摘要:

Reminiscences of Leo Vroman and his Interface Lab, presented by Ann L. Adams at the 75th Birthday Symposium of Dr Leo Vroman held in Gouda, The Netherlands, on 27 April, 1990.

ISSN:0920-5063    

DOI:10.1163/156856292X00033

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0920-5063    

DOI:10.1163/156856292X00024

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The exchange sequence of plasma proteins in narrow spaces on solid surfaces was studied by means of a modified 'lens-on-surface' method as originally described by Vroman and Adams [1]. In our studies, lateral scanning ellipsometry was used as the detection method. With the use of antibodies it was demonstrated and confirmed that immunologically detectable plasma protein antigens appear and disappear in a time- and concentration-dependent sequence [IgG followed by fibrinogen followed by high-molecular weight kininogen (HMWK)] on silica surfaces. Plasma protein exchange reactions were also studied on hydrophilic titanium (Ti), vanadium (V), and silver (Ag) surfaces. Atypical exchange patterns were found on V and Ag surfaces as compared with hydrophilic silica (adsorbed fibrinogen was not removed).

ISSN:0920-5063    

DOI:10.1163/156856292X00042

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0920-5063    

DOI:10.1163/156856292X00051

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The adsorption of three cell adhesive proteins with known thrombogenic activity [fibrinogen (FGN), fibronectin (FN), and vitronectin (VN)] was quantified from mono-component protein solutions, from a quaternary-component protein solution, and from plasma and diluted plasma in order to compare their potential for adsorption to polymeric substrates from solutions of varying complexity. The surfaces studied included polyethylene (PE), silicone rubber (SR), Teflon-FEP (FEP), and two polyetherurethanes : one with a poly(tetramethylene oxide) soft segment (PTMO-PU) and one with a poly(ethylene oxide) soft segment (PEO-PU). The adsorption of these proteins from single-component solutions followed the Freundlich isotherm and the adhesive proteins showed similar trends in Freundlich parameters for surfaces of similar surface wettability. Adsorption from a quaternary-component solution composed of physiological molar ratios of the three proteins and human serum albumin (HSA) revealed a significant enrichment of adsorbed vitronectin as determined from ratios of the adsorbed surface fraction of each protein to its respective bulk fraction. The other proteins' adsorption was enriched to a lesser extent in the decreasing order of FGN > FN > HSA for all surfaces. The relative enrichment of VN from plasma was also high as compared with its bulk concentration, whereas the enrichment of FGN, FN, and HSA was much lower and of approximately the same magnitude. Compared with the three other proteins, VN showed a resistance to displacement from the polymer substrates as either the plasma concentration was increased or the length of contact with plasma and diluted plasma was increased.

ISSN:0920-5063    

DOI:10.1163/156856292X00060

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A direct enzyme-linked immunosorbent assay (ELISA), using a polyclonal anti-fibrinogen conjugated to horseradish peroxidase, was used to detect fibrinogen adsorption from blood plasma to ten different materials. Adsorption was also measured with [121] I-fibrinogen. The materials studied included glass, Biomer®, Immulon I, and a series of hydroxyethylmethacrylate (HEMA) and ethylmethacrylate (EMA) co-polymers. For all the materials studied, the results from the ELISA technique closely paralleled those obtained using [125I] -fibrinogen. The cross-reactivity of the antibody with proteins other than fibrinogen was generally small. Both experimental methods detected the presence of a maximum in fibrinogen adsorption (as a function of the plasma dilution) to the more hydrophobic materials. For all but two HEMA/EMA co-polymers, a linear correlation between the ELISA and [125I] -fibrinogen measurements was indicated by inspection of cross plots as well as by a statistical test.

ISSN:0920-5063    

DOI:10.1163/156856292X00079

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Protein adsorption of human serum albumin (HSA), human fibrinogen (Fg), human immunoglobulin G (IgG), high density lipoprotein (HDL) and high molecular weight kininogen (HMWK) from plasma onto poly (n-alkyl methacrylate) (PAMA) surfaces was measured using a semi-quantitative enzyme-immunoassay. Adsorption was investigate for PAMA(n = 1) (n is the number of C-atoms in the n-alkyl side chain), PAMA(n = 8) and PAMA(n = 18). PAMA(n = 1) has a relatively hydrophilic surface as compared to the more hydrophobic PAMA(n = 8) surface. Both polymers have surface chains which do not reorient after contact with water. The PAMA(n = 18) surface is relatively hydrophobic but in this case polymer surface chains and segments are able to reorient after contact with water. Protein adsorption was measured both as a function of time and as a function of the plasma dilution. If adsorption from plasma was measured as a function of time no exchange of proteins could be observed. The amount of adsorbed protein was always larger in the case of the hydrophobic PAMA(n = 8) as compared to PAMAS(n = 1 and 18), probably due to hydrophobic interactions between the proteins and the PAMA(n = 8) surface. At high plasma concentration relatively large amounts of HDL adsorb onto PAMA(n = 8), indicating that this lipoprotein preferentially adsorbs onto this surface.

ISSN:0920-5063    

DOI:10.1163/156856292X00088

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Neither proteins nor bacteria adsorb or adhere homogeneously to a substratum surface. The final two-dimensional spatial arrangement depends on a complicated interplay between protein-protein (bacterium-bacterium) and protein (bacterium)-substratum interactions and the prevailing hydrodynamic conditions. In this paper, results are presented of two separate experiments in which bovine serum albumin (BSA) was adsorbed to, or Streptococcus sanguis 12 was deposited on substrata with different wettabilities in a search for analogies in the two-dimensional spatial arrangement of the adsorbed proteins and adhering bacteria. The spatial arrangement of adsorbed BSA, visualized by transmission electron microscopy on replicas of the surface, was island-like on substrata with a low wettability and well distributed on substrata with a high wettability. The spatial arrangement of adhering S. sanguis 12 was observed directly by light microscopy during the experiment and showed a relatively large collection of near-neighbour sites on the low wettability substrata compared with the high wettability substrata. Thus, it seems that the occurrence of island-like structures in protein adsorption is concurrent with a large collection of near-neighbour sites in bacterial adhesion. As a possible explanation for the above analogy, it is suggested that proteins or bacteria are insufficiently immobilized on low wettability substrata owing to weak interaction forces, and they can move over the substratum surface to yield the two-dimensional spatial arrangements observed.

ISSN:0920-5063    

DOI:10.1163/156856292X00097

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The successive displacement of plasma proteins adsorbed to artificial surfaces (biomaterials) is well documented, mostly by specially designed experiments that stretch out the effect in time and space. Analysis of displacement has been focused principally on molecular events on the adsorbing surface. In this paper attention is directed rather to the antecedent transport phenomena necessary to deliver successive proteins to a surface. The different limitations on protein arrival fixed by the total quantity present and by the rates of transport of super-sufficient quantities are distinguished. The transport perspective is then used to ask, and partly answer, the question: Can protein displacement be responsible for patterns of thrombus formation and cellular adhesion that are seen on the blood-wetted surfaces of devices found in medical practice: artificial organs and vascular prostheses? Calculations and a small amount of preliminary data suggest that such patterns may form when blood is introduced into these devices, particularly in the neighborhood of boundary shapes that cause separated flows.

ISSN:0920-5063    

DOI:10.1163/156856292X00105

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0920-5063    

DOI:10.1163/156856292X00114

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor