Platelet adhesion of the expanded polytetrafluoroethylene absorbed with hydrophilic polymers and with plasma proteins.

To highlight the mechanisms of artificial surface/protein/platelet interactions, results obtained by various methods have been integrated to elucidate some of the correlations between phenomena which occur at the macromolecular level and subsequently influence those at the cellular level, such as platelet adhesion. Microcinematographic evidence obtained under the controlled conditions of the Stagnation Point Flow Experiment (SPFE) indicate that, even on glass, platelet adhesion commences only after 30-60 sees of exposure to native blood. This lag period is consistent with diffusion kinetics predicting the arrival of plasma proteins should overhwelmingly precede that of the cellular components. During the lag period, native plasma proteins collide with the artificial surface and, in most cases, adsorb with surface-induced conformational changes. The energy for altering the secondary protein structure is supplied by the heat of adsorption. The extent of adsorption and structural alterations depend upon both the type of protein and the molecular architecture of the artificial surface, viz., the number density and orientation of polar, H-bonding, etc. groups accessible to proteins. Using microparticulate glass (< μ dia.) and a microcalorimeter sensitive to ±0.00001° C in 100 ml of sample volume, serum albumin was found to adsorb, release heat, and desorb in a conformationally altered state. In contrast, γ-(7S)-globulin and fibrinogen underwent irreversible multilayer attachment releasing (1.0-1.7) χ 103 Kcal/mole of protein adsorbed directly to the glass surface. Proteins in the second, etc. sorbed layers released much smaller heats. The electrophoretic mobility of the same particles coated with varying amounts of the same proteins confirmed that the relatively greatest conformational change occurred in the protein layer directly attached to the artificial surface. On homologous Nylons exposed under identical hemodynamic conditions in the SPFE, the surface number density of platelets remaining adherent at points of identical shear was proportionate to the polar force contribution of those surfaces. These results indicate that the protein layer which settles first, is acting as a “proportional transformer” mediating the effects of artificial surfaces onto platelets.

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Platelet Phagocytosis As A Model For Platelet Adhesion

10.1055/s-0038-1653285 ◽

1981 ◽

Cited By ~ 1

Author(s):

D R Absolom ◽

W Zingg ◽

A W Neumann ◽

C J van Oss

Keyword(s):

Experimental Data ◽

Free Energy ◽

Thermodynamic Model ◽

Platelet Adhesion ◽

Helmholtz Free Energy ◽

Hydrophilic Polymers ◽

Polymer Substrates ◽

Physical Conditions ◽

Insight Into

It has been suggested that platelet phagocytosis might be a useful model to provide insight into platelet adhesion to polymer substrates commonly employed in biocompatibility studies. To test this supposition the present study of platelet engulfment of four strains of bacteria (opsonized as well as non-opsonized) under well defined in vitro physical conditions was undertaken. In physiologic conditions, platelet adhesion is maximum on the more hydrophilic polymers and minimum on the more hydrophobic surfaces; bacterial engulfment under the same conditions follows an identical pattern in that the more hydrophilic bacteria are more readily engulfed. The experimental data further suggest that, unlike phagocytosis by neutrophils platelet interaction with bacteria is non-specific in that it does not appear to be antibody receptor modulated. Opsonization of the bacteria does however play an important role in that it serves to increase the hydrophobicity of the bacteria thereby influencing the degree of bacterial engulfment. A striking correlation between the extent of bacterial engulfment and the Helmholtz Free Energy of Engulfment exists. Platelet adhesion to polymer substrates and platelet engulfment of bacteria appear to follow the same thermodynamic model.

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Adsorption of plasma proteins and adhesion of platelets onto novel polyetherurethaneureas?relationship between denaturation of adsorbed proteins and platelet adhesion

Journal of Biomedical Materials Research ◽

10.1002/jbm.820240209 ◽

1990 ◽

Vol 24 (2) ◽

pp. 227-242 ◽

Cited By ~ 27

Author(s):

Y. Ito ◽

M. Sisido ◽

Y. Imanishi

Keyword(s):

Plasma Proteins ◽

Platelet Adhesion ◽

Adsorbed Proteins ◽

Adhesion Of Platelets

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Platelets, Surfaces and Plasma Proteins in Platelet Adhesion

Platelets, Drugs and Thrombosis ◽

10.1159/000395690 ◽

2015 ◽

pp. 15-26 ◽

Cited By ~ 1

Author(s):

H. L. Nossel

Keyword(s):

Plasma Proteins ◽

Platelet Adhesion

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Evaluation of in Vivo Adsorption of Plasma Proteins onto Hydrogel Coated Silicone Rubber by Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100054510 ◽

1982 ◽

Vol 40 ◽

pp. 378-379

Author(s):

Linda J. Miller ◽

Raymond T. Greer

Keyword(s):

Plasma Proteins ◽

Platelet Adhesion ◽

Competitive Adsorption ◽

Sequence Of Events ◽

Considerable Debate ◽

Platelet Reaction ◽

Coated Surface ◽

Foreign Surface ◽

Scanning Electron

Although there is considerable debate concerning the exact sequence of events that occur when blood contacts a foreign surface such as a polymer, most investigators agree on the basic sequence: polymer surfaceblood contact, competitive adsorption of plasma proteins, formation of protein coated surface, platelet approach, platelet reaction with glycoproteins, platelet adhesion, thrombus and coagulation.

