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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to investigate the adhesive properties of an in-house aminopropyltrimethoxysilane-methylenebisacrylamide (APTMS-MBA) siloxane system and compare them with a commercially available adhesive, n-butyl cyanoacrylate (nBCA). The ability of the material to perform as a soft tissue adhesive was established by measuring the physical (bond strength, curing time) and biological (cytotoxicity) properties of the adhesives on cartilage. Complementary physical techniques, X-ray photoelectron spectroscopy, Raman and infrared imaging, enabled the mode of action of the adhesive to the cartilage surface to be determined. Adhesion strength to cartilage was measured using a simple butt joint test after storage in phosphate-buffered saline solution at 37 degrees C for periods up to 1 month. The adhesives were also characterised using two in vitro biological techniques. A live/dead stain assay enabled a measure of the viability of chondrocytes attached to the two adhesives to be made. A water-soluble tetrazolium assay was carried out using two different cell types, human dermal fibroblasts and ovine meniscal chondrocytes, in order to measure material cytotoxicity as a function of both supernatant concentration and time. IR imaging of the surface of cartilage treated with APTMS-MBA siloxane adhesive indicated that the adhesive penetrated the tissue surface marginally compared to nBCA which showed a greater depth of penetration. The curing time and adhesion strength values for APTMS-MBA siloxane and nBCA adhesives were measured to be 60 s/0.23 MPa and 38 min/0.62 MPa, respectively. These materials were found to be significantly stronger than either commercially available fibrin (0.02 MPa) or gelatin resorcinol formaldehyde (GRF) adhesives (0.1 MPa) (P < 0.01). Cell culture experiments revealed that APTMS-MBA siloxane adhesive induced 2% cell death compared to 95% for the nBCA adhesive, which extended to a depth of approximately 100-150 microm into the cartilage surface. The WST-1 assay demonstrated that APTMS-MBA siloxane was significantly less cytotoxic than nBCA adhesive as an undiluted conditioned supernatant (P < 0.001). These results suggest that the APTMS-MBA siloxane may be a useful adhesive for medical applications.
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PMID:Physical and biological properties of a novel siloxane adhesive for soft tissue applications. 1588 53

The build-up of multilayers constructed from polyallylamine hydrochloride (PAH) and polyacrylic acid (PAA) under different pH conditions was continuously monitored using the quartz crystal microbalance with dissipation. The adsorbed amount of polymer as well as the amount of coupled water was determined. Furthermore, from dissipation measurements, it was possible to determine the visco-elastic properties of the adsorbed multilayer. These properties were highly dependent on the polyelectrolyte present in the outermost layer. The multilayer was far more rigid and elastic with PAA as the outermost layer. Furthermore, a link has been established between the conformability or rigidity of a multilayer covered surface and the adhesion between such surfaces. Adhesion measurements using the atomic force microscope showed a greater pull-off force when the more viscous PAH was present in the outermost layer.
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PMID:Visco-elastic and adhesive properties of adsorbed polyelectrolyte multilayers determined in situ with QCM-D and AFM measurements. 1597 4

Adhesion promoting monomers -5-(4-vinylbenzyl)-2-thiobarbituric acid (5VS), 9,10-epithiodecyl methacrylate (EP8MA), 9,10-epithiodecyl 4-vinylbenzoate (EP8VB), and 3,4-epithiobutyl 2,2-bis(methacryloyloxymethyl)propionate (EP2BMA)--were added to the MMA liquid of a MMA-PMMA/TBBO resin. Three dental precious metal alloys were butt-jointed together with the MMA-PMMA/TBBO adhesive resin, and tensile bond strength was measured after 2,000 thermocycles in water. Polymerization kinetics of MMA by 2,2'-azobis (isobutyronitrile) at 70 degrees C in the presence of 5VS, EP8MA, EP8VB, or EP2BMA were examined quantitatively using a DSC to clarify the relationship between the adhesive properties of MMA-PMMA/TBBO adhesive resin and the kinetic polymerization behavior thereof. Obtained kinetic parameters indicated that 5VS was not suitable as an adhesive monomer for adhesive resin formulations and that EP2BMA possessed the latent potential as an adhesive monomer. Further, tensile test results revealed the applicability of EP8MA, EP8VB, and EP2BMA as an adhesive monomer component of adhesive resin formulations.
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PMID:Adhesive properties and kinetic polymerization behavior of resins containing adhesion promoting monomers for precious metals. 1627 23

