The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
James M. Anderson - One of the best experts on this subject based on the ideXlab platform.
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staphylococcus epidermidis adhesion to hydrophobic Biomedical Polymer is mediated by platelets
The Journal of Infectious Diseases, 1993Co-Authors: Iwen Wang, James M. Anderson, Roger E MarchantAbstract:: A quantitative investigation on the effects of plasma proteins and platelets on the adhesion of Staphylococcus epidermidis RP62A to a hydrophobic Biomedical Polymer (National Heart, Lung, and Blood Institute reference polyethylene) was carried out under well-defined shear conditions approximating human blood circulation by using a rotating disk system. The results showed that contact-activated platelets mediated S. epidermidis adhesion to the Polymer surface. In the range of physiologic shear conditions, the adhesive coefficient (ratio of bacteria per unit area to the product of bacterial flux and the duration of the experiment) to platelets was significantly greater than to the protein-adsorbed polyethylene surface by at least one order of magnitude (P < or = .01). The presence of absorbed plasma proteins on polyethylene reduced the adhesion of S. epidermidis compared with that seen with the bare Polymer surface. These studies show that S. epidermidis adhesion to polyethylene is mediated by contact-activated platelets, not absorbed plasma proteins.
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Protein adsorption of Biomedical Polymers influences activated monocytes to produce fibroblast stimulating factors.
Journal of biomedical materials research, 1992Co-Authors: Tracey L. Bonfield, Erica Colton, James M. AndersonAbstract:The studies presented in this manuscript were based upon the hypothesis that monocytes/macrophages selectively produce cytokines and growth factors due to their interactions with Polymers and proteins which are adsorbed to their surfaces. These factors in turn selectively influence the ability of fibroblasts to proliferate. The factors which influence fibroblast proliferation were released from monocytes incubated with Polymers: Biomer, polydimethylsiloxane (PDMS), polyethylene (PE), expanded polytetrafluoroethylene (ePTFE), Dacron, and control polystyrene with and without preadsorption with physiological concentrations of IgG, fibrinogen, fibronectin, hemoglobin, or albumin. No simple correlation was found between adsorbed protein, Biomedical Polymer, and the ability of monocytes to produce growth factors and cytokines which influence fibroblast proliferation. This is evidence for selective protein-Polymer interactions which in turn selectively activate monocytes to produce variable cell cycle competence and progression factors controlling fibroblast growth.
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Biostability of Biomedical Polymers
MRS Bulletin, 1991Co-Authors: James M. Anderson, Q. H. ZhaoAbstract:The living body is an aggressive environment for almost all types of foreign materials, devices, prostheses, and artificial organs which are in contact with the tissues or body fluids of the living body. This aggressive environment can potentially produce changes in the chemical, physical, mechanical, and structural properties of biomaterials, i.e., biodegradation. The vast majority of Biomedical Polymers used today as biomaterials or in prostheses, devices, or artificial organs are considered biostable and are expected to resist the influence of the in vivo environment for the lifetime of the device or patient while retaining the necessary properties that fulfill the intended functions. In contrast, biodegradable or bioresorbable Biomedical Polymers are designed to be degraded and eliminated from the body by normal metabolic and physiological processes without adversely affecting body fluids, tissues, and organs.The term “biostability” commonly refers to the relative stability of Biomedical Polymers in the physiological environment as a function of time. It is advantageous to discuss biostability and biodegradation of Biomedical Polymers together. In vivo physiological mechanisms leading to changes in the properties of Biomedical Polymers are considered to be biodegradation phenomena, while biostable materials are considered to be those materials where physiological interactions do not lead to material property changes and loss of function during the service life of the Biomedical Polymer.
P. G. Kalman - One of the best experts on this subject based on the ideXlab platform.
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Surface modification of the Biomedical Polymer poly(ethylene terephthalate)
The Analyst, 1993Co-Authors: Lân N. Bùi, Michael Thompson, Neil B. Mckeown, Alex D. Romaschin, P. G. KalmanAbstract:X-ray photoelectron spectroscopy was used to characterize modified surfaces of a Biomedically important Polymer, poly(ethylene terephthalate). Several modification schemes were investigated and direct silanization with 3-aminopropyltriethoxysilane was found to be the optimum procedure, resulting in an aminated surface. Surface coverage of up to 100% was achieved with retention of the Polymeric structural integrity. Further activation of the silanized surface was accomplished with two cross-linkers, glutaraldehyde and sebacoyl chloride. A simple biomolecule, L-cysteine, was successfully immobilized onto a surface pre-treated with 3-aminopropyltriethoxysilane and glutaraldehyde, with a coverage of 42%.
