported posttranslational regulator of the E-cadherin complex. Hakai specifically targetted E-cadherin for internalization and degradation and thereby lowered epithelial cell-cell contact. Hakai was also implicated in controlling proliferation, and promoted cancer-related gene expression by increasing the binding of RNA-binding protein PSF to RNAs encoding oncogenic proteins. We sought to investigate the possible implication of Hakai in cell-substratum adhesions and invasion in epithelial cells. Parental MDCK cells and MDCK cells stably overexpressing Hakai were used to analyse cell-substratum adhesion and invasion capabilities. Western blot and immunofluoresecence analyses were performed to assess the roles of Paxillin, FAK and Vinculin in cell-substratum adhesion. The role of the proteasome in controlling cell-substratum adhesion was studied using two proteasome inhibitors, lactacystin and MG132. To study the molecular mechanisms controlling Paxillin expression, MDCK cells expressing E-cadherin shRNA in a tetracycline-inducible manner was employed. Here, we present evidence that implicate Hakai in reducing cell-substratum adhesion and increasing epithelial cell invasion, two hallmark features of cancer progression and metastasis. Paxillin, an important protein component of the cell-matrix adhesion, was completely absent from focal adhesions and focal contacts in Hakai-overexpressing MDCK cells. The

  5. Extracts from Flammulina velutipes Inhibit the Adhesion of Pathogenic Fungi to Epithelial Cells

    Science.gov (United States)

    Kashina, Svetlana; Villavicencio, Lérida Liss Flores; Balleza, Marco; Sabanero, Gloria Barbosa; Tsutsumi, Víctor; López, Myrna Sabanero

    2016-01-01

    Background: Recently, extracts from natural sources have been tested for their antifungal properties. In this aspect, Flammulina velutipes extracts possess a significant amount of branch-chained carbohydrates with mannose moieties that, hypothetically, can reduce the adhesion. Objective: In this study, we assessed the capacity of extracts from F. velutipes (wild-type AQF-1 and ATCC 34574 as the reference strain) to inhibit the adhesion of S. schenkii and C. albicans to epithelial cells. Materials and Methods: The aqueous extracts from F. velutipes strains were obtained by sonication, total carbohydrate and protein was analyzed by Dubois and Lowry methods respectively. Effect of the extracts (50, 100 and 150 μg/mL) on the fungi adhesion to host cells was evaluated after 1 h interaction, and the percentage of inhibition of adhesion was measured. After of interaction the cytoskeleton from cell was analyzed with phalloidin-FITC. Results: The extract from strain AQF-1 (50, 100 and 150 μg/mL) inhibited the adhesion of: S. schenkii in a dose-dependent manner (4.9, 7.5 and 12.7%, respectively) and C. albicans in a dose-independent manner (5.2%). The percentage of inhibition by extracts from the strain ATCC34574 at the same concentrations, shown that are dose independent for both fungi: 3.9% for S. schenkii and 2.6% for C. albicans. Conclusion: The extracts from F. velutipes inhibit the adhesion of pathogenic fungi to host cells. The mechanism molecular is unknown; however, is probably an interaction between the polysaccharides from extracts with the fungi receptors. This aspect is currently analyzed. SUMMARY The yields of mycelium from two strains of F. velutipes and the extract from it were similar.Extracts from both strains have inhibited adhesion of S. schenkii and C. albicans to epithelial cells in vitro, but the extract from strain AQF-1 was more effective.The extracts have not prevented damage to epithelial cells caused by pathogenic fungi. Abbreviation Used: YPG

  6. Role of cell adhesion signal molecules in hepatocellular carcinoma cell apoptosis

    Institute of Scientific and Technical Information of China (English)

    Jian-Min Su; Li-Ying Wang; Yu-Long Liang; Xi-Liang Zha

    2005-01-01

    AIM: Cell adhesion molecules and their signal molecules play a very important role in carcinogenesis. The aim of this study is to elucidate the role of these molecules and the signal molecules of integrins and E-cadherins, such as (focal adhesion kinase) FAK, (integrin linked kinase)ILK, and β-catenin in hepatocellular carcinoma cell apoptosis.METHODS: We first synthesized the small molecular compound, S-(1,2-dichlorovinyl)-L-cysteine (DCVC), and identified it, by element analysis and 1H NMR. To establish the apoptosis model of the SMMC-7721 hepatocellular carcinoma cell, we treated cells with DCVC in EBSS for different concentrations or for various length times in the presence of 20 μmol/L N,N-diphenyl-p-phenylenediamine,which blocks necrotic cell death and identified this model by flow cytometry and DNA ladder. Then we studied the changes of FAK, ILK, β-catenin, and PKB in this apoptotic model by Western blot.RESULTS: We found that the loss or decrease of cell adhesion signal molecules is an important reason in apoptosis of SMMC-7721 hepatocellular carcinoma cell and the apoptosis of SMMC-7721 cell was preceded by the loss or decrease of FAK, ILK, PKB, and β-catenin or the damage of cell-matrix and cell-cell adhesion.CONCLUSION: Our results suggested that the decrease of adhesion signal molecules, FAK, ILK, PKB, and β-catenin,could induce hepatocellular carcinoma cell apoptosis.

  7. Quantification of depletion-induced adhesion of Red Blood Cells

    CERN Document Server

    Steffen, Patrick; Wagner, Christian

    2012-01-01

    Red blood cells (RBC) are known to form aggregates in the forms of rouleaux due to the presence of plasma proteins under physiological conditions. Rouleaux formation can be also induced in vitro by the addition of macromolecules to the RBC solution. Current data on the adhesion strength between red blood cells in their natural discocyte shapes mostly rely on indirect measurements like flow chamber experiments, but on the single cell level data is lacking. Here we present measurements on the dextran induced aggregation of red blood cells by use of atomic force microscopy based single cell force spectroscopy (SCFS). The effects of dextran concentration and molecular weight on the interaction energy of adhering RBCs was determined. The results are in good agreement with a model based on the depletion effect and former experimental studies.

  8. CADM1 controls actin cytoskeleton assembly and regulates extracellular matrix adhesion in human mast cells.

    Directory of Open Access Journals (Sweden)

    Elena P Moiseeva

    Full Text Available CADM1 is a major receptor for the adhesion of mast cells (MCs to fibroblasts, human airway smooth muscle cells (HASMCs and neurons. It also regulates E-cadherin and alpha6beta4 integrin in other cell types. Here we investigated a role for CADM1 in MC adhesion to both cells and extracellular matrix (ECM. Downregulation of CADM1 in the human MC line HMC-1 resulted not only in reduced adhesion to HASMCs, but also reduced adhesion to their ECM. Time-course studies in the presence of EDTA to inhibit integrins demonstrated that CADM1 provided fast initial adhesion to HASMCs and assisted with slower adhesion to ECM. CADM1 downregulation, but not antibody-dependent CADM1 inhibition, reduced MC adhesion to ECM, suggesting indirect regulation of ECM adhesion. To investigate potential mechanisms, phosphotyrosine signalling and polymerisation of actin filaments, essential for integrin-mediated adhesion, were examined. Modulation of CADM1 expression positively correlated with surface KIT levels and polymerisation of cortical F-actin in HMC-1 cells. It also influenced phosphotyrosine signalling and KIT tyrosine autophosphorylation. CADM1 accounted for 46% of surface KIT levels and 31% of F-actin in HMC-1 cells. CADM1 downregulation resulted in elongation of cortical actin filaments in both HMC-1 cells and human lung MCs and increased cell rigidity of HMC-1 cells. Collectively these data suggest that CADM1 is a key adhesion receptor, which regulates MC net adhesion, both directly through CADM1-dependent adhesion, and indirectly through the regulation of other adhesion receptors. The latter is likely to occur via docking of KIT and polymerisation of cortical F-actin. Here we propose a stepwise model of adhesion with CADM1 as a driving force for net MC adhesion.

  9. Measurement of cell adhesion force by vertical forcible detachment using an arrowhead nanoneedle and atomic force microscopy

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • We developed a method to measure cell adhesion force by detaching cell using an arrowhead nanoneedle and AFM. • A nanofilm consisting of fibronectin and gelatin was formed on cell surface to reinforce the cell cortex. • By the nanofilm lamination, detachment efficiencies of strongly adherent cell lines were improved markedly. - Abstract: The properties of substrates and extracellular matrices (ECM) are important factors governing the functions and fates of mammalian adherent cells. For example, substrate stiffness often affects cell differentiation. At focal adhesions, clustered–integrin bindings link cells mechanically to the ECM. In order to quantitate the affinity between cell and substrate, the cell adhesion force must be measured for single cells. In this study, forcible detachment of a single cell in the vertical direction using AFM was carried out, allowing breakage of the integrin–substrate bindings. An AFM tip was fabricated into an arrowhead shape to detach the cell from the substrate. Peak force observed in the recorded force curve during probe retraction was defined as the adhesion force, and was analyzed for various types of cells. Some of the cell types adhered so strongly that they could not be picked up because of plasma membrane breakage by the arrowhead probe. To address this problem, a technique to reinforce the cellular membrane with layer-by-layer nanofilms composed of fibronectin and gelatin helped to improve insertion efficiency and to prevent cell membrane rupture during the detachment process, allowing successful detachment of the cells. This method for detaching cells, involving cellular membrane reinforcement, may be beneficial for evaluating true cell adhesion forces in various cell types

  10. Measurement of cell adhesion force by vertical forcible detachment using an arrowhead nanoneedle and atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Seunghwan; Hashizume, Yui; Mishima, Mari [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Kawamura, Ryuzo [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Tamura, Masato; Matsui, Hirofumi [Faculty of Medicine, University of Tsukuba, 1-1-1 Ten-nohdai, Tsukuba, Ibaraki 305-8573 (Japan); Matsusaki, Michiya; Akashi, Mitsuru [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nakamura, Chikashi, E-mail: chikashi-nakamura@aist.go.jp [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan)

    2014-08-15

    Graphical abstract: - Highlights: • We developed a method to measure cell adhesion force by detaching cell using an arrowhead nanoneedle and AFM. • A nanofilm consisting of fibronectin and gelatin was formed on cell surface to reinforce the cell cortex. • By the nanofilm lamination, detachment efficiencies of strongly adherent cell lines were improved markedly. - Abstract: The properties of substrates and extracellular matrices (ECM) are important factors governing the functions and fates of mammalian adherent cells. For example, substrate stiffness often affects cell differentiation. At focal adhesions, clustered–integrin bindings link cells mechanically to the ECM. In order to quantitate the affinity between cell and substrate, the cell adhesion force must be measured for single cells. In this study, forcible detachment of a single cell in the vertical direction using AFM was carried out, allowing breakage of the integrin–substrate bindings. An AFM tip was fabricated into an arrowhead shape to detach the cell from the substrate. Peak force observed in the recorded force curve during probe retraction was defined as the adhesion force, and was analyzed for various types of cells. Some of the cell types adhered so strongly that they could not be picked up because of plasma membrane breakage by the arrowhead probe. To address this problem, a technique to reinforce the cellular membrane with layer-by-layer nanofilms composed of fibronectin and gelatin helped to improve insertion efficiency and to prevent cell membrane rupture during the detachment process, allowing successful detachment of the cells. This method for detaching cells, involving cellular membrane reinforcement, may be beneficial for evaluating true cell adhesion forces in various cell types.

  11. Evaluation of the mechanical properties of dental adhesives and glass-ionomer cements.

    Science.gov (United States)

    Magni, Elisa; Ferrari, Marco; Hickel, Reinhard; Ilie, Nicoleta

    2010-02-01

    Adhesives and lining/base materials should relieve the stresses concentrated at the tooth/restoration interface. The study aimed at comparing the mechanical properties of eight adhesives and six glass-ionomer cements (GICs). The adhesives were applied on dentin disks, whereas 2 mm x 3 mm x 2 mm GICs specimens were prepared in a teflon mold. Vicker's hardness (VH), elastic modulus (E), creep (Cr) and elastic work (We/Wtot) were measured with a micro hardness indenter. One-way ANOVA and Tukey's test were used to compare the mechanical properties within each materials' type and among the materials' classes. Enamel and dentin were used as references. Significant differences were detected within each materials' type and among the materials' classes and enamel and dentin. GICs were superior to adhesives in VH and E and showed a VH similar to dentin. GICs presented mechanical properties more similar to enamel and dentin than adhesives. PMID:19241096

  12. Effects of fibulin-5 on attachment, adhesion, and proliferation of primary human endothelial cells

    International Nuclear Information System (INIS)

    Background: Fibulin-5 is a novel extracellular protein that is thought to act as a bridging peptide between elastin fibers and cell surface integrins in blood vessel wall. Fibulin-5 binding to endothelial cell (EC) surface integrins may effect cell proliferation and cell attachment to extracellular matrix (ECM) or to artificial surfaces. In this paper, we describe the effects of fibulin-5 on attachment, adhesion, and proliferation of primary human EC. After demonstrating that fibulin-5 over-expression inhibited EC proliferation, we tested the hypothesis that co-expression of fibulin-5 and VEGF165 will lead to unique EC phenotype that will exhibit increased adherence properties and retain its proliferation capacity. Methods and results: Fibulin-5 and VEGF165 gene transfer to primary human saphenous vein endothelial cells was accomplished using retroviral vectors encoding the two genes. Transgene expression was verified using immunohistochemistry, Western blotting, and ELISA. Fibulin 5 over-expression tended to improve immediate EC attachment (30 min after seeding) and improved significantly adhesion (>40%) under shear stress tested 24 h after EC seeding. The effects of fibulin-5 and VEGF165 on EC proliferation in the presence or absence of basic FGF were also tested. EC expressing fibulin-5 had reduced proliferation while VEGF165 co-expression ameliorated this effect. Conclusion: Fibulin-5 improved EC attachment to artificial surfaces. Dual transfer of fibulin-5 and VEGF165 resulted in EC phenotype with increased adhesion and improved proliferation. This unique EC phenotype can be useful for tissue engineering on endovascular prostheses

  13. Transchromosomic cell model of Down syndrome shows aberrant migration, adhesion and proteome response to extracellular matrix

    Directory of Open Access Journals (Sweden)

    Cotter Finbarr E

    2009-08-01

    Full Text Available Abstract Background Down syndrome (DS, caused by trisomy of human chromosome 21 (HSA21, is the most common genetic birth defect. Congenital heart defects (CHD are seen in 40% of DS children, and >50% of all atrioventricular canal defects in infancy are caused by trisomy 21, but the causative genes remain unknown. Results Here we show that aberrant adhesion and proliferation of DS cells can be reproduced using a transchromosomic model of DS (mouse fibroblasts bearing supernumerary HSA21. We also demonstrate a deacrease of cell migration in transchromosomic cells independently of their adhesion properties. We show that cell-autonomous proteome response to the presence of Collagen VI in extracellular matrix is strongly affected by trisomy 21. Conclusion This set of experiments establishes a new model system for genetic dissection of the specific HSA21 gene-overdose contributions to aberrant cell migration, adhesion, proliferation and specific proteome response to collagen VI, cellular phenotypes linked to the pathogenesis of CHD.

  14. Rapid and Localized Mechanical Stimulation and Adhesion Assay: TRPM7 Involvement in Calcium Signaling and Cell Adhesion

    OpenAIRE

    Wagner Shin Nishitani; Adriano Mesquita Alencar; Yingxiao Wang

    2015-01-01

    A cell mechanical stimulation equipment, based on cell substrate deformation, and a more sensitive method for measuring adhesion of cells were developed. A probe, precisely positioned close to the cell, was capable of a vertical localized mechanical stimulation with a temporal frequency of 207 Hz, and strain magnitude of 50%. This setup was characterized and used to probe the response of Human Umbilical Endothelial Vein Cells (HUVECs) in terms of calcium signaling. The intracellular calcium i...

  15. Conformational Dynamics of the Focal Adhesion Targeting Domain Control Specific Functions of Focal Adhesion Kinase in Cells

    KAUST Repository

    Kadaré, Gress

    2015-01-02

    Focal adhesion (FA) kinase (FAK) regulates cell survival and motility by transducing signals from membrane receptors. The C-terminal FA targeting (FAT) domain of FAK fulfils multiple functions, including recruitment to FAs through paxillin binding. Phosphorylation of FAT on Tyr925 facilitates FA disassembly and connects to the MAPK pathway through Grb2 association, but requires dissociation of the first helix (H1) of the four-helix bundle of FAT. We investigated the importance of H1 opening in cells by comparing the properties of FAK molecules containing wild-type or mutated FAT with impaired or facilitated H1 openings. These mutations did not alter the activation of FAK, but selectively affected its cellular functions, including self-association, Tyr925 phosphorylation, paxillin binding, and FA targeting and turnover. Phosphorylation of Tyr861, located between the kinase and FAT domains, was also enhanced by the mutation that opened the FAT bundle. Similarly phosphorylation of Ser910 by ERK in response to bombesin was increased by FAT opening. Although FAK molecules with the mutation favoring FAT opening were poorly recruited at FAs, they efficiently restored FA turnover and cell shape in FAK-deficient cells. In contrast, the mutation preventing H1 opening markedly impaired FAK function. Our data support the biological importance of conformational dynamics of the FAT domain and its functional interactions with other parts of the molecule.

  16. Epithelial to mesenchymal transition-the roles of cell morphology, labile adhesion and junctional coupling.

    Science.gov (United States)

    Abdulla, Tariq; Luna-Zurita, Luis; de la Pompa, José Luis; Schleich, Jean-Marc; Summers, Ron

    2013-08-01

    Epithelial to mesenchymal transition (EMT) is a fundamental process during development and disease, including development of the heart valves and tumour metastases. An extended cellular Potts model was implemented to represent the behaviour emerging from autonomous cell morphology, labile adhesion, junctional coupling and cell motility. Computer simulations normally focus on these functional changes independently whereas this model facilitates exploration of the interplay between cell shape changes, adhesion and migration. The simulation model is fitted to an in vitro model of endocardial EMT, and agrees with the finding that Notch signalling increases cell-matrix adhesion in addition to modulating cell-cell adhesion. PMID:23787029

  17. Cell adhesion and guidance by micropost-array chemical sensors

    Science.gov (United States)

    Pantano, Paul; Quah, Soo-Kim; Danowski, Kristine L.

    2002-06-01

    An array of ~50,000 individual polymeric micropost sensors was patterned across a glass coverslip by a photoimprint lithographic technique. Individual micropost sensors were ~3-micrometers tall and ~8-micrometers wide. The O2-sensitive micropost array sensors (MPASs) comprised a ruthenium complex encapsulated in a gas permeable photopolymerizable siloxane. The pH-sensitive MPASs comprised a fluorescein conjugate encapsulated in a photocrosslinkable poly(vinyl alcohol)-based polymer. PO2 and pH were quantitated by acquiring MPAS luminescence images with an epifluorescence microscope/charge coupled device imaging system. O2-sensitive MPASs displayed linear Stern-Volmer quenching behavior with a maximum Io/I of ~8.6. pH-sensitive MPASs displayed sigmoidal calibration curves with a pKa of ~5.8. The adhesion of undifferentiated rat pheochromocytoma (PC12) cells across these two polymeric surface types was investigated. The greatest PC12 cell proliferation and adhesion occurred across the poly(vinyl alcohol)-based micropost arrays relative to planar poly(vinyl alcohol)-based surfaces and both patterned and planar siloxane surfaces. An additional advantage of the patterned MPAS layers relative to planar sensing layers was the ability to direct the growth of biological cells. Preliminary data is presented whereby nerve growth factor-differentiated PC12 cells grew neurite-like processes that extended along paths defined by the micropost architecture.

  18. Cell adhesion molecule control of planar spindle orientation.

    Science.gov (United States)

    Tuncay, Hüseyin; Ebnet, Klaus

    2016-03-01

    Polarized epithelial cells align the mitotic spindle in the plane of the sheet to maintain tissue integrity and to prevent malignant transformation. The orientation of the spindle apparatus is regulated by the immobilization of the astral microtubules at the lateral cortex and depends on the precise localization of the dynein-dynactin motor protein complex which captures microtubule plus ends and generates pulling forces towards the centrosomes. Recent developments indicate that signals derived from intercellular junctions are required for the stable interaction of the dynein-dynactin complex with the cortex. Here, we review the molecular mechanisms that regulate planar spindle orientation in polarized epithelial cells and we illustrate how different cell adhesion molecules through distinct and non-overlapping mechanisms instruct the cells to align the mitotic spindle in the plane of the sheet. PMID:26698907

  19. The cell adhesion molecule Fasciclin2 regulates brush border length and organization in Drosophila renal tubules

    DEFF Research Database (Denmark)

    Halberg, Kenneth A; Rainey, Stephanie M; Veland, Iben R; Neuert, Helen; Dornan, Anthony J; Klämbt, Christian; Davies, Shireen-Anne; Dow, Julian A T

    2016-01-01

    Multicellular organisms rely on cell adhesion molecules to coordinate cell-cell interactions, and to provide navigational cues during tissue formation. In Drosophila, Fasciclin 2 (Fas2) has been intensively studied due to its role in nervous system development and maintenance; yet, Fas2 is most...... role for this well-known cell adhesion molecule, and propose that Fas2-mediated intermicrovillar homophilic adhesion complexes help stabilize the brush border....

  20. CD13 is a novel mediator of monocytic/endothelial cell adhesion

    OpenAIRE

    Mina-Osorio, Paola; Winnicka, Beata; O'Conor, Catherine; Grant, Christina L.; Vogel, Lotte K.; Rodriguez-Pinto, Daniel; Holmes, Kathryn V.; Ortega, Enrique; Shapiro, Linda H.

    2008-01-01

    During inflammation, cell surface adhesion molecules guide the adhesion and migration of circulating leukocytes across the endothelial cells lining the blood vessels to access the site of injury. The transmembrane molecule CD13 is expressed on monocytes and endothelial cells and has been shown to mediate homotypic cell adhesion, which may imply a role for CD13 in inflammatory monocyte trafficking. Here, we show that ligation and clustering of CD13 by mAb or viral ligands potently induce myelo...

  1. Intrinsic Surface-Drying Properties of Bio-adhesive Proteins

    OpenAIRE

    Akdogan, Yasar; Wei, Wei; Huang, Kuo-Ying; Kageyama, Yoshiyuki; Danner, Eric W.; Miller, Dusty R.; Martinez Rodriguez, Nadine R.; Herbert Waite, J.; Han, Songi

    2014-01-01

    Sessile marine mussels must “dry” underwater surfaces before adhering to them. Synthetic adhesives have yet to overcome this fundamental challenge. Previous studies of bio-inspired adhesion have largely been performed under applied compressive forces but these are poor predictors of an adhesive’s ability to spontaneously penetrate surface hydration layers. In a force-free approach to measuring molecular-level interaction via the surface water diffusivity, different mussel foot proteins were f...

  2. Cell-surface serglycin promotes adhesion of myeloma cells to collagen type I and affects the expression of matrix metalloproteinases.

    Science.gov (United States)

    Skliris, Antonis; Labropoulou, Vassiliki T; Papachristou, Dionysios J; Aletras, Alexios; Karamanos, Nikos K; Theocharis, Achilleas D

    2013-05-01

    Serglycin (SG) is mainly expressed by hematopoetic cells as an intracellular proteoglycan. Multiple myeloma cells constitutively secrete SG, which is also localized on the cell surface in some cell lines. In this study, SG isolated from myeloma cells was found to interact with collagen type I (Col I), which is a major bone matrix component. Notably, myeloma cells positive for cell-surface SG (csSG) adhered significantly to Col I, compared to cells lacking csSG. Removal of csSG by treatment of the cells with chondroitinase ABC or blocking of csSG by an SG-specific polyclonal antibody significantly reduced the adhesion of myeloma cells to Col I. Significant up-regulation of expression of the matrix metalloproteinases MMP-2 and MMP-9 at both the mRNA and protein levels was observed when culturing csSG-positive myeloma cells on Col I-coated dishes or in the presence of soluble Col I. MMP-9 and MMP-2 were also expressed in increased amounts by myeloma cells in the bone marrow of patients with multiple myeloma. Our data indicate that csSG of myeloma cells affects key functional properties, such as adhesion to Col I and the expression of MMPs, and imply that csSG may serve as a potential prognostic factor and/or target for pharmacological interventions in multiple myeloma. PMID:23387827

  3. CXC chemokine ligand 12/Stromal cell-derived factor-1 regulates cell adhesion in human colon cancer cells by induction of intercellular adhesion molecule-1

    OpenAIRE

    Tung Shui-Yi; Chang Shun-Fu; Chou Ming-Hui; Huang Wen-Shih; Hsieh Yung-Yu; Shen Chien-Heng; Kuo Hsing-Chun; Chen Cheng-Nan

    2012-01-01

    Abstract Background The CXC chemokine ligand 12 (CXCL12)/stromal cell-derived factor-1 (SDF-1) and CXC receptor 4 (CXCR4) axis is involved in human colorectal cancer (CRC) carcinogenesis and can promote the progression of CRC. Interaction between CRC cells and endothelium is a key event in tumor progression. The aim of this study was to investigate the effect of SDF-1 on the adhesion of CRC cells. Methods Human CRC DLD-1 cells were used to study the effect of SDF-1 on intercellular adhesion m...

  4. Differential expression of neural cell adhesion molecule and cadherins in pancreatic islets, glucagonomas, and insulinomas

    DEFF Research Database (Denmark)

    Møller, C J; Christgau, S; Williamson, M R; Madsen, O D; Niu, Z P; Bock, E; Baekkeskov, S

    1992-01-01

    a process where cell adhesion molecules are involved. In this study we have analyzed the expression of neural cell adhesion molecule (NCAM) and cadherin molecules in neonatal, young, and adult rat islet cells as well as in glucagonomas and insulinomas derived from a pluripotent rat islet cell tumor...

  5. Homophilic Adhesion Mechanism of Neurofascin, a Member of the L1 Family of Neural Cell Adhesion Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Heli; Focia, Pamela J.; He, Xiaolin (NWU, MED)

    2012-02-13

    The L1 family neural cell adhesion molecules play key roles in specifying the formation and remodeling of the neural network, but their homophilic interaction that mediates adhesion is not well understood. We report two crystal structures of a dimeric form of the headpiece of neurofascin, an L1 family member. The four N-terminal Ig-like domains of neurofascin form a horseshoe shape, akin to several other immunoglobulin superfamily cell adhesion molecules such as hemolin, axonin, and Dscam. The neurofascin dimer, captured in two crystal forms with independent packing patterns, reveals a pair of horseshoes in trans-synaptic adhesion mode. The adhesion interaction is mediated mostly by the second Ig-like domain, which features an intermolecular {beta}-sheet formed by the joining of two individual GFC {beta}-sheets and a large but loosely packed hydrophobic cluster. Mutagenesis combined with gel filtration assays suggested that the side chain hydrogen bonds at the intermolecular {beta}-sheet are essential for the homophilic interaction and that the residues at the hydrophobic cluster play supplementary roles. Our structures reveal a conserved homophilic adhesion mode for the L1 family and also shed light on how the pathological mutations of L1 affect its structure and function.

  6. Cell adhesion to agrin presented as a nanopatterned substrate is consistent with an interaction with the extracellular matrix and not transmembrane adhesion molecules

    Directory of Open Access Journals (Sweden)

    Wolfram Tobias

    2008-12-01

    Full Text Available Abstract Background Molecular spacing is important for cell adhesion in a number of ways, ranging from the ordered arrangement of matrix polymers extracellularly, to steric hindrance of adhesion/signaling complexes intracellularly. This has been demonstrated using nanopatterned RGD peptides, a canonical extracellular matrix ligand for integrin interactions. Cell adhesion was greatly reduced when the RGD-coated nanoparticles were separated by more than 60 nm, indicating a sharp spacing-dependent threshold for this form of cell adhesion. Results Here we show a similar dependence of cell adhesion on the spacing of agrin, a protein that exists as both a secreted, matrix-bound form and a type-2 transmembrane form in vivo. Agrin was presented as a substrate for cell adhesion assays by anchoring recombinant protein to gold nanoparticles that were arrayed at tunable distances onto glass coverslips. Cells adhered well to nanopatterned agrin, and when presented as uniformly coated substrates, adhesion to agrin was comparable to other well-studied adhesion molecules, including N-Cadherin. Adhesion of both mouse primary cortical neurons and rat B35 neuroblastoma cells showed a spacing-dependent threshold, with a sharp drop in adhesion when the space between agrin-coated nanoparticles increased from 60 to 90 nm. In contrast, adhesion to N-Cadherin decreased gradually over the entire range of distances tested (uniform, 30, 60, 90, and 160 nm. The spacing of the agrin nanopattern also influenced cell motility, and peptide competition suggested adhesion was partially integrin dependent. Finally, differences in cell adhesion to C-terminal agrin fragments of different lengths were detected using nanopatterned substrates, and these differences were not evident using uniformly coated substrates. Conclusion These results suggest nanopatterned substrates may provide a physiological presentation of adhesive substrates, and are consistent with cells adhering to agrin

  7. Biodegradable electrospun nanofibers coated with platelet-rich plasma for cell adhesion and proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Gomez, Luis [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Instituto de Ortopedia y Banco de Tejidos Musculoesqueléticos, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Alvarez-Lorenzo, Carmen, E-mail: carmen.alvarez.lorenzo@usc.es [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Concheiro, Angel [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Silva, Maite [Instituto de Ortopedia y Banco de Tejidos Musculoesqueléticos, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Dominguez, Fernando [Fundación Publica Galega de Medicina Xenómica, Santiago de Compostela (Spain); Sheikh, Faheem A.; Cantu, Travis; Desai, Raj; Garcia, Vanessa L. [Department of Chemistry, University of Texas Pan American, Edinburg, TX 78541 (United States); Macossay, Javier, E-mail: jmacossay@utpa.edu [Department of Chemistry, University of Texas Pan American, Edinburg, TX 78541 (United States)

    2014-07-01

    Biodegradable electrospun poly(ε-caprolactone) (PCL) scaffolds were coated with platelet-rich plasma (PRP) to improve cell adhesion and proliferation. PRP was obtained from human buffy coat, and tested on human adipose-derived mesenchymal stem cells (MSCs) to confirm cell proliferation and cytocompatibility. Then, PRP was adsorbed on the PCL scaffolds via lyophilization, which resulted in a uniform sponge-like coating of 2.85 (S.D. 0.14) mg/mg. The scaffolds were evaluated regarding mechanical properties (Young's modulus, tensile stress and tensile strain), sustained release of total protein and growth factors (PDGF-BB, TGF-β1 and VEGF), and hemocompatibility. MSC seeded on the PRP–PCL nanofibers showed an increased adhesion and proliferation compared to pristine PCL fibers. Moreover, the adsorbed PRP enabled angiogenesis features observed as neovascularization in a chicken chorioallantoic membrane (CAM) model. Overall, these results suggest that PRP–PCL scaffolds hold promise for tissue regeneration applications. - Highlights: • Platelet-rich plasma (PRP) can be adsorbed on electrospun fibers via lyophilization. • PRP coating enhanced mesenchymal stem cell adhesion and proliferation on scaffolds. • PRP-coated scaffolds showed sustained release of growth factors. • Adsorbed PRP provided angiogenic features. • PRP-poly(ε-caprolactone) scaffolds hold promise for tissue regeneration applications.

  8. Biodegradable electrospun nanofibers coated with platelet-rich plasma for cell adhesion and proliferation

    International Nuclear Information System (INIS)

    Biodegradable electrospun poly(ε-caprolactone) (PCL) scaffolds were coated with platelet-rich plasma (PRP) to improve cell adhesion and proliferation. PRP was obtained from human buffy coat, and tested on human adipose-derived mesenchymal stem cells (MSCs) to confirm cell proliferation and cytocompatibility. Then, PRP was adsorbed on the PCL scaffolds via lyophilization, which resulted in a uniform sponge-like coating of 2.85 (S.D. 0.14) mg/mg. The scaffolds were evaluated regarding mechanical properties (Young's modulus, tensile stress and tensile strain), sustained release of total protein and growth factors (PDGF-BB, TGF-β1 and VEGF), and hemocompatibility. MSC seeded on the PRP–PCL nanofibers showed an increased adhesion and proliferation compared to pristine PCL fibers. Moreover, the adsorbed PRP enabled angiogenesis features observed as neovascularization in a chicken chorioallantoic membrane (CAM) model. Overall, these results suggest that PRP–PCL scaffolds hold promise for tissue regeneration applications. - Highlights: • Platelet-rich plasma (PRP) can be adsorbed on electrospun fibers via lyophilization. • PRP coating enhanced mesenchymal stem cell adhesion and proliferation on scaffolds. • PRP-coated scaffolds showed sustained release of growth factors. • Adsorbed PRP provided angiogenic features. • PRP-poly(ε-caprolactone) scaffolds hold promise for tissue regeneration applications

  9. Involvement of cell surface phosphatidylinositol-anchored glycoproteins in cell-cell adhesion of chick embryo myoblasts

    OpenAIRE

    1989-01-01

    During myogenesis myoblasts fuse to form multinucleate cells that express muscle-specific proteins. A specific cell-cell adhesion process precedes lipid bilayer union during myoblast fusion (Knudsen, K. A., and A. F. Horwitz. 1977. Dev. Biol. 58:328-338) and is mediated by cell surface glycoproteins (Knudsen, K. A., 1985. J. Cell Biol. 101:891- 897). In this paper we show that myoblast adhesion and myotube formation are inhibited by treating fusion-competent myoblasts with phosphatidylinosito...

  10. A new technical approach to quantify cell-cell adhesion forces by AFM

    International Nuclear Information System (INIS)

    Cell-cell adhesion is a complex process that is involved in the tethering of cells, cell-cell communication, tissue formation, cell migration and the development and metastasis of tumors. Given the heterogeneous and complex nature of cell surfaces it has previously proved difficult to characterize individual cell-cell adhesion events. Force spectroscopy, using an atomic force microscope, is capable of resolving such individual cell-cell binding events, but has previously been limited in its application due to insufficient effective pulling distances. Extended pulling range is critical in studying cell-cell interactions due to the potential for large cell deformations. Here we describe an approach to such experiments, where the sample stage can be moved 100 μm in the z-direction, by closed loop, linearized piezo elements. Such an approach enables an increase in pulling distance sufficient for the observation of long-distance cell-unbinding events without reducing the imaging capabilities of the atomic force microscope. The atomic force microscope head and the piezo-driven sample stage are installed on an inverted optical microscope fitted with a piezo-driven objective, to allow the monitoring of cell morphology by conventional light microscopy, concomitant with force spectroscopy measurements. We have used the example of the WM115 melanoma cell line binding to human umbilical vein endothelial cells to demonstrate the capabilities of this system and the necessity for such an extended pulling range when quantifying cell-cell adhesion events

  11. Hepatocyte adhesion to carbohydrate-derivatized surfaces. II. Regulation of cytoskeletal organization and cell morphology

    OpenAIRE

    1991-01-01

    Rat hepatic lectins mediate adhesion of isolated rat hepatocytes to synthetic surfaces derivatized with galactosides. Initial weak adhesion is followed by rapid adhesion strengthening. After hepatocytes contact galactose-derivatized gels, the hepatic lectins move rapidly into an inaccessible patch at the adhesive surface (Weisz, O. A., and R. L. Schnaar. 1991. J. Cell Biol. 115:485-493). Hepatic lectin patching, which occurs both at 37 degrees C and 4 degrees C, is not responsible for adhesio...

  12. Cell Wall Microstructure Analysis Implicates Hemicellulose Polysaccharides in Cell Adhesion in Tomato Fruit Pericarp Parenchyma

    Institute of Scientific and Technical Information of China (English)

    Jose J. Ordaz-Ortiz; Susan E. Marcus; J. Paul Knox

    2009-01-01

    Methods developed to isolate intact cells from both unripe and ripe tomato fruit pericarp parenchyma have allowed the cell biological analysis of polysaccharide epitopes at the surface of separated cells. The LM7 pectic homoga-lacturonan epitope is a marker of the junctions of adhesion planes and intercellular spaces in parenchyma systems. The LM7 epitope persistently marked the former edge of adhesion planes at the surface of cells separated from unripe and ripened tomato fruit and also from fruits with the Cnr mutation. The LM 11 xylan epitope was associated, in sections, with cell walls lining intercellular space but the epitope was not detected at the surface of isolated cells, being lost during cell isolation. The LM15 xyloglucan epitope was present at the surface of cells isolated from unripe fruit in a pattern reflecting the former edge of cell adhesion planes/intercellular space but with gaps and apparent breaks, An equivalent pattern ofLM15 epitope occurrence was revealed at the surface of cells isolated by pectate lyase action but was not present in cells isolated from ripe fruit or from Cnr fruit. In contrast to wild-type cells, the LM5 galactan and LM21 mannan epitopes oc-curred predominantly in positions reflecting intercellular space in Cnr, suggesting a concerted alteration in cell wall mi-crostructure in response to this mutation. Galactanase and mannanase, along with pectic homogalacturonan-degrading enzymes, were capable of releasing cells from unripe fruit parenchyma. These observations indicate that hemicellulose polymers are present in architectural contexts reflecting cell adhesion and that several cell wall polysaccharide classes are likely to contribute to cell adhesion/cell separation in tomato fruit pericarp parenchyma.

