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  • 11
    Electronic Resource
    Electronic Resource
    The biocompatibility of solution cast and acetone-extracted cast biomer (1986)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 20 (1986), S. 799-815 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The cellular response to films of cast Biomer and acetone-extracted Biomer were investigated over a 21-day implantation period, using an in vivo cage implant system. Film samples were characterized by scanning electron microscopy (SEM), attenuated total reflectance infrared (ATRIR), electron spectroscopy for chemical analysis (ESCA) and by contact angle measurements before implantation, and by SEM and ESCA after implantation and cleaning. Cellular and protein components of the inflammatory response were analyzed at periodic observation points after implantation. In addition, film samples were retrieved at 4, 7, and 21 days after implantation and analyzed for leukocyte adhesion by light microscopy and SEM. The results demonstrated that cast Biomer contains an extractable fraction, which when removed significantly improves the biocompatibility of the material.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820200611
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  • 12
    Electronic Resource
    Electronic Resource
    Vascular graft-associated complement activation and leukocyte adhesion in an artificial circulation (1987)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 21 (1987), S. 379-397 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Complement-associated leukocyte adhesion appears to be a consistent in vitro and in vivo finding for many types of polymers; however, very little work has been done on the interaction of leukocytes with vascular graft materials. An in vitro perfusion system was used to study complement and leukocyte activation associated with the following vascular graft materials when tested with human blood: expanded polytetrafluoroethylene (ePTFE), crimped Dacron Bionit (DB) and preclotted Dacron Bionit. A decrease in the total leukocyte concentration with perfusion time was seen for all materials tested, and paralleled leukocyte adhesion to the graft surface as observed by scanning electron microscopy. The most dramatic decrease in leukocyte concentration was observed for the interaction of heparinized whole blood with Dacron. This was due to a selective decrease in neutrophils and monocytes, and was correlated with an increase in both leukocyte adhesiveness and complement activation, as measured by C5a elevation. Inhibiting complement activation by use of the anticoagulant, sodium citrate, curtailed Dacron-induced leukocyte adhesion. Little leukocyte or complement activation was observed for ePTFE or the silicone rubber control regardless of the anticoagulant used.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820210310
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  • 13
    Electronic Resource
    Electronic Resource
    Adhesion of Staphylococcus epidermidis and transposon mutant strains to hydrophobic polyethylene (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 39 (1998), S. 341-350 
    Details
    ISSN: 0021-9304
    Keywords: bacterial adhesion ; Staphylococcus epidermidis ; polysaccharide adhesin (PS/A) ; slime ; surface hydrophobicity ; biomaterials-adverse effects ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Staphylococcus epidermidis capsular polysaccharide adhesin (PS/A) and slime were studied as possible mediators of bacterial adhesion to NHLBI polyethylene (PE) under dynamic flow. This putative interaction was examined by quantifying the adhesion of M187 (PS/A+, slime+) parent strain and isogenic transposon mutant strain sn3 (PS/A-, slime-) to polyethylene (PE) under a range of physiologic shear stress conditions in both phosphate-buffered saline (PBS) and 1% platelet poor plasma (PPP). No significant differences in adhesion were noted between the M187 and sn3 strains in either test medium. However, adhesion of both strains in 1% PPP was decreased 75-95% compared to adhesion in PBS. In PBS, adhesion was shear stress dependent from 0-15 dyne/cm2, after which adhesion was comparatively shear stress independent. Adhesion in 1% PPP was independent of shear stress. Epifluorescent imaging of both strains labeled for slime confirmed the presence of slime on the surface of M187 and suggested that PS/A and slime promote the formation of large aggregates, as aggregates were totally absent in the images of the sn3 strain. The results suggest that PS/A and slime do not mediate S. epidermidis adhesion to bare PE or PE with adsorbed plasma proteins, but may be necessary for intercellular adhesion, which is important for biofilm formation. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 341-350, 1998.
    Additional Material: 5 Ill.
