Fibrinogen adsorption, surface

Chen et al. utUized a direct chemical reaction with a given solution (wet treatment) to modify the surface of the silicone rubber. The presence of a layer of PEO on a biomaterial surface is accompanied by reductions in protein adsorption, and cell and bacterial adhesion. In order to obtain a PEO layer on top of the silicone rabber surface, the surface was firstly modihed by incorporating an Si-H bond using (MeHSiO) , and followed by PEO grafting to the surface using a platinum-catalyzed hydrosilylation reaction. These PEO-modified surfaces were demonstrated by fibrinogen adsorption both from buffer and plasma, as well as albumin adsorption from buffer. Reductions in protein adsorption of as much as 90% were noted on these surfaces. 

Tegoulia VA, Rao W, Kalambur AT, Rabolt JF, Cooper SL (2001) Surface properties, fibrinogen adsorption, and cellular interactions of a novel phosphorylcholine-containing self-assembled monolayer on gold. Langmuir 17 4396-4404... 

The adsorption experiments were carried out by quantifying each of proteins adsorbed on the material from mono-component protein solutions, from four-component protein solutions, and from plasma and diluted plasma. Adsorption profiles of protein were largely different, depending on the aforementioned experimental conditions. For instance, the behavior of any particular protein from diluted plasma varied in response to the extent of plasma dilution. Cooper s results are illustrated in Fig. 3, on fibrinogen adsorption onto five polymer surfaces. It is seen that the adsorption profiles are different one another, being influenced by the different nature of the polymer surfaces. The surface concentrations of adsorbed protein are mostly time-dependent, and maxima in the adsorption profiles were observed. This is interpreted in terms of replacement of adsorbed fibrinogen molecules by other proteins later in time (Vroman effect). Corresponding profiles were also presented for FN and VN. 

Tang L, Wu Y, Timmons RB. Fibrinogen adsorption and host tissue responses to plasma functionalized surfaces. Journal of Biomedical Materials Research 1998, 42, 156-163. 

Journal of Materials Science. Materials in Medicine 14, No.10, Oct.2003, p.905-12 BLOOD RESPONSE TO PLASTICIZED POLYVINYL CHLORIDE. DEPENDENCE OF FIBRINOGEN ADSORPTION ON PLASTICIZER SELECTION AND SURFACE PLASTICIZER LEVEL... 

PLASTICISED POLYVINYL CHLORIDE. DEPENDENCE OF FIBRINOGEN ADSORPTION ON PLASTICISER SELECTION AND SURFACE PLASTICISER LEVEL... 

Three types of plasticised PVC sheet were investigated for blood compatibility using fibrinogen adsorption. Plasticisers used were diethylhexyl phthalate, triethylhexyl trimellitate and butyltrihexyl citrate. FTIR was used to monitor surface chemistry. 14 refs. 

A study has been carried out on the interactions of blood with plasticised poly(vinyl chloride) biomaterials in a tubular form. The influence of different factors such as the biomaterial, antithrombotic agent, blood condition and the nature of the application is represented when considering the blood response in the clinical utilisation of the plasticised PVC. The PVC was plasticised with di-(2-ethylhexyl)phthalate (DEHP) and tri-(2-ethylhexyl)trimellitate (TEHTM)and in-vitro and ex-vivo procedures used to study the biomaterial with respect to the selection of the plasticiser. The blood response was measured in terms of the measurement of fibrinogen adsorption capacity, thrombin-antithrombin III complex and the complement component C3a. X-ray photoelectron spectroscopy was used for surface characterisation of the polymers and the data obtained indicated that in comparison with DEHP-PVC, there is a higher reactivity... 

The time course of fibrinogen adsorption onto the two types of poly-(HEMA) is depicted in Figure 3 which also includes representative points for poly (HEMA) grafted onto Silastic. The slow rise to the final adsorption level seen for both types of poly (HEMA) is very similar to the kinetics observed for grafted poly (HEMA), as is the actual amount of adsorption. The slight disparity between the poly (HEMA) types is probably related to the more open and thus rougher surface of the heterogeneous poly (HEMA). 

Fibrinogen dominates the initial protein layer on most foreign materials, and fibrinogen adsorption leads to high thrombogenic potential for that surface. 

Thus, y-globulin appears to promote a faster rate of platelet adhesion to the surface while limiting fibrinogen adsorption and subsequent fibrin formation. In addition, embolization either was reduced or the time of emboli-... 

Figure 6. The intrinsic adsorption rate function, as a function of surface concentration, for fibrinogen adsorption on a DOPS doublelayer.

Title Fibrinogen Adsorption to Surfaces of Varying Hydrophilicity ... 

Fibrinogen adsorption was maximal to the 50 HEMA - 50 EMA copolymer, where albumin adsorption was minimal. IgG and hemoglobin adsorption generally increased with EMA content. Adsorption of all proteins was minimal on the 80 HEMA - 20 EMA surface. 

Polymer surface polarity appears to be a major determinant of fibrinogen adsorption and platelet thrombi formation, possibly because of differences in the state of the adsorbed fibrinogen. 

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