  13. Functional nanoparticles translocation into cell and adhesion force curve analysis.

    Science.gov (United States)

    Lee, Haisung; Veerapandian, Murugan; Kim, Byung Tae; Yun, Kyusik; Seo, Soo-Won

    2012-10-01

    The aim of this research is to investigate the cell translocation of two functional nanoparticles (barium sulfate (BaSO4NPs), europium (III) doped gadolinium oxide nanoparticles (Gd2O3@EuNPs)) into A549 cells by Bio-Atomic Force Microscopy (Bio-AFM). Successful cell translocation of these two nanoparticles are ensured from the measurement of changes in the cell surface roughness and interaction (extension), retraction forces from the vertical deflection of tip towards substrate surfaces through force-distance curve slope analysis. Measurement of typical adhesion forces (i.e., extension and retraction) between the tip-substrate (0.0963 and 1.155 nN), tip-A549 cell substrate (0.1177 and 2.468 nN), tip-Gd2O3@EuNPs/A549 substrate (0.0785 and 0.4276 nN) and tip-BaSO4NPs/A549 substrate (0.518 and 6.838 nN) confirms the successful cell translocation of functional nanoparticles into A549 cells. Further the nanoscale resolution of topographical height and 3D images evinces the surface characteristics of normal A549 cells and nanoparticles translocated A549 cells. PMID:23421137

  14. Evidence that talin alternative splice variants from Ciona intestinalis have different roles in cell adhesion

    Directory of Open Access Journals (Sweden)

    McCann Richard O

    2006-12-01

    Full Text Available Abstract Background Talins are large, modular cytoskeletal proteins found in animals and amoebozoans such as Dictyostelium discoideum. Since the identification of a second talin gene in vertebrates, it has become increasingly clear that vertebrate Talin1 and Talin2 have non-redundant roles as essential links between integrins and the actin cytoskeleton in distinct plasma membrane-associated adhesion complexes. The conserved C-terminal I/LWEQ module is important for talin function. This structural element mediates the interaction of talins with F-actin. The I/LWEQ module also targets mammalian Talin1 to focal adhesion complexes, which are dynamic multicomponent assemblies required for cell adhesion and cell motility. Although Talin1 is essential for focal adhesion function, Talin2 is not targeted to focal adhesions. The nonvertebrate chordate Ciona intestinalis has only one talin gene, but alternative splicing of the talin mRNA produces two proteins with different C-terminal I/LWEQ modules. Thus, C. intestinalis contains two talins, Talin-a and Talin-b, with potentially different activities, despite having only one talin gene. Results We show here that, based on their distribution in cDNA libraries, Talin-a and Talin-b are differentially expressed during C. intestinalis development. The I/LWEQ modules of the two proteins also have different affinities for F-actin. Consistent with the hypothesis that Talin-a and Talin-b have different roles in cell adhesion, the distinct I/LWEQ modules of Talin-a and Talin-b possess different subcellular targeting determinants. The I/LWEQ module of Talin-a is targeted to focal adhesions, where it most likely serves as the link between integrin and the actin cytoskeleton. The Talin-b I/LWEQ module is not targeted to focal adhesions, but instead preferentially labels F-actin stress fibers. These different properties of C. intestinalis the Talin-a and Talin-b I/LWEQ modules mimic the differences between mammalian

  15. Cell adhesion on Ti surface with controlled roughness

    Energy Technology Data Exchange (ETDEWEB)

    Burgos-Asperilla, L.; Garcia-Alonso, M. C.; Escudero, M. L.; Alonso, C.

    2015-07-01

    In this report, the in situ interaction between Saos-2 osteoblast cells and a smooth Ti surface was examined over time. The adhesion kinetics and mechanisms of cellular proliferation were monitored by quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). The rate of Saos-2 attachment on Ti surfaces, obtained from the measurements performed with the QCM, is a first-order reaction, with k=2.10{sup -}3 min{sup -}1. The impedance measurements indicate that in the absence of cells, the Ti resistance diminishes over time (7 days), due to the presence of amino acids and proteins from the culture medium that have been adsorbed, while in the presence of osteoblasts, this decrease is much greater because of the compounds generated by the cells that accelerate the dissolution of Ti. (Author)

  16. Surface deformation and shear flow in ligand mediated cell adhesion

    Science.gov (United States)

    Sircar, Sarthok; Roberts, Anthony; Sarthok Sircar / Anthony Roberts Collaboration

    We present a unified, multiscale model to study the attachment/detachment dynamics of two deforming, near spherical cells, coated with binding ligands and subject to a slow, homogeneous shear flow in a viscous fluid medium. The binding ligands on the surface of the cells experience attractive and repulsive forces in an ionic medium and exhibit finite resistance to rotation via bond tilting. The microscale drag forces and couples describing the fluid flow inside the small separation gap between the cells, are calculated using a combination of methods in lubrication theory and previously published numerical results. For a select range of material and fluid parameters, a hysteretic transition of the sticking probability curves (i.e., the function g*) between the adhesion phase (when g*>0.5) and the fragmentation phase (when g*University startup funds and AR is supported by the Australian Research Council Discovery Grant DP150102385.

  17. CD13 is a novel mediator of monocytic/endothelial cell adhesion

    DEFF Research Database (Denmark)

    Mina-Osorio, Paola; Winnicka, Beata; O'Conor, Catherine;

    2008-01-01

    rearrangement and filopodia formation. Treatment with soluble recombinant (r)CD13 blocks this CD13-dependent adhesion, and CD13 molecules from monocytic and endothelial cells are present in the same immunocomplex, suggesting a direct participation of CD13 in the adhesive interaction. This concept is......During inflammation, cell surface adhesion molecules guide the adhesion and migration of circulating leukocytes across the endothelial cells lining the blood vessels to access the site of injury. The transmembrane molecule CD13 is expressed on monocytes and endothelial cells and has been shown to...... mediate homotypic cell adhesion, which may imply a role for CD13 in inflammatory monocyte trafficking. Here, we show that ligation and clustering of CD13 by mAb or viral ligands potently induce myeloid cell/endothelial adhesion in a signal transduction-dependent manner involving monocytic cytoskeletal...

  18. Role of Lactobacillus reuteri cell and mucus-binding protein A (CmbA) in adhesion to intestinal epithelial cells and mucus in vitro.

    Science.gov (United States)

    Jensen, Hanne; Roos, Stefan; Jonsson, Hans; Rud, Ida; Grimmer, Stine; van Pijkeren, Jan-Peter; Britton, Robert A; Axelsson, Lars

    2014-04-01

    Lactobacillus reuteri, a symbiotic inhabitant of the gastrointestinal tract in humans and animals, is marketed as a probiotic. The ability to adhere to intestinal epithelial cells and mucus is an interesting property with regard to probiotic features such as colonization of the gastrointestinal tract and interaction with the host. Here, we present a study performed to elucidate the role of sortase (SrtA), four putative sortase-dependent proteins (SDPs), and one C-terminal membrane-anchored cell surface protein of Lactobacillus reuteri ATCC PTA 6475 in adhesion to Caco-2 cells and mucus in vitro. This included mutagenesis of the genes encoding these proteins and complementation of mutants. A null mutation in hmpref0536_10255 encoding srtA resulted in significantly reduced adhesion to Caco-2 cells and mucus, indicating involvement of SDPs in adhesion. Evaluation of the bacterial adhesion revealed that of the five putative surface protein mutants tested, only a null mutation in the hmpref0536_10633 gene, encoding a putative SDP with an LPxTG motif, resulted in a significant loss of adhesion to both Caco-2 cells and mucus. Complementation with the functional gene on a plasmid restored adhesion to Caco-2 cells. However, complete restoration of adhesion to mucus was not achieved. Overexpression of hmpref0536_10633 in strain ATCC PTA 6475 resulted in an increased adhesion to Caco-2 cells and mucus compared with the WT strain. We conclude from these results that, among the putative surface proteins tested, the protein encoded by hmpref0536_10633 plays a critical role in binding of Lactobacillus reuteri ATCC PTA 6475 to Caco-2 cells and mucus. Based on this, we propose that this LPxTG motif containing protein should be referred to as cell and mucus binding protein A (CmbA). PMID:24473252

  19. ELMO1 increases expression of extracellular matrix proteins and inhibits cell adhesion to ECMs.

    Science.gov (United States)

    Shimazaki, A; Tanaka, Y; Shinosaki, T; Ikeda, M; Watada, H; Hirose, T; Kawamori, R; Maeda, S

    2006-11-01

    We have previously identified the engulfment and cell motility 1 (ELMO1) as a susceptibility gene for diabetic nephropathy. To elucidate the role of ELMO1 in the pathogenesis of chronic renal injury, we examined the expression of Elmo1 in the kidney of a rat model for chronic glomerulonephritis (uninephrectomy plus anti-Thy1.1 antibody [E30] injection). We found that the expression of the Elmo1 was significantly increased in the renal cortex and glomeruli of uninephrectomized rats injected with E30 compared to controls. By in situ hybridization, the expression of Elmo1 was shown to be elevated in the diseased kidney, especially in glomerular epithelial cells. In COS cells, the overexpression of ELMO1 resulted in a substantial increase in fibronectin expression, whereas the depletion of the ELMO1 by small interfering RNA (siRNA) targeting ELMO1 significantly suppressed the fibronectin expression in ELMO1 overexpressing and control cells. We also found that the expression of integrin-linked kinase (ILK) was significantly increased in ELMO1 overexpressing cells, and the ELMO1-induced increase in fibronectin was partially, but significantly, inhibited by siRNA targeting ILK. Furthermore, we identified that the cell adhesion to ECMs was considerably inhibited in cells overexpressing ELMO1. These results suggest that the ELMO1 contributes to the development and progression of chronic glomerular injury through the dysregulation of ECM metabolism and the reduction in cell adhesive properties to ECMs. PMID:17021600

  20. Toward Cell Selective Surfaces: Cell Adhesion and Proliferation on Breath Figures with Antifouling Surface Chemistry.

    Science.gov (United States)

    Martínez-Campos, Enrique; Elzein, Tamara; Bejjani, Alice; García-Granda, Maria Jesús; Santos-Coquillat, Ana; Ramos, Viviana; Muñoz-Bonilla, Alexandra; Rodríguez-Hernández, Juan

    2016-03-16

    We report the preparation of microporous functional polymer surfaces that have been proven to be selective surfaces toward eukaryotic cells while maintaining antifouling properties against bacteria. The fabrication of functional porous films has been carried out by the breath figures approach that allowed us to create porous interfaces with either poly(ethylene glycol) methyl ether methacrylate (PEGMA) or 2,3,4,5,6-pentafluorostyrene (5FS). For this purpose, blends of block copolymers in a polystyrene homopolymer matrix have been employed. In contrast to the case of single functional polymer, using blends enables us to vary the chemical distribution of the functional groups inside and outside the formed pores. In particular, fluorinated groups were positioned at the edges while the hydrophilic PEGMA groups were selectively located inside the pores, as demonstrated by TOF-SIMS. More interestingly, studies of cell adhesion, growth, and proliferation on these surfaces confirmed that PEGMA functionalized interfaces are excellent candidates to selectively allow cell growth and proliferation while maintaining antifouling properties. PMID:26909529

  1. A Discrete-Element Approach for Blood Cell Adhesion

    Science.gov (United States)

    Chesnutt, Jennifer; Marshall, Jeffrey

    2006-11-01

    An efficient computational model for simulation of the individual dynamics of adhering blood cells is discussed. Each cell is represented as a discrete particle so that the model can extend existing discrete-element approaches for dense particulate fluid flows to account for receptor-ligand binding of particles, elliptical particle shape, and deformation of the particles due to shear forces. Capabilities of the method in simulating large numbers of particles are illustrated through simulations of the formation of red blood cell rouleaux in shear flow. The effects of several factors, such as aspect ratio of the elliptical particle, shear rate, strength of the cell adhesion force, and hematocrit are investigated. Comparison of the discrete-element results with results of a level-set approach which computes the entire flow field about a small number of cells is used to develop an improved model of the effect of nearby red blood cells on the cell drag force expression. The method is also being applied to examine the influence of red blood cells on other components of the blood, such as platelet dispersion and activation in high shear regions.

  2. Influence of Various Pulp Properties on the Adhesion Between Tissue Paper and Yankee Cylinder Surface

    OpenAIRE

    Boudreau, Jonna; Germgård, Ulf

    2014-01-01

    The strength of the adhesion between the paper and the drying Yankee cylinder is of great importance with respect to the final properties of a tissue paper product. Therefore, the effects of a few potentially important pulp properties have been evaluated in laboratory experiments. Four highly different kraft pulps were used, and the adhesion strength was measured by means of the force required when scraping off a paper from a metal surface with a specifically designed knife mounted on a movin...

  3. Effect of Zinc and Nitric Oxide on Monocyte Adhesion to Endothelial Cells under Shear Stress

    OpenAIRE

    Lee, Sungmun; Eskin, Suzanne G.; Shah, Ankit K.; Schildmeyer, Lisa A.; McIntire, Larry V.

    2011-01-01

    This study describes the effect of zinc on monocyte adhesion to endothelial cells under different shear stress regimens, which may trigger atherogenesis. Human umbilical vein endothelial cells were exposed to steady shear stress (15 dynes/cm2 or 1 dyne/cm2) or reversing shear stress (time average 1 dyne/cm2) for 24 hours. In all shear stress regimes, zinc deficiency enhanced THP-1 cell adhesion, while heparinase III reduced monocyte adhesion following reversing shear stress exposure. Unlike o...

  4. Proteomic and phosphoproteomic analysis of signalling by adhesion and growth factor receptors in mammary epithelial cells

    OpenAIRE

    Paul, Nikki

    2014-01-01

    Cell adhesion and communication are essential for tissue morphogenesis and repair in healthy multicellular organisms. However, dysregulation of these processes can drive disease progression in conditions such as cancer. Selective cell adhesion to the extracellular matrix is mediated by integrins, a family of transmembrane receptors that compartmentalise signalling and organise the cytoskeleton. Adhesion receptors provide spatial cues to cells to allow them to respond to growth factor and cyto...

  5. Multiple effects of electroporation on the adhesive behaviour of breast cancer cells and fibroblasts

    Directory of Open Access Journals (Sweden)

    Pehlivanova Viktoria N

    2012-03-01

    Full Text Available Abstract Background Recently electroporation using biphasic pulses was successfully applied in clinical developments for treating tumours in humans and animals. We evaluated the effects of electrical treatment on cell adhesion behaviour of breast cancer cells and fibroblasts. By applying bipolar electrical pulses we studied short- and long-lived effects on cell adhesion and survival, actin cytoskeleton and cell adhesion contacts in adherent cancer cells and fibroblasts. Methods Two cancer cell lines (MDA-MB-231 and MCF-7 and one fibroblast cell line 3T3 were used. Cells were exposed to high field intensity (200 - 1000 V/cm. Cell adhesion and survival after electrical exposure were studied by crystal violet assay and MTS assay. Cytoskeleton rearrangement and cell adhesion contacts were visualized by actin staining and fluorescent microscope. Results The degree of electropermeabilization of the adherent cells elevated steadily with the increasing of the field intensity. Adhesion behaviour of fibroblasts and MCF-7 was not significantly affected by electrotreatment. Interestingly, treating the loosely adhesive cancer cell line MDA-MB-231 with 200 V/cm and 500 V/cm resulted in increased cell adhesion. Cell replication of both studied cancer cell lines was disturbed after electropermeabilization. Electroporation influenced the actin cytoskeleton in cancer cells and fibroblasts in different ways. Since it disturbed temporarily the actin cytoskeleton in 3T3 cells, in cancer cells treated with lower and middle field intensity actin cytoskeleton was well presented in stress fibers, filopodia and lamellipodia. The electrotreatment for cancer cells provoked preferentially cell-cell adhesion contacts for MCF-7 and cell-ECM contacts for MDA-MB- 231. Conclusions Cell adhesion and survival as well as the type of cell adhesion (cell-ECM or cell-cell adhesion induced by the electroporation process is cell specific. The application of suitable electric pulses can

  6. Cell surface molecules and fibronectin-mediated cell adhesion: effect of proteolytic digestion of membrane proteins

    OpenAIRE

    1982-01-01

    Proteases have been used as a tool to investigate the role of surface molecules in fibronectin-mediated cell adhesion. Proteolytic digestion of membrane-proteins by pronase (1 mg/ml for 20 min at 37 degrees C) completely inhibited adhesion of baby hamster kidney (BHK) fibroblasts on fibronectin-coated plastic dishes. Various degrees of inhibition were also obtained after treatment with proteinase K, chymotrypsin, papain, subtilopeptidase A, and thermolysin. Protein synthesis was required to r...

  7. Neural cell adhesion molecule differentially interacts with isoforms of the fibroblast growth factor receptor

    DEFF Research Database (Denmark)

    Christensen, Claus; Berezin, Vladimir; Bock, Elisabeth

    2011-01-01

    The fibroblast growth factor receptor (FGFR) can be activated through direct interactions with various fibroblast growth factors or through a number of cell adhesion molecules, including the neural cell adhesion molecule (NCAM). We produced recombinant proteins comprising the ligand...... the expression pattern of various FGFR isoforms determines the cell context-specific effects of NCAM signaling through FGFR....

  8. Loss of Cell Adhesion Increases Tumorigenic Potential of Polarity Deficient Scribble Mutant Cells.

    Directory of Open Access Journals (Sweden)

    Indrayani Waghmare

    Full Text Available Epithelial polarity genes are important for maintaining tissue architecture, and regulating growth. The Drosophila neoplastic tumor suppressor gene scribble (scrib belongs to the basolateral polarity complex. Loss of scrib results in disruption of its growth regulatory functions, and downregulation or mislocalization of Scrib is correlated to tumor growth. Somatic scribble mutant cells (scrib- surrounded by wild-type cells undergo apoptosis, which can be prevented by introduction of secondary mutations that provide a growth advantage. Using genetic tools in Drosophila, we analyzed the phenotypic effects of loss of scrib in different growth promoting backgrounds. We investigated if a central mechanism that regulates cell adhesion governs the growth and invasive potential of scrib mutant cells. Here we show that increased proliferation, and survival abilities of scrib- cells in different genetic backgrounds affect their differentiation, and intercellular adhesion. Further, loss of scrib is sufficient to cause reduced cell survival, activation of the JNK pathway and a mild reduction of cell adhesion. Our data show that for scrib cells to induce aggressive tumor growth characterized by loss of differentiation, cell adhesion, increased proliferation and invasion, cooperative interactions that derail signaling pathways play an essential role in the mechanisms leading to tumorigenesis. Thus, our study provides new insights on the effects of loss of scrib and the modification of these effects via cooperative interactions that enhance the overall tumorigenic potential of scrib deficient cells.

  9. Adhesion Properties of Plywood Glue Containing Soybean Meal as Extender

    Science.gov (United States)

    This study was conducted to evaluate the performance of soybean meal as protein extender in plywood adhesive intended for sprayline coaters. Ground soybean meal, with 51.5% (dry basis, db) crude protein and 1.5% (db) residual oil, replaced the current industry extender, wheat flour, in the standard ...

  10. Decreased cell adhesion promotes angiogenesis in a Pyk2-dependent manner

    International Nuclear Information System (INIS)

    Angiogenesis is regulated by both soluble growth factors and cellular interactions with the extracellular matrix (ECM). While cell adhesion via integrins has been shown to be required for angiogenesis, the effects of quantitative changes in cell adhesion and spreading against the ECM remain less clear. Here, we show that angiogenic sprouting in natural and engineered three-dimensional matrices exhibited a biphasic response, with peak sprouting when adhesion to the matrix was limited to intermediate levels. Examining changes in global gene expression to determine a genetic basis for this response, we demonstrate a vascular endothelial growth factor (VEGF)-induced upregulation of genes associated with vascular invasion and remodeling when cell adhesion was limited, whereas cells on highly adhesive surfaces upregulated genes associated with proliferation. To explore a mechanistic basis for this effect, we turned to focal adhesion kinase (FAK), a central player in adhesion signaling previously implicated in angiogenesis, and its homologue, proline-rich tyrosine kinase 2 (Pyk2). While FAK signaling had some impact, our results suggested that Pyk2 can regulate both gene expression and endothelial sprouting through its enhanced activation by VEGF in limited adhesion contexts. We also demonstrate decreased sprouting of tissue explants from Pyk2-null mice as compared to wild type mice as further confirmation of the role of Pyk2 in angiogenic sprouting. These results suggest a surprising finding that limited cell adhesion can enhance endothelial responsiveness to VEGF and demonstrate a novel role for Pyk2 in the adhesive regulation of angiogenesis.

  11. Alcohol inhibits cell-cell adhesion mediated by human L1 [published erratum appears in J Cell Biol 1996 Jun;133(5):1139-40

    OpenAIRE

    1996-01-01

    Mental retardation, hydrocephalus, and agenesis of the corpus callosum are observed both in fetal alcohol syndrome (FAS) and in children with mutations in the gene for the cell adhesion molecule L1. We studied the effects of ethanol on cell-cell adhesion in mouse fibroblasts transfected with human L1. L1-transfected fibroblasts exhibited increased cell-cell adhesion compared with wild-type or vector- transfected controls. Ethanol potently and completely inhibited L1- mediated adhesion both in...

  12. Direct observation of catch bonds involving cell-adhesion molecules

    Science.gov (United States)

    Marshall, Bryan T.; Long, Mian; Piper, James W.; Yago, Tadayuki; McEver, Rodger P.; Zhu, Cheng

    2003-05-01

    Bonds between adhesion molecules are often mechanically stressed. A striking example is the tensile force applied to selectin-ligand bonds, which mediate the tethering and rolling of flowing leukocytes on vascular surfaces. It has been suggested that force could either shorten bond lifetimes, because work done by the force could lower the energy barrier between the bound and free states (`slip'), or prolong bond lifetimes by deforming the molecules such that they lock more tightly (`catch'). Whereas slip bonds have been widely observed, catch bonds have not been demonstrated experimentally. Here, using atomic force microscopy and flow-chamber experiments, we show that increasing force first prolonged and then shortened the lifetimes of P-selectin complexes with P-selectin glycoprotein ligand-1, revealing both catch and slip bond behaviour. Transitions between catch and slip bonds might explain why leukocyte rolling on selectins first increases and then decreases as wall shear stress increases. This dual response to force provides a mechanism for regulating cell adhesion under conditions of variable mechanical stress.

  13. Modulation of lens cell adhesion molecules by particle beams

    Science.gov (United States)

    McNamara, M. P.; Bjornstad, K. A.; Chang, P. Y.; Chou, W.; Lockett, S. J.; Blakely, E. A.

    2001-01-01

    Cell adhesion molecules (CAMs) are proteins which anchor cells to each other and to the extracellular matrix (ECM), but whose functions also include signal transduction, differentiation, and apoptosis. We are testing a hypothesis that particle radiations modulate CAM expression and this contributes to radiation-induced lens opacification. We observed dose-dependent changes in the expression of beta 1-integrin and ICAM-1 in exponentially-growing and confluent cells of a differentiating human lens epithelial cell model after exposure to particle beams. Human lens epithelial (HLE) cells, less than 10 passages after their initial culture from fetal tissue, were grown on bovine corneal endothelial cell-derived ECM in medium containing 15% fetal bovine serum and supplemented with 5 ng/ml basic fibroblast growth factor (FGF-2). Multiple cell populations at three different stages of differentiation were prepared for experiment: cells in exponential growth, and cells at 5 and 10 days post-confluence. The differentiation status of cells was characterized morphologically by digital image analysis, and biochemically by Western blotting using lens epithelial and fiber cell-specific markers. Cultures were irradiated with single doses (4, 8 or 12 Gy) of 55 MeV protons and, along with unirradiated control samples, were fixed using -20 degrees C methanol at 6 hours after exposure. Replicate experiments and similar experiments with helium ions are in progress. The intracellular localization of beta 1-integrin and ICAM-1 was detected by immunofluorescence using monoclonal antibodies specific for each CAM. Cells known to express each CAM were also processed as positive controls. Both exponentially-growing and confluent, differentiating cells demonstrated a dramatic proton-dose-dependent modulation (upregulation for exponential cells, downregulation for confluent cells) and a change in the intracellular distribution of the beta 1-integrin, compared to unirradiated controls. In contrast

  14. Activation of AMP-activated protein kinase attenuates hepatocellular carcinoma cell adhesion stimulated by adipokine resistin

    OpenAIRE

    Yang, Chen-Chieh; Chang, Shun-Fu; Chao, Jian-Kang; Lai, Yi-Liang; Chang, Wei-En; Hsu, Wen-Hsiu; Kuo, Wu-Hsien

    2014-01-01

    Background Resistin, adipocyte-secreting adipokine, may play critical role in modulating cancer pathogenesis. The aim of this study was to investigate the effects of resistin on HCC adhesion to the endothelium, and the mechanism underlying these resistin effects. Methods Human SK-Hep1 cells were used to study the effect of resistin on intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expressions as well as NF-κB activation, and hence cell adhesion to hu...

  15. Plakophilin3 downregulation leads to a decrease in cell adhesion and promotes metastasis.

    Science.gov (United States)

    Kundu, Samrat T; Gosavi, Prajakta; Khapare, Nileema; Patel, Rachana; Hosing, Amol S; Maru, Girish B; Ingle, Arvind; Decaprio, James A; Dalal, Sorab N

    2008-11-15

    Plakophilin3 is a desmosomal plaque protein whose levels are reduced in poorly differentiated tumors of the oropharyngeal cavity and in invasive colon carcinomas. To test the hypothesis that plakophilin3 loss stimulates neoplastic progression, plakophilin3 expression was inhibited by DNA vector driven RNA interference in 3 epithelial cell lines, HCT116, HaCaT and fetal buccal mucosa. The plakophilin3-knockdown clones showed a decrease in cell-cell adhesion as assessed in a hanging drop assay, which was accompanied by an increase in cell migration. The HCT116 plakophilin3-knockdown clones showed a decrease in desmosome size as revealed by electron microscopy. These altered desmosomal properties were accompanied by colony formation in soft agar and growth to high density in culture. The HCT116-derived clones showed accelerated tumor formation in nude mice and increased metastasis to the lung, a phenotype consistent with the increased migration observed in vitro and is consistent with data from human tumors that suggests that plakophililn3 is lost in invasive and metastatic tumors. These data indicate that plakophilin3 loss leads to a decrease in cell-cell adhesion leading to the stimulation of neoplastic progression and metastasis. PMID:18729189

  16. Flavonoids inhibit cytokine-induced endothelial cell adhesion protein gene expression.

    OpenAIRE

    Gerritsen, M. E.; Carley, W. W.; Ranges, G. E.; Shen, C. P.; Phan, S. A.; Ligon, G. F.; Perry, C. A.

    1995-01-01

    Treatment of human endothelial cells with cytokines such as interleukin-1, tumor necrosis factor-alpha (TNF-alpha) or interferon-gamma induces the expression of specific leukocyte adhesion molecules on the endothelial cell surface. Interfering with either leukocyte adhesion or adhesion protein upregulation is an important therapeutic target as evidenced by the potent anti-inflammatory actions of neutralizing antibodies to these ligands in various animal models and in patients. In the present ...

  17. Inflammatory mediators and cell adhesion molecules as indicators of severity of atherosclerosis: the Rotterdam Study

    OpenAIRE

    de Maat, Moniek; Bots, Michiel; Breteler, Monique; Meijer, John; Kiliaan, Amanda; Witteman, Jacqueline; Hofman, Albert

    2002-01-01

    textabstractInflammatory mediators and soluble cell adhesion molecules predict cardiovascular events. It is not clear whether they reflect the severity of underlying atherosclerotic disease. Within the Rotterdam Study, we investigated the associations of C-reactive protein (CRP), interleukin-6 (IL-6), soluble intercellular adhesion molecule-1, and soluble vascular cell adhesion molecule-1 with noninvasive measures of atherosclerosis. Levels of CRP were assessed in a random sample of 1317 part...

  18. Activated leukocyte cell adhesion molecule expression predicts lymph node metastasis in oral squamous cell carcinoma.

    NARCIS (Netherlands)

    Brand, M. van den; Takes, R.P.; Blokpoel-deRuyter, M.; Slootweg, P.J.; Kempen, L.C.L.T. van

    2010-01-01

    Lymphatic metastasis of oral squamous cell carcinoma (SCC) is important for prognosis and clinical decision making concerning the treatment of the neck but may be difficult to detect. Activated leukocyte cell adhesion molecule (ALCAM), has been shown to correlate with prognosis or tumor grade in dif

  19. Rupture force of cell adhesion ligand tethers modulates biological activities of a cell-laden hydrogel.

    Science.gov (United States)

    Lee, Min Kyung; Park, Jooyeon; Wang, Xuefeng; Roein-Peikar, Mehdi; Ko, Eunkyung; Qin, Ellen; Lee, Jonghwi; Ha, Taekjip; Kong, Hyunjoon

    2016-04-01

    Recent efforts to design a synthetic extracellular matrix for cell culture, engineering, and therapies greatly contributed to addressing biological roles of types and spatial organization of cell adhesion ligands. It is often suggested that ligand-matrix bond strength is another path to regulate cell adhesion and activities; however tools are lacking. To this end, this study demonstrates that a hydrogel coupled with integrin-binding deoxyribonucleic acid (DNA) tethers with pre-defined rupture forces can modulate cell adhesion, differentiation, and secretion activities due to the changes in the number and, likely, force of cells adhered to a gel. The rupture force of DNA tethers was tuned by altering the spatial arrangement of matrix-binding biotin groups. The DNA tethers were immobilized on a hydrogel of alginate grafted with biotin using avidin. Mesenchymal stem cells showed enhanced adhesion, neural differentiation, and paracrine secretion when cultured on the gel coupled with DNA tethers with higher rupture forces. Such innovative cell-matrix interface engineering would be broadly useful for a series of materials used for fundamental and applied studies on biological cells. PMID:26912186

  20. N-Glycosylation at the SynCAM (Synaptic Cell Adhesion Molecule) Immunoglobulin Interface Modulates Synaptic Adhesion

    Energy Technology Data Exchange (ETDEWEB)

    A Fogel; Y Li; Q Wang; T Lam; Y Modis; T Biederer

    2011-12-31

    Select adhesion molecules connect pre- and postsynaptic membranes and organize developing synapses. The regulation of these trans-synaptic interactions is an important neurobiological question. We have previously shown that the synaptic cell adhesion molecules (SynCAMs) 1 and 2 engage in homo- and heterophilic interactions and bridge the synaptic cleft to induce presynaptic terminals. Here, we demonstrate that site-specific N-glycosylation impacts the structure and function of adhesive SynCAM interactions. Through crystallographic analysis of SynCAM 2, we identified within the adhesive interface of its Ig1 domain an N-glycan on residue Asn(60). Structural modeling of the corresponding SynCAM 1 Ig1 domain indicates that its glycosylation sites Asn(70)/Asn(104) flank the binding interface of this domain. Mass spectrometric and mutational studies confirm and characterize the modification of these three sites. These site-specific N-glycans affect SynCAM adhesion yet act in a differential manner. Although glycosylation of SynCAM 2 at Asn(60) reduces adhesion, N-glycans at Asn(70)/Asn(104) of SynCAM 1 increase its interactions. The modification of SynCAM 1 with sialic acids contributes to the glycan-dependent strengthening of its binding. Functionally, N-glycosylation promotes the trans-synaptic interactions of SynCAM 1 and is required for synapse induction. These results demonstrate that N-glycosylation of SynCAM proteins differentially affects their binding interface and implicate post-translational modification as a mechanism to regulate trans-synaptic adhesion.

  1. Antifungal Activity of Condensed Tannins from Stryphnodendron adstringens: Effect on Candida tropicalis Growth and Adhesion Properties.

    Science.gov (United States)

    Morey, Alexandre T; de Souza, Felipe C; Santos, Jussevania P; Pereira, Caibe A; Cardoso, Juscelio D; de Almeida, Ricardo S C; Costa, Marco A; de Mello, João C P; Nakamura, Celso V; Pinge-Filho, Phileno; Yamauchi, Lucy M; Yamada-Ogatta, Sueli F

    2016-01-01

    Candida species are some of the most common causes of fungal infection worldwide. The limited efficacy of clinically available antifungals warrants the search for new compounds for treating candidiasis. This study evaluated the effect of condensed tannin-rich fraction (F2 fraction) of Stryphnodendron adstringens on in vitro and in vivo growth of Candida tropicalis, and on yeast adhesion properties. F2 exhibited a fungistatic effect with the minimum inhibitory concentration ranging from 0.5 to 8.0 μg/mL. A significant reduction in biofilm mass was observed after either pretreatment of planktonic cells for 2 h (mean reduction of 46.31±8.17%) or incubation during biofilm formation (mean reduction of 28.44±13.38%) with 4x MIC of F2. Prior exposure of planktonic cells to this F2 concentration also significantly decreased yeast adherence on HEp-2 cells (mean reduction of 43.13±14.29%), cell surface hydrophobicity (mean reduction of 25.89±10.49%) and mRNA levels of the genes ALST1-3 (2.9-, 1.8- and 1.8-fold decrease, respectively). Tenebrio molitor larvae, which are susceptible to C. tropicalis infection, were used for in vivo testing. Treatment with 128 and 256 μg/mL F2 significantly increased the survival of infected larvae. These results indicate a combined effect of F2 on inhibition of yeast growth and interference in yeast adhesion, which may contribute to the suppression of infection caused by C. tropicalis, thus reinforcing the potential of the condensed tannins from S. adstringens for the development of novel antifungal agents. PMID:26696018

  2. Poldip2 controls vascular smooth muscle cell migration by regulating focal adhesion turnover and force polarization

    Science.gov (United States)

    Datla, Srinivasa Raju; McGrail, Daniel J.; Vukelic, Sasa; Huff, Lauren P.; Lyle, Alicia N.; Pounkova, Lily; Lee, Minyoung; Seidel-Rogol, Bonnie; Khalil, Mazen K.; Hilenski, Lula L.; Terada, Lance S.; Dawson, Michelle R.; Lassègue, Bernard

    2014-01-01

    Polymerase-δ-interacting protein 2 (Poldip2) interacts with NADPH oxidase 4 (Nox4) and regulates migration; however, the precise underlying mechanisms are unclear. Here, we investigated the role of Poldip2 in focal adhesion turnover, as well as traction force generation and polarization. Poldip2 overexpression (AdPoldip2) in vascular smooth muscle cells (VSMCs) impairs PDGF-induced migration and induces a characteristic phenotype of long cytoplasmic extensions. AdPoldip2 also prevents the decrease in spreading and increased aspect ratio observed in response to PDGF and slightly impairs cell contraction. Moreover, AdPoldip2 blocks focal adhesion dissolution and sustains H2O2 levels in focal adhesions, whereas Poldip2 knockdown (siPoldip2) significantly decreases the number of focal adhesions. RhoA activity is unchanged when focal adhesion dissolution is stimulated in control cells but increases in AdPoldip2-treated cells. Inhibition of RhoA blocks Poldip2-mediated attenuation of focal adhesion dissolution, and overexpression of RhoA or focal adhesion kinase (FAK) reverses the loss of focal adhesions induced by siPoldip2, indicating that RhoA and FAK mediate the effect of Poldip2 on focal adhesions. Nox4 silencing prevents focal adhesion stabilization by AdPoldip2 and induces a phenotype similar to siPoldip2, suggesting a role for Nox4 in Poldip2-induced focal adhesion stability. As a consequence of impaired focal adhesion turnover, PDGF-treated AdPoldip2 cells are unable to reduce and polarize traction forces, a necessary first step in migration. These results implicate Poldip2 in VSMC migration via regulation of focal adhesion turnover and traction force generation in a Nox4/RhoA/FAK-dependent manner. PMID:25063792

  3. Durability properties for adhesively bonded structural aerospace applications

    International Nuclear Information System (INIS)

    This paper reports on the importance of good bond durability of adhesively joined aerospace components which has been recognized for many years. Military and civilian aircraft are exposed to harsh environments in addition to severe thermal and stress cycles during their service lives. Moisture is responsible for the majority of bond failures in the field. The presence of surface contaminants (e.g., fluoride, silicones) and the non-neutral pH of poor rinse water are common causes of adhesion problems in production environments. Honeycomb panels, stringer skins, doubler plates and core cowl assemblies are bonded joint structures that are subject to environmental- or contaminant-induced debonding. The identification and characterization of the causes of such bond failures leads to improved production quality, yield and cost reduction

  4. Micro patterning of cell and protein non-adhesive plasma polymerized coatings for biochip applications

    DEFF Research Database (Denmark)

    Bouaidat, Salim; Berendsen, C.; Thomsen, P.;

    2004-01-01

    Micro scale patterning of bioactive surfaces is desirable for numerous biochip applications. Polyethyleneoxide-like (PEO-like) coating with non-fouling functionality has been deposited using low frequency AC plasma polymerization. The non-fouling properties of the coating were tested with human...... cells ( HeLa) and fluorescence labeled proteins (isothiocyanate-labeled bovine serum albumin, i.e. FITC-BSA). The PEO-like coatings were fabricated by plasma polymerization of 12-crown-4 (ppCrown) with plasma polymerized hexene (ppHexene) as adhesion layer. The coatings were micro patterned using...

  5. Energy investigations on the adhesive properties of Al/TiC interfaces: First-principles study

    International Nuclear Information System (INIS)

    The work of adhesion and interface energy of Al(100)/TiC(100) and Al(110)/TiC(110) coherent interface systems have been investigated by first-principles methods. To account for the effects of misfit dislocations on the semicoherent interfaces, the Peierls–Nabarro model combined with generalized stacking fault energy is employed to determine interface energy. The energy level diagrams are introduced to describe the adhesive properties of coherent and semicoherent interfaces. It is found that misfit dislocations can reduce the adhesion of interface, and the reduction is increasing with the unstable stacking fault energy

  6. Loss of MLCK leads to disruption of cell-cell adhesion and invasive behavior of breast epithelial cells via increased expression of EGFR and ERK/JNK signaling.