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  • 14
    Electronic Resource
    Electronic Resource
    A novel fiber-optic pH sensor incorporating carboxy SNAFL-2 and fluorescent wavelength-ratiometric detection (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 39 (1998), S. 9-15 
    Details
    ISSN: 0021-9304
    Keywords: fiber-optic pH sensor ; pH sensing membrane ; fluorescent probe ; SNAFL ; photo-crosslinking ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A fiber-optic pH sensor was prepared using the self-referencing fluorescent pH probe carboxy seminaphthofluorescein (SNAFL-2). The ratio of the emission from the base form of this dye and the emission near the isoemissive point is insensitive to variations in the excitation intensity and photobleaching. The carboxy SNAFL-2 and a photoaffinity crosslinker, 4-azido-2,3,5,6-tetrafluorobenzoic acid, succinimidyl ester, were attached onto poly(acrylamide-co-vinylamine) to form a hydrophilic functional membrane for the fiber-optic sensor. Photo crosslinking was used to create a crosslinked pH-sensing membrane and covalently bind the membrane onto the surface of the PMMA optical fiber. The fluorescent properties of the membrane-fiber conjugate have been determined. The membrane is stable, and the pH sensor shows a fast response time and excellent resolution in a wide pH range of 3 to 11. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 9-15, 1998.
    Additional Material: 8 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    Bacterial surface properties of clinically isolated Staphylococcus epidermidis strains determine adhesion on polyethylene (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 42 (1998), S. 425-432 
    Details
    ISSN: 0021-9304
    Keywords: Staphylococcus epidermidis ; bacterial adhesion ; polyethylene ; rotating disk system ; microbial adhesion to hydrocarbon ; electrostatic chromatography ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The role of surface physiochemical properties of Staphylococcus epidermidis strains in adhesion to polyethylene (PE) was investigated under physiological flow conditions in phosphate buffered saline (PBS) and 1% platelet poor plasma (PPP). Four clinically isolated strains were divided into two groups: low and high relative hydrophobicity, and the F1198 and RP62A strains showing significantly greater hydrophobicity than the F21 and F1018 strains. In PBS, adhesion of all S. epidermidis strains was shear dependent from 0 to 15 dyn/cm2, after which adhesion becomes shear independent. Strains with higher surface hydrophobicity showed higher adhesion to PE, demonstrating the influence of bacterial surface hydrophobicity in nonspecific adhesion. Bacterial adhesion correlated well with bacterial surface hydrophobicity at low shear stresses (0-8 dyn/cm2). In 1% PPP, adhesion of all strains dramatically decreased and we found no correlation between bacterial surface hydrophobicity and adhesion. The presence of plasma proteins reduced nonspecific adhesion. S. epidermidis surface charge did not correlate with bacterial adhesion in either test media. The results suggested that S. epidermidis surface hydrophobicity may mediate nonspecific adhesion to PE at low shear stresses in protein-free media. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 425-432, 1998.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Biocompatibility studies on plasm polymerized interface materials encompassing both hydrophobic and hydrophilic surfaces (1992)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 26 (1992), S. 915-935 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The biocompatibility of radiofrequency plasma polymerized films (〈100 nm thick) deposited on biomedical polymer supports has been characterized by in vitro and in vivo methods. The polymer interface materials covered a wide range of elemental composition and surface properties, and were prepared from N-vinyl-2- pyrrolidone, γ-butyrolactone, n-hexane, and hexamethyldisilazane (PPHMDSZ). The biocompatibility studies showed that the interface materials were noncytotoxic to mouse and human fibroblasts, as shown by morphologic evaluation, and by determination of extracellular LDH; and they did not stimulate interleukin-1-like production from human monocytes, as indicated by a thymocyte proliferation assay. The human fibroblast proliferation assay showed that three of the polymers supported cell growth at levels comparable to, or greater than, polymer controls, while the hydrophobic PPHMDSZ inhibited both cell attachment and proliferation. The response to subcutaneous implantation for all test materials was indicative of biocompatibility, with rapid resolution of the acute phase response and normal wound healing. The wide range of composition and surface properties for the plasma polymerized films evaluated in this study suggest that this general class of materials is likely to exhibit excellent biocompatibility.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820260707
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  • 17
    Electronic Resource
    Electronic Resource
