Grafting collagenous surfaces

Fig. 17. Collagen immobilization onto the PAAc-grafted polymer surface with the use of carbodiimide...

Modification of Collagenous Surfaces by Grafting Polymeric Side Chains to Collagen and Soft and Hard Tissues... 

Grafting of Polymeric Side Chains to Collagenous Surfaces Reaction Times 3 hours Temperature 37°C... 

PTFEand PET Use argon plasma to activate surface, then graft collagen IV and laminin Reduced fibrinogen adsorption and platelet adhesion Vascular graft 57... 

Figure 26. Reconstruction of the tunica intima on the inner surface of a clinically used polyethylene terephtalate vascular prosthesis. A non-modified inner surface of the prosthesis, B immobilization of defined assemblies of protein molecules (e.g., collagenfiarninin or collagen+fibrin) on the inner surface of the graft, C immunofluorescence of von Willebrand factor, a marker of the identity a differentiation of vascular endothelial cells, in human saphenous vein endothelial cells in cultures on the inner surface of a prosthesis coated with collagen and larninin, D detail of a layer of endothelial cells growing on a layer of collagen and fibrin. Note well developed talin-containing focal adhesion plaques. A, B conventional optical microscope, C, D confocal microscope Leica DM 2500 [30,31].

Collagen immobilization onto a silicone rubber surface which underwent plasma-induced graft polymerization of PHEMA was also reported to have improved attachment and growth of corneal epithelial cells onto the rubber surface [48,50,182]. 

This model mimics a deep arterial injury since the adventitial surface is a non-endothelial tissue containing tissue factor and collagen. The rabbit model described here uses a carotid graft inserted into the femoral graft to avoid vasoconstriction often occurring in the inverted femoral segments. 

Some of the areas where interfacial protein layers dominate the boundary chemistry are reviewed, and we introduce some nondestructive armlytical methods which can be used simultaneously and/or sequentially to detect and characterize the microscopic amounts of matter at protein or other substrates which spontaneously acquire protein conditioning films. Examples include collagen and gelatin, synthetic polypeptides, nylons, and the biomedically important surfaces of vessel grafts, skin, tissue, and blood. The importance of prerequisite adsorbed films of proteins during thrombus formation, cell adhesion, use of intrauterine contraceptives, development of dental adhesives, and prevention of maritime fouling is discussed. Specifics of protein adsorption at solid/liquid and gas/liquid interfaces are compared. 

The appearance of the products of the reaction of collagen and various monomers often varied considerably from the original collagen powder 45, 48). With some monomers, the graft copolymer consisted of powders while with others mats or films were formed. The modification of surface properties could often be detected by visual inspection. 

Figure 7.76 Development of human osteoblasts on the surfaces of as-HVOF-sprayed (a), alkali treated (b) and collagen grafted (c) HAp/Ti02 coatings. Fluorescence staining shows that in live cells the non-fluorescent calcein-AM is converted to a...

However, in spite of these similarities, the adsorbed amounts and the structure of the adsorbed mucin and collagen layers on the surfaces studied are entirely different. The behavior of these proteins is analyzed here on the hydrophobic polyethylene surface (water contact angle 0 20 95°), on the surface modified polyethy-lenes oxidized polyethylene (0h q 74°) and poly(maleic acid) grafted polyethylene ( Ho0 74°) a d on the hydrophilic mica surface ( H2 0 0°) Acidic pH = 2.75 (for collagen) and slightly alkaline pH = 7.2 (for mucin) were chosen in order to minimize the association of these proteins in solution and to make possible the analysis of their adsorbabilities in comparable conditions. 

The surface density/solution concentration isotherms, not shown in this paper, reflect also the differences in the behavior of mucin and collagen upon their adsorption at solid interfaces. While the collagen isotherms on polyethylene and surface-grafted polyethylene show a plateau of adsorption at solution concentrations higher than 0.05 mg/ml, no plateau values for mucin adsorption are observed on polyethylene and surface oxidized polyethylene. 

Figure 9. Desorption-adsorption relationships (a) polyethylene-collagen (a) poly(maleic acid) grafted polyethylene-collagen (o) polyethylene-mucin ) surface oxidized polyethylene-mucin. Adsorption time 20 hrs temp. 20°C. Adsorption conditions as indicated in Figure 7.

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