    Science.gov (United States)

    Kim, D Y; Helfman, D M

    2016-08-25

    Myosin light chain kinase (MLCK) expression is downregulated in breast cancer, including invasive ductal carcinoma compared with ductal breast carcinoma in situ and metastatic breast tumors. However, little is known about how loss of MLCK expression contributes to tumor progression. MLCK is a component of the actin cytoskeleton and its known role is the phosphorylation of the regulatory light chain of myosin II. To gain insights into the role of MLCK in breast cancer, we perturbed its function using small interfering RNA (siRNA) or pharmacological inhibition in untransformed breast epithelial cells (MCF10A). Loss of MLCK by siRNAs led to increased cell migration and invasion, disruption of cell-cell adhesions and enhanced formation of focal adhesions at the leading edge of migratory cells. In addition, downregulation of MLCK cooperated with HER2 in MCF10A cells to promote cell migration and invasion and low levels of MLCK is associated with a poor prognosis in HER2-positive breast cancer patients. Associated with these altered migratory behaviors were increased expression of epidermal growth factor receptor and activation of extracellular signal-regulated kinase and c-Jun N-terminal kinase signaling pathways in MLCK downregulated MCF10A cells. By contrast, inhibition of the kinase function of MLCK using pharmacological agents inhibited cell migration and invasion, and did not affect cellular adhesions. Our results show that loss of MLCK contributes to the migratory properties of epithelial cells resulting from changes in cell-cell and cell-matrix adhesions, and increased epidermal growth factor receptor signaling. These findings suggest that decreased expression of MLCK may have a critical role during tumor progression by facilitating the metastatic potential of tumor cells. PMID:26876209

  7. Polymer surface properties and their effect on the adhesion of Proteus mirabilis.

    Science.gov (United States)

    Downer, A; Morris, N; Feast, W J; Stickler, D

    2003-01-01

    A problem encountered in patients undergoing long-term catheterization of the urinary tract is that of encrustation and blockage of the catheter by crystalline bacterial biofilms. This is principally caused by the action of the urease-producing pathogen Proteus mirabilis. A major aim of this work is to develop materials resistant to encrustation. Here, the effects of polymer surface properties on the adhesion of P. mirabilis are examined. Spin-coated polymer films were characterized through contact angle measurements to give the Lifschitz-van der Waals, electron acceptor and electron donor terms of the surface free energy, gamma(s)LW, gamma(s)+ and gamma(s)- respectively. A parallel-plate flow cell was used to assess adhesion to these polymer films of P. mirabilis suspended in an aqueous phosphate buffer, pH 7.4, ionic strength 0.26 mol/kg. P. mirabilis was found to adhere significantly less (p < 0.02) to films of agarose, poly(2-hydroxyethylmethacrylate) and cross-linked poly(vinyl alcohol) than to more hydrophobic materials. These polymer films were found to be strongly electron donating, i.e. possessing large gamma(s)-. Films examined using scanning electron microscopy mostly showed no evidence of roughness down to a scale of 1-10 microm. The better performance is thought to be due to a repulsive interaction with the bacterial surface caused by acid/base-type interactions. PMID:12885198

  8. Mechanical Properties and Adhesion of a Micro Structured Polymer Blend

    Directory of Open Access Journals (Sweden)

    Brunero Cappella

    2011-07-01

    Full Text Available A 50:50 blend of polystyrene (PS and poly(n-butyl methacrylate (PnBMA has been characterized with an Atomic Force Microscope (AFM in Tapping Mode and with force-distance curves. The polymer solution has been spin-coated on a glass slide. PnBMA builds a uniform film on the glass substrate with a thickness of @200 nm. On top of it, the PS builds an approximately 100 nm thick film. The PS-film undergoes dewetting, leading to the formation of holes surrounded by about 2 µm large rims. In those regions of the sample, where the distance between the holes is larger than about 4 µm, light depressions in the PS film can be observed. Topography, dissipated energy, adhesion, stiffness and elastic modulus have been measured on these three regions (PnBMA, PS in the rims and PS in the depressions. The two polymers can be distinguished in all images, since PnBMA has a higher adhesion and a smaller stiffness than PS, and hence a higher dissipated energy. Moreover, the polystyrene in the depressions shows a very high adhesion (approximately as high as PnBMA and its stiffness is intermediate between that of PnBMA and that of PS in the rims. This is attributed to higher mobility of the PS chains in the depressions, which are precursors of new holes.

  9. Integrin-mediated adhesion of human mesenchymal stem cells to extracellular matrix proteins adsorbed to polymer surfaces

    International Nuclear Information System (INIS)

    In vitro, degradable aliphatic polyesters are widely used as cell carriers for bone tissue engineering, despite their lack of biological cues. Their biological active surface is rather determined by an adsorbed layer of proteins from the surrounding media. Initial cell fate, including adhesion and proliferation, which are key properties for efficient cell carriers, is determined by the adsorbed layer of proteins. Herein we have investigated the ability of human bone marrow derived stem cells (hBMSC) to adhere to extracellular matrix (ECM) proteins, including fibronectin and vitronectin which are present in plasma and serum. hBMSC expressed integrins for collagens, laminins, fibronectin and vitronectin. Accordingly, hBMSC strongly adhered to these purified ECM proteins by using the corresponding integrins. Although purified fibronectin and vitronectin adsorbed to aliphatic polyesters to a lower extent than to cell culture polystyrene, these low levels were sufficient to mediate adhesion of hBMSC. It was found that plasma- and serum-coated polystyrene adsorbed significant levels of both fibronectin and vitronectin, and fibronectin was identified as the major adhesive component of plasma for hBMSC; however, aliphatic polyesters adsorbed minimal levels of fibronectin under similar conditions resulting in impaired cell adhesion. Altogether, the results suggest that the efficiency of aliphatic polyesters cell carriers could be improved by increasing their ability to adsorb fibronectin. (paper)

  10. Reinforcing endothelial junctions prevents microvessel permeability increase and tumor cell adhesion in microvessels in vivo

    Science.gov (United States)

    Fu, Bingmei M.; Yang, Jinlin; Cai, Bin; Fan, Jie; Zhang, Lin; Zeng, Min

    2015-10-01

    Tumor cell adhesion to the microvessel wall is a critical step during tumor metastasis. Vascular endothelial growth factor (VEGF), a secretion of tumor cells, can increase microvessel permeability and tumor cell adhesion in the microvessel. To test the hypothesis that inhibiting permeability increase can reduce tumor cell adhesion, we used in vivo fluorescence microscopy to measure both microvessel permeability and adhesion rates of human mammary carcinoma MDA-MB-231 cells in post-capillary venules of rat mesentery under the treatment of VEGF and a cAMP analog, 8-bromo-cAMP, which can decrease microvessel permeability. By immunostaining adherens junction proteins between endothelial cells forming the microvessel wall, we further investigated the structural mechanism by which cAMP abolishes VEGF-induced increase in microvessel permeability and tumor cell adhesion. Our results demonstrate that 1) Pretreatment of microvessels with cAMP can abolish VEGF-enhanced microvessel permeability and tumor cell adhesion; 2) Tumor cells prefer to adhere to the endothelial cell junctions instead of cell bodies; 3) VEGF increases microvessel permeability and tumor cell adhesion by compromising endothelial junctions while cAMP abolishes these effects of VEGF by reinforcing the junctions. These results suggest that strengthening the microvessel wall integrity can be a potential approach to inhibiting hematogenous tumor metastasis.

  11. Effects of Different Hardeners on the Working Properties and Bonding Strength of Urea-formaldehyde Adhesives

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The addition of a hardener is necessary for the curing of urea-formaldehyde (UF) adhesives in the production of MDF and particleboard. The most commonly used hardener, ammonium chloride, however, is suspected to cause the formation of poisonous dioxin when waste boards are combusted and hence considered as a potential source of pollution. To assess the feasibility of substituting ammonium sulphate for ammonium chloride, working properties and bonding strength were measured for UF adhesives with the two ...

  12. Adhesion and osteogenic differentiation of human mesenchymal stem cells on titanium nanopores

    Directory of Open Access Journals (Sweden)

    S Lavenus

    2011-08-01

    Full Text Available Titanium implants are widely used in orthopaedic and dental surgery. Surface properties play a major role in cell and tissue interactions. The adhesion and differentiation of mesenchymal stem cells were studied as a function of nanostructures. Titanium surfaces with nanopores 30, 150 and 300 nm in diameter were prepared by physical vapour deposition. PCR arrays indicated that the expression of integrins was modulated by the nanopore size. Human Mesenchymal Stem Cells (hMSCs exhibited more branched cell morphology on Ti30 than on other surfaces. Ti30 and Ti150 induced osteoblastic differentiation while Ti300 had a limited effect. Overall, nanopores of 30 nm may promote early osteoblastic differentiation and, consequently, rapid osseointegration of titanium implants.

  13. Micropatterning of poly(4-hydroxystyrene) by ion beam contact lithography for the control of cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, In Tae; Jung, Chan Hee; Choi, Jae Hak; Nho, Young Chang [Korea Atomic Energy Research Institte, Daejeon (Korea, Republic of); Lee, Byoung Min; Hong, Sung Kwon [Chungnam National University, Daejeon (Korea, Republic of)

    2009-06-15

    In this study, we report on a simple method of micropatterning of cells by using ion beam contact lithography. Thin poly(4-hydroxystyrene) (Phds) films spin-coated on a silicon wafer were irradiated through a pattern mask in a contact mode with proton ions and then developed to generate the patterns of the Phds. Well-defined 50 {mu}m line (pitch 150 {mu}m) patterns were obtained without using any additives. The remaining thickness after development was increased with an increasing fluence up to 3 x 10{sup 14} ions cm{sup -2} after which it leveled off. The in-vitro cell culture test revealed that the cells were preferentially adhered to and proliferated only on the space regions between the Phds line patterns. Inhibition of cell adhesion on the Phds patterns could be due to antifouling property of the irradiated PHS.

  14. Micropatterning of poly(4-hydroxystyrene) by ion beam contact lithography for the control of cell adhesion

    International Nuclear Information System (INIS)

    In this study, we report on a simple method of micropatterning of cells by using ion beam contact lithography. Thin poly(4-hydroxystyrene) (Phds) films spin-coated on a silicon wafer were irradiated through a pattern mask in a contact mode with proton ions and then developed to generate the patterns of the Phds. Well-defined 50 μm line (pitch 150 μm) patterns were obtained without using any additives. The remaining thickness after development was increased with an increasing fluence up to 3 x 1014 ions cm-2 after which it leveled off. The in-vitro cell culture test revealed that the cells were preferentially adhered to and proliferated only on the space regions between the Phds line patterns. Inhibition of cell adhesion on the Phds patterns could be due to antifouling property of the irradiated PHS

  15. Laminin-dependent and laminin-independent adhesion of human melanoma cells to sulfatides

    DEFF Research Database (Denmark)

    Roberts, D D; Wewer, U M; Liotta, L A; Ginsburg, V

    1988-01-01

    Sulfatides (galactosylceramide-I3-sulfate) but not neutral glycolipids or gangliosides adsorbed on plastic promote adhesion of the human melanoma cell line G361. Direct adhesion of G361 cells requires densities of sulfatide greater than 1 pmol/mm2. In the presence of laminin, however, specific...

  16. Selective cell adhesion inhibitors: Barbituric acid based alpha4beta7--MAdCAM inhibitors.

    Science.gov (United States)

    Harriman, Geraldine C; Brewer, Matthias; Bennett, Robert; Kuhn, Cyrille; Bazin, Marc; Larosa, Greg; Skerker, Paul; Cochran, Nancy; Gallant, Debra; Baxter, Deborah; Picarella, Dominic; Jaffee, Bruce; Luly, Jay R; Briskin, Michael J

    2008-04-01

    A novel series of barbituric acid derivatives were identified as selective inhibitors of alpha4beta7 MAdCAM (mucosal addressin cell adhesion molecule-1) interactions via a high throughput screening exercise. These inhibitors were optimized to submicromolar potencies in whole cell adhesion assays, retaining their selectivity over alpha4beta1 VCAM. PMID:18331794

  17. Non-viral gene delivery regulated by stiffness of cell adhesion substrates

    Science.gov (United States)

    Kong, Hyun Joon; Liu, Jodi; Riddle, Kathryn; Matsumoto, Takuya; Leach, Kent; Mooney, David J.

    2005-06-01

    Non-viral gene vectors are commonly used for gene therapy owing to safety concerns with viral vectors. However, non-viral vectors are plagued by low levels of gene transfection and cellular expression. Current efforts to improve the efficiency of non-viral gene delivery are focused on manipulations of the delivery vector, whereas the influence of the cellular environment in DNA uptake is often ignored. The mechanical properties (for example, rigidity) of the substrate to which a cell adheres have been found to mediate many aspects of cell function including proliferation, migration and differentiation, and this suggests that the mechanics of the adhesion substrate may regulate a cell's ability to uptake exogeneous signalling molecules. In this report, we present a critical role for the rigidity of the cell adhesion substrate on the level of gene transfer and expression. The mechanism relates to material control over cell proliferation, and was investigated using a fluorescent resonance energy transfer (FRET) technique. This study provides a new material-based control point for non-viral gene therapy.

  18. The Cell Adhesion-associated Protein Git2 Regulates Morphogenetic Movements during Zebrafish Embryonic Development

    OpenAIRE

    Yu, Jianxin A.; Foley, Fiona C.; Amack, Jeffrey D.; Christopher E Turner

    2010-01-01

    Signaling through cell adhesion complexes plays a critical role in coordinating cytoskeletal remodeling necessary for efficient cell migration. During embryonic development, normal morphogenesis depends on a series of concerted cell movements; but the roles of cell adhesion signaling during these movements are poorly understood. The transparent zebrafish embryo provides an excellent system to study cell migration during development. Here, we have identified zebrafish git2a and git2b, two new ...

  19. Surface grafting of carboxylic groups onto thermoplastic polyurethanes to reduce cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Alves, P., E-mail: palves@eq.uc.pt [CIEPQPF, Departamento de Engenharia Química, Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-790 Coimbra (Portugal); Ferreira, P. [CIEPQPF, Departamento de Engenharia Química, Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-790 Coimbra (Portugal); Kaiser, Jean-Pierre [EMPA, St. Gallen, Lerchenfeldstrasse 5, CH-9014 St. Gallen (Switzerland); Salk, Natalie [Mikrofertigung – Micro Engineering, Fraunhofer IFAM, Wiener Strasse 12, D-288359 Bremen (Germany); Bruinink, Arie [EMPA, St. Gallen, Lerchenfeldstrasse 5, CH-9014 St. Gallen (Switzerland); Sousa, Hermínio C. de; Gil, M.H. [CIEPQPF, Departamento de Engenharia Química, Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-790 Coimbra (Portugal)

    2013-10-15

    The interaction of polymers with other materials is an important issue, being their surface properties clearly crucial. For some important polymer applications, their surfaces have to be modified. Surface modification aims to tailor the surface characteristics of a material for a specific application without affecting its bulk properties. Materials can be surface modified by using biological, chemical or physical methods. The aim of this work was to improve the reactivity of the thermoplastic polyurethane (TPU) material (Elastollan{sup ®}) surface and to make its surface cell repellent by grafting carboxylic groups onto its surface. Two TPU materials were studied: a polyether-based TPU and a polyester-based TPU. The grafting efficiency was evaluated by contact angle measurements and by analytical determination of the COOH groups. Scanning electron microscopy (SEM) of the membranes surface was performed as well as cell adhesion tests. It was proved that the surfaces of the TPUs membranes were successfully modified and that cell adhesion was remarkably reduced.

  20. Dennexin peptides modeled after the homophilic binding sites of the neural cell adhesion molecule (NCAM) promote neuronal survival, modify cell adhesion and impair spatial learning

    DEFF Research Database (Denmark)

    Køhler, Lene B; Christensen, Claus; Rossetti, Clara; Fantin, Martina; Sandi, Carmen; Bock, Elisabeth; Berezin, Vladimir

    2010-01-01

    Neural cell adhesion molecule (NCAM)-mediated cell adhesion results in activation of intracellular signaling cascades that lead to cellular responses such as neurite outgrowth, neuronal survival, and modulation of synaptic activity associated with cognitive processes. The crystal structure of the...... between Ig1 and Ig3 and between Ig2 and Ig2, respectively, observed in the crystal structure. Although the two dennexin peptides differed in amino acid sequence, they both modulated cell adhesion, reflected by inhibition of NCAM-mediated neurite outgrowth. Both dennexins also promoted neuronal survival...... immunoglobulin (Ig) 1-2-3 fragment of the NCAM ectodomain has revealed novel mechanisms for NCAM homophilic adhesion. The present study addressed the biological significance of the so called dense zipper formation of NCAM. Two peptides, termed dennexinA and dennexinB, were modeled after the contact interfaces...

  1. Dependence of the initial adhesion of biofilm forming Pseudomonas putida mt2 on physico-chemical material properties.

    Science.gov (United States)

    Montag, Dominik; Frant, Marion; Horn, Harald; Liefeith, Klaus

    2012-01-01

    Bacterial adhesion is strongly dependent on the physico-chemical properties of materials and plays a fundamental role in the development of a growing biofilm. Selected materials were characterized with respect to their physico-chemical surface properties. The different materials, glass and several polymer foils, showed a stepwise range of surface tensions (γ(s)) between 10.3 and 44.7 mN m(-1). Measured zeta potential values were in the range between -74.8 and -28.3 mV. The initial bacterial adhesion parameter q(max) was found to vary between 6.6 × 10(6) and 28.1 × 10(6) cm(-2). By correlation of the initial adhesions kinetic parameters with the surface tension data, the optimal conditions for the immobilization of Pseudomonas putida mt2 were found to be at a surface tension of 24.7 mN m(-1). Both higher and lower surface tensions lead to a smaller number of adherent cells per unit surface area. Higher energy surfaces, commonly termed hydrophilic, could constrain bacterial adhesion because of their more highly ordered water structure (exclusion zone) close to the surface. At low energy surfaces, commonly referred to as hydrophobic, cell adhesion is inhibited due to a thin, less dense zone (depletion layer or clathrate structure) close to the surface. Correlation of q (max) with zeta potential results in a linear relationship. Since P. putida carries weak negative charges, a measurable repulsive effect can be assumed on negative surfaces. PMID:22452391

  2. Controlling Gel Structure to Modulate Cell Adhesion and Spreading on the Surface of Microcapsules.

    Science.gov (United States)

    Zheng, Huizhen; Gao, Meng; Ren, Ying; Lou, Ruyun; Xie, Hongguo; Yu, Weiting; Liu, Xiudong; Ma, Xiaojun

    2016-08-01

    The surface properties of implanted materials or devices play critical roles in modulating cell behavior. However, the surface properties usually affect cell behaviors synergetically so that it is still difficult to separately investigate the influence of a single property on cell behavior in practical applications. In this study, alginate-chitosan (AC) microcapsules with a dense or loose gel structure were fabricated to understand the effect of gel structure on cell behavior. Cells preferentially adhered and spread on the loose gel structure microcapsules rather than on the dense ones. The two types of microcapsules exhibited nearly identical surface positive charges, roughness, stiffness, and hydrophilicity; thus, the result suggested that the gel structure was the principal factor affecting cell behavior. X-ray photoelectron spectroscopy analyses demonstrated that the overall percentage of positively charged amino groups was similar on both microcapsules. The different gel structures led to different states and distributions of the positively charged amino groups of chitosan, so we conclude that the loose gel structure facilitated greater cell adhesion and spreading mainly because more protonated amino groups remained unbound and exposed on the surface of these microcapsules. PMID:27404911

  3. Transfection of glioma cells with the neural-cell adhesion molecule NCAM

    DEFF Research Database (Denmark)

    Edvardsen, K; Pedersen, P H; Bjerkvig, R; Hermann, G G; Zeuthen, J; Laerum, O D; Walsh, F S; Bock, E

    1994-01-01

    The tumor growth and the invasive capacity of a rat glioma cell line (BT4Cn) were studied after transfection with the human transmembrane 140-kDa isoform of the neural-cell adhesion molecule, NCAM. After s.c. injection, the NCAM-transfected cells showed a slower growth rate than the parent cell...... line (BT4Cn). Upon intracerebral implantation with BT4Cn cells and different clones of NCAM-transfected cells, all animals developed neurological symptoms within 13-16 days. However, the tumors showed different growth characteristics. The NCAM-transfected BT4Cn cells were localized in the region of the...

  4. Nitric Oxide Inhibits Hetero-adhesion of Cancer Cells to Endothelial Cells: Restraining Circulating Tumor Cells from Initiating Metastatic Cascade

    Science.gov (United States)

    Lu, Yusheng; Yu, Ting; Liang, Haiyan; Wang, Jichuang; Xie, Jingjing; Shao, Jingwei; Gao, Yu; Yu, Suhong; Chen, Shuming; Wang, Lie; Jia, Lee

    2014-03-01

    Adhesion of circulating tumor cells (CTCs) to vascular endothelial bed becomes a crucial starting point in metastatic cascade. We hypothesized that nitric oxide (NO) may prevent cancer metastasis from happening by its direct vasodilation and inhibition of cell adhesion molecules (CAMs). Here we show that S-nitrosocaptopril (CAP-NO, a typical NO donor) produced direct vasorelaxation that can be antagonized by typical NO scavenger hemoglobin and guanylate cyclase inhibitor. Cytokines significantly stimulated production of typical CAMs by the highly-purified human umbilical vein endothelial cells (HUVECs). CAP-NO inhibited expression of the stimulated CAMs (particularly VCAM-1) and the resultant hetero-adhesion of human colorectal cancer cells HT-29 to the HUVECs in a concentration-dependent manner. The same concentration of CAP-NO, however, did not significantly affect cell viability, cell cycle and mitochondrial membrane potential of HT-29, thus excluding the possibility that inhibition of the hetero-adhesion was caused by cytotoxicity by CAP-NO on HT-29. Hemoglobin reversed the inhibition of CAP-NO on both the hetero-adhesion between HT-29 and HUVECs and VCAM-1 expression. These data demonstrate that CAP-NO, by directly releasing NO, produces vasorelaxation and interferes with hetero-adhesion of cancer cells to vascular endothelium via down-regulating expression of CAMs. The study highlights the importance of NO in cancer metastatic prevention.

  5. Cell adhesion to agrin presented as a nanopatterned substrate is consistent with an interaction with the extracellular matrix and not transmembrane adhesion molecules

    OpenAIRE

    Wolfram Tobias; Spatz Joachim P; Burgess Robert W

    2008-01-01

    Abstract Background Molecular spacing is important for cell adhesion in a number of ways, ranging from the ordered arrangement of matrix polymers extracellularly, to steric hindrance of adhesion/signaling complexes intracellularly. This has been demonstrated using nanopatterned RGD peptides, a canonical extracellular matrix ligand for integrin interactions. Cell adhesion was greatly reduced when the RGD-coated nanoparticles were separated by more than 60 nm, indicating a sharp spacing-depende...

  6. Tyrosine Phosphorylation of CD13 Regulates Inflammatory Cell-Cell Adhesion and Monocyte Trafficking

    OpenAIRE

    Subramani, Jaganathan; Ghosh, Mallika; Rahman, M. Mamunur; Caromile, Leslie A.; Gerber, Claire; Rezaul, Karim; David K. Han; Shapiro, Linda H.

    2013-01-01

    CD13 is a large cell surface peptidase expressed on the monocytes and activated endothelial cells important for homing to and resolving the damaged tissue at sites of injury. We have previously shown that crosslinking of human monocytic CD13 with activating antibodies induces strong adhesion to endothelial cells in a tyrosine kinase- and microtubule-dependent manner. In the current study we examined the molecular mechanisms underlying these observations in vitro and in vivo. We found that cro...

  7. Red cell adhesion molecules, foetal haemoglobin and endothelial factors in sickle cell disorders

    OpenAIRE

    Mundee, Y.

    2001-01-01

    Sickle cell anaemia (SS) is a haemoglobinopathy involving production of sickle haemoglobin (HbS, β⁶Glu-->Val), which is able to polymerise leading to vaso-occlusion. Hydroxyurea (HU) treatment increases foetal haemoglobin (HbF) levels but decreases vaso-occlusion and red cell adhesion molecule (AM) expression, and therefore improves clinical symptoms. In this thesis, the contribution of AMs, HbF and endothelial factors to the severity of sickle cell disease has been studied....

  8. Cysteine-rich domain of human ADAM 12 (meltrin alpha) supports tumor cell adhesion

    DEFF Research Database (Denmark)

    Iba, K; Albrechtsen, R; Gilpin, B J;

    1999-01-01

    tumor cell adhesion. We found that the disintegrin-like domain of human ADAM 15 supported adhesion of alphavbeta3-expressing A375 melanoma cells. In the case of human ADAM 12, however, recombinant polypeptides of the cysteine-rich domain but not the disintegrin-like domain supported cell adhesion of a...... panel of carcinoma cell lines. On attachment to recombinant polypeptides from the cysteine-rich domain of human ADAM 12, most tumor cell lines, such as MDA-MB-231 breast carcinoma cells, were rounded and associated with numerous actin-containing filopodia and used a cell surface heparan sulfate...... proteoglycan to attach. Finally, we demonstrated that authentic full-length human ADAM 12 could bind to heparin Sepharose. Together these results suggest a novel role of the cysteine-rich domain of ADAM 12 -- that of supporting tumor cell adhesion....

  9. Strong adhesion of Saos-2 cells to multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Makoto, E-mail: matsuoka@den.hokudai.ac.jp [Department of Oral and Maxillofacial Surgery, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Akasaka, Tsukasa [Department of Dental Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Totsuka, Yasunori [Department of Oral and Maxillofacial Surgery, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan); Watari, Fumio [Department of Dental Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Kita 13 Nishi 7, Kita-ku, Sapporo 060-8586 (Japan)

    2010-10-15

    In recent years, carbon nanotubes (CNTs) have been considered potential biomedical materials because of their unique character. The aim of this study was to investigate the response of a human osteoblast-like cell line - Saos-2 - on single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs). The surface of a culture dish was coated with CNTs, and Saos-2 cells were cultured for three days. Cell morphology, viability, alkaline phosphatase (ALP) activity, adhesion, and vinculin expression were evaluated. The result showed high cell viability and strong adhesion to MWCNTs. Saos-2 cultured on MWCNTs exhibited vinculin expression throughout the cell body, while the cells attached to SWCNTs and glass were mostly limited to their periphery. Our results suggest that CNT coatings promote cell activity and adhesiveness. These findings indicate that MWCNTs could be used as surface coating materials to promote cell adhesion.

  10. Antigenic variation of pilin regulates adhesion of Neisseria meningitidis to human epithelial cells.

    Science.gov (United States)

    Nassif, X; Lowy, J; Stenberg, P; O'Gaora, P; Ganji, A; So, M

    1993-05-01

    Pili have been shown to play an essential role in the adhesion of Neisseria meningitidis to epithelial cells. However, among piliated strains, both inter- and intrastrain variability exist with respect to their degree of adhesion to epithelial cells in vitro (Virji et al., 1992). This suggests that factors other than the presence of pili per se are involved in this process. The N. meningitidis pilin subunit undergoes extensive antigenic variation. Piliated low- and high-adhesive derivatives of the same N. meningitidis strain were selected and the nucleotide sequence of the pilin gene expressed in each was determined. The highly adhesive derivatives had the same pilin sequence. The alleles encoding the pilin subunit of the low-adhesive derivatives were completely different from the one found in the high-adhesive isolates. Using polyclonal antibodies raised against one hyperadhesive variant, it was confirmed that the low-adhesive piliated derivatives expressed pilin variants antigenically different from the highly adhesive strains. The role of antigenic variation in the adhesive process of N. meningitidis was confirmed by performing allelic exchanges of the pilE locus between low- and high-adhesive isolates. Antigenic variation has been considered a means by which virulent bacteria evade the host immune system. This work provides genetic proof that a bacterial pathogen, N. meningitidis, can use antigenic variation to modulate their degree of virulence. PMID:8332064

  11. The effect of graphene substrate on osteoblast cell adhesion and proliferation.

    Science.gov (United States)

    Aryaei, Ashkan; Jayatissa, Ahalapitiya H; Jayasuriya, Ambalangodage C

    2014-09-01

    Understanding the effect of graphene substrate on graphene-cell interaction is important for considering graphene as a potential candidate for biomedical applications. In this article, biocompatibility of few layers of graphene film transferred to different substrates was evaluated using osteoblasts. The substrates were oxidized silicon wafer (SiO2/Si stack), soda lime glass, and stainless steel. Chemical vapor deposition method was employed to synthesize graphene on copper substrate using methane and hydrogen as precursors. The quality and the thickness of graphene films on different substrates were estimated by Raman spectra, whereas the thickness of graphene film was confirmed by reflectance and transmittance spectroscopy. The study was also focused on cell attachment and morphology at two time points. The results show that graphene does not have any toxic effect on osteoblasts. The cell adhesion improves with graphene coated substrate than the substrate alone. It seems that graphene substrate properties play a dominant role in cell adhesion. The result of this study suggests that a layer of graphene on bone implants will be beneficial for osteoblast attachment and proliferation. PMID:24178155

  12. Cell adhesion molecules involved in the leukocyte recruitment induced by venom of the snake Bothrops jararaca

    OpenAIRE

    Catarina F. P. Teixeira; Stella R. Zamuner

    2002-01-01

    It has been shown that Bothrops jararaca venom (BjV) induces a significant leukocyte accumulation, mainly neutrophils, at the local of tissue damage. Therefore, the role of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1), LECAM-1, CD18, leukocyte function-associated antigen-1 (LFA-1) and platelet endothelial cell adhesion molecule-1 (PECAM-1) on the BjV-induced neutrophil accumulation and the correlation with release of LTB4, TXA2, tumor necrosis factor-alpha, interleukin (I...

  13. Evaluation of the Correlation between Focal Adhesion Kinase Phosphorylation and Cell Adhesion Force Using “DEP” Technology

    Directory of Open Access Journals (Sweden)

    Huaang-Youh Hurng

    2012-05-01

    Full Text Available Dielectrophoresis (DEP is the phenomenon in which a particle, such as a living cell, is polarized and moved by electrical gravity in a non-uniform electric field. In the present study, the DEP force is utilized to act on the cells to induce spatial movement for investigating the correlation between the cell adhesion force and activation level of focal adhesion kinase (FAK. The DEP force produced by the non-uniform electric field was used to measure the cell adhesion force of ECV304 cells, on type 1 collagen (COL1- and fibronectin (FN-coated polydimethylsiloxane (PDMS membranes. For COL1-coating, ECV304 cells revealed weak and variable adhesion force (0.343–0.760 nN in the first eight hours of incubation. Interestingly, the cell adhesion force of ECV304 at two and five hours of cultivation was significantly high and matched their FAK activation level. In comparison, ECV304 on FN-coated membrane had higher and more stable cell adhesion force (0.577–2.053 nN. FN coating intensified the cell adhesion force of ECV304 with culture time and similar outcome was present on the activation level of FAK. Therefore, this study demonstrated a relationship between cell adhesion force and FAK activation level that was dependant on the choice of the extracellular matrix (ECM component. Subsequently, two tyrosine kinase inhibitors (AG18 and genistein and one PI3K inhibitor (LY294002 were applied to study the influence of protein phosphorylation on the cell adhesion force. FAK plays an important role on cell attachment and DEP force measurement is a useful technique for studying cell adhesion.

  14. Embedded proteins and sacrificial bonds provide the strong adhesive properties of gastroliths.

    Science.gov (United States)

    Thormann, Esben; Mizuno, Hiroyasu; Jansson, Kjell; Hedin, Niklas; Fernández, M Soledad; Arias, José Luis; Rutland, Mark W; Pai, Ranjith Krishna; Bergström, Lennart

    2012-07-01

    The adhesive properties of gastroliths from a freshwater crayfish (Cherax quadricarinatus) were quantified by colloidal probe atomic force microscopy (AFM) between heavily demineralized gastrolith microparticles and gastrolith substrates of different composition. Combined AFM and transmission electron microscopy studies demonstrated that the sequential detachment and large adhesion energies that characterise the adhesive behaviour of a native gastrolith substrate are dominated by sacrificial bonds between chitin fibres and between chitin fibres and CaCO(3). The sacrificial bonds were shown to be strongly related to the gastrolith proteins and when the majority of these proteins were removed by ethylenediaminetetraacetic acid (EDTA), the sequential detachment disappeared and the adhesive energy was reduced by more than two orders of magnitude. PMID:22653376

  15. Polyglycerol dendrimers immobilized on radiation grafted poly-HEMA hydrogels: Surface chemistry characterization and cell adhesion

    International Nuclear Information System (INIS)

    Radiation induced grafting of poly(2-hydroxyethylmethacrylate) (PHEMA) on low density polyethylene (LDPE) films and subsequent immobilization of poly(glycerol) dendrimer (PGLD) has been performed with the aim to improve cell adhesion and proliferation on the surface of the polymer, in order to enhance their properties for bone tissue engineering scaffolding applications. Radiation grafting of PHEMA onto LDPE was promoted by γ-ray radiation. The covalent immobilization of PGLD on LDPE-g-PHEMA surface was performed by using a dicyclohexyl carbodiimide (DCC)/N,N-dimethylaminopyridine (DMAP) method. The occurrence of grafting polymerization of PHEMA and further immobilization of PGLD was quantitatively confirmed by photoelectron spectroscopy (XPS) and fluorescence, respectively. The LDPE-g-PHEMA surface topography after PGLD coupling was studied by atomic force microscopy (AFM). The hydrophilicity of the LDPE-g-PHEMA film was remarkably improved compared to that of the ungrafted LDPE. The core level XPS ESCA spectrum of PHEMA-grafted LDPE showed two strong peaks at 286.6 eV (from hydroxyl groups and ester groups) and 289.1 eV (from ester groups) due to PHEMA brushes grafted onto LDPE surfaces. The results from the cell adhesion studies show that MCT3-E1 cells tended to spread more slowly on the LDPE-g-PHEMA than on the LDPE-g-PHEMA-i-PGLD. - Highlights: • Radiation-grafted PHEMA hydrogels have been obtained by simultaneous gamma-irradiation of LDPE and HEMA monomer. • PGLD dendrimer was immobilized onto PHEMA for application in tissue engineering. • The microstructural characterization of LDPE-g-PHEMA-i-PGLD by RMN, XPS, AFM and MALDI-TOF are made. • Measurements of water uptake and contact angle of LDPE-g-PHEMA are compared to those of LDPE-g-PHEMA-i-PGLD. • The MC3T-E1 osteoblast cell adhesion and growth on LDPE-g-PHEMA-i-PGLD were studied

  16. Biogenesis and fate of the cell-cell adhesion molecule, agglutinin, during gametogenesis and fertilization of Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Fertilization in Chlamydomonas begins with the species-specific recognition and adhesion between gametes of opposite mating types via agglutinin molecules on the flagellar surface. This adhesion generates a cAMP-mediated sexual signal that initiates the subsequent events of call wall release, mating structure activation, and cell fusion. Although flagella of paired gametes remain attached to each other until the zygote forms, the process is dynamic. Engaged agglutinins rapidly become inactivated and turnover, requiring the constant supply of new agglutinins to replace the lost molecules. A population of cell body associated agglutinins has been postulated to the pool of agglutinins recruited during this turnover. Cell body agglutinins, therefore were identified, purified, localized within the cells and compared to flagellar agglutinins. The relationship between these two agglutinin populations was also examined. Cell body agglutinins were biochemically indistinguishable from the flagellar form with respect to their Mr, sedimentation coefficient, and hydrophobicity elution properties. Functionally, however, these molecules were inactive in situ. The calculated surface density of agglutinins in the cell body and flagellar domains was similar and thus could not explain their functional difference, but two domains contiguous and yet distinctive suggested they may be separated by a functional barrier. To test this, a method was developed, using a monoclonal antibody and cycloheximide, that removed the flagellar agglutinins so movement between the domains could be monitored. Mobilization of agglutinins onto the flagella did not occur unless sexual signaling was induced with cAMP and papaverine

  17. Cell surface heparan sulfate proteoglycans control adhesion and invasion of breast carcinoma cells

    DEFF Research Database (Denmark)

    Lim, Hooi Ching; Multhaupt, Hinke A. B.; Couchman, John R.

    2015-01-01

    breast carcinoma. This may derive from their regulation of cell adhesion, but roles for specific syndecans are unresolved. Methods: The MDA-MB231 human breast carcinoma cell line was exposed to exogenous glycosaminoglycans and changes in cell behavior monitored by western blotting, immunocytochemistry......, invasion and collagen degradation assays. Selected receptors including PAR-1 and syndecans were depleted by siRNA treatments to assess cell morphology and behavior. Immunohistochemistry for syndecan-2 and its interacting partner, caveolin-2 was performed on human breast tumor tissue arrays. Two......-tailed paired t-test and one-way ANOVA with Tukey¿s post-hoc test were used in the analysis of data. Results: MDA-MB231 cells were shown to be highly sensitive to exogenous heparan sulfate or heparin, promoting increased spreading, focal adhesion and adherens junction formation with concomitantly reduced...

  18. Biocompatibility of a novel cyanoacrylate based tissue adhesive: cytotoxicity and biochemical property evaluation.

    Directory of Open Access Journals (Sweden)

    Young Ju Lee

    Full Text Available Cyanoacrylate (CA is most widely used as a medical and commercial tissue adhesive because of easier wound closure, good cosmetic results and little discomfort. But, CA-based tissue adhesives have some limitations including the release of cytotoxic chemicals during biodegradation. In previous study, we made prepolymerized allyl 2-CA (PACA based tissue adhesive, resulting in longer chain structure. In this study, we investigated a biocompatibility of PACA as alternative tissue adhesive for medical application, comparing with that of Dermabond® as commercial tissue adhesive. The biocompatibility of PACA was evaluated for short-term (24 hr and long-term (3 and 7 days using conventional cytotoxicity (WST, neutral red, LIVE/DEAD and TUNEL assays, hematoxylin-eosin (H&E and Masson trichrome (MT staining. Besides we examined the biochemical changes in cells and DNA induced by PACA and Dermabond® utilizing Raman spectroscopy which could observe the denaturation and conformational changes in protein, as well as disintegration of the DNA/RNA by cell death. In particular, we analyzed Raman spectrum using the multivariate statistical methods including principal component analysis (PCA and support vector machine (SVM. As a result, PACA and Dermabond® tissue adhesive treated cells and tissues showed no difference of the cell viability values, histological analysis and Raman spectral intensity. Also, the classification analysis by means of PCA-SVM classifier could not discriminate the difference between the PACA and Dermabond® treated cells and DNA. Therefore we suggest that novel PACA might be useful as potential tissue adhesive with effective biocompatibility.

  19. Cell Adhesion, the Backbone of the Synapse: “Vertebrate” and “Invertebrate” Perspectives

    OpenAIRE

    Giagtzoglou, Nikolaos; Ly, Cindy V.; Bellen, Hugo J.

    2009-01-01

    Synapses are asymmetric intercellular junctions that mediate neuronal communication. The number, type, and connectivity patterns of synapses determine the formation, maintenance, and function of neural circuitries. The complexity and specificity of synaptogenesis relies upon modulation of adhesive properties, which regulate contact initiation, synapse formation, maturation, and functional plasticity. Disruption of adhesion may result in structural and functional imbalance that may lead to neu...