Photodynamic therapy of superficial neoplastic lesions generally uses high aminolevulinic acid (ALA) loadings (20%, w/w) in emulsion-type systems under occlusion. This approach makes ALA dosing difficult and delivery to demanding areas, such as the vulval, perineal and perianal skin, are seldom possible. This work evaluated a water-soluble bioadhesive patch, loaded with ALA, which can adhere to both intact skin and mucous surfaces. ALA loading in the patch (38 mg cm(-2)) was chosen using a simple comparative procedure. Tensile measurements showed that large ALA loadings did not adversely affect adhesion to porcine skin, achieving a mean strength of 1.7 N cm(-2). Increasing the loading was, however, shown to lower break strength and enhance percentage elongation at break. Water uptake studies showed an initial, rapid weight gain followed by gradual patch dissolution over 60 min. Drug release studies demonstrated that 57% of ALA was released across an aqueous semi-permeable membrane within 6 h, compared to 42% released from a proprietary cream formulation. The patch designed in this work is suited to definable ALA delivery to diverse regions, such as the lower female reproductive tract and lesions on exposed skin. Adhesion is sufficiently tenacious to allow photodynamic therapy (PDT), without the need to immobilise patients for up to 6 h, as was common with the cream-under-occlusion approach.
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PMID:Design and evaluation of a water-soluble bioadhesive patch formulation for cutaneous delivery of 5-aminolevulinic acid to superficial neoplastic lesions. 1633 Jan 92

Conidia of the plant pathogenic fungus Botrytis cinerea adhered to tomato cuticle and to certain other substrata immediately upon hydration. This immediate adhesion occurred with both living and nonliving conidia. Adhesion was not consistently influenced by several lectins, sugars, or salts or by protease treatment, but it was strongly inhibited by ionic or nonionic detergents. With glass and oxidized polyethylene, substrata whose surface hydrophobicities could be conveniently varied, there was a direct relationship between water contact angle and percent adhesion. Immediate adhesion did not involve specific conidial attachment structures, although the surfaces of attached conidia were altered by contact with a substratum. Freshly harvested conidia were very hydrophobic, with more than 97% partitioning into the organic layer when subjected to a phase distribution test. Percent adhesion of germinated conidia was larger than that of nongerminated conidia. Evidence suggests that immediate adhesion of conidia of B. cinerea depends, at least in part, on hydrophobic interactions between the conidia and substratum.
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PMID:Adhesion of Nongerminated Botrytis cinerea Conidia to Several Substrata. 1634 54

Proteins are important in bacterial adhesion, but interactions at molecular-scales between proteins and specific functional groups are not well understood. The adhesion forces between four proteins [bovine serum albumin (BSA), protein A, lysozyme, and poly-d-lysine] and COOH, NH2 and OH-functionalized (latex) colloids were examined using colloid probe atomic force microscopy (AFM) as the function of colloid residence time (T) and solution ionic strength (IS). For three of the proteins, OH-functionalized colloids produced higher adhesion forces to proteins (2.6-30.5 nN; IS=1 mM, T=10s) than COOH- and NH2-functionalized colloids (1.6-6.8 nN). However, protein A produced the largest adhesion force (8.1+/-1.0 nN, T=10 s) with the COOH-functionalized colloid, demonstrating the importance of specific and unanticipated protein-functional group interactions. The NH2-functionalized colloid typically produced the lowest adhesion forces with all proteins, likely due to repulsive electrostatic forces and weak bonds for NH2-NH2 interactions. The adhesion force (F) between functionalized colloids and proteins consistently increased with residence time (T), and data was well fitted by F=ATn. The constant value of n=0.21+/-0.07 for all combinations of proteins and functionalized colloids indicated that water exclusion and protein rearrangement were the primary factors affecting adhesion over time. Adhesion forces decreased inversely with IS for all functional groups interacting with surface proteins, consistent with previous findings. These results demonstrate the importance of specific molecular-scale interactions between functional groups and proteins that will help us to better understand factors colloidal adhesion to surfaces.
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PMID:Adhesion forces between functionalized latex microspheres and protein-coated surfaces evaluated using colloid probe atomic force microscopy. 1650 91

A stable cellulose paper system was studied to relate water distribution data, as obtained previously from plant tissues, to the analysis of freezing energy. Water distribution data for the cellulose system were obtained by several techniques and were coordinated with calorimetric data. The effect of the cellulose system on the latent heat of freezing was evaluated to estimate activation energies as functions of the amount of associated liquid water. Similar activation energies of water phase transitions in critical plant tissue systems may be heritable characteristics that affect freezing stress. Adhesion energy, that develops between ice and hydrophilic polymer systems as they compete for liquid water in a complex interface, was suggested as one possible source of freezing stress. This does not occur in frost desiccation.
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PMID:Energies of freezing and frost desiccation. 1665 85