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A surface graft polymerization process on chemically stable medical ePTFE for suppressing platelet adhesion and activation

Biomaterials Science ◽

10.1039/c8bm00364e ◽

2018 ◽

Vol 6 (7) ◽

pp. 1908-1915 ◽

Cited By ~ 16

Author(s):

Yihua Liu ◽

Maria Chiara Munisso ◽

Atsushi Mahara ◽

Yusuke Kambe ◽

Kyoko Fukazawa ◽

...

Keyword(s):

Platelet Adhesion ◽

Graft Polymerization ◽

Polymerization Process ◽

Expanded Polytetrafluoroethylene ◽

Surface Graft

An effective grafting method for modifying chemically inert and elaborately porous medical expanded-polytetrafluoroethylene (ePTFE).

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Interaction Of Plasma Proteins With Artificial Surfaces With Reference To Platelet Adhesion

10.1055/s-0038-1652941 ◽

1981 ◽

Author(s):

O P Malhotra ◽

M N Helmus ◽

D F Gibbons

Keyword(s):

Plasma Proteins ◽

Platelet Adhesion ◽

Platelet Rich Plasma ◽

Gel Filtration ◽

Platelet Suspension ◽

Platelet Poor Plasma ◽

Artificial Surfaces ◽

Glass Surfaces

On occasion, fewer platelets from platelet rich plasma (PRP), adhered to hydrophilic (glass) surfaces exposed to platelet poor plasma (PPP) for 3 min than areas exposed for 3 s. The decrease was dramatic and consistent when platelet suspension (gel-PLS, obtained from PRP by 2B Sepharose gel filtration) was used instead of PRP. To further explore the factors which influence platelet adhesion, we used the following: for surfaces, a) sparkleen-cleaned glass (hydrophilic), b) acid-washed (somewhat hydrophobic), and c) siliconized (hydrophobic); for proteins, a) PPP, b) fibrinogen (96% clottable), c) defi-brinogenated (defib.) plasma, and d) defib. plasma plus fibrinogen; for platelet suspension, a) PRP, b) gel-PLS, and c) platelets in defib. plasma (defib. PLS).From gel-PLS, non-siliconized surfaces exposed to fibrinogen for 3 s attached more platelets (F<0.05) than those exposed to PPP or defib. plasma plus fibrinogen. The latter two attracted more platelets (P<0.01) than defib. plasma. Hydrophilic sparkleen-cleaned glass previously exposed to PPP (or defib. plasma plus fibrinogen) attached a minimum of 10-fold as many platelets from gel-PLS than from PRP. Under similar conditions acid-cleaned surfaces attached 2-fold from gel-PLS, while hydrophobic glass did not show any change. By exposing the surfaces to PPP followed by gel-PLS, the sparkleen-cleaned glass showed the greatest decrease (P<0.001) in the number of platelets attached to areas exposed to PPP for 3 min as compared to 3 s, while siliconized showed no such decrease. If, however, the surfaces were exposed to defib. plasma, they all showed decreases in platelet attraction at 3 min.

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Optimization of Hemocompatibility of Silicon Oxynitride Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.727 ◽

2009 ◽

Vol 79-82 ◽

pp. 727-730 ◽

Cited By ~ 1

Author(s):

Qi Yi Wang ◽

Ping Yang ◽

Ju Huang ◽

Jun Liang ◽

Hong Sun ◽

...

Keyword(s):

Plasma Proteins ◽

Platelet Adhesion ◽

Single Crystal Silicon ◽

Silicon Oxynitride ◽

Medical Implants ◽

Crystal Silicon ◽

Angle Measurements ◽

Contact Angle Measurements ◽

Interventional Devices ◽

Pyrolitic Carbon

Low hemocompatibility is a major problem of biomaterials that come in contact with blood. Surface modification has become an important way to improve the hemocompatibility of medical implants and interventional devices. Recently, researchers attempt to investigate the possibility of silicon oxynitride (Si-N-O) films to be applied as novel coating of blood-contacting biomaterials. However, no detailed investigation has been conducted. In this study, our work was focused on the optimization of the hemocompatibility of Si-N-O films prepared on single-crystal silicon wafers by unbalance magnetron sputtering (UBMS). The structure and chemical composition of films were characterized by X-ray photoelectron spectrometry (XPS), and their physical chemistry property was characterized by contact angle measurements. Platelet adhesion test was performed to investigate the platelet adhesion and activation. Our results suggested that films composed of Si3N4 and SiOx (x<2) exhibited better hemocompatibility than low temperature isotropic pyrolitic carbon (LTIC) that is a common material used in blood-contacting implants. It was also revealed that the higher N/O ratio in films composed of Si3N4 and SiOx (x<2) was attributed to the lower platelet adhesion and activation, and the interaction of samples with plasma proteins was demonstrated to play an important role in the adhesion and activation of platelets.

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