  20. SU-8 hollow cantilevers for AFM cell adhesion studies

    International Nuclear Information System (INIS)

    A novel fabrication method was established to produce flexible, transparent, and robust tipless hollow atomic force microscopy (AFM) cantilevers made entirely from SU-8. Channels of 3 μm thickness and several millimeters length were integrated into 12 μm thick and 40 μm wide cantilevers. Connected to a pressure controller, the devices showed high sealing performance with no leakage up to 6 bars. Changing the cantilever lengths from 100 μm to 500 μm among the same wafer allowed the targeting of various spring constants ranging from 0.5 to 80 N m−1 within a single fabrication run. These hollow polymeric AFM cantilevers were operated in the optical beam deflection configuration. To demonstrate the performance of the device, single-cell force spectroscopy experiments were performed with a single probe detaching in a serial protocol more than 100 Saccharomyces cerevisiae yeast cells from plain glass and glass coated with polydopamine while measuring adhesion forces in the sub-nanoNewton range. SU-8 now offers a new alternative to conventional silicon-based hollow cantilevers with more flexibility in terms of complex geometric design and surface chemistry modification. (paper)

  1. Naxos disease: Cardiocutaneous syndrome due to cell adhesion defect

    Directory of Open Access Journals (Sweden)

    Protonotarios Nikos

    2006-03-01

    Full Text Available Abstract Naxos disease is a recessively inherited condition with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C and a cutaneous phenotype, characterised by peculiar woolly hair and palmoplantar keratoderma. The disease was first described in families originating from the Greek island of Naxos. Moreover, affected families have been identified in other Aegean islands, Turkey, Israel and Saudi Arabia. A syndrome with the same cutaneous phenotype and predominantly left ventricular involvement has been described in families from India and Ecuador (Carvajal syndrome. Woolly hair appears from birth, palmoplantar keratoderma develop during the first year of life and cardiomyopathy is clinically manifested by adolescence with 100% penetrance. Patients present with syncope, sustained ventricular tachycardia or sudden death. Symptoms of right heart failure appear during the end stages of the disease. In the Carvajal variant the cardiomyopathy is clinically manifested during childhood leading more frequently to heart failure. Mutations in the genes encoding the desmosomal proteins plakoglobin and desmoplakin have been identified as the cause of Naxos disease. Defects in the linking sites of these proteins can interrupt the contiguous chain of cell adhesion, particularly under conditions of increased mechanical stress or stretch, leading to cell death, progressive loss of myocardium and fibro-fatty replacement. Implantation of an automatic cardioverter defibrillator is indicated for prevention of sudden cardiac death. Antiarrhythmic drugs are used for preventing recurrences of episodes of sustained ventricular tachycardia and classical pharmacological treatment for congestive heart failure, while heart transplantation is considered at the end stages.

  2. SU-8 hollow cantilevers for AFM cell adhesion studies

    Science.gov (United States)

    Martinez, Vincent; Behr, Pascal; Drechsler, Ute; Polesel-Maris, Jérôme; Potthoff, Eva; Vörös, Janos; Zambelli, Tomaso

    2016-05-01

    A novel fabrication method was established to produce flexible, transparent, and robust tipless hollow atomic force microscopy (AFM) cantilevers made entirely from SU-8. Channels of 3 μm thickness and several millimeters length were integrated into 12 μm thick and 40 μm wide cantilevers. Connected to a pressure controller, the devices showed high sealing performance with no leakage up to 6 bars. Changing the cantilever lengths from 100 μm to 500 μm among the same wafer allowed the targeting of various spring constants ranging from 0.5 to 80 N m‑1 within a single fabrication run. These hollow polymeric AFM cantilevers were operated in the optical beam deflection configuration. To demonstrate the performance of the device, single-cell force spectroscopy experiments were performed with a single probe detaching in a serial protocol more than 100 Saccharomyces cerevisiae yeast cells from plain glass and glass coated with polydopamine while measuring adhesion forces in the sub-nanoNewton range. SU-8 now offers a new alternative to conventional silicon-based hollow cantilevers with more flexibility in terms of complex geometric design and surface chemistry modification.

  3. A role for cell adhesion in beryllium-mediated lung disease

    Energy Technology Data Exchange (ETDEWEB)

    Hong-geller, Elizabeth [Los Alamos National Laboratory

    2008-01-01

    Chronic beryllium disease (CBD) is a debilitating lung disorder in which exposure to the lightweight metal beryllium (Be) causes the accumulation of beryllium-specific CD4+ T cells in the lung and formation of noncaseating pulmonary granulomas. Treatment for CBD patients who exhibit progressive pulmonary decline is limited to systemic corticosteroids, which suppress the severe host inflammatory response. Studies in the past several years have begun to highlight cell-cell adhesion interactions in the development of Be hypersensitivity and CBD. In particular, the high binding affinity between intercellular adhesion molecule 1 (I-CAM1) on lung epithelial cells and the {beta}{sub 2} integrin LFA-1 on migrating lymphocytes and macrophages regulates the concerted rolling of immune cells to sites of inflammation in the lung. In this review, we discuss the evidence that implicates cell adhesion processes in onset of Be disease and the potential of cell adhesion as an intervention point for development of novel therapies.

  4. Constitutive activation of BMP signalling abrogates experimental metastasis of OVCA429 cells via reduced cell adhesion

    Directory of Open Access Journals (Sweden)

    Shepherd Trevor G

    2010-02-01

    Full Text Available Abstract Background Activation of bone morphogenetic protein (BMP4 signalling in human ovarian cancer cells induces a number of phenotypic changes in vitro, including altered cell morphology, adhesion, motility and invasion, relative to normal human ovarian surface epithelial cells. From these in vitro analyses, we had hypothesized that active BMP signalling promotes the metastatic potential of ovarian cancer. Methods To test this directly, we engineered OVCA429 human ovarian cancer cells possessing doxycycline-inducible expression of a constitutively-active mutant BMP receptor, ALK3QD, and administered these cells to immunocompromised mice. Further characterization was performed in vitro to address the role of activated BMP signalling on the EOC phenotype, with particular emphasis on epithelial-mesenchymal transition (EMT and cell adhesion. Results Unexpectedly, doxycycline-induced ALK3QD expression in OVCA429 cells reduced tumour implantation on peritoneal surfaces and ascites formation when xenografted into immunocompromised mice by intraperitoneal injection. To determine the potential mechanisms controlling this in vivo observation, we followed with several cell culture experiments. Doxycycline-induced ALK3QD expression enhanced the refractile, spindle-shaped morphology of cultured OVCA429 cells eliciting an EMT-like response. Using in vitro wound healing assays, we observed that ALK3QD-expressing cells migrated with long, cytoplasmic projections extending into the wound space. The phenotypic alterations of ALK3QD-expressing cells correlated with changes in specific gene expression patterns of EMT, including increased Snail and Slug and reduced E-cadherin mRNA expression. In addition, ALK3QD signalling reduced β1- and β3-integrin expression, critical molecules involved in ovarian cancer cell adhesion. The combination of reduced E-cadherin and β-integrin expression correlates directly with the reduced EOC cell cohesion in spheroids and

  5. Syndecan-4 and integrins: combinatorial signaling in cell adhesion

    DEFF Research Database (Denmark)

    Couchman, J R; Woods, A

    site for protein kinase C(&agr;) and phosphatidylinositol 4, 5-bisphosphate acts as a dominant negative inhibitor of focal adhesion formation. Focal adhesion induction does not require interaction between heparan sulfate glycosaminoglycan and ligand but can occur when non-glycanated core protein is...

  6. Adhesion of bio-functionalized ultrasound microbubbles to endothelial cells by targeting to vascular cell adhesion molecule-1 under shear flow

    Directory of Open Access Journals (Sweden)

    Yang H

    2011-09-01

    Full Text Available Hong Yang, Xiaoyan Xiong, Lie Zhang, Chunhui Wu, Yiyao LiuDepartment of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of ChinaAbstract: The expression of certain endothelial cell adhesion molecules is increased during endothelial dysfunction or inflammatory activation. This has led to the concept of using microbubbles for targeted molecular imaging or drug delivery. In this approach, microbubbles with a specific ligand to receptors expressed at the site of specific diseases are constructed. The present study aimed to engineer a novel type of bio-functionalized microbubbles (vascular cell adhesion molecule 1 [VCAM-1]-targeted microbubbles, and determine whether VCAM-1-targeted microbubbles exhibit specific adhesion to lipopolysaccharide (LPS-activated endothelial cells. Our data showed that VCAM-1expression was significantly upregulated in both LPS-activated endothelial cells in vitro and endothelium in a rat atherosclerosis model in vivo. Targeted microbubbles were designed by conjugating anti-VCAM-1 monoclonal antibodies to the shell of microbubbles using biotin–avidin bridging chemistry methods. Microbubble adhesion to endothelial cells was assessed in a flow chamber at two shear stress conditions (6.3 and 10.4 dynes/cm2. Our data showed that microbubble adhesion depends on both the surface anti-VCAM-1 antibody densities and the exposed shear stresses. Adhesion of VCAM-1-targeted microbubbles onto LPS-activated endothelial cells increased with the surface antibody densities, and decreased with the exposed shear stresses. These findings showed that the specific ligand-carrying microbubbles have considerable potential in targeted ultrasound molecular imaging or ultrasound-assisted drug/gene delivery applications.Keywords: targeted microbubbles, VCAM-1, adhesion, HUVEC-CS, shear flow

  7. Galectin-1-mediated cell adhesion, invasion and cell death in human anaplastic large cell lymphoma: Regulatory roles of cell surface glycans

    OpenAIRE

    Suzuki, Osamu; Abe, Masafumi

    2014-01-01

    Galectin-1 is known to be one of the extracellular matrix proteins. To elucidate the biological roles of galectin-1 in cell adhesion and invasion of human anaplastic large cell lymphoma, we performed cell adhesion and invasion assays using the anaplastic large cell lymphoma cell line H-ALCL, which was previously established in our laboratory. From the cell surface lectin array, treatment with neuraminidase from Arthrobacter ureafaciens which cleaves all linkage types of cell surface sialic ac...

  8. Insights into the Alteration of Osteoblast Mechanical Properties upon Adhesion on Chitosan

    Directory of Open Access Journals (Sweden)

    Antonia G. Moutzouri

    2014-01-01

    Full Text Available Cell adhesion on substrates is accompanied by significant changes in shape and cytoskeleton organization, which affect subsequent cellular and tissue responses, determining the long-term success of an implant. Alterations in osteoblast stiffness upon adhesion on orthopaedic implants with different surface chemical composition and topography are, thus, of central interest in the field of bone implant research. This work aimed to study the mechanical response of osteoblasts upon adhesion on chitosan-coated glass surfaces and to investigate possible correlations with the level of adhesion, spreading, and cytoskeleton reorganization. Using the micropipette aspiration technique, the osteoblast elastic modulus was found higher on chitosan-coated than on uncoated control substrates, and it was found to increase in the course of spreading for both substrates. The cell-surface contact area was measured throughout several time points of adhesion to quantify cell spreading kinetics. Significant differences were found between chitosan and control surfaces regarding the response of cell spreading, while both groups displayed a sigmoidal kinetical behavior with an initially elevated spreading rate which stabilizes in the second hour of attachment. Actin filament structural changes were confirmed after observation with confocal microscope. Biomaterial surface modification can enhance osteoblast mechanical response and induce favorable structural organization for the implant integration.

  9. Bactericidal and anti-adhesive properties of culinary and medicinal plants against Helicobacter pylori

    Institute of Scientific and Technical Information of China (English)

    Rachel O'Mahony; Huda Al-Khtheeri; Deepeka Weerasekera; Neluka Fernando; Dino Vaira; John Holton; Christelle Basset

    2005-01-01

    AIM: To investigate the bactericidal and anti-adhesive properties of 25 plants against Helicobacter pylori (H pylori).METHODS: Twenty-five plants were boiled in water to produce aqueous extracts that simulate the effect of cooking. The bactericidal activity of the extracts was assessed by a standard kill-curve with seven strains of H pylori. The anti-adhesive property was assessed by the inhibition of binding of four strains of FITC-labeled H pylori to stomach sections. RESULTS: Of all the plants tested, eight plants, including Bengal quince, nightshade, garlic, dill, black pepper, coriander, fenugreek and black tea, were found to have no bactericidal effect on any of the isolates. Columbo weed, long pepper, parsley, tarragon, nutmeg, yellow-berried nightshade, threadstem carpetweed, sage and cinnamon had bactericidal activities against H pylori, but total inhibition of growth was not achieved in this study. Among the plants that killed H pylori, turmeric was the most efficient, followed by cumin, ginger, chilli, borage, black caraway, oregano and liquorice. Moreover, extracts of turmeric; borage and parsley were able to inhibit the adhesion of H pylori strains to the stomach sections.CONCLUSION: Several plants that were tested in our study had bactericidal and/or anti-adhesive effects on H pylori. Ingestion of the plants with anti-adhesive properties could therefore provide a potent alternative therapy for H pylori infection, which overcomes the problem of resistance associated with current antibiotic treatment.

  10. Reciprocal interactions between cell adhesion molecules of the immunoglobulin superfamily and the cytoskeleton in neurons

    Directory of Open Access Journals (Sweden)

    Vladimir eSytnyk

    2016-02-01

    Full Text Available Cell adhesion molecules of the immunoglobulin superfamily (IgSF including the neural cell adhesion molecule (NCAM and members of the L1 family of neuronal cell adhesion molecules play important functions in the developing nervous system by regulating formation, growth and branching of neurites and establishment of the synaptic contacts between neurons. In the mature brain, members of IgSF regulate synapse composition, function and plasticity required for learning and memory. The intracellular domains of IgSF cell adhesion molecules interact with the components of the cytoskeleton including the submembrane actin-spectrin meshwork, actin microfilaments, and microtubules. In this review, we summarize current data indicating that interactions between IgSF cell adhesion molecules and the cytoskeleton are reciprocal, and that while IgSF cell adhesion molecules regulate the assembly of the cytoskeleton, the cytoskeleton plays an important role in regulation of the functions of IgSF cell adhesion molecules. Reciprocal interactions between NCAM and L1 family members and the cytoskeleton and their role in neuronal differentiation and synapse formation are discussed in detail.

  11. Reciprocal Interactions between Cell Adhesion Molecules of the Immunoglobulin Superfamily and the Cytoskeleton in Neurons.

    Science.gov (United States)

    Leshchyns'ka, Iryna; Sytnyk, Vladimir

    2016-01-01

    Cell adhesion molecules of the immunoglobulin superfamily (IgSF) including the neural cell adhesion molecule (NCAM) and members of the L1 family of neuronal cell adhesion molecules play important functions in the developing nervous system by regulating formation, growth and branching of neurites, and establishment of the synaptic contacts between neurons. In the mature brain, members of IgSF regulate synapse composition, function, and plasticity required for learning and memory. The intracellular domains of IgSF cell adhesion molecules interact with the components of the cytoskeleton including the submembrane actin-spectrin meshwork, actin microfilaments, and microtubules. In this review, we summarize current data indicating that interactions between IgSF cell adhesion molecules and the cytoskeleton are reciprocal, and that while IgSF cell adhesion molecules regulate the assembly of the cytoskeleton, the cytoskeleton plays an important role in regulation of the functions of IgSF cell adhesion molecules. Reciprocal interactions between NCAM and L1 family members and the cytoskeleton and their role in neuronal differentiation and synapse formation are discussed in detail. PMID:26909348

  12. Adhesion properties of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based adhesives in the presence of phenol formaldehyde resin

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available The adhesion properties, i. e. viscosity, tack and peel strength of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based pressure-sensitive adhesive was studied using phenol formaldehyde resin as the tackifying resin. Toluene was used as the solvent throughout the experiment. SBR composition in SBR/SMR L blend used was 0, 20, 40, 60, 80, 100%. Three different resin loadings, i. e. 40, 80 and 120 parts per hundred parts of rubber (phr were used in the adhesive formulation. The viscosity of adhesive was determined by a HAAKE Rotary Viscometer whereas loop tack and peel strength of paper/polyethylene terephthalate (PET film were measured using a Lloyd Adhesion Tester operating at 30 cm/min. Results indicate that the viscosity of adhesive decreases with increasing % SBR whereas loop tack passes through a maximum value at 20% SBR for all resin loadings. Except for the control sample (without resin, the peel strength shows a maximum value at 60% SBR for the three modes of peel tests. For a fixed % SBR, adhesive sample containing 40 phr phenol formaldehyde resin always exhibits the highest loop tack and peel strength, an observation which is associated to the optimum wettability of adhesive on the substrate.

  13. Complementarity of PALM and SOFI for super-resolution live cell imaging of focal adhesions

    CERN Document Server

    Deschout, Hendrik; Sharipov, Azat; Szlag, Daniel; Feletti, Lely; Vandenberg, Wim; Dedecker, Peter; Hofkens, Johan; Leutenegger, Marcel; Lasser, Theo; Radenovic, Aleksandra

    2016-01-01

    Live cell imaging of focal adhesions requires a sufficiently high temporal resolution, which remains a challenging task for super-resolution microscopy. We have addressed this important issue by combining photo-activated localization microscopy (PALM) with super-resolution optical fluctuation imaging (SOFI). Using simulations and fixed cell focal adhesion images, we investigated the complementarity between PALM and SOFI in terms of spatial and temporal resolution. This PALM-SOFI framework was used to image focal adhesions in living cells, while obtaining a temporal resolution below 10 s. We visualized the dynamics of focal adhesions, and revealed local mean velocities around 190 nm per minute. The complementarity of PALM and SOFI was assessed in detail with a methodology that integrates a quantitative resolution and signal-to-noise metric. This PALM and SOFI concept provides an enlarged quantitative imaging framework, allowing unprecedented functional exploration of focal adhesions through the estimation of m...

  14. Silencing of VAMP3 inhibits cell migration and integrin-mediated adhesion

    International Nuclear Information System (INIS)

    Integrins are transmembrane receptors for cell adhesion to the extracellular matrix. In cell migration, integrins are endocytosed from the plasma membrane or the cell surface, transported in vesicles and exocytosed actively at the cell front. In the present study, we examined the roles of VAMP3, a SNARE protein that mediates exocytosis, in cell migration and integrin trafficking. Small interfering RNA (siRNA)-induced silencing of VAMP3 inhibited chemotactic cell migration by more than 60% without affecting cell proliferation. VAMP3 silencing reduced the levels of β1 integrin at the cell surface but had no effect on total cellular β1 integrin, indicating that VAMP3 is required for trafficking of β1 integrin to the plasma membrane. Furthermore, VAMP3 silencing diminished cell adhesion to laminin but not to fibronectin or collagen. Taken together, these data suggest that VAMP3-dependent integrin trafficking is crucial in cell migration and cell adhesion to laminin.

  15. Effect of Cell Adhesion Molecule 1 Expression on Intracellular Granule Movement in Pancreatic α Cells.

    Science.gov (United States)

    Yokawa, Satoru; Furuno, Tadahide; Suzuki, Takahiro; Inoh, Yoshikazu; Suzuki, Ryo; Hirashima, Naohide

    2016-09-01

    Although glucagon secreted from pancreatic α cells plays a role in increasing glucose concentrations in serum, the mechanism regulating glucagon secretion from α cells remains unclear. Cell adhesion molecule 1 (CADM1), identified as an adhesion molecule in α cells, has been reported not only to communicate among α cells and between nerve fibers, but also to prevent excessive glucagon secretion from α cells. Here, we investigated the effect of CADM1 expression on the movement of intracellular secretory granules in α cells because the granule transport is an important step in secretion. Spinning disk microscopic analysis showed that granules moved at a mean velocity of 0.236 ± 0.010 μm/s in the mouse α cell line αTC6 that expressed CADM1 endogenously. The mean velocity was significantly decreased in CADM1-knockdown (KD) cells (mean velocity: 0.190 ± 0.016 μm/s). The velocity of granule movement decreased greatly in αTC6 cells treated with the microtubule-depolymerizing reagent nocodazole, but not in αTC6 cells treated with the actin-depolymerizing reagent cytochalasin D. No difference in the mean velocity was observed between αTC6 and CADM1-KD cells treated with nocodazole. These results suggest that intracellular granules in pancreatic α cells move along the microtubule network, and that CADM1 influences their velocity. PMID:27262873

  16. Cellular Adhesion Tripeptide RGD Inhibits Growth of Human Ileocecal Adenocarcinoma Cells HCT-8 and Induces Apoptosis

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; ZENG Hong-bin; YANG Shao-juan; GAO Shen; HUANG Yi-bing; HOU Rui-zhen; ZHAO Mi-feng; XU Li; ZHANG Xue-zhong

    2007-01-01

    The tripeptide, Arg-Gly-Asp(RGD) motif is an integrin-recognition site found in adhesive proteins present in extracellular matrices(ECM) and in the blood. HCT-8 cells were treated with cellular adhesion tripeptide RGD at various concentrations. MTT assay was performed to examine the growth and proliferation of HCT-8 cells after treatment with RGD for 48 h. Haematoxylin and Eosin(HE) staining and electromicroscope were used to observe the morphology of apoptotic cells. Survivin and flow cytometry were also used to analyze the HCT-8 apoptosis. Cellular adhesion tripeptide RGD significantly inhibits the growth and proliferation of HCT-8 cells in a dose-dependent manner and induces apoptosis of HCT-8. These results indicate that cellular adhesion tripeptide RGD inhibits the growth and proliferation of tumor HCT-8 cell, probably by the aid of inducing apoptosis of HCT-8 cell.

  17. Surface free energy predominates in cell adhesion to hydroxyapatite through wettability.

    Science.gov (United States)

    Nakamura, Miho; Hori, Naoko; Ando, Hiroshi; Namba, Saki; Toyama, Takeshi; Nishimiya, Nobuyuki; Yamashita, Kimihiro

    2016-05-01

    The initial adhesion of cells to biomaterials is critical in the regulation of subsequent cell behaviors. The purpose of this study was to investigate a mechanism through which the surface wettability of biomaterials can be improved and determine the effects of biomaterial surface characteristics on cellular behaviors. We investigated the surface characteristics of various types of hydroxyapatite after sintering in different atmospheres and examined the effects of various surface characteristics on cell adhesion to study cell-biomaterial interactions. Sintering atmosphere affects the polarization capacity of hydroxyapatite by changing hydroxide ion content and grain size. Compared with hydroxyapatite sintered in air, hydroxyapatite sintered in saturated water vapor had a higher polarization capacity that increased surface free energy and improved wettability, which in turn accelerated cell adhesion. We determined the optimal conditions of hydroxyapatite polarization for the improvement of surface wettability and acceleration of cell adhesion. PMID:26952425

  18. Signaling through intercellular adhesion molecule 1 (ICAM-1) in a B cell lymphoma line

    DEFF Research Database (Denmark)

    Holland, J; Owens, T

    1997-01-01

    Intercellular adhesion molecule 1 (ICAM-1) (CD54) is an adhesion molecule of the immunoglobulin superfamily. The interaction between ICAM-1 on B lymphocytes and leukocyte function-associated antigen 1 on T cells plays a major role in several aspects of the immune response, including T-dependent B...

  19. Focal Adhesion of Osteoblastic Cells on Titanium Surface with Amine Functionalities Formed by Plasma Polymerization

    Science.gov (United States)

    Song, Heesang; Jung, Sang Chul; Kim, Byung Hoon

    2012-08-01

    To enhance the focal adhesion of osteoblastic cells on a titanium surface, plasma polymerized allyl amine (AAm) thin films were deposited by plasma polymerization. This plasma polymer functionalization of titanium is advantageous for osteoblastic focal adhesion formation. Such Ti surfaces are useful for the fabrication of titanium-based dental implants for enhancement of osseointegration.

  20. Short Peptides Enhance Single Cell Adhesion and Viability onMicroarrays

    Energy Technology Data Exchange (ETDEWEB)

    Veiseh, Mandana; Veiseh, Omid; Martin, Michael C.; Asphahani,Fareid; Zhang, Miqin

    2007-01-19

    Single cell patterning holds important implications forbiology, biochemistry, biotechnology, medicine, and bioinformatics. Thechallenge for single cell patterning is to produce small islands hostingonly single cells and retaining their viability for a prolonged period oftime. This study demonstrated a surface engineering approach that uses acovalently bound short peptide as a mediator to pattern cells withimproved single cell adhesion and prolonged cellular viabilityon goldpatterned SiO2 substrates. The underlying hypothesis is that celladhesion is regulated bythe type, availability, and stability ofeffective cell adhesion peptides, and thus covalently bound shortpeptides would promote cell spreading and, thus, single cell adhesion andviability. The effectiveness of this approach and the underlyingmechanism for the increased probability of single cell adhesion andprolonged cell viability by short peptides were studied by comparingcellular behavior of human umbilical cord vein endothelial cells on threemodelsurfaces whose gold electrodes were immobilized with fibronectin,physically adsorbed Arg-Glu-Asp-Val-Tyr, and covalently boundLys-Arg-Glu-Asp-Val-Tyr, respectively. The surface chemistry and bindingproperties were characterized by reflectance Fourier transform infraredspectroscopy. Both short peptides were superior to fibronectin inproducing adhesion of only single cells, whereas the covalently boundpeptide also reduced apoptosis and necrosisof adhered cells. Controllingcell spreading by peptide binding domains to regulate apoptosis andviability represents a fundamental mechanism in cell-materialsinteraction and provides an effective strategy in engineering arrays ofsingle cells.

  1. Activation of AMP-activated protein kinase attenuates hepatocellular carcinoma cell adhesion stimulated by adipokine resistin

    International Nuclear Information System (INIS)

    Resistin, adipocyte-secreting adipokine, may play critical role in modulating cancer pathogenesis. The aim of this study was to investigate the effects of resistin on HCC adhesion to the endothelium, and the mechanism underlying these resistin effects. Human SK-Hep1 cells were used to study the effect of resistin on intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expressions as well as NF-κB activation, and hence cell adhesion to human umbilical vein endothelial cells (HUVECs). 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR), an AMP-activated protein kinase (AMPK) activator, was used to determine the regulatory role of AMPK on HCC adhesion to the endothelium in regard to the resistin effects. Treatment with resistin increased the adhesion of SK-Hep1 cells to HUVECs and concomitantly induced NF-κB activation, as well as ICAM-1 and VCAM-1 expressions in SK-Hep1 cells. Using specific blocking antibodies and siRNAs, we found that resistin-induced SK-Hep1 cell adhesion to HUVECs was through NF-κB-regulated ICAM-1 and VCAM-1 expressions. Moreover, treatment with AICAR demonstrated that AMPK activation in SK-Hep1 cells significantly attenuates the resistin effect on SK-Hep1 cell adhesion to HUVECs. These results clarify the role of resistin in inducing HCC adhesion to the endothelium and demonstrate the inhibitory effect of AMPK activation under the resistin stimulation. Our findings provide a notion that resistin play an important role to promote HCC metastasis and implicate AMPK may be a therapeutic target to against HCC metastasis

  2. The evaluation of p,p′-DDT exposure on cell adhesion of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Low doses p,p′-DDT exposure disrupts cell–cell adhesion and cell–matrix adhesion in HepG2 cells. • Both oxidative stress and JAK/STAT3 pathway are activated in p,p′-DDT-treated HepG2 cells. • The stimulation of JAK/STAT3 pathway is mediated by oxidative stress. • p,p′-DDT regulates adhesion molecules via the JAK/STAT3 pathway. • p,p′-DDT stimulates JAK/STAT3 signal pathway and disrupts the expressions of cell adhesion molecules in nude mice models. - Abstract: Many studies have found a positive association between the progression of hepatocellular carcinoma and DDT exposure. These studies mainly focus on the effect of DDT exposure on cell proliferation and epithelial to mesenchymal transition (EMT) promotion. However, the influence of DDT on cell adhesion of hepatocellular carcinoma remains to be unclear. The aim of our study was to determine the effect of p,p′-DDT on cell adhesion of hepatocellular carcinoma in vitro and in vivo. The data showed that p,p′-DDT, exposing HepG2 cells for 6 days, decreased cell–cell adhesion and elevated cell–matrix adhesion. Strikingly, p,p′-DDT increased reactive oxygen species (ROS) content, and this was accompanied by the activation of JAK/STAT3 pathway. Moreover, ROS inhibitor supplement reversed these effects significantly. However, the addition of ER inhibitor, ICI, had no effect on the p,p′-DDT-induced effects. p,p′-DDT altered the mRNA levels of related adhesion molecules, including inhibition of E-cadherin and promotion of N-cadherin along with CD29. Interestingly, the p,p′-DDT-altered adhesion molecules could be reversed with JAK inhibitor or STAT3 inhibitor. Likewise, p,p′-DDT stimulated the JAK/STAT3 pathway in nude mice, as well as altered the mRNA levels of E-cadherin, N-cadherin, and CD29. Taken together, these results indicate that p,p′-DDT profoundly promotes the adhesion process by decreasing cell–cell adhesion and inducing cell

  3. Decreased astroglial cell adhesion and proliferation on zinc oxide nanoparticle polyurethane composites

    Directory of Open Access Journals (Sweden)

    Justin T Seil

    2008-11-01

    Full Text Available Justin T Seil, Thomas J WebsterLaboratory for Nanomedicine Research, Division of Engineering, Brown University, Providence, RI, USAAbstract: Nanomaterials offer a number of properties that are of interest to the field of neural tissue engineering. Specifically, materials that exhibit nanoscale surface dimensions have been shown to promote neuron function while simultaneously minimizing the activity of cells such as astrocytes that inhibit central nervous system regeneration. Studies demonstrating enhanced neural tissue regeneration in electrical fields through the use of conductive materials have led to interest in piezoelectric materials (or those materials which generate a transient electrical potential when mechanically deformed such as zinc oxide (ZnO. It has been speculated that ZnO nanoparticles possess increased piezoelectric properties over ZnO micron particles. Due to this promise in neural applications, the objective of the present in vitro study was, for the first time, to assess the activity of astroglial cells on ZnO nanoparticle polymer composites. ZnO nanoparticles embedded in polyurethane were analyzed via scanning electron microscopy to evaluate nanoscale surface features of the composites. The surface chemistry was characterized via X-ray photoelectron spectroscopy. Astroglial cell response was evaluated based on cell adhesion and proliferation. Astrocyte adhesion was significantly reduced on ZnO nanoparticle/polyurethane (PU composites with a weight ratio of 50:50 (PU:ZnO wt.%, 75:25 (PU:ZnO wt.%, and 90:10 (PU:ZnO wt.% in comparison to pure PU. The successful production of ZnO nanoparticle composite scaffolds suitable for decreasing astroglial cell density demonstrates their potential as a nerve guidance channel material with greater efficiency than what may be available today.Keywords: zinc oxide, nanoparticles, astrocytes, neural tissue, nervous system, biomaterials

  4. Hyaluronan-mediated cellular adhesion

    Science.gov (United States)

    Curtis, Jennifer

    2005-03-01

    Many cells surround themselves with a cushioning halo of polysaccharides that is further strengthened and organized by proteins. In fibroblasts and chrondrocytes, the primary component of this pericellular matrix is hyaluronan, a large linear polyanion. Hyaluronan production is linked to a variety of disease, developmental, and physiological processes. Cells manipulate the concentration of hyaluronan and hyaluronan receptors for numerous activities including modulation of cell adhesion, cell motility, and differentiation. Recent investigations by identify hyaluronan's role in mediating early-stage cell adhesion. An open question is how the cell removes the 0.5-10 micron thick pericellular matrix to allow for further mature adhesion events requiring nanometer scale separations. In this investigation, holographic optical tweezers are used to study the adhesion and viscoelastic properties of chondrocytes' pericellular matrix. Ultimately, we aim to shed further light on the spatial and temporal details of the dramatic transition from micron to nanometer gaps between the cell and its adhesive substrate.

  5. A metal-ion-responsive adhesive material via switching of molecular recognition properties

    Science.gov (United States)

    Nakamura, Takashi; Takashima, Yoshinori; Hashidzume, Akihito; Yamaguchi, Hiroyasu; Harada, Akira

    2014-08-01

    Common adhesives stick to a wide range of materials immediately after they are applied to the surfaces. To prevent indiscriminate sticking, smart adhesive materials that adhere to a specific target surface only under particular conditions are desired. Here we report a polymer hydrogel modified with both β-cyclodextrin (βCD) and 2,2‧-bipyridyl (bpy) moieties (βCD-bpy gel) as a functional adhesive material responding to metal ions as chemical stimuli. The adhesive property of βCD-bpy gel based on interfacial molecular recognition is expressed by complexation of metal ions to bpy that controlled dissociation of supramolecular cross-linking of βCD-bpy. Moreover, adhesion of βCD-bpy gel exhibits selectivity on the kinds of metal ions, depending on the efficiency of metal-bpy complexes in cross-linking. Transduction of two independent chemical signals (metal ions and host-guest interactions) is achieved in this adhesion system, which leads to the development of highly orthogonal macroscopic joining of multiple objects.

  6. Steric Interference of Adhesion Supports In-Vitro Chondrogenesis of Mesenchymal Stem Cells on Hydrogels for Cartilage Repair

    Science.gov (United States)

    Goldshmid, Revital; Cohen, Shlomit; Shachaf, Yonatan; Kupershmit, Ilana; Sarig-Nadir, Offra; Seliktar, Dror; Wechsler, Roni

    2015-01-01

    Recent studies suggest the presence of cell adhesion motifs found in structural proteins can inhibit chondrogenesis. In this context, the current study aims to determine if a polyethylene glycol (PEG)-modified fibrinogen matrix could support better chondrogenesis of human bone marrow mesenchymal stem cells (BM-MSC) based on steric interference of adhesion, when compared to a natural fibrin matrix. Hydrogels used as substrates for two-dimensional (2D) BM-MSC cultures under chondrogenic conditions were made from cross-linked PEG-fibrinogen (PF) and compared to thrombin-activated fibrin. Cell morphology, protein expression, DNA and sulfated proteoglycan (GAG) content were correlated to substrate properties such as stiffness and adhesiveness. Cell aggregation and chondrogenic markers, including collagen II and aggrecan, were observed on all PF substrates but not on fibrin. Shielding fibrinogen’s adhesion domains and increasing stiffness of the material are likely contributing factors that cause the BM-MSCs to display a more chondrogenic phenotype. One composition of PF corresponding to GelrinC™—a product cleared in the EU for cartilage repair—was found to be optimal for supporting chondrogenic differentiation of BM-MSC while minimizing hypertrophy (collagen X). These findings suggest that semi-synthetic biomaterials based on ECM proteins can be designed to favourably affect BM-MSC towards repair processes involving chondrogenesis. PMID:26411496

  7. Expression and function of neural cell adhesion molecule during limb regeneration.

    OpenAIRE

    Maier, C E; Watanabe, M.(Niigata University, 950-2181, Niigata, Japan); Singer, M.; McQuarrie, I G; Sunshine, J.; Rutishauser, U.

    1986-01-01

    The neural cell adhesion molecule (NCAM) has been detected in regenerating limb bud of adult newts in addition to brain and peripheral nerves. In the regenerating tissue, NCAM was found primarily on mesenchymal cells and also in wound epidermis. Infusion of Fab fragments of antibodies to NCAM into limb buds at the early blastema stage delayed the regenerative process. Previous studies have indicated that NCAM serves as a homophilic ligand for adhesion among cells that express this molecule an...

  8. Homophilic interaction of the L1 family of cell adhesion molecules

    OpenAIRE

    Wei, Chun Hua; Ryu, Seong Eon

    2012-01-01

    Homophilic interaction of the L1 family of cell adhesion molecules plays a pivotal role in regulating neurite outgrowth and neural cell networking in vivo. Functional defects in L1 family members are associated with neurological disorders such as X-linked mental retardation, multiple sclerosis, low-IQ syndrome, developmental delay, and schizophrenia. Various human tumors with poor prognosis also implicate the role of L1, a representative member of the L1 family of cell adhesion molecules, and...

  9. Mass spectrometry assisted lithography for the patterning of cell adhesion ligands on self-assembled monolayers.

    Science.gov (United States)

    Kim, Young-Kwan; Ryoo, Soo-Ryoon; Kwack, Sul-Jin; Min, Dal-Hee

    2009-01-01

    Pattern of events: A simple and flexible method has been developed for patterning cell adhesion ligands. Locally erasing self-assembled monolayers with tri(ethyleneglycol) groups on a gold substrate by using a MALDI-TOF MS nitrogen laser and filling the exposed gold surface with an alkanethiol presenting carboxylic acid groups enables subsequent immobilization of maleimide and a cell adhesion peptide, which can then recognize cells (see scheme). PMID:19347909

  10. Laser Phototherapy Enhances Mesenchymal Stem Cells Survival in Response to the Dental Adhesives

    OpenAIRE

    Ivana Márcia Alves Diniz; Adriana Bona Matos; Márcia Martins Marques

    2015-01-01

    Background. We investigated the influence of laser phototherapy (LPT) on the survival of human mesenchymal stem cells (MSCs) submitted to substances leached from dental adhesives. Method. MSCs were isolated and characterized. Oral mucosa fibroblasts and osteoblast-like cells were used as comparative controls. Cultured medium conditioned with two adhesive systems was applied to the cultures. Cell monolayers were exposed or not to LPT. Laser irradiations were performed using a red laser (GaAlAs...

  11. Snail1 controls epithelial–mesenchymal lineage commitment in focal adhesion kinase–null embryonic cells

    OpenAIRE

    Li, Xiao-Yan; Zhou, Xiaoming; Rowe, R. Grant; Hu, Yuexian; Schlaepfer, David D.; Ilić, Dusko; Dressler, Gregory; Park, Ann; Guan, Jun-Lin; Weiss, Stephen J.

    2011-01-01

    Mouse embryonic cells isolated from focal adhesion kinase (FAK)–null animals at embryonic day 7.5 display multiple defects in focal adhesion remodeling, microtubule dynamics, mechanotransduction, proliferation, directional motility, and invasion. To date, the ability of FAK to modulate cell function has been ascribed largely to its control of posttranscriptional signaling cascades in this embryonic cell population. In this paper, we demonstrate that FAK unexpectedly exerts control over an epi...

  12. Contributions of chemical and mechanical surface properties and temperature effect on the adhesion at the nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Awada, Houssein, E-mail: houssein.awada@uqtr.c [Centre Integre en Pates et Papiers, Universite du Quebec a Trois-Rivieres (UQTR), 3351, boul. des Forges Trois-Rivieres, G9A 5H7, Quebec (Canada); Noel, Olivier [Universite du Maine, Molecular landscapes and biophotonics, CNRS-UMR 6087, Le Mans (France); Hamieh, Tayssir [Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA, CHAMSI) Faculty of Sciences, Lebanese University, Beirut (Lebanon); Kazzi, Yolla [Faculty of Sciences, Lebanese University, Beirut (Lebanon); Brogly, Maurice [Laboratoire LECOB, Universite de Haute-Alsace, 68057 Mulhouse Cedex (France)

    2011-03-31

    The atomic force microscope (AFM) is a powerful tool to investigate surface properties of model systems at the nanoscale. However, to get semi-quantitative and reproducible data with the AFM, it is necessary to establish a rigorous experimental procedure. In particular, a systematic calibration procedure of AFM measurements is necessary before producing reliable semi-quantitative data. In this paper, we study the contributions of the chemical and mechanical surface properties or the temperature influence on the adhesion energy at a local scale. To reach this objective, two types of model systems were considered. The first one is composed of rigid substrates (silicon wafers or AFM tips covered with gold) which were chemically modified by molecular self-assembling monolayers to display different surface properties (methyl and hydroxyl functional groups). The second one consists of model polymer networks (cross-linked polydimethylsiloxane) of variable mechanical properties. The comparison of the force curves obtained from the two model systems shows that the viscoelastic contributions dominate for the adhesion with polymer substrates, whereas, chemical contributions dominate for the rigid substrates. The temperature effect on the adhesion energy is also reported. Finally, we propose a relation for the adhesion energy at the nanoscale. This relation relates the energy measured during the separation of the contact to the three parameters: the surface properties of the polymer, the energy dissipated within the contact zone and the temperature.