Nicholas A. Peppas - One of the best experts on this subject based on the ideXlab platform.
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Micropatterning of Biomedical Polymer surfaces by novel UV Polymerization techniques.
Journal of biomedical materials research, 2001Co-Authors: Jennifer H. Ward, Rashid Bashir, Nicholas A. PeppasAbstract:The "living" radical Polymerization with an ini- ferter was used to create micropatterned Biomedical sur- faces. Novel, photosensitive Biomedical Polymers were cre- ated by the incorporation of dithiocarbamate groups from iniferters. A second monomer layer was then irradiated onto the photosensitive Polymer substrate created with the ini- ferter to form a coPolymer. Patterns were created on the films by application of modified microfabrication-based photolithographic techniques. The technique was used to create patterns with depths from 5 to 80 mm. In addition, various Polymers were incorporated, including polyethyl- ene glycol methacrylates, styrene, and methacrylic acid, to synthesize regions with different physico-chemical proper- ties. Applications include novel surfaces for biosensors and biomaterials for the selective adhesion of cells and proteins. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res 56: 351-360, 2001
Mark E. Meyerhoff - One of the best experts on this subject based on the ideXlab platform.
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Study of Crystal Formation and Nitric Oxide (NO) Release Mechanism from S-Nitroso-N-acetylpenicillamine (SNAP)-Doped CarboSil Polymer Composites for Potential Antimicrobial Applications.
Composites Part B-engineering, 2017Co-Authors: Yaqi Wo, Alessandro Colletta, Chuanwu Xi, Zi Li, Jianfeng Wu, Robert H Bartlett, Elizabeth J Brisbois, Adam J Matzger, Mark E. MeyerhoffAbstract:Abstract Stable and long-term nitric oxide (NO) releasing Polymeric materials have many potential Biomedical applications. Herein, we report the real-time observation of the crystallization process of the NO donor, S-nitroso-N-acetylpenicillamine (SNAP), within a thermoplastic silicone-polycarbonate-urethane Biomedical Polymer, CarboSil 20 80A. It is demonstrated that the NO release rate from this composite material is directly correlated with the surface area that the CarboSil Polymer film is exposed to when in contact with aqueous solution. The decomposition of SNAP in solution (e.g. PBS, ethanol, THF, etc.) is an apparent first-order reaction proportional to the SNAP concentration. Further, catheters fabricated with this novel NO releasing composite material are shown to exhibit significant effects on preventing biofilm formation on catheter surface by Pseudomonas aeruginosa and Proteus mirabilis grown in CDC bioreactor over 14 days, with a 2 and 3 log-unit reduction in the number of live bacteria on their surfaces, respectively. Therefore, the SNAP-CarboSil composite is a promising new material for antimicrobial catheters, as well as other Biomedical devices.
Lân N. Bùi - One of the best experts on this subject based on the ideXlab platform.
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Surface modification of the Biomedical Polymer poly(ethylene terephthalate)
The Analyst, 1993Co-Authors: Lân N. Bùi, Michael Thompson, Neil B. Mckeown, Alex D. Romaschin, P. G. KalmanAbstract:X-ray photoelectron spectroscopy was used to characterize modified surfaces of a Biomedically important Polymer, poly(ethylene terephthalate). Several modification schemes were investigated and direct silanization with 3-aminopropyltriethoxysilane was found to be the optimum procedure, resulting in an aminated surface. Surface coverage of up to 100% was achieved with retention of the Polymeric structural integrity. Further activation of the silanized surface was accomplished with two cross-linkers, glutaraldehyde and sebacoyl chloride. A simple biomolecule, L-cysteine, was successfully immobilized onto a surface pre-treated with 3-aminopropyltriethoxysilane and glutaraldehyde, with a coverage of 42%.