    Platelet-mediated adhesion of Staphylococcus epidermidis to hydrophobic NHLBI reference polyethylene (1993)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 27 (1993), S. 1119-1128 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The effects of platelets and plasma proteins on the adhesion of Staphylococcus epidermidis strain RP62A to hydrophobic NHLBI reference polyethylene was quantitatively studied using a rotating disk system to generate well-defined shear conditions simulating the hemodynamics of human blood circulation. Bacterial adhesion was quantified by adhesive coefficient, the percentage of bacteria transported to the surface that becomes adherent. The results showed that surface modification by adsorption of plasma proteins reduced the adhesion of S epidermidis as compared to the bare polymer surface. This surface modification was not sufficient to eliminate completely bacterial adhesion, even at the highest physiologic shear stress level. S epidermidis did adhere strongly to polyethylene surface modified by platelets. This is readily evident as approximately 50% of the adherent S epidermidis were bound to contact-activated platelets which occupied only 4% of the surface area. Adhesive coefficients to platelets were significantly greater than to the protein-adsorbed polyethylene surface by at least one order of magnitude (P ≤ .01) across the range of physiological shear conditions investigated. These studies show that it is biologic surface modification by contact-activated platelets, and not plasma proteins, which mediates S epidermidis adhesion to polyethylene. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820270902
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  • 18
    Electronic Resource
    Electronic Resource
    Adhesion of Staphylococcus epidermidis to biomedical polymers: Contributions of surface thermodynamics and hemodynamic shear conditions (1995)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 485-493 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Adhesion studies of Staphylococcus epidermidis RP62A were conducted using a rotating disk system to determine the roles of surface physicochemistry and topographies under physiologic shear conditions. Six materials were investigated: biomedical reference polyethylene and polydimethylsiloxane; argon plasma-treated reference polyethylene (Ar-PE); Silastic®; expanded polytetrafluoroethylene; and woven Dacron. All of the polymers except Dacron demonstrated reduced bacterial adhesion with increasing shear stress. Argon plasma treatment of polyethylene reduced the level of staphylococcal adhesion. Adsorption of human plasma proteins effected significantly lower numbers of adherent bacteria. The lowest adhesion was observed for Ar-PE in 1% human plasma protein solution, whereas Dacron had the highest number of adherent bacteria. The high adhesion on Dacron was attributed to increased bacterial flux caused by topography-induced turbulent flow and physical entrapment of the bacteria in the fiber interstices. The results indicate that the driving force for S. epidermidis adhesion is strongly influenced by substrate physicochemistry, but this may be dominated by physical forces such as shear and turbulence. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820290408
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  • 19
    Electronic Resource
    Electronic Resource
    Interactions of human von Willebrand Factor with a hydrophobic self-assembled monolayer studied by atomic force microscopy (1994)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 28 (1994), S. 971-980 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Human von Willebrand Factor (vWF) was studied by atomic force microscopy under physiologic buffer on a hydrophobic octadecyltrichlorosilane self-assembled monolayer. The self-assembled monolayer deposited on glass was sufficiently smooth (root mean square roughness = 0.25 ± 0.12 nm) to permit identification of adsorbed vWF. Adhesion of the protein to the hydrophobic substrate was sufficient to allow repeated scanning by the atomic force microscope probe, and images of vWF on a submolecular scale were obtained. The frictional force between the surface and the protein was sufficient to withstand an applied lateral force of 19 nN. This result shows that vWF experiences strong interaction with a hydrophobic surface in aqueous media. Statistical analysis of adsorbed vWF shows that the protein is composed of large globular domains with elliptical cross sections of average dimensions 56 ± 24 nm (major axis) 26 ± 19 nm (minor axis), and 2.8 ± 1.0 nm (height). Further analysis of the major axis dimension shows that the molecular chain of vWF contains two statistically different populations of domain size. However, no sequence order of the different population of domains within the individual molecule was found. On the basis of our analysis of the globular domains, we present a model describing the three-dimensional structure of vWF protomer adsorbed on a hydrophobic surface in a physiologic solution. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820280902
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  • 20
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    Unknown
    Formation of hydroxyl groups in plasma-polymerized N-vinyl-2-pyrrolidone by reduction with sodium borohydride (1989)
    American Chemical Society
    Details
    Publication Date: 1989-07-01
    Print ISSN: 0024-9297
    Electronic ISSN: 1520-5835
    Topics: Chemistry and Pharmacology , Physics
    Published by American Chemical Society
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