  13. Ochratoxim A alters cell adhesion and gap junction intercellular communication in MDCK cells

    International Nuclear Information System (INIS)

    Ochratoxin A (OTA) is one of the most potent renal carcinogens studied to date, but the mechanism of tumor formation by ochratoxin A remains largely unknown. Cell adhesion and cell-cell communication participate in the regulation of signaling pathways involved in cell proliferation and growth control and it is therefore not surprising that modulation of cell-cell signaling has been implicated in cancer development. Several nephrotoxicants and renal carcinogens have been shown to alter cell-cell signaling by interference with gap junction intercell communication (GJIC) and/or cell adhesion, and the aim of this study was to determine if disruption of cell-cell interactions occurs in kidney epithelial cells in response to OTA treatment. MDCK cells were treated with OTA (0-50 μM) for up to 24 h and gap junction function was analyzed using the scrape-load/dye transfer assay. In addition, expression and intracellular localization of Cx43, E-cadherin and β-catenin were determined by immunoblot and immunofluorescence analysis. A clear decrease in the distance of dye transfer was evident following treatment with OTA at concentrations/incubation times which did not affect cell viability. Consistent with the functional inhibition of GJIC, treatment with OTA resulted in a dose-dependent decrease in Cx43 expression. In contrast to Cx43, OTA did not alter total amount of the adherens junction proteins E-cadherin and β-catenin. Moreover, Western blot analysis of Triton X-100 soluble and insoluble protein fractions did not indicate translocation of cell adhesion molecules from the membrane to the cytoplasm. However, a ∼78 kDa fragment of β-catenin was detected in the detergent soluble fraction, indicating proteolytic cleavage of β-catenin. Immunofluorescence analysis also revealed changes in the pattern of both β-catenin and E-cadherin labeling, suggesting that OTA may alter cell-adhesion. Taken together, these data support the hypothesis that disruption of cell-cell

  14. Label-free continuous cell sorter with specifically adhesive oblique micro-grooves

    International Nuclear Information System (INIS)

    We report the development of a label-free continuous cell sorting method based on specific adhesivity between cells and surface-immobilized adhesion molecules. The separation of cells is induced by cross-flow adhesive force on micron-sized stripes with adhesion molecules immobilized on the surface. In order to accurately form the adhesive stripes on a microchannel wall, 1 µm wide micro-grooves are fabricated at a certain angle with respect to the flow direction using direct electron-beam lithography. Amino-functionalized parylene is used as the groove surface material, and streptavidin is immobilized on the entire surface, resulting in a surface with periodic adhesive patterns. The effectiveness of the proposed cell sorting principle is verified by flow-through experiments using functionalized particles as model cells. Measurements of the motion of biotin-coated microparticles show that the particles decelerated by specific adhesivity are displaced in the cross-flow direction. The observed cross-flow displacement is around 0.8% of the streamwise travelling distance. It is also shown that the rate of cross-flow displacement is independent of the flow rate or the stripe angle. Finally, it is demonstrated that a mixture of streptavidin- and biotin-coated microparticles can be completely separated after flowing over a 20 mm long patterned surface. The proposed label-free continuous lateral separation scheme has a wide range of potential applications for separation of cells which could not be distinguished by size or separated using dielectric forces

  15. Biosynthesis of the neural cell adhesion molecule: characterization of polypeptide C

    DEFF Research Database (Denmark)

    Nybroe, O; Albrechtsen, M; Dahlin, J; Linnemann, D; Lyles, J M; Møller, C J; Bock, E

    1985-01-01

    The biosynthesis of the neural cell adhesion molecule (N-CAM) was studied in primary cultures of rat cerebral glial cells, cerebellar granule neurons, and skeletal muscle cells. The three cell types produced different N-CAM polypeptide patterns. Glial cells synthesized a 135,000 Mr polypeptide B...

  16. Mechanical and water soaking properties of medium density fiberboard with wood fiber and soybean protein adhesive.

    Science.gov (United States)

    Li, Xin; Li, Yonghui; Zhong, Zhikai; Wang, Donghai; Ratto, Jo A; Sheng, Kuichuan; Sun, Xiuzhi Susan

    2009-07-01

    Soybean protein is a renewable and abundant material that offers an alternative to formaldehyde-based resins. In this study, soybean protein was modified with sodium dodecyl sulfate (SDS) as an adhesive for wood fiber medium density fiberboard (MDF) preparation. Second-order response surface regression models were used to study the effects and interactions of initial moisture content (IMC) of coated wood fiber, press time (PT) and temperature on mechanical and water soaking properties of MDF. Results showed that IMC of coated fiber was the dominant influencing factor. Mechanical and soaking properties improved as IMC increased and reached their highest point at an IMC of 35%. Press time and temperature also had a significant effect on mechanical and water soaking properties of MDF. Second-order regression results showed that there were strong relationships between mechanical and soaking properties of MDF and processing parameters. Properties of MDF made using soybean protein adhesive are similar to those of commercial board. PMID:19329303

  17. Laminin isoform-specific promotion of adhesion and migration of human bone marrow progenitor cells.

    Science.gov (United States)

    Gu, Yu-Chen; Kortesmaa, Jarkko; Tryggvason, Karl; Persson, Jenny; Ekblom, Peter; Jacobsen, Sten-Eirik; Ekblom, Marja

    2003-02-01

    Laminins are alphabetagamma heterotrimeric extracellular proteins that regulate cellular functions by adhesion to integrin and nonintegrin receptors. Laminins containing alpha4 and alpha5 chains are expressed in bone marrow, but their interactions with hematopoietic progenitors are unknown. We studied human bone marrow cell adhesion to laminin-10/11 (alpha5beta1gamma1/alpha5beta2gamma1), laminin-8 (alpha4beta1gamma1), laminin-1 (alpha1beta1gamma1), and fibronectin. About 35% to 40% of CD34(+) and CD34(+)CD38(-) stem and progenitor cells adhered to laminin-10/11, and 45% to 50% adhered to fibronectin, whereas they adhered less to laminin-8 and laminin-1. Adhesion of CD34(+)CD38(-) cells to laminin-10/11 was maximal without integrin activation, whereas adhesion to other proteins was dependent on protein kinase C activation by 12-tetradecanoyl phorbol-13-acetate (TPA). Fluorescence-activated cell-sorting (FACS) analysis showed expression of integrin alpha6 chain on most CD34(+) and CD34(+)CD38(-) cells. Integrin alpha6 and beta1 chains were involved in binding of both cell fractions to laminin-10/11 and laminin-8. Laminin-10/11 was highly adhesive to lineage-committed myelomonocytic and erythroid progenitor cells and most lymphoid and myeloid cell lines studied, whereas laminin-8 was less adhesive. In functional assays, both laminin-8 and laminin-10/11 facilitated stromal-derived factor-1alpha (SDF-1alpha)-stimulated transmigration of CD34(+) cells, by an integrin alpha6 receptor-mediated mechanism. In conclusion, we demonstrate laminin isoform-specific adhesive interactions with human bone marrow stem, progenitor, and more differentiated cells. The cell-adhesive laminins affected migration of hematopoietic progenitors, suggesting a physiologic role for laminins during hematopoiesis. PMID:12393739

  18. The Role of Lipid Rafts in Cancer Cell Adhesion and Migration

    Directory of Open Access Journals (Sweden)

    Toshiyuki Murai

    2012-01-01

    Full Text Available Lipid rafts are cholesterol-enriched microdomains of the cell membrane and possess a highly dynamic nature. They have been involved in various cellular functions including the regulation of cell adhesion and membrane signaling through proteins within lipid rafts. The dynamic features of the cancer cell surface may modulate the malignant phenotype of cancer, including adhesion disorders and aggressive phenotypes of migration and invasion. Recently, it was demonstrated that lipid rafts play critical roles in cancer cell adhesion and migration. This article summarizes the important roles of lipid rafts in cancer cell adhesion and migration, with a focus on the current state of knowledge. This article will improve the understanding of cancer progression and lead to the development of novel targets for cancer therapy.

  19. Biodegradable copolymers carrying cell-adhesion peptide sequences.

    Science.gov (United States)

    Proks, Vladimír; Machová, Lud'ka; Popelka, Stepán; Rypácek, Frantisek

    2003-01-01

    Amphiphilic block copolymers are used to create bioactive surfaces on biodegradable polymer scaffolds for tissue engineering. Cell-selective biomaterials can be prepared using copolymers containing peptide sequences derived from extracellular-matrix proteins (ECM). Here we discuss alternative ways for preparation of amphiphilic block copolymers composed of hydrophobic polylactide (PLA) and hydrophilic poly(ethylene oxide) (PEO) blocks with cell-adhesion peptide sequences. Copolymers PLA-b-PEO were prepared by a living polymerisation of lactide in dioxane with tin(II)2-ethylhexanoate as a catalyst. The following approaches for incorporation of peptides into copolymers were elaborated. (a) First, a side-chain protected Gly-Arg-Gly-Asp-Ser-Gly (GRGDSG) peptide was prepared by solid-phase peptide synthesis (SPPS) and then coupled with delta-hydroxy-Z-amino-PEO in solution. In the second step, the PLA block was grafted to it via a controlled polymerisation of lactide initiated by the hydroxy end-groups of PEO in the side-chain-protected GRGDSG-PEO. Deprotection of the peptide yielded a GRGDSG-b-PEO-b-PLA copolymer, with the peptide attached through its C-end. (b) A protected GRGDSG peptide was built up on a polymer resin and coupled with Z-carboxy-PEO using a solid-phase approach. After cleavage of the delta-hydroxy-PEO-GRGDSG copolymer from the resin, polymerisation of lactide followed by deprotection of the peptide yielded a PLA-b-PEO-b-GRGDSG block copolymer, in which the peptide is linked through its N-terminus. PMID:12903721

  20. Silver nanowire based flexible electrodes with improved properties: High conductivity, transparency, adhesion and low haze

    International Nuclear Information System (INIS)

    Graphical abstract: This graphical abstract illustrates the schematic representation of the main drawbacks and rectifications for AgNWs based transparent electrodes. - Highlights: • Films exhibited low sheet resistance and optical properties with Rs ≤ 30 Ω/□ and T ≥ 90%. • We decreased haze to 2% by controlling AgNWs length, diameter, and concentration. • We achieved good adhesion for AgNWs on PET film. • There is no significant change in resistance in the bending angle from 0° to 180°, and on twisting. - Abstract: Recent work has been focusing on solution processable transparent electrodes for various applications including solar cells and displays. As well as, the research aims majorly at silver nanowires (AgNWs) to replace ITO. We enhance the transparent electrode performance as a function of optical and mechanical properties with low sheet resistance, by controlling the AgNWs accept ratios, ink composition, and processing conditions. The nanowire network of transparent films agrees with the 2D percolation law. The film transmittance values at 550 nm are coping with a reference ITO film. Sheet resistance and haze values are suitable for flexible electronic applications. We fabricate transparent flexible film using a low-cost processing technique

  1. In vivo tumor cell adhesion in the pulmonary microvasculature is exclusively mediated by tumor cell - endothelial cell interaction

    Directory of Open Access Journals (Sweden)

    Mees Soeren T

    2010-04-01

    Full Text Available Abstract Background Metastasis formation is the leading cause of death among colon cancer patients. We established a new in-situ model of in vivo microscopy of the lung to analyse initiating events of metastatic tumor cell adhesion within this typical metastatic target of colon cancer. Methods Anaesthetized CD rats were mechanically ventilated and 106 human HT-29LMM and T84 colon cancer cells were injected intracardially as single cell suspensions. Quantitative in vivo microscopy of the lung was performed in 10 minute intervals for a total of 40 minutes beginning with the time of injection. Results After vehicle treatment of HT-29LMM controls 15.2 ± 5.3; 14.2 ± 7.5; 11.4 ± 5.5; and 15.4 ± 6.5 cells/20 microscopic fields were found adherent within the pulmonary microvasculature in each 10 minute interval. Similar numbers were found after injection of the lung metastasis derived T84 cell line and after treatment of HT-29LMM with unspecific mouse control-IgG. Subsequently, HT-29LMM cells were treated with function blocking antibodies against β1-, β4-, and αv-integrins wich also did not impair tumor cell adhesion in the lung. In contrast, after hydrolization of sialylated glycoproteins on the cells' surface by neuraminidase, we observed impairment of tumor cell adhesion by more than 50% (p Conclusions These results demonstrate that the initial colon cancer cell adhesion in the capillaries of the lung is predominantly mediated by tumor cell - endothelial cell interactions, possibly supported by platelets. In contrast to reports of earlier studies that metastatic tumor cell adhesion occurs through integrin mediated binding of extracellular matrix proteins in liver, in the lung, the continuously lined endothelium appears to be specifically targeted by circulating tumor cells.

  2. Triterpene glycoside cucumarioside A(2)-2 from sea cucumber stimulates mouse immune cell adhesion, spreading, and motility.

    Science.gov (United States)

    Aminin, Dmitry L; Gorpenchenko, Tatyana Y; Bulgakov, Viktor P; Andryjashchenko, Polina V; Avilov, Sergey A; Kalinin, Vladimir I

    2011-06-01

    Holothurian triterpene glycosides are known to possess multiple biological activities. Here we show that cucumarioside A(2)-2 from the Far-Eastern edible holothurian Cucumaria japonica possesses potent immunomodulatory properties. The present studies were done to determine if cucumarioside A(2)-2 would affect macrophage adhesion, spreading, and motility. Resident peritoneal macrophages, collected from BALB/c mice, were exposed in vitro to low concentrations of cucumarioside A(2)-2 and compared with appropriate controls. Results indicate that 0.02 μg/mL cucumarioside A(2)-2 significantly enhanced macrophage morphology parameters and behavior. The glycoside stimulated these parameters by increasing the number of cells with increased adhesion properties as well as the spreading reaction and motility velocity by at least almost twofold. The data are discussed in terms of possible mechanisms underlying the immunomodulatory properties of cucumarioside A(2)-2. PMID:21554137

  3. Interlayer adhesion in roll-to-roll processed flexible inverted polymer solar cells

    KAUST Repository

    Dupont, Stephanie R.

    2012-02-01

    The interlayer adhesion of roll-to-roll processed flexible inverted P3HT:PCBM bulk heterojunction (BHJ) polymer solar cells is reported. Poor adhesion between adjacent layers may result in loss of device performance from delamination driven by the thermomechanical stresses in the device. We demonstrate how a thin-film adhesion technique can be applied to flexible organic solar cells to obtain quantitative adhesion values. For the P3HT:PCBM-based BHJ polymer solar cells, the interface of the BHJ with the conductive polymer layer PEDOT:PSS was found to be the weakest. The adhesion fracture energy varied from 1.6 J/m2 to 0.1 J/m2 depending on the composition of the P3HT:PCBM layer. Post-deposition annealing time and temperature were shown to increase the adhesion at this interface. Additionally the PEDOT:PSS cells are compared with V2O5 cells whereby adhesive failure marked by high fracture energies was observed. © 2011 Elsevier B.V.

  4. Tuning cell adhesion on polymeric and nanocomposite surfaces: Role of topography versus superhydrophobicity.

    Science.gov (United States)

    Zangi, Sepideh; Hejazi, Iman; Seyfi, Javad; Hejazi, Ehsan; Khonakdar, Hossein Ali; Davachi, Seyed Mohammad

    2016-06-01

    Development of surface modification procedures which allow tuning the cell adhesion on the surface of biomaterials and devices is of great importance. In this study, the effects of different topographies and wettabilities on cell adhesion behavior of polymeric surfaces are investigated. To this end, an improved phase separation method was proposed to impart various wettabilities (hydrophobic and superhydrophobic) on polypropylene surfaces. Surface morphologies and compositions were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. Cell culture was conducted to evaluate the adhesion of 4T1 mouse mammary tumor cells. It was found that processing conditions such as drying temperature is highly influential in cell adhesion behavior due to the formation of an utterly different surface topography. It was concluded that surface topography plays a more significant role in cell adhesion behavior rather than superhydrophobicity since the nano-scale topography highly inhibited the cell adhesion as compared to the micro-scale topography. Such cell repellent behavior could be very useful in many biomedical devices such as those in drug delivery and blood contacting applications as well as biosensors. PMID:27040256

  5. Integrin Activation by Regulated Dimerization and Oligomerization of Platelet Endothelial Cell Adhesion Molecule (Pecam)-1 from within the Cell

    OpenAIRE

    Zhao, Tieming; Newman, Peter J.

    2001-01-01

    Platelet endothelial cell adhesion molecule (PECAM)-1 is a 130-kD transmembrane glycoprotein having six Ig homology domains within its extracellular domain and an immunoreceptor tyrosine–based inhibitory motif within its cytoplasmic domain. Previous studies have shown that addition of bivalent anti–PECAM-1 mAbs to the surface of T cells, natural killer cells, neutrophils, or platelets result in increased cell adhesion to immobilized integrin ligands. However, the mechanism by which this occur...

  6. A fast and quantitative evaluation of the Aspergillus fumigatus biofilm adhesion properties by means of digital pulsed force mode

    International Nuclear Information System (INIS)

    The opportunistic pathogenic mould Aspergillus fumigatus (A. fumigatus) is an increasing cause of morbidity and mortality in immunocompromised and in part immunocompetent patients. A. fumigatus can grow in multicellular communities by the formation of a hyphal network embedded in an extracellular matrix (ECM) meanly composed by polysaccharides, melanin, proteins. Because adhesion properties is one primary factor affecting the balance between growth, detachment and biofilm formation, its quantification is essential in understanding, predicting, and modelling biofilm development. Atomic force microscopy (AFM) imaging and force spectroscopy have recently opened a range of novel applications in microbiology including the imaging and manipulation of membrane proteins at the subnanometer level, the observation of the surface of living cells at high resolution, the mapping of local properties such as surface charges, the measurement of elastic properties of cell-surface constituents and the probing of cellular interactions using functionalized probes. Nevertheless, the principal disadvantage of this approach is the relatively slow acquisition rate that makes AFM is not able to detect fast dynamics. In this study we demonstrated that digital pulsed force mode (DPFM) atomic force microscopy can be used to obtain high-resolution topographical images and to quantify the adhesion properties of the A. fumigatus biofilm with an high acquisition rate. Here we show by means of DPFM-AFM that Alginate Lyase (AlgL), an enzyme known to reduce negatively charged alginate levels in microbial biofilm, is able to reduce the biofilm adhesion forces forming several nano-fractures in the ECM. These results suggest that the AlgL could used to enhance the antifungal drugs transit through the ECM.

  7. A fast and quantitative evaluation of the Aspergillus fumigatus biofilm adhesion properties by means of digital pulsed force mode

    Energy Technology Data Exchange (ETDEWEB)

    Maiorana, Alessandro [Istituto di Fisica, Università Cattolica del S. Cuore, L. go F. Vito 1, 00168 Roma (Italy); Papi, Massimiliano, E-mail: m.papi@rm.unicatt.it [Istituto di Fisica, Università Cattolica del S. Cuore, L. go F. Vito 1, 00168 Roma (Italy); Bugli, Francesca; Torelli, Riccardo [Istituto di Microbiologia, Università Cattolica del S. Cuore, L. go F. Vito 1, 00168 Roma (Italy); Maulucci, Giuseppe [Istituto di Fisica, Università Cattolica del S. Cuore, L. go F. Vito 1, 00168 Roma (Italy); Cacaci, Margherita; Posteraro, Brunella; Sanguinetti, Maurizio [Istituto di Microbiologia, Università Cattolica del S. Cuore, L. go F. Vito 1, 00168 Roma (Italy); De Spirito, Marco [Istituto di Fisica, Università Cattolica del S. Cuore, L. go F. Vito 1, 00168 Roma (Italy)

    2013-08-15

    The opportunistic pathogenic mould Aspergillus fumigatus (A. fumigatus) is an increasing cause of morbidity and mortality in immunocompromised and in part immunocompetent patients. A. fumigatus can grow in multicellular communities by the formation of a hyphal network embedded in an extracellular matrix (ECM) meanly composed by polysaccharides, melanin, proteins. Because adhesion properties is one primary factor affecting the balance between growth, detachment and biofilm formation, its quantification is essential in understanding, predicting, and modelling biofilm development. Atomic force microscopy (AFM) imaging and force spectroscopy have recently opened a range of novel applications in microbiology including the imaging and manipulation of membrane proteins at the subnanometer level, the observation of the surface of living cells at high resolution, the mapping of local properties such as surface charges, the measurement of elastic properties of cell-surface constituents and the probing of cellular interactions using functionalized probes. Nevertheless, the principal disadvantage of this approach is the relatively slow acquisition rate that makes AFM is not able to detect fast dynamics. In this study we demonstrated that digital pulsed force mode (DPFM) atomic force microscopy can be used to obtain high-resolution topographical images and to quantify the adhesion properties of the A. fumigatus biofilm with an high acquisition rate. Here we show by means of DPFM-AFM that Alginate Lyase (AlgL), an enzyme known to reduce negatively charged alginate levels in microbial biofilm, is able to reduce the biofilm adhesion forces forming several nano-fractures in the ECM. These results suggest that the AlgL could used to enhance the antifungal drugs transit through the ECM.

  8. A fast and quantitative evaluation of the Aspergillus fumigatus biofilm adhesion properties by means of digital pulsed force mode

    Science.gov (United States)

    Maiorana, Alessandro; Papi, Massimiliano; Bugli, Francesca; Torelli, Riccardo; Maulucci, Giuseppe; Cacaci, Margherita; Posteraro, Brunella; Sanguinetti, Maurizio; De Spirito, Marco

    2013-08-01

    The opportunistic pathogenic mould Aspergillus fumigatus (A. fumigatus) is an increasing cause of morbidity and mortality in immunocompromised and in part immunocompetent patients. A. fumigatus can grow in multicellular communities by the formation of a hyphal network embedded in an extracellular matrix (ECM) meanly composed by polysaccharides, melanin, proteins. Because adhesion properties is one primary factor affecting the balance between growth, detachment and biofilm formation, its quantification is essential in understanding, predicting, and modelling biofilm development. Atomic force microscopy (AFM) imaging and force spectroscopy have recently opened a range of novel applications in microbiology including the imaging and manipulation of membrane proteins at the subnanometer level, the observation of the surface of living cells at high resolution, the mapping of local properties such as surface charges, the measurement of elastic properties of cell-surface constituents and the probing of cellular interactions using functionalized probes. Nevertheless, the principal disadvantage of this approach is the relatively slow acquisition rate that makes AFM is not able to detect fast dynamics. In this study we demonstrated that digital pulsed force mode (DPFM) atomic force microscopy can be used to obtain high-resolution topographical images and to quantify the adhesion properties of the A. fumigatus biofilm with an high acquisition rate. Here we show by means of DPFM-AFM that Alginate Lyase (AlgL), an enzyme known to reduce negatively charged alginate levels in microbial biofilm, is able to reduce the biofilm adhesion forces forming several nano-fractures in the ECM. These results suggest that the AlgL could used to enhance the antifungal drugs transit through the ECM.

  9. Protein kinase C, focal adhesions and the regulation of cell migration

    DEFF Research Database (Denmark)

    Fogh, Betina S; Multhaupt, Hinke A B; Couchman, John Robert

    2014-01-01

    Cell adhesion to extracellular matrix is a complex process involving protrusive activity driven by the actin cytoskeleton, engagement of specific receptors, followed by signaling and cytoskeletal organization. Thereafter, contractile and endocytic/recycling activities may facilitate migration and...

  10. Activated leukocyte cell adhesion molecule and prognosis in acute ischemic stroke

    DEFF Research Database (Denmark)

    Smedbakken, Linda; Jensen, Jesper K; Hallén, Jonas;

    2011-01-01

    Biomarkers predicting mortality and functional outcome in stroke may be clinically helpful in identification of patients likely to benefit from intervention. Activated leukocyte cell adhesion molecule (ALCAM) is upregulated during neuroinflammation; we investigated whether ALCAM concentrations ar...

  11. Inflammatory mediators and cell adhesion molecules as indicators of severity of atherosclerosis: the Rotterdam Study

    NARCIS (Netherlands)

    M.P.M. de Maat (Moniek); M.L. Bots (Michiel); M.M.B. Breteler (Monique); J. Meijer (John); A.J. Kiliaan (Amanda); J.C.M. Witteman (Jacqueline); A. Hofman (Albert)

    2002-01-01

    textabstractInflammatory mediators and soluble cell adhesion molecules predict cardiovascular events. It is not clear whether they reflect the severity of underlying atherosclerotic disease. Within the Rotterdam Study, we investigated the associations of C-reactive protein (CRP), i

  12. PI3Kγ activation by CXCL12 regulates tumor cell adhesion and invasion

    International Nuclear Information System (INIS)

    Tumor dissemination is a complex process, in which certain steps resemble those in leukocyte homing. Specific chemokine/chemokine receptor pairs have important roles in both processes. CXCL12/CXCR4 is the most commonly expressed chemokine/chemokine receptor pair in human cancers, in which it regulates cell adhesion, extravasation, metastatic colonization, angiogenesis, and proliferation. All of these processes require activation of signaling pathways that include G proteins, phosphatidylinositol-3 kinase (PI3K), JAK kinases, Rho GTPases, and focal adhesion-associated proteins. We analyzed these pathways in a human melanoma cell line in response to CXCL12 stimulation, and found that PI3Kγ regulates tumor cell adhesion through mechanisms different from those involved in cell invasion. Our data indicate that, following CXCR4 activation after CXCL12 binding, the invasion and adhesion processes are regulated differently by distinct downstream events in these signaling cascades.

  13. Combined modeling of cell aggregation and adhesion mediated by receptor–ligand interactions under shear flow

    Directory of Open Access Journals (Sweden)

    Yu Du

    2015-11-01

    Full Text Available Blood cell aggregation and adhesion to endothelial cells under shear flow are crucial to many biological processes such as thrombi formation, inflammatory cascade, and tumor metastasis, in which these cellular interactions are mainly mediated by the underlying receptor–ligand bindings. While theoretical modeling of aggregation dynamics and adhesion kinetics of interacting cells have been well studied separately, how to couple these two processes remains unclear. Here we develop a combined model that couples cellular aggregation dynamics and adhesion kinetics under shear flow. The impacts of shear rate (or shear stress and molecular binding affinity were elucidated. This study provides a unified model where the action of a fluid flow drives cell aggregation and adhesion under the modulations of the mechanical shear flow and receptor–ligand interaction kinetics. It offers an insight into understanding the relevant biological processes and functions.

  14. Displacement of p130Cas from focal adhesions links actomyosin contraction to cell migration.

    Science.gov (United States)

    Machiyama, Hiroaki; Hirata, Hiroaki; Loh, Xia Kun; Kanchi, Madhu Mathi; Fujita, Hideaki; Tan, Song Hui; Kawauchi, Keiko; Sawada, Yasuhiro

    2014-08-15

    Cell adhesion complexes provide platforms where cell-generated forces are transmitted to the extracellular matrix (ECM). Tyrosine phosphorylation of focal adhesion proteins is crucial for cells to communicate with the extracellular environment. However, the mechanisms that transmit actin cytoskeletal motion to the extracellular environment to drive cell migration are poorly understood. We find that the movement of p130Cas (Cas, also known as BCAR1), a mechanosensor at focal adhesions, correlates with actin retrograde flow and depends upon actomyosin contraction and phosphorylation of the Cas substrate domain (CasSD). This indicates that CasSD phosphorylation underpins the physical link between Cas and the actin cytoskeleton. Fluorescence recovery after photobleaching (FRAP) experiments reveal that CasSD phosphorylation, as opposed to the association of Cas with Src, facilitates Cas displacement from adhesion complexes in migrating cells. Furthermore, the stabilization of Src-Cas binding and inhibition of myosin II, both of which sustain CasSD phosphorylation but mitigate Cas displacement from adhesion sites, retard cell migration. These results indicate that Cas promotes cell migration by linking actomyosin contractions to the adhesion complexes through a dynamic interaction with Src as well as through the phosphorylation-dependent association with the actin cytoskeleton. PMID:24928898

  15. Effect of oligosaccharides on the adhesion of gut bacteria to human HT-29 cells.

    Science.gov (United States)

    Altamimi, M; Abdelhay, O; Rastall, R A

    2016-06-01

    The influence of five oligosaccharides (cellobiose, stachyose, raffinose, lactulose and chito-oligosaccharides) on the adhesion of eight gut bacteria (Bifidobacterium bifidum ATCC 29521, Bacteroides thetaiotaomicron ATCC 29148D-5, Clostridium leptum ATCC 29065, Blautia coccoides ATCC 29236, Faecalibacterium prausnitzii ATCC 27766, Bacteroides fragilis ATCC 23745, Clostridium difficile ATCC 43255 and Lactobacillus casei ATCC 393) to mucous secreting and non-mucous secreting HT-29 human epithelial cells, was investigated. In pure culture, the bacteria showed variations in their ability to adhere to epithelial cells. The effect of oligosaccharides diminished adhesion and the presence of mucus played a major factor in adhesion, likely due to high adhesiveness to mucins present in the native human mucus layer covering the whole cell surface. However, clostridia displayed almost the same level of adhesion either with or without mucus being present. Bl. coccoides adhesion was decreased by stachyose and cellobiose in non-mucus-secreting cells in pure culture, while in mixed faecal culture cellobiose displayed the highest antiadhesive activity with an overall average of 65% inhibition amongst tested oligomers and lactulose displayed the lowest with an average of 47.4%. Bifidobacteria, Bacteroides, lactobacilli and clostridia were inhibited within the following ranges 47-78%, 32-65%, 11.7-58% and 64-85% respectively. This means that clostridia were the most strongly influenced members of the microflora amongst the bacterial groups tested in mixed culture. In conclusion, introducing oligosaccharides which are candidate prebiotics into pure or mixed cultures has affected bacterial adhesion. PMID:27018325

  16. Mechanical principle of enhancing cell-substrate adhesion via pre-tension in the cytoskeleton.

    Science.gov (United States)

    Chen, Bin; Gao, Huajian

    2010-05-19

    Motivated by our earlier study on the effect of pre-tension in gecko adhesion, here we investigate whether and how pre-tension in cytoskeleton influences cell adhesion by developing a stochastic-elasticity model of a stress fiber attached on a rigid substrate via molecular bonds. By comparing the variations in adhesion lifetime and observing the sequences of bond breaking with and without pre-tension in the stress fiber under the same applied force, we demonstrate that the effect of pre-tension is to shift the interfacial failure mode from cracklike propagation toward uniform bond failure within the contact region, thereby greatly increasing the adhesion lifetime. Since stress fibers are the primary load-bearing components of cells, as well as the basic functional units of cytoskeleton that facilitate cell adhesion, this study suggests a feasible mechanism by which cell adhesion could be actively controlled via cytoskeletal contractility and proposes that pre-tension may be a general principle in biological adhesion. PMID:20483323

  17. Quantitative multicolor compositional imaging resolves molecular domains in cell-matrix adhesions.

    Directory of Open Access Journals (Sweden)

    Eli Zamir

    Full Text Available BACKGROUND: Cellular processes occur within dynamic and multi-molecular compartments whose characterization requires analysis at high spatio-temporal resolution. Notable examples for such complexes are cell-matrix adhesion sites, consisting of numerous cytoskeletal and signaling proteins. These adhesions are highly variable in their morphology, dynamics, and apparent function, yet their molecular diversity is poorly defined. METHODOLOGY/PRINCIPAL FINDINGS: We present here a compositional imaging approach for the analysis and display of multi-component compositions. This methodology is based on microscopy-acquired multicolor data, multi-dimensional clustering of pixels according to their composition similarity and display of the cellular distribution of these composition clusters. We apply this approach for resolving the molecular complexes associated with focal-adhesions, and the time-dependent effects of Rho-kinase inhibition. We show here compositional variations between adhesion sites, as well as ordered variations along the axis of individual focal-adhesions. The multicolor clustering approach also reveals distinct sensitivities of different focal-adhesion-associated complexes to Rho-kinase inhibition. CONCLUSIONS/SIGNIFICANCE: Multicolor compositional imaging resolves "molecular signatures" characteristic to focal-adhesions and related structures, as well as sub-domains within these adhesion sites. This analysis enhances the spatial information with additional "contents-resolved" dimensions. We propose that compositional imaging can serve as a powerful tool for studying complex multi-molecular assemblies in cells and for mapping their distribution at sub-micron resolution.

  18. Synthesis and Properties of Waterborne Polyurethane (WBPU/Modified Lignin Amine (MLA Adhesive: A Promising Adhesive Material

    Directory of Open Access Journals (Sweden)

    Mohammad Mizanur Rahman

    2016-08-01

    Full Text Available A series of waterborne polyurethane (WBPU/modified lignin amine (MLA adhesives was prepared using MLA as a chain extender by a prepolymer mixing process. A successful Mannich reaction was achieved during the synthesis of MLA by reacting lignin with bis(3-aminopropylamine. Higher tensile strength, Young’s modulus, and thermal stability were recorded for WBPU/MLA adhesives with higher MLA contents. The WBPU/MLA adhesive materials were used to coat polyvinyl chloride (PVC substrates. The adhesive strength increased with increasing MLA content. More importantly, the MLA also enhanced the WBPU/MLA coating in terms of adhesive strength at moderately high temperatures as well as under natural weather exposed conditions. The adhesive strength was essentially unaffected with 6.48 mol % MLA in the WBPU/MLA coating after exposure to natural weather conditions for 180 days.

  19. Covalent and stable CuAAC modification of silicon surfaces for control of cell adhesion

    DEFF Research Database (Denmark)

    Vutti, Surendra; Buch-Månson, Nina; Schoffelen, Sanne; Bovet, Nicolas Emile; Martinez, Karen Laurence; Meldal, Morten Peter

    2015-01-01

    the vapor or liquid phase. In this work, we compared these two methods for oxidized silicon surfaces and thoroughly characterized the functionalization steps by tagging and fluorescence imaging. We demonstrate that the vapor-phase functionalization only provided transient surface modification that was......-transfer reaction. Subsequently, D-amino acid adhesion peptides could be immobilized on the surface by use of Cu(I)-catalyzed click chemistry. This enabled the study of cell adhesion to the metal surface. In contrast to unmodified surfaces, the peptide-modified surfaces were able to maintain cell adhesion during...

  20. Cell adhesion on Ti surface with controlled roughness

    Directory of Open Access Journals (Sweden)

    Burgos-Asperilla, Laura

    2015-06-01

    Full Text Available In this report, the in situ interaction between Saos-2 osteoblast cells and a smooth Ti surface was examined over time. The adhesion kinetics and mechanisms of cellular proliferation were monitored by quartz crystal microbalance (QCM and electrochemical impedance spectroscopy (EIS. The rate of Saos-2 attachment on Ti surfaces, obtained from the measurements performed with the QCM, is a first-order reaction, with k=2.10−3 min−1. The impedance measurements indicate that in the absence of cells, the Ti resistance diminishes over time (7 days, due to the presence of amino acids and proteins from the culture medium that have been a dsorbed, while in the presence of osteoblasts, this decrease is much greater because of the compounds generated by the cells that accelerate the dissolution of Ti.En este trabajo, se ha estudiado la interacción in situ entre células osteoblásticas Saos-2 y una superficie de Ti de rugosidad controlada a lo largo del tiempo. El estudio de la cinética y los mecanismos de proliferación celular de adhesión se ha realizado a través de la microbalanza de cristal de cuarzo (QCM y espectroscopía de impedancia electroquímica (EIS. La velocidad de adhesión de los osteoblastos sobre la superficie de Ti obtenida a través de medidas con la QCM, sigue una reacción de primer orden, con k=2×10−3 min−1. Los ensayos de impedancia indican que, en ausencia de las células, la resistencia del Ti disminuye con el tiempo (7 días, debido a la presencia de aminoácidos y proteínas del medio de cultivo que se han adsorbido, mientras que en presencia de células, esta disminución es mucho mayor debido a los productos metabólicos generados por las células que aceleran la disolución del Ti.

  1. Monocytes mediate metastatic breast tumor cell adhesion to endothelium under flow

    OpenAIRE

    Evani, Shankar J.; Prabhu, Rajesh G.; Gnanaruban, V.; Finol, Ender A.; Anand K. Ramasubramanian

    2013-01-01

    Endothelial adhesion is necessary for the hematogenous dissemination of tumor cells. However, the metastatic breast tumor cell MDA-MB-231 does not bind to the endothelium under physiological flow conditions, suggesting alternate mechanisms of adhesion. Since monocytes are highly represented in the tumor microenvironment, and also bind to endothelium during inflammation, we hypothesized that the monocytes assist in the arrest of MDA-MB-231 on the endothelium. Using in vitro models of the dynam...

  2. Characterization of antibody-mediated inhibition of Pseudomonas aeruginosa adhesion to epithelial cells.

    OpenAIRE

    Sexton, M; Reen, D J

    1992-01-01

    An enzyme-linked immunosorbent assay system was developed and used to study adhesion of Pseudomonas aeruginosa to human epithelial cells and the abilities of specific antibodies to inhibit this process. Human buccal epithelial cells coated onto microtiter plates were incubated with P. aeruginosa suspensions, and adherent bacteria were detected by using anti-P. aeruginosa serum and a horseradish peroxidase-conjugated secondary antiserum. Adhesion, quantitated as an increase in A405, varied lin...

  3. Expression of intercellular adhesion molecule-1 in rat heart with ischemia/reperfusion and limitation of infarct size by treatment with antibodies against cell adhesion molecules.

    OpenAIRE

    Yamazaki, T; Seko, Y; Tamatani, T; Miyasaka, M.; Yagita, H; Okumura, K.; R. Nagai; Yazaki, Y

    1993-01-01

    To elucidate the mechanism(s) of myocardial reperfusion injury, we investigated the roles of cell adhesion molecules on both leukocytes and vascular endothelial cells in the reperfused myocardia. We found that within 2 hours after reperfusion leukocytes began to infiltrate into the rat myocardia subjected to 30 minutes of ischemia and clarified, for the first time, that the expression of intercellular adhesion molecule-1 was enhanced on the capillary and venous endothelial cells from 8 to 96 ...