To understand the role of surface wettability in adhesion of cells, the attachment of two different marine algae was studied on hydrophobic and hydrophilic polymer surfaces. Adhesion of cells of the diatom Navicula and sporelings (young plants) of the green macroalga Ulva to an underwater surface is mainly by interactions between the surface and the adhesive exopolymers, which the cells secrete upon settlement and during subsequent colonization and growth. Two types of block copolymers, one with poly(ethylene glycol) side-chains and the other with liquid crystalline, fluorinated side-chains, were used to prepare the hydrophilic and hydrophobic surfaces, respectively. The formation of a liquid crystalline smectic phase in the latter inhibited molecular reorganization at the surface, which is generally an issue when a highly hydrophobic surface is in contact with water. The adhesion strength was assessed by the fraction of settled cells (Navicula) or biomass (Ulva) that detached from the surface in a water flow channel with a wall shear stress of 53 Pa. The two species exhibited opposite adhesion behavior on the same sets of surfaces. While Navicula cells released more easily from hydrophilic surfaces, Ulva sporelings showed higher removal from hydrophobic surfaces. This highlights the importance of differences in cell-surface interactions in determining the strength of adhesion of cells to substrates.
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PMID:Comparison of the fouling release properties of hydrophobic fluorinated and hydrophilic PEGylated block copolymer surfaces: attachment strength of the diatom Navicula and the green alga Ulva. 1667 26

Growing evidence from clinical studies suggests that mothers using xylitol gums or lozenges have decreased levels of Streptococcus mutans (SM) and do not transmit these cariogenic bacteria as readily to their children. To begin to determine mechanisms for these clinical findings and to explore potential synergism of antimicrobial combinations, we studied the effect of multiple exposures of chlorhexidine (CHX) combined with copper gluconate (CG) or zinc gluconate (ZG) followed by xylitol (XYL) on the ability of SM to adhere and form biofilms. Cell suspensions of SM were exposed two times to CHX; CG; CHX plus CG; ZG; and CHX plus ZG, and then four times to XYL. Control cells were exposed six times to water or XYL or received no treatment. For biofilm assessment, glass slides were inoculated with treated cells, and numbers of bacteria were enumerated after 48 hours of incubation. To assess the ability of SM to adhere, microtiter plate wells coated with primary S. sanguinis biofilms grown in sucrose were inoculated with treated SM, and adhesion was determined. Cells exposed to CHX-XYL combinations exhibited significant but transient inhibition of growth. The multiple-exposure regimen groups showed significant decreases in the ability of SM to form biofilms (P < 0.05). However, the CHX-XYL group exhibited a much greater effect than the other treatment groups (P < 0.001). Adhesion studies revealed that none of the multiple-exposure regimens had a significant effect on adhesion of SM to primary biofilms of S. sanguinis. We concluded that significant inhibition of SM growth and subsequent inability to grow as biofilms in the presence of sucrose occurs after a staggered exposure regimen to CHX initially and then to XYL. This may help explain the clinical data showing the decreased levels of SM in mothers treated with CHX and XYL.
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PMID:Multiple exposures to chlorhexidine and xylitol: adhesion and biofilm formation by Streptococcus mutans. 1673 49

It is uncertain whether single-phase self-etching adhesives form bonds to enamel as reliable as those of etch-and-rinse adhesives. This study compared the microtensile bond strengths to ground enamel of three self-etching adhesive systems, a self-etching primer system and an etchand-rinse adhesive system. Human enamel was ground flat with 320-grit silicone carbide paper. The self-etching adhesives iBond (Heraeus Kulzer), Prompt L-Pop (3M ESPE) and Xeno III (Caulk/Dentsply), the adhesive with a self-etching primer Clearfil SE Bond (Kuraray) and the etch-and-rinse adhesive Scotchbond Multipur-pose (3M/ESPE) were applied as directed, followed by a core of the same manufacturers' hybrid resin composite. A microtensile bond strength evaluation was performed after 48 hours of water storage, using untrimmed beams approximately 0.9 mm2 in cross-sectional area at a crosshead speed of 0.6 mm/minute. There were no pretest failures in any group, and failures were predominately adhesive or mixed. Adhesion to enamel of Clearfil SE was not significantly different from Scotchbond Multi-Purpose, while the three self-etching adhesive systems demonstrated significantly lower bond strengths (One-way ANOVA, Tukey-Kramer Multiple-Comparison Test, p < 0.00001).
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PMID:The microtensile bond strength of self-etching adhesives to ground enamel. 1680 41


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