  4. Laser Phototherapy Enhances Mesenchymal Stem Cells Survival in Response to the Dental Adhesives

    Directory of Open Access Journals (Sweden)

    Ivana Márcia Alves Diniz

    2015-01-01

    Full Text Available Background. We investigated the influence of laser phototherapy (LPT on the survival of human mesenchymal stem cells (MSCs submitted to substances leached from dental adhesives. Method. MSCs were isolated and characterized. Oral mucosa fibroblasts and osteoblast-like cells were used as comparative controls. Cultured medium conditioned with two adhesive systems was applied to the cultures. Cell monolayers were exposed or not to LPT. Laser irradiations were performed using a red laser (GaAlAs, 780 nm, 0.04 cm2, 40 mW, 1 W/cm2, 0.4 J, 10 seconds, 1 point, 10 J/cm2. After 24 h, cell viability was assessed by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide reduction assay. Data were statistically compared by ANOVA followed by Tukey’s test (P<0.05. Results. Different cell types showed different viabilities in response to the same materials. Substances leached from adhesives were less cytotoxic to MSCs than to other cell types. Substances leached from Clearfil SE Bond were highly cytotoxic to all cell types tested, except to the MSCs when applied polymerized and in association with LPT. LPT was unable to significantly increase the cell viability of fibroblasts and osteoblast-like cells submitted to the dental adhesives. Conclusion. LPT enhances mesenchymal stem cells survival in response to substances leached from dental adhesives.

  5. Rapid and serial quantification of adhesion forces of yeast and Mammalian cells.

    Directory of Open Access Journals (Sweden)

    Eva Potthoff

    Full Text Available Cell adhesion to surfaces represents the basis for niche colonization and survival. Here we establish serial quantification of adhesion forces of different cell types using a single probe. The pace of single-cell force-spectroscopy was accelerated to up to 200 yeast and 20 mammalian cells per probe when replacing the conventional cell trapping cantilever chemistry of atomic force microscopy by underpressure immobilization with fluidic force microscopy (FluidFM. In consequence, statistically relevant data could be recorded in a rapid manner, the spectrum of examinable cells was enlarged, and the cell physiology preserved until approached for force spectroscopy. Adhesion forces of Candida albicans increased from below 4 up to 16 nN at 37°C on hydrophobic surfaces, whereas a Δhgc1-mutant showed forces consistently below 4 nN. Monitoring adhesion of mammalian cells revealed mean adhesion forces of 600 nN of HeLa cells on fibronectin and were one order of magnitude higher than those observed for HEK cells.

  6. Isolation and characterization of Chinese hamster ovary cell variants defective in adhesion to fibronectin-coated collagen

    OpenAIRE

    1980-01-01

    Variant clones of Chinese hamster ovary (CHO) cells were selected for reduced adhesion to serum-coated tissue culture plates. These clones also displayed reduced adhesion to substrata composed of collagen layers coated with bovine serum or with fibronectin (cold-insoluble globulin). Wild-type (WT) and adhesion variant (ADv) cells grew at comparable rates in suspension culture, but the adhesion variants could not be grown in monolayer culture because of their inability to attach to the substra...

  7. Effects of protein tyrosine kinase inhibitors on cytokine-induced adhesion molecule expression by human umbilical vein endothelial cells.

    OpenAIRE

    May, M. J.; Wheeler-Jones, C. P.; Pearson, J. D.

    1996-01-01

    1. Endothelial cells can be stimulated by the pro-inflammatory cytokines interleukin (IL)-1 alpha and tumour necrosis factor (TNF) alpha to express the leukocyte adhesion molecules E-selectin, vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1 but the intracellular signalling mechanisms leading to this expression are incompletely understood. We have investigated the role of protein tyrosine kinases (PTK) in adhesion molecule expression by cytokine-activated ...

  8. The adhesion receptor CD44 promotes atherosclerosis by mediating inflammatory cell recruitment and vascular cell activation

    Science.gov (United States)

    Cuff, Carolyn A.; Kothapalli, Devashish; Azonobi, Ijeoma; Chun, Sam; Zhang, Yuanming; Belkin, Richard; Yeh, Christine; Secreto, Anthony; Assoian, Richard K.; Rader, Daniel J.; Puré, Ellen

    2001-01-01

    Atherosclerosis causes most acute coronary syndromes and strokes. The pathogenesis of atherosclerosis includes recruitment of inflammatory cells to the vessel wall and activation of vascular cells. CD44 is an adhesion protein expressed on inflammatory and vascular cells. CD44 supports the adhesion of activated lymphocytes to endothelium and smooth muscle cells. Furthermore, ligation of CD44 induces activation of both inflammatory and vascular cells. To assess the potential contribution of CD44 to atherosclerosis, we bred CD44-null mice to atherosclerosis-prone apoE-deficient mice. We found a 50–70% reduction in aortic lesions in CD44-null mice compared with CD44 heterozygote and wild-type littermates. We demonstrate that CD44 promotes the recruitment of macrophages to atherosclerotic lesions. Furthermore, we show that CD44 is required for phenotypic dedifferentiation of medial smooth muscle cells to the “synthetic” state as measured by expression of VCAM-1. Finally, we demonstrate that hyaluronan, the principal ligand for CD44, is upregulated in atherosclerotic lesions of apoE-deficient mice and that the low-molecular-weight proinflammatory forms of hyaluronan stimulate VCAM-1 expression and proliferation of cultured primary aortic smooth muscle cells, whereas high-molecular-weight forms of hyaluronan inhibit smooth muscle cell proliferation. We conclude that CD44 plays a critical role in the progression of atherosclerosis through multiple mechanisms. PMID:11581304

  9. A fucan from the brown seaweed Spatoglossum schröederi inhibits Chinese hamster ovary cell adhesion to several extracellular matrix proteins

    Directory of Open Access Journals (Sweden)

    Rocha H.A.O.

    2001-01-01

    Full Text Available Fucans, a family of sulfated polysaccharides present in brown seaweed, have several biological activities. Their use as drugs would offer the advantage of no potential risk of contamination with viruses or particles such as prions. A fucan prepared from Spatoglossum schröederi was tested as a possible inhibitor of cell-matrix interactions using wild-type Chinese hamster ovary cells (CHO-K1 and the mutant type deficient in xylosyltransferase (CHO-745. The effect of this polymer on adhesion properties with specific extracellular matrix components was studied using several matrix proteins as substrates for cell attachment. Treatment with the polymer inhibited the adhesion of fibronectin to both CHO-K1 (2 x 10(5(and CHO-745 (2 x 10(5 and 5 x 10(5 cells. No effect was detected with laminin, using the two cell types. On the other hand, adhesion to vitronectin was inhibited in CHO-K1 cells and adhesion to type I collagen was inhibited in CHO-745 cells. In spite of this inhibition, the fucan did not affect either cell proliferation or cell cycle. These results demonstrate that this polymer is a new anti-adhesive compound with potential pharmacological applications.

  10. Non-destructive method of determination of elastic properties and adhesion coefficient of different coating materials

    Directory of Open Access Journals (Sweden)

    M. Kubisztal

    2010-12-01

    Full Text Available Purpose: The paper presents a non-destructive method of determination of Young’s modulus and adhesion coefficient of different coating materials (metallic coatings, polymer, composite etc.. Some of the results obtained by applying this method are discussed in detail.Design/methodology/approach: The presented method consists in measuring the dynamic response of the examined material in the form of a flat rectangular bar subjected to external periodic mechanical stress i.e. the so called vibrating reed technique. General equations describing elastic properties of the sample consisting of a substrate and a deposited coating are derived and discussed in detail.Findings: It was shown that the application of the proposed approach to the metallic, polymeric and composite coatings allowed to obtain a quantitative data concerning the change of both the elastic properties and the adhesion coefficient with a change of: coating thickness, measurement temperature, chemical composition of coating, surface preparation or in the case of epoxy resin coatings with a change of curing time or curing temperature.Research limitations/implications: The proposed method can be applied in many scientific problems in the field of coating materials (e.g. elastic properties of porous coating, crystallization of amorphous coating, adhesion of different polymeric coatings.Practical implications: It was shown that the described method can be successfully used in optimisation of some technological processes of deposition of different coatings on metallic substrate.Originality/value: The paper presents methodology of a non-destructive approach to determination of elastic properties and adhesion coefficient of coating materials with an overview of some applications already publish and also the new ones. Especially interesting are the results concerning the influence of surface preparation on adhesion coefficient which are published for the first time.

  11. RNA and DNA aptamers as potential tools to prevent cell adhesion in disease

    Directory of Open Access Journals (Sweden)

    Ulrich H.

    2001-01-01

    Full Text Available Recent research has shown that receptor-ligand interactions between surfaces of communicating cells are necessary prerequisites for cell proliferation, cell differentiation and immune defense. Cell-adhesion events have also been proposed for pathological conditions such as cancer growth, metastasis, and host-cell invasion by parasites such as Trypanosoma cruzi. RNA and DNA aptamers (aptus = Latin, fit that have been selected from combinatorial nucleic acid libraries are capable of binding to cell-adhesion receptors leading to a halt in cellular processes induced by outside signals as a consequence of blockage of receptor-ligand interactions. We outline here a novel approach using RNA aptamers that bind to T. cruzi receptors and interrupt host-cell invasion in analogy to existing procedures of blocking selectin adhesion and function in vitro and in vivo.

  12. CHOLESTEROL BIOTRANSFORMATION TO CHOLESTA-4, 6-DIEN-3-OL AND EFFECT OF ASSIMILATION ON ADHESION PROPERTIES OF LACTOBACILLUS HELVETICUS CD6

    Directory of Open Access Journals (Sweden)

    Jayesh J. Ahire

    2014-04-01

    Full Text Available Cholesterol biotransformation by Lactobacillus helveticus CD6 was observed in minimal medium supplemented with 3 mM cholesterol when grown for 120 h at 37 °C. Its gas chromatography-mass spectrometry (GC-MS showed production of cholesta-4, 6-dien-3-ol and cholest-5-en-3-ol (3.beta with 12 U ∕mg cholesterol oxidase-like enzyme activity. The cholesterol assimilation was evaluated at varied concentrations of bile salt in MRS medium. The cell survival and cholesterol assimilation was found to be adversely affected in presence of bile salt. Microscopic studies revealed changed cell morphology when grown with cholesterol. The cell adhesion properties like autoaggregation, microbial adhesion to solvents where found to be affected by cholesterol. The 7.49 % cell adhesion to ethyl acetate indicates the decrease in electron accepting properties of cell surface, while 9 % decrease in xylene adhesion and 13 % decrease in autoaggregation was observed which would be helpful in cholesterol lowering when supplemented in the form of probiotic preparation.

  13. Galectin-1-mediated cell adhesion, invasion and cell death in human anaplastic large cell lymphoma: regulatory roles of cell surface glycans.

    Science.gov (United States)

    Suzuki, Osamu; Abe, Masafumi

    2014-05-01

    Galectin-1 is known to be one of the extracellular matrix proteins. To elucidate the biological roles of galectin-1 in cell adhesion and invasion of human anaplastic large cell lymphoma, we performed cell adhesion and invasion assays using the anaplastic large cell lymphoma cell line H-ALCL, which was previously established in our laboratory. From the cell surface lectin array, treatment with neuraminidase from Arthrobacter ureafaciens which cleaves all linkage types of cell surface sialic acid enhanced Arachis hypogaea (PNA), Helix pomatia (HPA) and Phaseolus vulgaris-L (L-PHA) lectin binding reactivity to cell surface of lymphoma cells suggesting that neuraminidase removes cell surface sialic acid. In cell adhesion and invasion assays treatment with neuraminidase markedly enhanced cell adhesion to galectin-1 and decreased cell invasive capacity through galectin-1. α2,6-linked sialic acid may be involved in masking the effect of the interaction between galectin-1 and cell surface glycans. H-ALCL cells expressed the β-galactoside-α2,6-sialyltransferase ST6Gal1. On resialylation assay by recombinant ST6Gal1 with CMP-Neu5Ac, α2,6-resialylation of L-PHA reactive oligosaccharide by ST6Gal1 resulted in inhibition of H-ALCL cell adhesion to galectin-1 compared to the desialylated H-ALCL cells. On knockdown experiments, knockdown of ST6Gal1 dramatically enhanced cell adhesion to galectin-1. N-glycosylation inhibitor swainsonine treatment resulted in enhancement of cell adhesion to galectin-1. In glycomic analysis using the lectin blocking assay treatment with PNA, Artocarpus integrifolia (Jacalin), Glycine max (SBA), Helix pomatia (HPA), Vicia villosa (VVA), Ulex europaeus (UEA-1), Triticum vulgaris (WGA), Canavalia ensiformis (ConA), Phaseolus vulgaris-L (L-PHA), Phaseolus vulgaris-E4 (E-PHA), Datura stramonium (DSA) lectins resulted in modulation of lymphoma cell to galectin-1 suggesting that several types of glycans may regulate cell adhesion to galectin-1 by

  14. Activated leukocyte cell adhesion molecule in breast cancer: prognostic indicator

    International Nuclear Information System (INIS)

    Activated leukocyte cell adhesion molecule (ALCAM) (CD166) is an immunoglobulin molecule that has been implicated in cell migration. The present study examined the expression of ALCAM in human breast cancer and assessed its prognostic value. The immunohistochemical distribution and location of ALCAM was assessed in normal breast tissue and carcinoma. The levels of ALCAM transcripts in frozen tissue (normal breast, n = 32; breast cancer, n = 120) were determined using real-time quantitative PCR. The results were then analyzed in relation to clinical data including the tumor type, the grade, the nodal involvement, distant metastases, the tumor, node, metastasis (TNM) stage, the Nottingham Prognostic Index (NPI), and survival over a 6-year follow-up period. Immunohistochemical staining on tissue sections in ducts/acini in normal breast and in breast carcinoma was ALCAM-positive. Differences in the number of ALCAM transcripts were found in different types of breast cancer. The level of ALCAM transcripts was lower (P = 0.05) in tumors from patients who had metastases to regional lymph nodes compared with those patients without, in higher grade tumors compared with Grade 1 tumors (P < 0.01), and in TNM Stage 3 tumors compared with TNM Stage 1 tumors (P < 0.01). Tumors from patients with poor prognosis (with NPI > 5.4) had significantly lower levels (P = 0.014) of ALCAM transcripts compared with patients with good prognosis (with NPI < 3.4), and tumors from patients with local recurrence had significantly lower levels than those patients without local recurrence or metastases (P = 0.04). Notably, tumors from patients who died of breast cancer had significantly lower levels of ALCAM transcripts (P = 0.0041) than those with primary tumors but no metastatic disease or local recurrence. Patients with low levels of ALCAM transcripts had significantly (P = 0.009) more incidents (metastasis, recurrence, death) compared with patients with primary breast tumors with high levels of

  15. ADHESION INDUCES MATRIX METALLOPROTEINASE-9 GENE EXPRESSION IN OVARIAN CANCER CELLS

    Institute of Scientific and Technical Information of China (English)

    田方; 颜春洪; 薛红; 肖凤君

    2002-01-01

    Objective: To investigate the expression of matrix metalloproteinase-9 (MMP-9) gene in cancer cells induced by adhesion with fibronectin and the underlying mechanism of cell invasion. Methods: Following adhesion of ovarian cancer cells A2780 to fibronectin, MMP mRNA expression was assayed by using reverse transcription-polymerase chain reaction (RT-PCR). MMP-9 promoter was cloned from genomic DNA of HT1080 cells with PCR. The MMP-9-pGL2 reporter gene vector was constructed and then transiently transfected into A2780 cells. Results: Adhesion could induce the expression of MMP-9 gene in A2780 cells, but did not affect longer theexpression of MMP-2 or TIMP-1 gene. The induction was enhanced with longer adhesion time. When the transfected cells were allowed to adhere and spread on FN-coated surface, the promoter activity of MMP-9 gene was also enhanced dramatically. Conclusion: adhesion of cells with ECM may stimulate the expression of MMP-9 gene through stimulating the promoter activity, thereby enhancing cancer cell invasion and metastasis.

  16. Adhesion of Human B Cells to Germinal Centers in Vitro Involves VLA-4 and INCAM-110

    Science.gov (United States)

    Freedman, Arnold S.; Munro, J. Michael; Rice, G. Edgar; Bevilacqua, Michael P.; Morimoto, Chikao; McIntyre, Bradley W.; Rhynhart, Kurt; Pober, Jordan S.; Nadler, Lee M.

    1990-08-01

    Human B lymphocytes localize and differentiate within the microenvironment of lymphoid germinal centers. A frozen section binding assay was developed for the identification of those molecules involved in the adhesive interactions between B cells and lymphoid follicles. Activated human B cells and B cell lines were found to selectively adhere to germinal centers. The VLA-4 molecule on the lymphocyte and the adhesion molecule INCAM-110, expressed on follicular dendritic cells, supported this interaction. This cellular interaction model can be used for the study of how B cells differentiate.

  17. The Influences of Overlap Length, Bond Line Thickness and Pretreatmant on the Mechanical Properties of Adhesives: Focussing on Bonding Glass

    OpenAIRE

    Vervloed, J.; Kwakernaak, A.; Poulis, H.

    2008-01-01

    This paper focuses on the influences of overlap length, bond line thickness and pretreatment on the mechanical properties of adhesive bonds. In order to determine the bond strength, lap shear tests were performed. The researched adhesives are a 2 component epoxy and MS polymer. The smallest overlap length of the epoxy adhesive results in the highest maximum bond stress. However, there is nosignificant difference in maximum bond stresses due to different overlap lengths of the MS polymer. When...

  18. Effect of surface treatments on the flexural properties and adhesion of glass fiber-reinforced composite post to self-adhesive luting agent and radicular dentin.

    Science.gov (United States)

    Elnaghy, Amr M; Elsaka, Shaymaa E

    2016-01-01

    This study evaluated the effect of different surface treatments on the flexural properties and adhesion of glass fiber post to self-adhesive luting agent and radicular dentin. Seventy-five single-rooted human teeth were prepared to receive a glass fiber post (Reblida). The posts were divided into five groups according to the surface treatment: Gr C (control; no treatment), Gr S (silanization for 60 s), Gr AP (airborne-particle abrasion), Gr HF (etching with 9 % hydrofluoric acid for 1 min), and Gr M10 (etching with CH2Cl2 for 10 min). Dual-cure self-adhesive luting agent (Rely X Unicem) was applied to each group for testing the adhesion using micropush-out test. Failure types were examined with stereomicroscope and surface morphology of the posts was characterized using a scanning electron microscopy (SEM). Flexural properties of posts were assessed using a three-point bending test. Data were analyzed using ANOVA and Tukey's HSD test. Statistical significance was set at the 0.05 probability level. Groups treated with M10 showed significantly higher bond strength than those obtained with other surface treatments (P C > S > AP > HF. Most failure modes were adhesive type of failures between dentin and luting agent (48.2%). SEM analysis revealed that the fiber post surfaces were modified after surface treatments. The surface treatments did not compromise the flexural properties of fiber posts. Application of M10 to the fiber post surfaces enhanced the adhesion to self-adhesive luting agent and radicular dentin. PMID:25424595

  19. The cell adhesion molecules Echinoid and Friend of Echinoid coordinate cell adhesion and cell signaling to regulate the fidelity of ommatidial rotation in the Drosophila eye.

    Science.gov (United States)

    Fetting, Jennifer L; Spencer, Susan A; Wolff, Tanya

    2009-10-01

    Directed cellular movements are a universal feature of morphogenesis in multicellular organisms. Differential adhesion between the stationary and motile cells promotes these cellular movements to effect spatial patterning of cells. A prominent feature of Drosophila eye development is the 90 degrees rotational movement of the multicellular ommatidial precursors within a matrix of stationary cells. We demonstrate that the cell adhesion molecules Echinoid (Ed) and Friend of Echinoid (Fred) act throughout ommatidial rotation to modulate the degree of ommatidial precursor movement. We propose that differential levels of Ed and Fred between stationary and rotating cells at the initiation of rotation create a permissive environment for cell movement, and that uniform levels in these two populations later contribute to stopping the movement. Based on genetic data, we propose that ed and fred impart a second, independent, ;brake-like' contribution to this process via Egfr signaling. Ed and Fred are localized in largely distinct and dynamic patterns throughout rotation. However, ed and fred are required in only a subset of cells - photoreceptors R1, R7 and R6 - for normal rotation, cells that have only recently been linked to a role in planar cell polarity (PCP). This work also provides the first demonstration of a requirement for cone cells in the ommatidial rotation aspect of PCP. ed and fred also genetically interact with the PCP genes, but affect only the degree-of-rotation aspect of the PCP phenotype. Significantly, we demonstrate that at least one PCP protein, Stbm, is required in R7 to control the degree of ommatidial rotation. PMID:19736327

  20. The pro-adhesive and pro-survival effects of glucocorticoid in human ovarian cancer cells.

    Science.gov (United States)

    Yin, Lijuan; Fang, Fang; Song, Xinglei; Wang, Yan; Huang, Gaoxiang; Su, Jie; Hui, Ning; Lu, Jian

    2016-07-01

    Cell adhesion to extracellular matrix (ECM) is controlled by multiple signaling molecules and intracellular pathways, and is pivotal for survival and growth of cells from most solid tumors. Our previous works demonstrated that dexamethasone (DEX) significantly enhances cell adhesion and cell resistance to chemotherapeutics by increasing the levels of integrin β1, α4, and α5 in human ovarian cancer cells. However, it is unclear whether the components of ECM or other membrane molecules are also involved in the pro-adhesive effect of DEX in ovarian cancer cells. In this study, we demonstrated that the treatment of cells with DEX did not change the expression of collagens (I, III, and IV), laminin, CD44, and its principal ligand hyaluronan (HA), but significantly increased the levels of intracellular and secreted fibronectin (FN). Inhibiting the expression of FN with FN1 siRNA or blocking CD44, another FN receptor, with CD44 blocking antibody significantly attenuated the pro-adhesion of DEX, indicating that upregulation of FN mediates the pro-adhesive effect of DEX by its interaction with CD44 besides integrin β1. Moreover, DEX significantly enhanced cell resistance to the chemotherapeutic agent paclitaxel (PTX) by activating PI-3K-Akt pathway. Finally, we found that DEX also significantly upregulated the expression of MUC1, a transmembrane glycoprotein. Inhibiting the expression of MUC1 with MUC1 siRNA significantly attenuated the DEX-induced effects of pro-adhesion, Akt-activation, and pro-survival. In conclusion, these results provide new data that upregulation of FN and MUC1 by DEX contributes to DEX-induced pro-adhesion and protects ovarian cancer cells from chemotherapy. PMID:27151574

  1. Enhanced biocompatibility and wound healing properties of biodegradable polymer-modified allyl 2-cyanoacrylate tissue adhesive.

    Science.gov (United States)

    Lee, Young Ju; Son, Ho Sung; Jung, Gyeong Bok; Kim, Ji Hye; Choi, Samjin; Lee, Gi-Ja; Park, Hun-Kuk

    2015-06-01

    As poly L-lactic acid (PLLA) is a polymer with good biocompatibility and biodegradability, we created a new tissue adhesive (TA), pre-polymerized allyl 2-cyanoacrylate (PACA) mixed with PLLA in an effort to improve biocompatibility and mechanical properties in healing dermal wound tissue. We determined optimal mixing ratios of PACA and PLLA based on their bond strengths and chemical structures analyzed by the thermal gravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. In vitro biocompatibility of the PACA/PLLA was evaluated using direct- and indirect-contact methods according to the ISO-10993 cytotoxicity test for medical devices. The PACA/PLLA have similar or even better biocompatibility than those of commercially available cyanoacrylate (CA)-based TAs such as Dermabond® and Histoacryl®. The PACA/PLLA were not different from those exposed to Dermabond® and Histoacryl® in Raman spectra when biochemical changes of protein and DNA/RNA underlying during cell death were compared utilizing Raman spectroscopy. Histological analysis revealed that incised dermal tissues of rats treated with PACA/PLLA showed less inflammatory signs and enhanced collagen formation compared to those treated with Dermabond® or Histoacryl®. Of note, tissues treated with PACA/PLLA were stronger in the tensile strength compared to those treated with the commercially available TAs. Therefore, taking all the results into consideration, the PACA/PLLA we created might be a clinically useful TA for treating dermal wounds. PMID:25842106

  2. Competition of elastic and adhesive properties of carbon nanotubes anchored to atomic force microscopy tips

    International Nuclear Information System (INIS)

    In this paper we address the mechanical properties of carbon nanotubes anchored to atomic force microscopy (AFM) tips in a detailed analysis of experimental results and exhaustive description of a simple model. We show that volume elastic and surface adhesive forces both contribute to the dynamical AFM experimental signals. Their respective weights depend on the nanotube properties and on an experimental parameter: the oscillation amplitude. To quantify the elastic and adhesive contributions, a simple analytical model is used. It enables analytical expressions of the resonance frequency shift and dissipation that can be measured in the atomic force microscopy dynamical frequency modulation mode. It includes the nanotube adhesive contribution to the frequency shift. Experimental data for single-wall and multi-wall carbon nanotubes compare well to the model predictions for different oscillation amplitudes. Three parameters can be extracted: the distance necessary to unstick the nanotube from the surface and two spring constants corresponding to tube compression and to the elastic force required to overcome the adhesion force

  3. Handling sticky resin by Stingless Bees: adhesive properties of surface structures.

    Science.gov (United States)

    Gastauer, Markus; Campos, Lucio A O; Wittmann, Dieter

    2013-09-01

    Many Stingless Bees (Hymenoptera: Meliponini) like Tetragonisca angustula collect resin to defend their nests against intruders like ants or Robber Bees. Small portions of resin are attached to intruders bodies and extremities causing their immobilization. It has been observed that resin is removed easily from the bee's mandible but adheres strongly to the intruder's cuticle. We tested the hypothesis that resin sticks lesser to the mandibles of Stingless Bees than to the surface of intruders due to special surface structures or adhesive properties of these structures. The surface structures of the mandible of T. angustula and the trochanter of Camponotus sericeiventris were studied by scanning electron microscopy. To measure adhesion properties, selected surfaces were fixed on a fine glass pin and withdrawn from a glass tip covered with resin. The deformation of the glass pin indicates adhesion forces operating between the resin and the selective surface. The absolute value of the forces is computed from the glass pin's stiffness. It has been shown that resin sticks more to the smooth mandible of the bee than to the structured trochanter of the ant. A new hypothesis to be tested says that the bees might lubricate their mandibles with nectar or honey to reduce the resin's adhesion temporarily. PMID:24068098

  4. Effect of silver nanoparticles on the physicochemical and antimicrobial properties of an orthodontic adhesive

    Science.gov (United States)

    DEGRAZIA, Felipe Weidenbach; LEITUNE, Vicente Castelo Branco; GARCIA, Isadora Martini; ARTHUR, Rodrigo Alex; SAMUEL, Susana Maria Werner; COLLARES, Fabrício Mezzomo

    2016-01-01

    ABSTRACT Orthodontic treatment with fixed brackets plays a major role on the formation of white spot lesions. Objective This study aimed to incorporate silver nanoparticle solutions (AgNP) in an orthodontic adhesive and evaluate its physicochemical and antimicrobial properties. Material and Methods Silver nanoparticle solutions were added to a commercial adhesive in different concentrations (w/w): 0%, 0.11%, 0.18%, and 0.33%. Shear bond strength (SBS) test was performed after bonding metal brackets to enamel. Raman spectroscopy was used to analyze in situ the degree of conversion (DC) of the adhesive layer. The surface free energy (SFE) was evaluated after the measurement of contact angles. Growth inhibition of Streptococcus mutans in liquid and solid media was determined by colony-forming unit count and inhibition halo, respectively. One-way ANOVA was performed for SBS, DC, SFE, and growth inhibition. Results The incorporation of AgNP solution decreased the SBS (padhesive primer inhibited S. mutans growth. SBS, DC, and SFE values decreased after incorporation up to 0.33% AgNP solution without compromising the chemical and physical properties of the adhesive. PMID:27556213

  5. Polymer films with surfaces unmodified and modified by non-thermal plasma as new substrates for cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Borges, A.M.G.; Benetoli, L.O. [Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Licínio, M.A. [Department of Clinical Analysis, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Zoldan, V.C. [Department of Physical, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Santos-Silva, M.C. [Department of Clinical Analysis, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Assreuy, J. [Department of Pharmacology, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Pasa, A.A. [Department of Physical, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Debacher, N.A. [Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil); Soldi, V., E-mail: vsoldi@pq.cnpq.br [Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianopolis (Brazil)

    2013-04-01

    The surface properties of biomaterials, such as wettability, polar group distribution, and topography, play important roles in the behavior of cell adhesion and proliferation. Gaseous plasma discharges are among the most common means to modify the surface of a polymer without affecting its properties. Herein, we describe the surface modification of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) films using atmospheric pressure plasma processing through exposure to a dielectric barrier discharge (DBD). After treatment the film surface showed significant changes from hydrophobic to hydrophilic as the water contact angle decreasing from 95° to 37°. All plasma-treated films developed more hydrophilic surfaces compared to untreated films, although the reasons for the change in the surface properties of PS and PMMA differed, that is, the PS showed chemical changes and in the case of PMMA they were topographical. Excellent adhesion and cell proliferation were observed in all films. In vitro studies employing flow cytometry showed that the proliferation of L929 cells was higher in the film formed by a 1:1 mixture of PS/PMMA, which is consistent with the results of a previous study. These findings suggest better adhesion of L929 onto the 1:1 PS/PMMA modified film, indicating that this system is a new candidate biomaterial for tissue engineering. Highlights: ► The PS/PMMA films showed hydrophilic surface after DBD-treatment. ► The 1:1 PS/PMMA modified film is a new substrate for L929 cell proliferation. ► The 1:1 PS/PMMA blend film showed additional 170 × 10{sup 3} cells after treatment. ► The proliferation of cells in the blend film triplicated when compared to control. ► Synergistic effect improves cell proliferation in the blend film.

  6. Polymer films with surfaces unmodified and modified by non-thermal plasma as new substrates for cell adhesion

    International Nuclear Information System (INIS)

    The surface properties of biomaterials, such as wettability, polar group distribution, and topography, play important roles in the behavior of cell adhesion and proliferation. Gaseous plasma discharges are among the most common means to modify the surface of a polymer without affecting its properties. Herein, we describe the surface modification of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) films using atmospheric pressure plasma processing through exposure to a dielectric barrier discharge (DBD). After treatment the film surface showed significant changes from hydrophobic to hydrophilic as the water contact angle decreasing from 95° to 37°. All plasma-treated films developed more hydrophilic surfaces compared to untreated films, although the reasons for the change in the surface properties of PS and PMMA differed, that is, the PS showed chemical changes and in the case of PMMA they were topographical. Excellent adhesion and cell proliferation were observed in all films. In vitro studies employing flow cytometry showed that the proliferation of L929 cells was higher in the film formed by a 1:1 mixture of PS/PMMA, which is consistent with the results of a previous study. These findings suggest better adhesion of L929 onto the 1:1 PS/PMMA modified film, indicating that this system is a new candidate biomaterial for tissue engineering. Highlights: ► The PS/PMMA films showed hydrophilic surface after DBD-treatment. ► The 1:1 PS/PMMA modified film is a new substrate for L929 cell proliferation. ► The 1:1 PS/PMMA blend film showed additional 170 × 103 cells after treatment. ► The proliferation of cells in the blend film triplicated when compared to control. ► Synergistic effect improves cell proliferation in the blend film

  7. AFM method to detect differences in adhesion of silica bids to cancer and normal epithelial cells

    Science.gov (United States)

    Sokolov, Igor; Iyer, Swaminathan; Gaikwad, Ravi; Woodworth, Craig

    2009-03-01

    To date, the methods of detection of cancer cells have been mostly based on traditional techniques used in biology, such as visual identification of malignant changes, cell growth analysis, specific ligand-receptor labeling, or genetic tests. Despite being well developed, these methods are either insufficiently accurate or require a lengthy complicated analysis. A search for alternative methods for the detection of cancer cells may be a fruitful approach. Here we describe an AFM study that may result in a new method for detection of cancer cells in vitro. Here we use atomic force microscopy (AFM) to study adhesion of single silica beads to malignant and normal cells cultured from human cervix. We found that adhesion depends on the time of contact, and can be statistically different for malignant and normal cells. Using these data, one could develop an optical method of cancer detection based on adhesion of various silica beads.

  8. RP1 is a phosphorylation target of CK2 and is involved in cell adhesion.

    Directory of Open Access Journals (Sweden)

    Frank Stenner

    Full Text Available RP1 (synonym: MAPRE2, EB2 is a member of the microtubule binding EB1 protein family, which interacts with APC, a key regulatory molecule in the Wnt signalling pathway. While the other EB1 proteins are well characterized the cellular function and regulation of RP1 remain speculative to date. However, recently RP1 has been implicated in pancreatic cancerogenesis. CK2 is a pleiotropic kinase involved in adhesion, proliferation and anti-apoptosis. Overexpression of protein kinase CK2 is a hallmark of many cancers and supports the malignant phenotype of tumor cells. In this study we investigate the interaction of protein kinase CK2 with RP1 and demonstrate that CK2 phosphorylates RP1 at Ser(236 in vitro. Stable RP1 expression in cell lines leads to a significant cleavage and down-regulation of N-cadherin and impaired adhesion. Cells expressing a Phospho-mimicking point mutant RP1-ASP(236 show a marked decrease of adhesion to endothelial cells under shear stress. Inversely, we found that the cells under shear stress downregulate endogenous RP1, most likely to improve cellular adhesion. Accordingly, when RP1 expression is suppressed by shRNA, cells lacking RP1 display significantly increased cell adherence to surfaces. In summary, RP1 phosphorylation at Ser(236 by CK2 seems to play a significant role in cell adhesion and might initiate new insights in the CK2 and EB1 family protein association.

  9. Controlling cell adhesion via replication of laser micro/nano-textured surfaces on polymers

    International Nuclear Information System (INIS)

    The aim of this study is to investigate cell adhesion and viability on highly rough polymeric surfaces with gradient roughness ratios and wettabilities prepared by microreplication of laser micro/nano-textured Si surfaces. Negative replicas on polydimethylsiloxane as well as positive ones on a photocurable (organically modified ceramic) and a biodegradable (poly(lactide-co-glycolide)) polymer have been successfully reproduced. The final culture substrates comprised from forests of micron-sized conical spikes exhibiting a range of roughness ratios and wettabilities, was achieved by changing the laser fluence used to fabricate the original template surfaces. Cell culture experiments were performed with the fibroblast NIH/3T3 and PC12 neuronal cell lines in order to investigate how these surfaces are capable of modulating different types of cellular responses including, viability, adhesion and morphology. The results showed a preferential adhesion of both cell types on the microstructured surfaces compared to the unstructured ones. In particular, the fibroblast NIH/3T3 cells show optimal adhesion for small roughness ratios, independent of the surface wettability and polymer type, indicating a non-monotonic dependence of cell adhesion on surface energy. In contrast, the PC12 cells were observed to adhere well to the patterned surfaces independent of the roughness ratio and wettability. These experimental findings are correlated with micromechanical measurements performed on the unstructured and replicated surfaces and discussed on the basis of previous observations describing the relation of cell response to surface energy and rigidity.

  10. Adhesion of MRC-5 and A549 cells on poly(dimethylsiloxane) surface modified by proteins.

    Science.gov (United States)

    Zuchowska, Agnieszka; Kwiatkowski, Piotr; Jastrzebska, Elzbieta; Chudy, Michal; Dybko, Artur; Brzozka, Zbigniew

    2016-02-01

    PDMS is a very popular material used for fabrication of Lab-on-a-Chip systems for biological applications. Although PDMS has numerous advantages, it is a highly hydrophobic material, which inhibits adhesion and proliferation of the cells. PDMS surface modifications are used to enrich growth of the cells. However, due to the fact that each cell type has specific adhesion, it is necessary to optimize the parameters of these modifications. In this paper, we present an investigation of normal (MRC-5) and carcinoma (A549) human lung cell adhesion and proliferation on modified PDMS surfaces. We have chosen these cell types because often they are used as models for basic cancer research. To the best of our knowledge, this is the first presentation of this type of investigation. The combination of a gas-phase processing (oxygen plasma or ultraviolet irradiation) and wet chemical methods based on proteins' adsorption was used in our experiments. Different proteins such as poly-l-lysine, fibronectin, laminin, gelatin, and collagen were incubated with the activated PDMS samples. To compare with other works, here, we also examined how ratio of prepolymer to curing agent (5:1, 10:1, and 20:1) influences PDMS hydrophilicity during further modifications. The highest adhesion of the tested cells was observed for the usage of collagen, regardless of PDMS ratio. However, the MRC-5 cell line demonstrated better adhesion than A549 cells. This is probably due to the difference in their morphology and type (normal/cancer). PMID:26311334

  11. Controlling cell adhesion via replication of laser micro/nano-textured surfaces on polymers

    Energy Technology Data Exchange (ETDEWEB)

    Koufaki, Niki; Ranella, Anthi; Barberoglou, Marios; Psycharakis, Stylianos; Fotakis, Costas; Stratakis, Emmanuel [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 711 10, Heraklion, Crete (Greece); Aifantis, Katerina E, E-mail: stratak@iesl.forth.gr [Lab of Mechanics and Materials, Aristotle University of Thessaloniki, Thessaloniki (Greece)

    2011-12-15

    The aim of this study is to investigate cell adhesion and viability on highly rough polymeric surfaces with gradient roughness ratios and wettabilities prepared by microreplication of laser micro/nano-textured Si surfaces. Negative replicas on polydimethylsiloxane as well as positive ones on a photocurable (organically modified ceramic) and a biodegradable (poly(lactide-co-glycolide)) polymer have been successfully reproduced. The final culture substrates comprised from forests of micron-sized conical spikes exhibiting a range of roughness ratios and wettabilities, was achieved by changing the laser fluence used to fabricate the original template surfaces. Cell culture experiments were performed with the fibroblast NIH/3T3 and PC12 neuronal cell lines in order to investigate how these surfaces are capable of modulating different types of cellular responses including, viability, adhesion and morphology. The results showed a preferential adhesion of both cell types on the microstructured surfaces compared to the unstructured ones. In particular, the fibroblast NIH/3T3 cells show optimal adhesion for small roughness ratios, independent of the surface wettability and polymer type, indicating a non-monotonic dependence of cell adhesion on surface energy. In contrast, the PC12 cells were observed to adhere well to the patterned surfaces independent of the roughness ratio and wettability. These experimental findings are correlated with micromechanical measurements performed on the unstructured and replicated surfaces and discussed on the basis of previous observations describing the relation of cell response to surface energy and rigidity.

  12. Nuclear factor kappaB-mediated down-regulation of adhesion molecules: possible mechanism for inhibitory activity of bigelovin against inflammatory monocytes adhesion to endothelial cells.

    Science.gov (United States)

    Nam, Kung-Woo; Oh, Goo Taeg; Seo, Eun-Kyoung; Kim, Kyeong Ho; Koo, Uk; Lee, Sung-Jin; Mar, Woongchon

    2009-06-22

    The flowers of Inula britannica L. var. chinensis (Rupr.) Reg. (Compositae) are used in traditional medicine to treat asthma, chronic bronchitis, and acute pleurisy in China and Korea. However, the pharmacological actions of Inula britannica L. var. chinensis on endothelial cells and inflammatory monocytes are not clear. In this study, we investigated whether bigelovin, a sesquiterpene lactone isolated from the flowers of Inula britannica L. var. chinensis, inhibits monocyte adhesion and adhesion molecule expression in brain endothelial cells. We measured tumor necrosis factor-alpha (TNF-alpha)-enhanced Raw264.7 monocyte binding to brain endothelial cells and the levels of cell adhesion molecules, including vascular adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), and endothelial-selectin (E-selectin) on the surface of brain endothelial cells. Bigelovin significantly inhibited these in a dose-dependent manner without affecting cell viability. Furthermore, bigelovin suppressed the nuclear factor kappaB (NF-kappaB) promoter-driven luciferase activity, NF-kappaB activation, and degradation of NF-kappaB inhibitor protein alpha (IkappaBalpha). These results indicate that bigelovin inhibits inflammatory monocyte adhesion to endothelial cells and the expression of VCAM-1, ICAM-1, and E-selectin by blocking IkappaBalpha degradation and NF-kappaB activation. PMID:19429369

  13. Receptor FGFRL1 does not promote cell proliferation but induces cell adhesion.

    Science.gov (United States)

    Yang, Xiaochen; Steinberg, Florian; Zhuang, Lei; Bessey, Ralph; Trueb, Beat

    2016-07-01

    Fibroblast growth factor receptor (FGFR)-like protein 1 (FGFRL1) is the most recently discovered member of the FGFR family. Owing to the fact that it interacts with FGF ligands, but lacks the intracellular tyrosine kinase domain, several researchers have speculated that it may function as a decoy receptor and exert a negative effect on cell proliferation. In this study, we performed overexpression experiments with TetOn‑inducible cell clones and downregulation experiments with siRNA oligonucleotides, and found that FGFRL1 had absolutely no effect on cell growth and proliferation. Likewise, we did not observe any influence of FGFRL1 on ERK1/2 activation and on the phosphorylation of 250 other signaling proteins analyzed by the Kinexus antibody microarray. On the other hand, with bacterial petri dishes, we observed a clear effect of FGFRL1 on cell adhesion during the initial hours after cell seeding. Our results suggest that FGFRL1 is a cell adhesion protein similar to the nectins rather than a signaling receptor similar to FGFR1-FGFR4. PMID:27220341

  14. How actin/myosin crosstalks guide the adhesion, locomotion and polarization of cells.

    Science.gov (United States)

    Sackmann, Erich

    2015-11-01

    Cell-tissue-tissue interaction is determined by specific short range forces between cell adhesion molecules (CAMs) and ligands of the tissue, long range repulsion forces mediated by cell surface grafted macromolecules and adhesion-induced elastic stresses in the cell envelope. This interplay of forces triggers the rapid random clustering of tightly coupled linkers. By coupling of actin gel patches to the intracellular domains of the CAMs, these clusters can grow in a secondary process resulting in the formation of functional adhesion microdomains (ADs). The ADs can act as biochemical steering centers by recruiting and activating functional proteins, such as GTPases and associated regulating proteins, through electrostatic-hydrophobic forces with cationic lipid domains that act as attractive centers. First, I summarize physical concepts of cell adhesion revealed by studies of biomimetic systems. Then I describe the role of the adhesion domains as biochemical signaling platforms and force transmission centers promoting cellular protrusions, in terms of a shell string model of cells. Protrusion forces are generated by actin gelation triggered by molecular machines (focal adhesion kinase (FAK), Src-kinases and associated adaptors) which assemble around newly formed integrin clusters. They recruit and activate the GTPases Rac-1 and actin gelation promoters to charged membrane domains via electrostatic-hydrophobic forces. The cell front is pushed forward in a cyclic and stepwise manner and the step-width is determined by the dynamics antagonistic interplay between Rac-1 and RhoA. The global cell polarization in the direction of motion is mediated by the actin-microtubule (MT) crosstalk at adhesion domains. Supramolecular actin-MT assemblies at the front help to promote actin polymerization. At the rear they regulate the dismantling of the ADs through the Ca(++)-mediated activation of the protease calpain and trigger their disruption by RhoA mediated contraction via

  15. Intercellular adhesion molecule-1 and gelatinase expression in human peritoneal mesothelial cells during propagation in culture.

    NARCIS (Netherlands)

    Sikkink, C.J.J.M.; Reijnen, M.M.P.J.; Duffhues, B.A.; Man, B.M. de; Lomme, R.M.L.M.; Goor, H. van

    2009-01-01

    Mesothelial cells are involved in a variety of biological processes, which include the formation of peritoneal adhesions. The cultures of human peritoneal mesothelial cells comprise an important tool to investigate the behavior and functions of mesothelial cells. Very little is known about the diffe

  16. Persistent downregulation of the pancarcinoma-associated epithelial cell adhesion molecule via active intranuclear methylation

    NARCIS (Netherlands)

    van der Gun, Bernardina T. F.; Wasserkort, Reinhold; Monami, Amelie; Jeltsch, Albert; Rasko, Tamits; Slaska-Kiss, Krystyna; Cortese, Rene; Rots, Marianne G.; de Leij, Lou F. M. H.; Ruiters, Marcel H. J.; Kiss, Antal; Weinhold, Elmar; McLaughlin, Pamela M. J.

    2008-01-01

    The epithelial cell adhesion molecule (EpCAM) is expressed at high levels on the surface of most carcinoma cells. SiRNA silencing of EpCAM expression leads to reduced metastatic potential of tumor cells demonstrating its importance in oncogenesis and tumor progression. However, siRNA therapy require

  17. Lipid Raft is required for PSGL-1 ligation induced HL-60 cell adhesion on ICAM-1.

    Directory of Open Access Journals (Sweden)

    Tingshuang Xu

    Full Text Available P-selectin glycoprotein ligand-1 (PSGL-1 and integrins are adhesion molecules that play critical roles in host defense and innate immunity. PSGL-1 mediates leukocyte rolling and primes leukocytes for integrin-mediated adhesion. However, the mechanism that PSGL-1 as a rolling receptor in regulating integrin activation has not been well characterized. Here, we investigate the function of lipid raft in regulating PSGL-1 induced β2 integrin-mediated HL-60 cells adhesion. PSGL-1 ligation with antibody enhances the β2 integrin activation and β2 integrin-dependent adhesion to ICAM-1. Importantly, with the treatment of methyl-β-cyclodextrin (MβCD, we confirm the role of lipid raft in regulating the activation of β2 integrin. Furthermore, we find that the protein level of PSGL-1 decreased in raft fractions in MβCD treated cells. PSGL-1 ligation induces the recruitment of spleen tyrosine kinase (Syk, a tyrosine kinase and Vav1 (the pivotal downstream effector of Syk signaling pathway involved in cytoskeleton regulation to lipid raft. Inhibition of Syk activity with pharmacologic inhibitor strongly reduces HL-60 cells adhesion, implicating Syk is crucial for PSGL-1 mediated β2 integrin activation. Taken together, we report that ligation of PSGL-1 on HL-60 cells activates β2 integrin, for which lipid raft integrity and Syk activation are responsible. These findings have shed new light on the mechanisms that connect leukocyte initial rolling with subsequent adhesion.

  18. Sialylation by β-galactoside α-2,6-sialyltransferase and N-glycans regulate cell adhesion and invasion in human anaplastic large cell lymphoma

    OpenAIRE

    Suzuki, Osamu; Abe, Masafumi; HASHIMOTO, YUKO

    2015-01-01

    The interaction between cell surface glycans and extracellular matrix (ECM) including galectins is known to be closely associated with tumor cell adhesion, invasion and metastasis. We analyzed the roles of cell surface sialylation or glycosylation in galectin or ECM-mediated cell adhesion and invasion of human malignant lymphoma cells. Neuraminidase from Arthrobacter ureafaciens (AU) treatment resulted in reduction of cell adhesion to galectin-8 in human anaplastic large cell lymphoma (H-ALCL...

  19. Construction of force measuring optical tweezers instrumentation and investigations of biophysical properties of bacterial adhesion organelles

    CERN Document Server

    Andersson, Magnus

    2015-01-01

    Optical tweezers are a technique in which microscopic-sized particles, including living cells and bacteria, can be non-intrusively trapped with high accuracy solely using focused light. The technique has therefore become a powerful tool in the field of biophysics. Optical tweezers thereby provide outstanding manipulation possibilities of cells as well as semi-transparent materials, both non-invasively and non-destructively, in biological systems. In addition, optical tweezers can measure minute forces (< 10-12 N), probe molecular interactions and their energy landscapes, and apply both static and dynamic forces in biological systems in a controlled manner. The assessment of intermolecular forces with force measuring optical tweezers, and thereby the biomechanical structure of biological objects, has therefore considerably facilitated our understanding of interactions and structures of biological systems. Adhesive bacterial organelles, so called pili, mediate adhesion to host cells and are therefore crucial...

  20. Contact angle, adhesion and friction properties of micro-and nanopatterned polymers for superhydrophobicity

    International Nuclear Information System (INIS)

    Superhydrophobic surfaces have considerable technological potential for various applications due to their extreme water-repellent properties. A number of studies have been carried out to produce artificial biomimetic roughness-induced hydrophobic surfaces. It is not clear whether microstructures or nanostructures or their certain combination on the surface, are required for superhydrophobicity. A variety of micro- and nanopatterned surfaces of two different polymers, poly(methyl methacrylate) (PMMA) and polystyrene (PS), were fabricated. We show how static contact angles vary with micro- and nanopatterns on the polymer surfaces. Based on the experimental data and a numerical model, the trends are explained. Tribological properties play an important role in many applications requiring water-repellent properties. Therefore, it is important to study the adhesion and friction properties of these surfaces that mimic nature. An atomic/friction force microscope (AFM/FFM) was used for surface characterization and adhesion and friction measurements. To further examine the effect of meniscus force and real area of contact, scale dependence is considered with the use of AFM tips of various radii. The effect of relative humidity is also investigated to study the environmental effects on adhesion and friction

  1. Motion of an Adhesive Gel in a Swelling Gradient a Mechanism for Cell Locomotion

    CERN Document Server

    Joanny, J F; Prost, J; Joanny, Jean-Francois; Julicher, Frank; Prost, Jacques

    2003-01-01

    Motivated by the motion of nematode sperm cells, we present a model for the motion of an adhesive gel on a solid substrate. The gel polymerizes at the leading edge and depolymerizes at the rear. The motion results from a competition between a self-generated swelling gradient and the adhesion on the substrate. The resulting stress provokes the rupture of the adhesion points and allows for the motion. The model predicts an unusual force-velocity relation which depends in significant ways on the point of application of the force.

  2. Mechanical Principle of Enhancing Cell-Substrate Adhesion via Pre-Tension in the Cytoskeleton

    OpenAIRE

    Chen, Bin; Gao, Huajian

    2010-01-01

    Motivated by our earlier study on the effect of pre-tension in gecko adhesion, here we investigate whether and how pre-tension in cytoskeleton influences cell adhesion by developing a stochastic-elasticity model of a stress fiber attached on a rigid substrate via molecular bonds. By comparing the variations in adhesion lifetime and observing the sequences of bond breaking with and without pre-tension in the stress fiber under the same applied force, we demonstrate that the effect of pre-tensi...

  3. The Role of Immunoglobulin Superfamily Cell Adhesion Molecules in Cancer Metastasis

    Directory of Open Access Journals (Sweden)

    Chee Wai Wong

    2012-01-01

    Full Text Available Metastasis is a major clinical problem and results in a poor prognosis for most cancers. The metastatic pathway describes the process by which cancer cells give rise to a metastatic lesion in a new tissue or organ. It consists of interconnecting steps all of which must be successfully completed to result in a metastasis. Cell-cell adhesion is a key aspect of many of these steps. Adhesion molecules belonging to the immunoglobulin superfamily (Ig-SF commonly play a central role in cell-cell adhesion, and a number of these molecules have been associated with cancer progression and a metastatic phenotype. Surprisingly, the contribution of Ig-SF members to metastasis has not received the attention afforded other cell adhesion molecules (CAMs such as the integrins. Here we examine the steps in the metastatic pathway focusing on how the Ig-SF members, melanoma cell adhesion molecule (MCAM, L1CAM, neural CAM (NCAM, leukocyte CAM (ALCAM, intercellular CAM-1 (ICAM-1 and platelet endothelial CAM-1 (PECAM-1 could play a role. Although much remains to be understood, this review aims to raise the profile of Ig-SF members in metastasis formation and prompt further research that could lead to useful clinical outcomes.

  4. A protocadherin-cadherin-FLRT3 complex controls cell adhesion and morphogenesis.

    Directory of Open Access Journals (Sweden)

    Xuejun Chen

    Full Text Available BACKGROUND: Paraxial protocadherin (PAPC and fibronectin leucine-rich domain transmembrane protein-3 (FLRT3 are induced by TGFbeta signaling in Xenopus embryos and both regulate morphogenesis by inhibiting C-cadherin mediated cell adhesion. PRINCIPAL FINDINGS: We have investigated the functional and physical relationships between PAPC, FLRT3, and C-cadherin. Although neither PAPC nor FLRT3 are required for each other to regulate C-cadherin adhesion, they do interact functionally and physically, and they form a complex with cadherins. By itself PAPC reduces cell adhesion physiologically to induce cell sorting, while FLRT3 disrupts adhesion excessively to cause cell dissociation. However, when expressed together PAPC limits the cell dissociating and tissue disrupting activity of FLRT3 to make it effective in physiological cell sorting. PAPC counteracts FLRT3 function by inhibiting the recruitment of the GTPase RND1 to the FLRT3 cytoplasmic domain. CONCLUSIONS/SIGNIFICANCE: PAPC and FLRT3 form a functional complex with cadherins and PAPC functions as a molecular "governor" to maintain FLRT3 activity at the optimal level for physiological regulation of C-cadherin adhesion, cell sorting, and morphogenesis.

  5. Influence of fermentation conditions on the surface properties and adhesion of Lactobacillus rhamnosus GG

    OpenAIRE

    Deepika Gurjot; Karunakaran Esther; Hurley Claire R; Biggs Catherine A; Charalampopoulos Dimitris

    2012-01-01

    Abstract Background The surface properties of probiotic bacteria influence to a large extent their interactions within the gut ecosystem. There is limited amount of information on the effect of the production process on the surface properties of probiotic lactobacilli in relation to the mechanisms of their adhesion to the gastrointestinal mucosa. The aim of this work was to investigate the effect of the fermentation pH and temperature on the surface properties and adhesion ability to Caco-2 c...

  6. Cell adhesion and EGFR activation regulate EphA2 expression in cancer

    DEFF Research Database (Denmark)

    Larsen, Alice Bjerregaard; Stockhausen, Marie-Thérése; Poulsen, Hans Skovgaard

    2010-01-01

    largely unknown. Here we show that the expression of EphA2 in in vitro cultured cells, is restricted to cells growing adherently and that adhesion-induced EphA2 expression is dependent upon activation of the epidermal growth factor receptor (EGFR), mitogen activated protein kinase kinase (MEK) and Src...... family kinases (SRC). Moreover, the results show that adhesion-induced EGFR activation and EphA2 expression is affected by interactions with extracellular matrix (ECM) proteins working as integrin ligands. Stimulation with the EphA2 ligand, ephrinA1 inhibited ERK phosphorylation and cancer cell viability....... These effects were however abolished by activation of the EGF-receptor ligand system favoring Ras/MAPK signaling and cell proliferation. Based on our results, we propose a regulatory mechanism where cell adhesion induces EGFR kinase activation and EphA2 expression; and where the effect of ephrinA1...

  7. Inhibitors of 5-lipoxygenase inhibit expression of intercellular adhesion molecule-1 in human melanoma cells

    Institute of Scientific and Technical Information of China (English)

    Yin WANG; Bin ZHOU; Ji LI; Yong-bing CAO; Xin-sheng CHEN; Ming-he CHENG; Ming YIN

    2004-01-01

    AIM: To study the effect of 5-lipoxygenase inhibitors on the expression of intercellular adhesion molecule-1 (ICAM-1) in melanoma cells. METHODS: ICAM-1 protein of human melanoma cell a375 was detected by enzyme-linked immunosorbent, flow cytometry and Western blot analysis. Level of ICAM-1 mRNA in a375 was evaluated by Northern blot analysis. Adhesion of a375 to endothelial cell EC304 was analyzed by isotopic tracing. RESULTS:5-Lipoxygenase inhibitors nordihydroguaiaretic acid, AA861 and MK886, could suppress the expression of ICAM-1 protein as well as of its mRNA in a375 cells and reduce the adhesion of a375 to EC304. CONCLUSION:5-Lipoxygenase inhibitors can inhibit the expression of ICAM-1 in human melanoma cells and may be valuable for treatment of melanoma metastasis.

  8. Mycophenolate mofetil modulates adhesion receptors of the beta1 integrin family on tumor cells: impact on tumor recurrence and malignancy

    Directory of Open Access Journals (Sweden)

    Beecken Wolf-Dietrich

    2005-01-01

    Full Text Available Abstract Background Tumor development remains one of the major obstacles following organ transplantation. Immunosuppressive drugs such as cyclosporine and tacrolimus directly contribute to enhanced malignancy, whereas the influence of the novel compound mycophenolate mofetil (MMF on tumor cell dissemination has not been explored. We therefore investigated the adhesion capacity of colon, pancreas, prostate and kidney carcinoma cell lines to endothelium, as well as their beta1 integrin expression profile before and after MMF treatment. Methods Tumor cell adhesion to endothelial cell monolayers was evaluated in the presence of 0.1 and 1 μM MMF and compared to unstimulated controls. beta1 integrin analysis included alpha1beta1 (CD49a, alpha2beta1 (CD49b, alpha3beta1 (CD49c, alpha4beta1 (CD49d, alpha5beta1 (CD49e, and alpha6beta1 (CD49f receptors, and was carried out by reverse transcriptase-polymerase chain reaction, confocal microscopy and flow cytometry. Results Adhesion of the colon carcinoma cell line HT-29 was strongly reduced in the presence of 0.1 μM MMF. This effect was accompanied by down-regulation of alpha3beta1 and alpha6beta1 surface expression and of alpha3beta1 and alpha6beta1 coding mRNA. Adhesion of the prostate tumor cell line DU-145 was blocked dose-dependently by MMF. In contrast to MMF's effects on HT-29 cells, MMF dose-dependently up-regulated alpha1beta1, alpha2beta1, alpha3beta1, and alpha5beta1 on DU-145 tumor cell membranes. Conclusion We conclude that MMF possesses distinct anti-tumoral properties, particularly in colon and prostate carcinoma cells. Adhesion blockage of HT-29 cells was due to the loss of alpha3beta1 and alpha6beta1 surface expression, which might contribute to a reduced invasive behaviour of this tumor entity. The enhancement of integrin beta1 subtypes observed in DU-145 cells possibly causes re-differentiation towards a low-invasive phenotype.

  9. Mycophenolate mofetil modulates adhesion receptors of the beta1 integrin family on tumor cells: impact on tumor recurrence and malignancy

    International Nuclear Information System (INIS)

    Tumor development remains one of the major obstacles following organ transplantation. Immunosuppressive drugs such as cyclosporine and tacrolimus directly contribute to enhanced malignancy, whereas the influence of the novel compound mycophenolate mofetil (MMF) on tumor cell dissemination has not been explored. We therefore investigated the adhesion capacity of colon, pancreas, prostate and kidney carcinoma cell lines to endothelium, as well as their beta1 integrin expression profile before and after MMF treatment. Tumor cell adhesion to endothelial cell monolayers was evaluated in the presence of 0.1 and 1 μM MMF and compared to unstimulated controls. beta1 integrin analysis included alpha1beta1 (CD49a), alpha2beta1 (CD49b), alpha3beta1 (CD49c), alpha4beta1 (CD49d), alpha5beta1 (CD49e), and alpha6beta1 (CD49f) receptors, and was carried out by reverse transcriptase-polymerase chain reaction, confocal microscopy and flow cytometry. Adhesion of the colon carcinoma cell line HT-29 was strongly reduced in the presence of 0.1 μM MMF. This effect was accompanied by down-regulation of alpha3beta1 and alpha6beta1 surface expression and of alpha3beta1 and alpha6beta1 coding mRNA. Adhesion of the prostate tumor cell line DU-145 was blocked dose-dependently by MMF. In contrast to MMF's effects on HT-29 cells, MMF dose-dependently up-regulated alpha1beta1, alpha2beta1, alpha3beta1, and alpha5beta1 on DU-145 tumor cell membranes. We conclude that MMF possesses distinct anti-tumoral properties, particularly in colon and prostate carcinoma cells. Adhesion blockage of HT-29 cells was due to the loss of alpha3beta1 and alpha6beta1 surface expression, which might contribute to a reduced invasive behaviour of this tumor entity. The enhancement of integrin beta1 subtypes observed in DU-145 cells possibly causes re-differentiation towards a low-invasive phenotype

  10. Aging effects of plasma polymerized ethylenediamine (PPEDA) thin films on cell-adhesive implant coatings

    Energy Technology Data Exchange (ETDEWEB)

    Testrich, H., E-mail: holger.testrich@uni-greifswald.de [University of Greifswald, Institute of Physics, Felix-Hausdorff Str. 6, 17489 Greifswald (Germany); Rebl, H. [University of Rostock, Biomedical Research Center, Department of Cell Biology, Schillingallee 69, 18057 Rostock (Germany); Finke, B.; Hempel, F. [Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff Str. 2, 17489 Greifswald (Germany); Nebe, B. [University of Rostock, Biomedical Research Center, Department of Cell Biology, Schillingallee 69, 18057 Rostock (Germany); Meichsner, J. [University of Greifswald, Institute of Physics, Felix-Hausdorff Str. 6, 17489 Greifswald (Germany)

    2013-10-15

    Thin plasma polymer films from ethylenediamine were deposited on planar substrates placed on the powered electrode of a low pressure capacitively coupled 13.56 MHz discharge. The chemical composition of the plasma polymer films was analyzed by Fourier Transform Infrared Reflection Absorption Spectroscopy (FT-IRRAS) as well as by X-ray photoelectron spectroscopy (XPS) after derivatization of the primary amino groups. The PPEDA films undergo an alteration during the storage in ambient air, particularly, due to reactions with oxygen. The molecular changes in PPEDA films were studied over a long-time period of 360 days. Simultaneously, the adhesion of human osteoblast-like cells MG-63 (ATCC) was investigated on PPEDA coated corundum blasted titanium alloy (Ti-6Al-4V), which is applied as implant material in orthopedic surgery. The cell adhesion was determined by flow cytometry and the cell shape was analyzed by scanning electron microscopy. Compared to uncoated reference samples a significantly enhanced cell adhesion and proliferation were measured for PPEDA coated samples, which have been maintained after long-time storage in ambient air and additional sterilization by γ−irradiation. - Highlights: • Development of cell-adhesive nitrogen-rich coatings for biomedical applications. • Plasma polymer films from low pressure 13.56 MHz discharge in argon-ethylenediamine. • Enhanced osteoblast adhesion/proliferation on coated implant material (Ti-6Al-4V). • Despite film aging over 360 days the enhanced cell adhesion of the coating remains. • No influence of additional y-sterilization on the enhanced cell adhesion.

  11. Study on adhesion and electro-optical properties of ITO films on flexible PET substrate

    Institute of Scientific and Technical Information of China (English)

    TANG Wu; WENG Xiaolong; WU Yutao; DENG Longjiang

    2006-01-01

    High-quality ITO films on flexible PET substrate were prepared by RF magnetron sputtering at low deposition temperature with different Ar gas sputtering pressure.Adhesion and electro-optical properties of ITO films were investigated as a function of Ar partial pressure.The sputtering conditions provide very uniform ITO films with high transparency (>85% in 400-760 nm spectra) and low electrical resistivity (1.408×10-3-1.956×10-3 Ω·cm).Scratch test experiments indicate that there is a good adhesion property between ITO films and PET substrate, the critical characteristic load increases from 16.5 to 23.2 N with increasing Ar sputtering pressure from 0.2 to 1.4 Pa.

  12. Optimization and characterization of adhesion properties of DLC coatings on different substrates

    International Nuclear Information System (INIS)

    The Diamond Like Carbon coatings (DLC) are gaining prime importance in the field of surface engineering especially cutting tools technology. The self lubricating property of these coatings makes them unique among other coatings like TiN, TiAlN, CrN etc. Unlike other coatings, DLC coatings give better surface finish and their self lubrication reduces the wear of a part to large extent. In present work, different substrates were selected to study the wear and adhesion behavior of DLC coatings. The coating was produced by physical Vapor Deposition (PVD) technique and the adhesive properties of DLC coatings were analyzed under ambient conditions using nano Scratch testing. Scanning electron microscope (SEM) was used to observe the scratches and their mechanisms. (author)

  13. Optimization and characterization of adhesion properties of DLC coatings on different substrates

    International Nuclear Information System (INIS)

    The Diamond Like Carbon coatings (DLC) are gaining prime importance in the field of surface engineering especially cutting tools technology. The self lubricating property of these coatings makes them unique among other coatings like TiN, TiAlN, CrN etc. Unlike other coatings, DLC coatings give better surface finish and their self lubrication reduces the wear of a part to large extent. In present work, different substrates were selected to study the wear and adhesion behavior of DLC coatings. The coating was produced by physical Vapor Deposition (PVD) technique and the adhesive properties of DLC coatings were analyzed under ambient conditions using nano Scratch testing. Scanning electron microscope (SEM) was used to observe the scratches and their mechanisms

  14. The calcium-dependent myoblast adhesion that precedes cell fusion is mediated by glycoproteins

    OpenAIRE

    1985-01-01

    Presumptive myoblasts from explants of chick embryo pectoral muscle proliferate, differentiate, and fuse to form multinucleate myotubes. One event critical to multinucleate cell formation is the specific adhesion of myoblasts before union of their membranes. In the studies reported here five known inhibitors of myotube formation-- trifluoperazine, sodium butyrate, chloroquine, 1,10 phenanthroline, and tunicamycin--were tested for their effect on the Ca++-dependent myoblast adhesion step. The ...

  15. A computational study of stress fiber-focal adhesion dynamics governing cell contractility

    OpenAIRE

    Maraldi, Mirko; Valero, Clara; Garikipati, Krishna

    2014-01-01

    We apply a recently developed model of cytoskeletal force generation to study a cell intrinsic contractility, as well as its response to external loading. The model is based on a non-equilibrium thermodynamic treatment of the mechano-chemistry governing force in the stress fiber-focal adhesion system. Our computational study suggests that the mechanical coupling between the stress fibers and focal adhesions leads to a complex, dynamic, mechano-chemical response. We collect the results in resp...

  16. A Protocadherin-Cadherin-FLRT3 Complex Controls Cell Adhesion and Morphogenesis

    OpenAIRE

    Chen, Xuejun; Koh, Eunjin; Yoder, Michael; Gumbiner, Barry M.

    2009-01-01

    Background Paraxial protocadherin (PAPC) and fibronectin leucine-rich domain transmembrane protein-3 (FLRT3) are induced by TGFβ signaling in Xenopus embryos and both regulate morphogenesis by inhibiting C-cadherin mediated cell adhesion. Principal Findings We have investigated the functional and physical relationships between PAPC, FLRT3, and C-cadherin. Although neither PAPC nor FLRT3 are required for each other to regulate C-cadherin adhesion, they do interact functionally and physically, ...

  17. Effect of sterilization and water rinsing on cell adhesion to titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Mitsuhiro; Kozuka, Taro; Asano, Yuta; Kakuchi, Yuko [Instrument Analysis Center, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507 (Japan); Arai, Hirofumi [Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507 (Japan); Ohtsu, Naofumi, E-mail: nohtsu@mail.kitami-it.ac.jp [Instrument Analysis Center, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507 (Japan)

    2014-08-30

    Highlights: • Sterilization and water rinsing affected the cell adhesion performance on Ti substrates. • The chemical state of the Ti surfaces was altered by sterilization and water rinsing. • There is a clear correlation between cell adhesiveness and the surface OH{sup −} concentration. - Abstract: In this study, the effects of sterilization and water rinsing on cell adhesion to titanium (Ti) surfaces were investigated. Ti substrates were treated using autoclave, dry-heating, and 70% ethanol. Thereafter, some of the substrates were rinsed with sterilized ultrapure water. Osteoblast-like MC3T3-E1 cells were seeded on the Ti surfaces and the numbers of adhered cells were counted after cultivation for 24 h. The number of cells adhered to ethanol-treated plates was lower than that on autoclave- and dry-heat-sterilized Ti substrates. However, interestingly, the cell adhesion performance on the ethanol-treated substrates was superior compared to that of the other substrates, after rinsing with ultrapure water. To investigate the origin of these differences, the chemical state of the treated surfaces was analyzed by X-ray photoelectron spectroscopy. We found a clear correlation between the number of adhered cells and the concentration of hydroxide groups (OH{sup −}) on the surface, thus indicating that a change in OH{sup −} concentration affects the cell adhesion performance on Ti substrates. Since the sterilization and subsequent water rinsing affect the cell adhesion on Ti substrates, we suggest that the sterilization methods should be unified to correctly evaluate the cytocompatibility of metallic materials.

  18. Novel pharmacologic targeting of tight junctions and focal adhesions in prostate cancer cells.

    Directory of Open Access Journals (Sweden)

    Patrick J Hensley

    Full Text Available Cancer cell resistance to anoikis driven by aberrant signaling sustained by the tumor microenvironment confers high invasive potential and therapeutic resistance. We recently generated a novel lead quinazoline-based Doxazosin® derivative, DZ-50, which impairs tumor growth and metastasis via anoikis. Genome-wide analysis in the human prostate cancer cell line DU-145 identified primary downregulated targets of DZ-50, including genes involved in focal adhesion integrity (fibronectin, integrin-α6 and talin, tight junction formation (claudin-11 as well as insulin growth factor binding protein 3 (IGFBP-3 and the angiogenesis modulator thrombospondin 1 (TSP-1. Confocal microscopy demonstrated structural disruption of both focal adhesions and tight junctions by the downregulation of these gene targets, resulting in decreased cell survival, migration and adhesion to extracellular matrix (ECM components in two androgen-independent human prostate cancer cell lines, PC-3 and DU-145. Stabilization of cell-ECM interactions by overexpression of talin-1 and/or exposing cells to a fibronectin-rich environment mitigated the effect of DZ-50. Loss of expression of the intracellular focal adhesion signaling effectors talin-1 and integrin linked kinase (ILK sensitized human prostate cancer to anoikis. Our findings suggest that DZ-50 exerts its antitumor effect by targeting the key functional intercellular interactions, focal adhesions and tight junctions, supporting the therapeutic significance of this agent for the treatment of advanced prostate cancer.

  19. Coating of Carbon Nanotube Fibers: Variation of Tensile Properties, Failure Behavior, and Adhesion Strength

    OpenAIRE

    Mäder, Edith; Liu, Jianwen; Hiller, Janett; Lu, Weibang; Li, Qingwen; Zhandarov, Serge; Chou, Tsu-Wei

    2015-01-01

    An experimental study of the tensile properties of CNT fibers and their interphasial behavior in epoxy matrices is reported. One of the most promising applications of CNT fibers is their use as reinforcement in multifunctional composites. For this purpose, an increase of the tensile strength of the CNT fibers in unidirectional composites as well as strong interfacial adhesion strength is desirable. However, the mechanical performance of the CNT fiber composites manufactured so far is comparab...

  20. Adhesive and Stress-Strain Properties of the Polymeric Layered Materials Reinforced by the Knitted Net

    Directory of Open Access Journals (Sweden)

    Rakhimov Farhod Hushbakovich

    2012-10-01

    Full Text Available It is known that the textile materials (woven fabric and mesh used for reinforcing of various polymer films and coatings. This paper discusses reinforcement of thermoplastic polymers based on PE (Polyethylene and PVC (Polyvinyl Chloride with a knitted mesh weave loin. According by the research identified adhesion, strength and deformation properties of new polymer laminates. The production of such materials has been discussed in detail and performance of resultant composites material is analyzed and compared with other materials.

  1. Corneal cell adhesion to contact lens hydrogel materials enhanced via tear film protein deposition.

    Directory of Open Access Journals (Sweden)

    Claire M Elkins

    Full Text Available Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS, borate buffered saline (BBS, or Sensitive Eyes Plus Saline Solution (Sensitive Eyes, either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.

  2. Antiadhesive Properties of Arabinogalactan Protein from Ribes nigrum Seeds against Bacterial Adhesion of Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    Jutta Messing

    2014-03-01

    Full Text Available Fruit extracts from black currants (Ribes nigrum L. are traditionally used for treatment of gastritis based on seed polysaccharides that inhibit the adhesion of Helicobacter pylori to stomach cells. For detailed investigations an arabinogalactan protein (F2 was isolated from seeds and characterized concerning molecular weight, carbohydrate, amino acid composition, linkage, configuration and reaction with β-glucosyl Yariv. Functional testing of F2 was performed by semiquantitative in situ adhesion assay on sections of human gastric mucosa and by quantitative in vitro adhesion assay with FITC-labled H. pylori strain J99 and human stomach AGS cells. Bacterial adhesins affected were identified by overlay assay with immobilized ligands. 125I-radiolabeled F2 served for binding studies to H. pylori and interaction experiments with BabA and SabA. F2 had no cytotoxic effects against H. pylori and AGS cells; but inhibited bacterial binding to human gastric cells. F2 inhibited the binding of BabA and fibronectin-binding adhesin to its specific ligands. Radiolabeled F2 bound non-specifically to different strains of H. pylori; and to BabA deficient mutant. F2 did not lead to subsequent feedback regulation or increased expression of adhesins or virulence factors. From these data the non-specific interactions between F2 and the H. pylori lead to moderate antiadhesive effects.

  3. Antiadhesive properties of arabinogalactan protein from ribes nigrum seeds against bacterial adhesion of Helicobacter pylori.

    Science.gov (United States)

    Messing, Jutta; Niehues, Michael; Shevtsova, Anna; Borén, Thomas; Hensel, Andreas

    2014-01-01

    Fruit extracts from black currants (Ribes nigrum L.) are traditionally used for treatment of gastritis based on seed polysaccharides that inhibit the adhesion of Helicobacter pylori to stomach cells. For detailed investigations an arabinogalactan protein (F2) was isolated from seeds and characterized concerning molecular weight, carbohydrate, amino acid composition, linkage, configuration and reaction with β-glucosyl Yariv. Functional testing of F2 was performed by semiquantitative in situ adhesion assay on sections of human gastric mucosa and by quantitative in vitro adhesion assay with FITC-labled H. pylori strain J99 and human stomach AGS cells. Bacterial adhesins affected were identified by overlay assay with immobilized ligands. ¹²⁵I-radiolabeled F2 served for binding studies to H. pylori and interaction experiments with BabA and SabA. F2 had no cytotoxic effects against H. pylori and AGS cells; but inhibited bacterial binding to human gastric cells. F2 inhibited the binding of BabA and fibronectin-binding adhesin to its specific ligands. Radiolabeled F2 bound non-specifically to different strains of H. pylori; and to BabA deficient mutant. F2 did not lead to subsequent feedback regulation or increased expression of adhesins or virulence factors. From these data the non-specific interactions between F2 and the H. pylori lead to moderate antiadhesive effects. PMID:24662083

  4. Mechanical properties of hepatocellular carcinoma cells

    Institute of Scientific and Technical Information of China (English)

    Gang Zhang; Mian Long; Zhe-Zhi Wu; Wei-Qun Yu

    2002-01-01

    AIM: To study the viscoelastic properties of humanhepatocytss and helatocellulsr carcinoma (HCC) cellsunder cytoslelstal perturbation, and to further to study theviscoelastic properties and the adhesive properties of mousehepatorna cells (HTC) in different cell cycls.METHODS: Micropipette aspiration technique was adopted tomeasure viscoelastic coefficients and adhesion force tocollagen coated surface ofthe cells. Three kinds ofcytoskeleton perturbing agents, colchiclnes (Col),cytochalssin D (CD) and vinblastine (VBL), were used totreat HCC cells and hepatocytes and the effects of thesetreatent on cell viscoelastic coefficients were investigated.The experimental results were analyzed with a thres-elsmentstandard linear solid. Further, the viscoelastic properties ofHTC cells and the adhesion force of different cycle HTC cellswere also investigated. The synchronous G1 and S phasecells were achieved through thymine-2-desoryriboside andcolchicines sequential blockage method and thymine-2-desoryriboside blockage method respectively.RESULTS: The elastic coefficients, but not viscouscoefficient of HCC cells (k1 = 103.6± 12.6N.m-2, k2 =42.5±10.4N. m-2, μ = 4.5 ± 1.9Pa. s), were significantly higherthan the corresponding value for hepatocytes (K1 = 87.5 ±12.1N.m-2, k2 =33.3± 10.3N.m-2, μ=5.9±3.0Pa. s, P<0.01). Upon treatment with CD, the viscoelastic coefficients ofboth hepotocytes and HCC cells decreased consistently,with magnitudes for the decrease in elastic coefficients ofHCC cells (k1: 68.7 N.m-2 to 81.7N.m-2, 66.3 % to 78.9 %;k2: 34.5 N.m-2 to37.1N.m-2, 81.2% to 87.3 %, P<0.001)larger than those for normal hepatocytes (k1: 42.6N. m-2 to49.8N.nt-2, 48.7% to56.9 %; k2: 17.2N.m-2 to 20.4N.m-2,51.7 % to 61.3 %, P< 0.001). There was a little decrease inthe vlscous coefficient of HCC cells (2.0 to 3.4Pa. s, 44.4 to75.6 %, P<0.001) than that for hepatocytes (3.0 to 3.gPa.s, 50.8to 66.1% P<0.001). Upon trastment with Col andVBL, the elastic coefficients

  5. Antibacterial properties of cyanoacrylate tissue adhesive: Does the polymerization reaction play a role?

    Directory of Open Access Journals (Sweden)

    Romero Ivana

    2009-01-01

    Full Text Available Purpose: To ascertain if the polymerization reaction also contributes additionally to the antibacterial effects of two commonly used cyanoacrylate tissue adhesives. Materials and Methods: Fresh liquid ethyl-cyanoacrylate (EC and N-butyl-cyanoacrylate (BC adhesives were applied onto 6-mm sterile filter paper discs. In the first group, the adhesive-soaked discs were immediately placed onto confluent monolayer cultures of bacteria, allowing the polymerization reaction to proceed while in culture. In the second group, the adhesive-soaked disc was allowed to first polymerize prior to being placed onto the bacterial cultures. Four types of bacteria were studied: Staphylococcus aureus , Streptococcus pneumoniae , Escherichia coli , and Pseudomonas aeruginosa . Immediately after the discs were applied, the cultures were incubated at 35° C for 24 h. Bacterial inhibitory halos were measured in the cultures at the end of the incubation period. Results: For EC, exposure of the bacteria to the cyanoacrylate polymerization reaction increased the bacterial inhibitory halos in Streptococcus pneumonia, Staphylococcus aureus and Escherichia coli. For BC, it increased the bacterial inhibitory halos in Staphylococcus aureus and Streptococcus pneumoniae . No inhibitory halos were observed in Pseudomonas aeruginosa. The bactericidal effect was higher in actively polymerizing EC, compared to previously polymerized EC in Staphylococcus aureus , Streptococcus pneumoniae, and Escherichia coli ; however, no such differences were observed for BC. Conclusions: The polymerization reaction may also be an important factor in the antibacterial properties of EC and BC.

  6. How solid-liquid adhesive property regulates liquid slippage on solid surfaces?

    Science.gov (United States)

    Xue, Yahui; Wu, Yang; Pei, Xiaowei; Duan, Huiling; Xue, Qunji; Zhou, Feng

    2015-01-13

    The influence of solid-liquid adhesive property on liquid slippage at solid surfaces has been investigated using experiment approach on well-defined model surfaces as well as theoretical analysis. Based on a classical molecular-kinetic description for molecular and hydrodynamic slip, we propose a simple theoretical model that directly relates the liquid slip length to the liquid adhesive force on solid surfaces, which yields an exponential decay function. Well-defined smooth surfaces with varied surface wettability/adhesion are fabricated by forming self-assembled monolayers on gold with different mole ratios of hydrophobic and hydrophilic thiols. The adhesive force of a water droplet and the molecular slippage on these surfaces are probed by surface force apparatus and quartz crystal microbalance measurements, respectively. The experiment results are well consistent with our theoretical prediction. Our finding benefits the understanding of the underlying mechanism of liquid slippage on solid surfaces at molecular level and the rational design of microfluidics with an aim to be frictionless or highly controllable. PMID:25511171

  7. Negative staining and immunoelectron microscopy of adhesion-deficient mutants of Streptococcus salivarius reveal that the adhesive protein antigens are separate classes of cell surface fibril.

    Science.gov (United States)

    Weerkamp, A H; Handley, P S; Baars, A; Slot, J W

    1986-01-01

    The subcellular distribution of the cell wall-associated protein antigens of Streptococcus salivarius HB, which are involved in specific adhesive properties of the cells, was studied. Mutants which had lost the adhesive properties and lacked the antigens at the cell surface were compared with the parent strain. Immunoelectron microscopy of cryosections of cells labeled with affinity-purified, specific antisera and colloidal gold-protein A complexes was used to locate the antigens. Antigen C (AgC), a glycoprotein involved in attachment to host surfaces, was mainly located in the fibrillar layer outside the cell wall. A smaller amount of label was also found throughout the cytoplasmic area in the form of small clusters of gold particles, which suggests a macromolecular association. Mutant HB-7, which lacks the wall-associated AgC, accumulated AgC reactivity intracellularly. Intracellular AgC was often found associated with isolated areas of increased electron density, but sometimes seemed to fill the entire interior of the cell. Antigen B (AgB), a protein responsible for interbacterial coaggregation, was also located in the fibrillar layer, although its distribution differed from that of the wall-associated AgC since AgB was found predominantly in the peripheral areas. A very small amount of label was also found in the cytoplasmic area as discrete gold particles. Mutant HB-V5, which lacks wall-associated AgB, was not labeled in the fibrillar coat, but showed the same weak intracellular label as the parent strain. Immunolabeling with serum against AgD, another wall-associated protein but of unknown function, demonstrated its presence in the fibrillar layer of strain HB. Negatively stained preparations of whole cells of wild-type S. salivarius and mutants that had lost wall-associated AgB or AgC revealed that two classes of short fibrils are carried on the cell surface at the same time. AgB and AgC are probably located on separate classes of short, protease

  8. Integrin engagement mediates tyrosine dephosphorylation on platelet-endothelial cell adhesion molecule 1.

    OpenAIRE

    Lu, T T; Yan, L G; Madri, J. A.

    1996-01-01

    Platelet-endothelial cell adhesion molecule 1 (PECAM-1, CD31) is a 130-kDa member of the immunoglobulin gene superfamily expressed on endothelial cells, platelets, neutrophils, and monocytes and plays a role during endothelial cell migration. Phosphoamino acid analysis and Western blot analysis with anti-phosphotyrosine antibody show that endothelial PECAM-1 is tyrosine-phosphorylated. Phosphorylation is decreased with endothelial cell migration on fibronectin and collagen and with cell sprea...

  9. Degranulation of human mast cells induces an endothelial antigen central to leukocyte adhesion.

    OpenAIRE

    Klein, L M; Lavker, R M; Matis, W L; Murphy, G F

    1989-01-01

    To understand better the role of mast cell secretory products in the genesis of inflammation, a system was developed for in vitro degranulation of human mast cells in skin organ cultures. Within 2 hr after morphine sulfate-induced degranulation, endothelial cells lining microvessels adjacent to affected mast cells expressed an activation antigen important for endothelial-leukocyte adhesion. Identical results were obtained when other mast cell secretagogues (anti-IgE, compound 48/80, and calci...

  10. Adhesion and Proliferation of Human Periodontal Ligament Cells on Poly(2-methoxyethyl acrylate)

    OpenAIRE

    Erika Kitakami; Makiko Aoki; Chikako Sato; Hiroshi Ishihata; Masaru Tanaka

    2014-01-01

    Human periodontal ligament (PDL) cells obtained from extracted teeth are a potential cell source for tissue engineering. We previously reported that poly(2-methoxyethyl acrylate) (PMEA) is highly biocompatible with human blood cells. In this study, we investigated the adhesion, morphology, and proliferation of PDL cells on PMEA and other types of polymers to design an appropriate scaffold for tissue engineering. PDL cells adhered and proliferated on all investigated polymer surfaces except fo...

  11. Robust Adhesive Precision Bonding in Automated Assembly Cells

    OpenAIRE

    Müller, Tobias; Haag, Sebastian; Bastuck, Thomas; Gisler, Thomas; Moser, Hansruedi; Uusimaa, Petteri; Axt, Christoph; Brecher, Christian

    2014-01-01

    The assembly of optical components goes along with highest requirements regarding assembly precision. Laser products have become an integral part of many industrial, medical, and consumer applications and their relevance will increase significantly in the years to come. Still economic challenges remain. Assembly costs are driven by the demanding requirements regarding alignment and adhesive bonding. Especially challenging in precision bonding are the interdependencies between alignment and bo...

  12. Quantal concept of T-cell activation: adhesion domains as immunological synapses

    Science.gov (United States)

    Sackmann, Erich

    2011-06-01

    Adhesion micro-domains (ADs) formed during encounters of lymphocytes with antigen-presenting cells (APC) mediate the genetic expression of quanta of cytokines interleukin-2 (IL-2). The IL-2-induced activation of IL-2 receptors promotes the stepwise progression of the T-cells through the cell cycle, hence their name, immunological synapses. The ADs form short-lived reaction centres controlling the recruitment of activators of the biochemical pathway (the kinases Lck and ZAP) while preventing the access of inhibitors (phosphatase CD45) through steric repulsion forces. CD45 acts as the generator of adhesion domains and, through its role as a spacer protein, also as the promoter of the reaction. In a second phase of T-cell-APC encounters, long-lived global reaction spaces (called supramolecular activation complexes (SMAC)) form by talin-mediated binding of the T-cell integrin (LFA-1) to the counter-receptor ICAM-1, resulting in the formation of ring-like tight adhesion zones (peripheral SMAC). The ADs move to the centre of the intercellular adhesion zone forming the central SMAC, which serve in the recycling of the AD. We propose that cell stimulation is triggered by integrating the effect evoked by the short-lived adhesion domains. Similar global reaction platforms are formed by killer cells to destruct APC. We present a testable mechanical model showing that global reaction spaces (SMAC or dome-like contacts between cytotoxic cells and APC) form by self-organization through delayed activation of the integrin-binding affinity and stabilization of the adhesion zones by F-actin recruitment. The mechanical stability and the polarization of the adhering T-cells are mediated by microtubule-actin cross-talk.

  13. Quantal concept of T-cell activation: adhesion domains as immunological synapses

    Energy Technology Data Exchange (ETDEWEB)

    Sackmann, Erich, E-mail: sackmann@ph.tum.de [Physics Department E22, Technical University Munich, D-85748 Garching (Germany)

    2011-06-15

    Adhesion micro-domains (ADs) formed during encounters of lymphocytes with antigen-presenting cells (APC) mediate the genetic expression of quanta of cytokines interleukin-2 (IL-2). The IL-2-induced activation of IL-2 receptors promotes the stepwise progression of the T-cells through the cell cycle, hence their name, immunological synapses. The ADs form short-lived reaction centres controlling the recruitment of activators of the biochemical pathway (the kinases Lck and ZAP) while preventing the access of inhibitors (phosphatase CD45) through steric repulsion forces. CD45 acts as the generator of adhesion domains and, through its role as a spacer protein, also as the promoter of the reaction. In a second phase of T-cell-APC encounters, long-lived global reaction spaces (called supramolecular activation complexes (SMAC)) form by talin-mediated binding of the T-cell integrin (LFA-1) to the counter-receptor ICAM-1, resulting in the formation of ring-like tight adhesion zones (peripheral SMAC). The ADs move to the centre of the intercellular adhesion zone forming the central SMAC, which serve in the recycling of the AD. We propose that cell stimulation is triggered by integrating the effect evoked by the short-lived adhesion domains. Similar global reaction platforms are formed by killer cells to destruct APC. We present a testable mechanical model showing that global reaction spaces (SMAC or dome-like contacts between cytotoxic cells and APC) form by self-organization through delayed activation of the integrin-binding affinity and stabilization of the adhesion zones by F-actin recruitment. The mechanical stability and the polarization of the adhering T-cells are mediated by microtubule-actin cross-talk.

  14. Cell adhesion, inflammation and therapy: Old ideas and a significant step forward

    Institute of Scientific and Technical Information of China (English)

    Roberto GONZ(A)LEZ-AMARO

    2011-01-01

    Cell-to-cell adhesion as well as the interaction of cells with the extracellular matrix are key phenomena in different physiological and pathological conditions,including embryogenesis,blood coagulation,lymphocyte homing,immune response,angiogenesis,metastasis,thrombosis and inflammation[1,2].Thus,it has been widely proposed that cell adhesion molecules are an important therapeutic target in a wide array of diseases with high impact on public health,including atherosclerosis,thromboembolic disorders,cancer,graft rejection and autoimmune inflammatory conditions[1,2].However,anti-adhesion therapy with either biological agents (mainly blocking monoclonal antibodies,mAb's) or chemical inhibitors (mainly synthetic peptides) has not yet fulfilled these expectations and has not been devoid of undesirable effects[3,4

  15. Coupling of cytoplasm and adhesion dynamics determines cell polarization and locomotion

    CERN Document Server

    Bock, Martin; Möhl, Christoph

    2009-01-01

    Observations of single epidermal cells on flat adhesive substrates have revealed two distinct morphological and functional states, namely a non-migrating symmetric unpolarized state and a migrating asymmetric polarized state. These states are characterized by different spatial distributions and dynamics of important biochemical cell components: F-actin and myosin-II form the contractile part of the cytoskeleton, and integrin receptors in the plasma membrane connect F-actin filaments to the substratum. In this way, focal adhesion complexes are assembled, which determine cytoskeletal force transduction and subsequent cell locomotion. So far, physical models have reduced this phenomenon either to gradients in regulatory control molecules or to different mechanics of the actin filament system in different regions of the cell. Here we offer an alternative and self-organizational model incorporating polymerization, pushing and sliding of filaments, as well as formation of adhesion sites and their force dependent ki...

  16. Cell adhesion of Shewanella oneidensis to iron oxide minerals: Effect of different single crystal faces

    Directory of Open Access Journals (Sweden)

    Hochella Michael F

    2005-12-01

    Full Text Available The results of experiments designed to test the hypothesis that near-surface molecular structure of iron oxide minerals influences adhesion of dissimilatory iron reducing bacteria are presented. These experiments involved the measurement, using atomic force microscopy, of interaction forces generated between Shewanella oneidensis MR-1 cells and single crystal growth faces of iron oxide minerals. Significantly different adhesive force was measured between cells and the (001 face of hematite, and the (100 and (111 faces of magnetite. A role for electrostatic interactions is apparent. The trend in relative forces of adhesion generated at the mineral surfaces is in agreement with predicted ferric site densities published previously. These results suggest that near-surface structure does indeed influence initial cell attachment to iron oxide surfaces; whether this is mediated via specific cell surface-mineral surface interactions or by more general interfacial phenomena remains untested.

  17. Enhanced adhesion of early endothelial progenitor cells to radiation-induced senescence-like vascular endothelial cells in vitro

    International Nuclear Information System (INIS)

    The effects of ionizing radiation (IR) on tumor neovascularization are still unclear. We previously reported that vascular endothelial cells (ECs) expressing the IR-induced senescence-like (IRSL) phenotype exhibit a significant decrease in angiogenic activity in vitro. In this study, we examined the effects of the IRSL phenotype on adhesion to early endothelial progenitor cells (early EPCs). Adhesion of human peripheral blood-derived early EPCs to human umbilical vein endothelial cells (HUVECs) expressing the IRSL phenotype was evaluated by an adhesion assay under static conditions. It was revealed that the IRSL HUVECs supported significantly more adhesion of early EPCs than normal HUVECs. Expressions of ICAM-1, VCAM-1 and E-selectin were up-regulated in IRSL HUVECs. Pre-treatment of IRSL HUVECs with adhesion-blocking monoclonal antibodies against E-selectin and VCAM-1 significantly reduced early EPC adhesion to IRSL HUVECs, suggesting a potential role for the E-selectin and VCAM-1 in the adhesion between IRSL ECs and early EPCs. Therefore, the IRSL phenotype expressed in ECs may enhance neovascularization via increased homing of early EPCs. Our findings are first to implicate the complex effects of this phenotype on tumor neovascularization following irradiation. (author)

  18. Cytotoxic effects of one-step self-etching adhesives on an odontoblast cell line.

    Science.gov (United States)

    Lee, Yoon; An, So-Youn; Park, Yoon-Jung; Yu, Frank H; Park, Joo-Cheol; Seo, Deog-Gyu

    2016-01-01

    The aim of this study was to evaluate the cytotoxic effects of one-step self-etching adhesives. Cells from an immortalized mouse odontoblast cell line (MDPC-23) were cultured with six different dental adhesive systems (diluted to concentrations of 0.5% for 4 h): Adper Easy Bond (EB), Xeno V (XV), iBond (IB), AdheSE One (AO), Clearfil SE primer (CS), and Adper Single Bond 2 (SB). MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and flow cytometric apoptosis assays were used to evaluate cell viability and the rate of apoptosis. The odontoblasts were also examined under a scanning electron microscope. While all of the cultures with adhesives showed reduced viability, the viabilities in the IB and SB groups were not significantly different from the control group. Although increased apoptosis rates were observed in all of the cultures with adhesives, the rate in the SB group was not significantly different from the rate in the control. The control group showed the lowest apoptosis rate followed by the SB, AO, IB, EB, XV, and CS groups. When examined under a scanning electron microscope, control odontoblasts and the SB group exhibited relatively large cytoplasmic extensions. In contrast, in the EB and CS groups, fewer fibroblasts remained adhered to the plate surface. Cytoplasmic membrane shrinkage and cell-free areas with residual membrane fragments from dead cells were observed. In conclusion, all cultures with one-step self-etching adhesives showed increased apoptotic activity. SB, an etch-and-rinse adhesive, was comparable to the control group, and CS and EB showed the lowest odontoblast viabilities according to the MTT assay. SCANNING 38:36-42, 2016. © 2015 Wiley Periodicals, Inc. PMID:26186405

  19. The first EGF domain of coagulation factor IX attenuates cell adhesion and induces apoptosis.

    Science.gov (United States)

    Ishikawa, Tomomi; Kitano, Hisataka; Mamiya, Atsushi; Kokubun, Shinichiro; Hidai, Chiaki

    2016-07-01

    Coagulation factor IX (FIX) is an essential plasma protein for blood coagulation. The first epidermal growth factor (EGF) motif of FIX (EGF-F9) has been reported to attenuate cell adhesion to the extracellular matrix (ECM). The purpose of the present study was to determine the effects of this motif on cell adhesion and apoptosis. Treatment with a recombinant EGF-F9 attenuated cell adhesion to the ECM within 10 min. De-adhesion assays with native FIX recombinant FIX deletion mutant proteins suggested that the de-adhesion activity of EGF-F9 requires the same process of FIX activation as that which occurs for coagulation activity. The recombinant EGF-F9 increased lactate dehydrogenase (LDH) activity release into the medium and increased the number of cells stained with annexin V and activated caspase-3, by 8.8- and 2.7-fold respectively, indicating that EGF-F9 induced apoptosis. Activated caspase-3 increased very rapidly after only 5 min of administration of recombinant EGF-F9. Treatment with EGF-F9 increased the level of phosphorylated p38 mitogen-activated protein kinase (MAPK), but not that of phosphorylated MAPK 44/42 or c-Jun N-terminal kinase (JNK). Inhibitors of caspase-3 suppressed the release of LDH. Caspase-3 inhibitors also suppressed the attenuation of cell adhesion and phosphorylation of p38 MAPK by EGF-F9. Our data indicated that EGF-F9 activated signals for apoptosis and induced de-adhesion in a caspase-3 dependent manner. PMID:27129300

  20. Crosslinking of the T cell-specific accessory molecules CD7 and CD28 modulates T cell adhesion

    OpenAIRE

    1992-01-01

    Regulated adhesion enables T cells to migrate through tissue and transiently interact with an endless succession of cells. Monoclonal antibody (mAb) engagement of the CD3/T cell receptor (TCR) complex results in a rapid and transient augmentation of the adhesion function of LFA-1 and VLA integrin molecules on human T cells. We show in this study that mAb crosslinking of the T cell-specific accessory molecules CD7 and CD28, or treatment with the Ca2+ ionophore A23187, results in the rapid indu...

  1. Antiadhesive Properties of Arabinogalactan Protein from Ribes nigrum Seeds against Bacterial Adhesion of Helicobacter pylori

    OpenAIRE

    Jutta Messing; Michael Niehues; Anna Shevtsova; Thomas Borén; Andreas Hensel

    2014-01-01

    Fruit extracts from black currants (Ribes nigrum L.) are traditionally used for treatment of gastritis based on seed polysaccharides that inhibit the adhesion of Helicobacter pylori to stomach cells. For detailed investigations an arabinogalactan protein (F2) was isolated from seeds and characterized concerning molecular weight, carbohydrate, amino acid composition, linkage, configuration and reaction with beta-glucosyl Yariv. Functional testing of F2 was performed by semiquantitative in situ...

  2. Role of Polysaccharides on Mechanical and Adhesion Properties of Flax Fibres in Flax/PLA Biocomposite

    Directory of Open Access Journals (Sweden)

    Gijo Raj

    2011-01-01

    Full Text Available The effect of alkali and enzymatic treatments on flax fibre morphology, mechanical, and adhesion properties was investigated. The multilength scale analysis allows for the correlation of the fibre's morphological changes induced by the treatments with mechanical properties to better explain the adherence properties between flax and PLA. The atomic force microscopy (AFM images revealed the removal of primary layers, upon treatments, down to cellulose microfibrils present in the secondary layers. The variation in mechanical properties was found to be dependent, apart from the crystalline content, on interaction between cellulose microfibrils and encrusting polysaccharides, pectins and hemicelluloses, in the secondary layers. Finally, microbond tests between the modified fibres and PLA emphasize the important role of the outer fibre's surface on the overall composite properties. It was observed here that gentle treatments of the fibres, down to the oriented microfibrils, are favourable to a better adherence with a PLA drop. This paper highlights the important role of amorphous polymers, hemicellulose and pectin, in the optimisation of the adhesion and mechanical properties of flax fibres in the biocomposite.

  3. Hyaluronan synthase 3 (HAS3) overexpression downregulates MV3 melanoma cell proliferation, migration and adhesion

    International Nuclear Information System (INIS)

    Malignant skin melanoma is one of the most deadly human cancers. Extracellular matrix (ECM) influences the growth of malignant tumors by modulating tumor cells adhesion and migration. Hyaluronan is an essential component of the ECM, and its amount is altered in many tumors, suggesting an important role for hyaluronan in tumorigenesis. Nonetheless its role in melanomagenesis is not understood. In this study we produced a MV3 melanoma cell line with inducible expression of the hyaluronan synthase 3 (HAS3) and studied its effect on the behavior of the melanoma cells. HAS3 overexpression expanded the cell surface hyaluronan coat and decreased melanoma cell adhesion, migration and proliferation by cell cycle arrest at G1/G0. Melanoma cell migration was restored by removal of cell surface hyaluronan by Streptomyces hyaluronidase and by receptor blocking with hyaluronan oligosaccharides, while the effect on cell proliferation was receptor independent. Overexpression of HAS3 decreased ERK1/2 phosphorylation suggesting that inhibition of MAP-kinase signaling was responsible for these suppressive effects on the malignant phenotype of MV3 melanoma cells. - Highlights: • Inducible HAS3-MV3 melanoma cell line was generated using Lentiviral transduction. • HAS3 overexpression inhibits MV3 cell migration via hyaluronan–receptor interaction. • HAS3 overexpression decreases MV3 melanoma cell proliferation and adhesion. • ERK1/2 phosphorylation is downregulated by 50% in HAS3 overexpressing cells. • The results suggest that hyaluronan has anti-cancer like effects in melanoma

  4. Hyaluronan synthase 3 (HAS3) overexpression downregulates MV3 melanoma cell proliferation, migration and adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Takabe, Piia, E-mail: piia.takabe@uef.fi [University of Eastern Finland, Institute of Biomedicine, 70211 Kuopio (Finland); Bart, Geneviève [University of Eastern Finland, Institute of Biomedicine, 70211 Kuopio (Finland); Ropponen, Antti [University of Eastern Finland, Institute of Clinical Medicine, 70211 Kuopio (Finland); Rilla, Kirsi; Tammi, Markku; Tammi, Raija; Pasonen-Seppänen, Sanna [University of Eastern Finland, Institute of Biomedicine, 70211 Kuopio (Finland)

    2015-09-10

    Malignant skin melanoma is one of the most deadly human cancers. Extracellular matrix (ECM) influences the growth of malignant tumors by modulating tumor cells adhesion and migration. Hyaluronan is an essential component of the ECM, and its amount is altered in many tumors, suggesting an important role for hyaluronan in tumorigenesis. Nonetheless its role in melanomagenesis is not understood. In this study we produced a MV3 melanoma cell line with inducible expression of the hyaluronan synthase 3 (HAS3) and studied its effect on the behavior of the melanoma cells. HAS3 overexpression expanded the cell surface hyaluronan coat and decreased melanoma cell adhesion, migration and proliferation by cell cycle arrest at G1/G0. Melanoma cell migration was restored by removal of cell surface hyaluronan by Streptomyces hyaluronidase and by receptor blocking with hyaluronan oligosaccharides, while the effect on cell proliferation was receptor independent. Overexpression of HAS3 decreased ERK1/2 phosphorylation suggesting that inhibition of MAP-kinase signaling was responsible for these suppressive effects on the malignant phenotype of MV3 melanoma cells. - Highlights: • Inducible HAS3-MV3 melanoma cell line was generated using Lentiviral transduction. • HAS3 overexpression inhibits MV3 cell migration via hyaluronan–receptor interaction. • HAS3 overexpression decreases MV3 melanoma cell proliferation and adhesion. • ERK1/2 phosphorylation is downregulated by 50% in HAS3 overexpressing cells. • The results suggest that hyaluronan has anti-cancer like effects in melanoma.

  5. An open source based high content screening method for cell biology laboratories investigating cell spreading and adhesion.

    Directory of Open Access Journals (Sweden)

    Andre Schmandke

    Full Text Available BACKGROUND: Adhesion dependent mechanisms are increasingly recognized to be important for a wide range of biological processes, diseases and therapeutics. This has led to a rising demand of pharmaceutical modulators. However, most currently available adhesion assays are time consuming and/or lack sensitivity and reproducibility or depend on specialized and expensive equipment often only available at screening facilities. Thus, rapid and economical high-content screening approaches are urgently needed. RESULTS: We established a fully open source high-content screening method for identifying modulators of adhesion. We successfully used this method to detect small molecules that are able to influence cell adhesion and cell spreading of Swiss-3T3 fibroblasts in general and/or specifically counteract Nogo-A-Δ20-induced inhibition of adhesion and cell spreading. The tricyclic anti-depressant clomipramine hydrochloride was shown to not only inhibit Nogo-A-Δ20-induced cell spreading inhibition in 3T3 fibroblasts but also to promote growth and counteract neurite outgrowth inhibition in highly purified primary neurons isolated from rat cerebellum. CONCLUSIONS: We have developed and validated a high content screening approach that can be used in any ordinarily equipped cell biology laboratory employing exclusively freely available open-source software in order to find novel modulators of adhesion and cell spreading. The versatility and adjustability of the whole screening method will enable not only centers specialized in high-throughput screens but most importantly also labs not routinely employing screens in their daily work routine to investigate the effects of a wide range of different compounds or siRNAs on adhesion and adhesion-modulating molecules.

  6. Tuning the kinetics of cadherin adhesion

    OpenAIRE

    Sivasankar, Sanjeevi

    2013-01-01

    Cadherins are Ca2+ dependent cell-cell adhesion proteins that maintain the structural integrity of the epidermis; their principle function is to resist mechanical force. This review summarizes the biophysical mechanisms by which classical cadherins tune adhesion and withstand mechanical stress. We first relate the structure of classical cadherins to their equilibrium binding properties. We then review the role of mechanical perturbations in tuning the kinetics of cadherin adhesion. In particu...

  7. The improvement of adhesive properties of PEEK through different pre-treatments

    Science.gov (United States)

    Hallmann, Lubica; Mehl, Albert; Sereno, Nuno; Hämmerle, Christoph H. F.

    2012-07-01

    The purpose of this in vitro study was the evaluation of the bond strength of the adhesives/composite resin to Poly Ether Ether Ketone (PEEK) based dental polymer after using different surface conditioning methods. PEEK blanks were cut into discs. All disc specimens were polished with 800 grit SiC paper and divided into 6 main groups. Main groups were divided into 2 subgroups. The main groups of 32 specimens each were treated as follow: (1) control specimens (no treatment), (2) piranha solution etching, (3) abraded with 50 μm alumina particles and chemical etching, (4) abraded with 110 μm alumina particles and chemical etching, (5) abraded with 30 μm silica-coated alumina particles and chemical etching, (6) abraded with 110 μm silica-coated alumina particles and chemical etching. Plexiglas tubes filled with a composite resin (RelyX Unicem) were bonded to the specimens. The adhesives used were Heliobond and Clearfil Ceramic Primer. Each specimen was stored in distilled water (37 °C) for 3 days. Tensile bond strength was measured in a universal testing machine and failure methods were evaluated. Abraded surface with 50 μm alumina particles followed by etching with piranha solution lead to the highest bond strength of 21.4 MPa when Heliobond like adhesive was used. Tribochemical silica coated/etched PEEK surfaces did not have an effect on the bond strength. Non-treated PEEK surface was not able to establish a bond with composite resin. The proper choice of adhesive/composite resin system leads to a strong bond. ConclusionAirborne particle abrasion in combination with piranha solution etching improves the adhesive properties of PEEK.

  8. Cancer Cell Adhesion and Metastasis: Selectins, Integrins, and the Inhibitory Potential of Heparins

    Directory of Open Access Journals (Sweden)

    Gerd Bendas

    2012-01-01

    Full Text Available Cell adhesion molecules play a significant role in cancer progression and metastasis. Cell-cell interactions of cancer cells with endothelium determine the metastatic spread. In addition, direct tumor cell interactions with platelets, leukocytes, and soluble components significantly contribute to cancer cell adhesion, extravasation, and the establishment of metastatic lesions. Clinical evidence indicates that heparin, commonly used for treatment of thromboembolic events in cancer patients, is beneficial for their survival. Preclinical studies confirm that heparin possesses antimetastatic activities that lead to attenuation of metastasis in various animal models. Heparin contains several biological activities that may affect several steps in metastatic cascade. Here we focus on the role of cellular adhesion receptors in the metastatic cascade and discuss evidence for heparin as an inhibitor of cell adhesion. While P- and L-selectin facilitation of cellular contacts during hematogenous metastasis is being accepted as a potential target of heparin, here we propose that heparin may also interfere with integrin activity and thereby affect cancer progression. This review summarizes recent findings about potential mechanisms of tumor cell interactions in the vasculature and antimetastatic activities of heparin.

  9. BigA is a novel adhesin of Brucella that mediates adhesion to epithelial cells.

    Science.gov (United States)

    Czibener, Cecilia; Merwaiss, Fernando; Guaimas, Francisco; Del Giudice, Mariela Giselda; Serantes, Diego Armando Rey; Spera, Juan Manuel; Ugalde, Juan Esteban

    2016-04-01

    Adhesion to cells is the initial step in the infectious cycle of basically all pathogenic bacteria, and to do so, microorganisms have evolved surface molecules that target different cellular receptors. Brucella is an intracellular pathogen that infects a wide range of mammals whose virulence is completely dependent on the capacity to replicate in phagocytes. Although much has been done to elucidate how Brucella multiplies in macrophages, we still do not understand how bacteria invade epithelial cells to perform a replicative cycle or what adhesion molecules are involved in the process. We report the identification in Brucella abortus of a novel adhesin that harbours a bacterial immunoglobulin-like domain and demonstrate that this protein is involved in the adhesion to polarized epithelial cells such as the Caco-2 and Madin-Darby canine kidney models targeting the bacteria to the cell-cell interaction membrane. While deletion of the gene significantly reduced adhesion, over-expression dramatically increased it. Addition of the recombinant protein to cells induced cytoskeleton rearrangements and showed that this adhesin targets proteins of the cell-cell interaction membrane in confluent cultures. PMID:26400021

  10. Epithelial to mesenchymal transition-The roles of cell morphology, labile adhesion and junctional coupling.

    OpenAIRE

    Abdulla, Tariq; Schleich, Jean-Marc; Summers, Ron

    2013-01-01

    International audience Epithelial to mesenchymal transition (EMT) is a fundamental process during development and disease, including development of the heart valves and tumour metastases. An extended cellular Potts model was implemented to represent the behaviour emerging from autonomous cell morphology, labile adhesion, junctional coupling and cell motility. Computer simulations normally focus on these functional changes independently whereas this model facilitates exploration of the inte...

  11. Spatiotemporal distribution and function of N-cadherin in postnatal Schwann cells: A matter of adhesion?

    DEFF Research Database (Denmark)

    Corell, Mikael; Wicher, Grzegorz; Limbach, Christoph;

    2010-01-01

    During embryonic development of the peripheral nervous system (PNS), the adhesion molecule neuronal cadherin (N-cadherin) is expressed by Schwann cell precursors and associated with axonal growth cones. N-cadherin expression levels decrease as precursors differentiate into Schwann cells. In this ...

  12. Adhesion and Proliferation of Human Periodontal Ligament Cells on Poly(2-methoxyethyl acrylate

    Directory of Open Access Journals (Sweden)

    Erika Kitakami

    2014-01-01

    Full Text Available Human periodontal ligament (PDL cells obtained from extracted teeth are a potential cell source for tissue engineering. We previously reported that poly(2-methoxyethyl acrylate (PMEA is highly biocompatible with human blood cells. In this study, we investigated the adhesion, morphology, and proliferation of PDL cells on PMEA and other types of polymers to design an appropriate scaffold for tissue engineering. PDL cells adhered and proliferated on all investigated polymer surfaces except for poly(2-hydroxyethyl methacrylate and poly[(2-methacryloyloxyethyl phosphorylcholine-co-(n-butyl methacrylate]. The initial adhesion of the PDL cells on PMEA was comparable with that on polyethylene terephthalate (PET. In addition, the PDL cells on PMEA spread well and exhibited proliferation behavior similar to that observed on PET. In contrast, platelets hardly adhered to PMEA. PMEA is therefore expected to be an excellent scaffold for tissue engineering and for culturing tissue-derived cells in a blood-rich environment.

  13. Adhesion and proliferation of human periodontal ligament cells on poly(2-methoxyethyl acrylate).

    Science.gov (United States)

    Kitakami, Erika; Aoki, Makiko; Sato, Chikako; Ishihata, Hiroshi; Tanaka, Masaru

    2014-01-01

    Human periodontal ligament (PDL) cells obtained from extracted teeth are a potential cell source for tissue engineering. We previously reported that poly(2-methoxyethyl acrylate) (PMEA) is highly biocompatible with human blood cells. In this study, we investigated the adhesion, morphology, and proliferation of PDL cells on PMEA and other types of polymers to design an appropriate scaffold for tissue engineering. PDL cells adhered and proliferated on all investigated polymer surfaces except for poly(2-hydroxyethyl methacrylate) and poly[(2-methacryloyloxyethyl phosphorylcholine)-co-(n-butyl methacrylate)]. The initial adhesion of the PDL cells on PMEA was comparable with that on polyethylene terephthalate (PET). In addition, the PDL cells on PMEA spread well and exhibited proliferation behavior similar to that observed on PET. In contrast, platelets hardly adhered to PMEA. PMEA is therefore expected to be an excellent scaffold for tissue engineering and for culturing tissue-derived cells in a blood-rich environment. PMID:25165689

  14. Diferenças nas propriedades adesivas de Staphylococcus saprophyticus a células HEp-2 e eritrócitos Differences on the adhesive property of Staphylococcus saprophyticus to HEp-2 cells and erythrocytes

    Directory of Open Access Journals (Sweden)

    Lucimar Gonçalves Milagres

    1992-08-01

    Full Text Available S. saprophyticus é freqüentemente isolado de infecções do trato urinário de mulheres jovens e sexualmente ativas. Ao contrário de S. aureus, esta espécie não possui fatores de virulência bem definidos. O objetivo deste estudo é analisar a aderência de S. saprophyticus a células HEp-2 e eritrócitos de carneiro. As amostras foram isoladas a partir da urina de pacientes com infecção urinária. Foram realizados testes de hemaglutinação, aderência a células HEp-2 e a capacidade de carboidratos específicos inibirem as interações entre estes tipos celulares e S. saprophyticus. A maioria das cepas se mostrou hemaglutinante e sensível a inibição da hemaglutinação pela manose (100mM. Foram verificados altos níveis de aderência às células HEp-2. As diferenças em especificidade e nível de aderência do microrganismo a células de HEp-2 e eritrócitos sugerem a participação de diferentes adesinas nos processos de interações celulares.S. saprophyticus has been frequently isolated from urinary tract infections in young women. In contrast with S. aureus, no defined virulence factors have been recognized for the coagulase negative Staphylococcus species. The objective this study was to analyze the adherence of S. saprophyticus to HEp-2 cells and sheep erythrocytes. The sample were isolated from urine of patients with urinary infection. Hemagglutination, adherence to HEp-2 cells tests and inhibition by specific carbohydrates of the interactions between these cells were analyzed. Most of the strains were hemagglutinanting whose properties was inhibited by mannose (100mM. There was a high adherence level to HEp-2 cells. The differences in specificity and attachment level noted in this study suggest that multiple adhesins are involved in the mechanism of cellular interaction.

  15. Intercellular adhesion molecule-1 expression by skeletal muscle cells augments myogenesis

    International Nuclear Information System (INIS)

    We previously demonstrated that the expression of intercellular adhesion molecule-1 (ICAM-1) by skeletal muscle cells after muscle overload contributes to ensuing regenerative and hypertrophic processes in skeletal muscle. The objective of the present study is to reveal mechanisms through which skeletal muscle cell expression of ICAM-1 augments regenerative and hypertrophic processes of myogenesis. This was accomplished by genetically engineering C2C12 myoblasts to stably express ICAM-1, and by inhibiting the adhesive and signaling functions of ICAM-1 through the use of a neutralizing antibody or cell penetrating peptide, respectively. Expression of ICAM-1 by cultured skeletal muscle cells augmented myoblast–myoblast adhesion, myotube formation, myonuclear number, myotube alignment, myotube–myotube fusion, and myotube size without influencing the ability of myoblasts to proliferate or differentiate. ICAM-1 augmented myotube formation, myonuclear accretion, and myotube alignment through a mechanism involving adhesion-induced activation of ICAM-1 signaling, as these dependent measures were reduced via antibody and peptide inhibition of ICAM-1. The adhesive and signaling functions of ICAM-1 also facilitated myotube hypertrophy through a mechanism involving myotube–myotube fusion, protein synthesis, and Akt/p70s6k signaling. Our findings demonstrate that ICAM-1 expression by skeletal muscle cells augments myogenesis, and establish a novel mechanism through which the inflammatory response facilitates growth processes in skeletal muscle. - Highlights: • We examined mechanisms through which skeletal muscle cell expression of ICAM-1 facilitates events of in vitro myogenesis. • Expression of ICAM-1 by cultured myoblasts did not influence their ability to proliferate or differentiate. • Skeletal muscle cell expression of ICAM-1 augmented myoblast fusion, myotube alignment, myotube–myotube fusion, and myotube size. • ICAM-1 augmented myogenic processes through

  16. Intercellular adhesion molecule-1 expression by skeletal muscle cells augments myogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Qingnian; Dearth, Christopher L.; Corbett, Jacob T. [Department of Kinesiology, The University of Toledo, Toledo, OH (United States); Pierre, Philippe [Centre d’Immunologie de Marseille-Luminy U2M, Aix-Marseille Université, Mars