Composition adsorbed protein

PSS-SG composite film was tested for sorption of heme proteins hemoglobin (Hb) and myoglobin (Mb). The peroxidaze activity of adsorbed proteins were studied and evaluated by optical and voltammetric methods. Mb-PSS-SG film on PG electrode was shown to be perspective for detection of dissolved oxygen and hydrogen peroxide by voltammetry with linear calibration in the range 2-30 p.M, and detection limit -1.5 p.M. Obtained composite films can be modified by different types of biological active compounds which is important for the development of sensitive elements of biosensors. 

Thus, cell adhesion is determined by nonspecifically adsorbed serum proteins on the surface. Therefore, it is important to consider the characteristics of adsorbed proteins including the amount, composition, and conformation or orientation. 

Various methods have been used to examine the composition of proteins adsorbed to SAMs. Overall adsorption patterns can be examined with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) [50, 76, 77]. Absorbed proteins are eluted from the surface with surfactant (SDS), and then separated by electrophoresis. The proteins of interest are examined by western blotting [50, 76, 77]. Protein-specific antibodies can be used to detect proteins of... 

Resuspend the particles to a final concentration of 1 percent in coating buffer containing a preservative. Avoid changing the composition of the storage buffer from that used to coat the protein, as any pH or compositional changes often result in elution of some of the adsorbed protein. 

When a biopolymer mixture is either close to phase separation or lies in the composition space of liquid-liquid coexistence (see Figure 7.6a), the effect of thermodynamically unfavourable interactions is to induce biopolymer multilayer formation at the oil-water interface, as observed for the case of legumin + dextran (Dickinson and Semenova, 1992 Tsapkina et al, 1992). Figure 7.6b shows that there are three concentration regions describing the protein adsorption onto the emulsion droplets. The first one (Cprotein< 0.6 wt%) corresponds to incomplete saturation of the protein adsorption layer. The second concentration region (0.6 wt% < 6 proiem < 6 wt%) represents protein monolayer adsorption (T 2 mg m 2). And the third region (Cprotein > 6 wt%) relates to formation of adsorbed protein multilayers on the emulsion droplets. 

Protein Adsorption. The development of medical implant polymers has stimulated interest in the use of ATR techniques for monitoring the kinetics of adsorption of proteins involved in thrombogenesis onto polymer surfaces. Such studies employ optical accessories in which an aqueous protein solution (93) or even ex - vivo whole blood (94-%) can be flowed over the surface of the internal reflection element (IRE), which may be coated with a thin layer of the experimental polymer. Modem FT-IR spectrometers are rapid - scanning devices, and hence spectra of the protein layer adsorbed onto the IRE can be computed from a series of inteiferograms recorded continuously in time, yielding ah effective time resolution of as little as 0.8 s early in the kinetic runs. Such capability is important because of the rapid changes in the composition of the adsorbed protein layers which can occur in the first several minutes (97). 

Several investigators have found that foreign surfaces, when exposed to blood, adsorb plasma proteins (21, 22). Platelet adhesion to this proteinated surface is the first observable event in thrombosis on the foreign surface. If we consider the proteinated surface as an acceptor in a platelet adhesion mechanism (23), the significance of the nature and composition of adsorbed protein is its role in platelet adhesion (24). 

The capacity of the nanoparticles to adsorb proteins and to activate the complement in vivo after intravenous administration will influence the fate of the carrier and its body distribution. To approach this aspect, in vitro tests have been developed to investigate the profile of the type of serum proteins that adsorbed onto the nanoparticle surface after incubation in serum and to evaluate the capacity of the nanoparticles to induce complement activation. The analysis of the protein adsorbed onto the nanoparticle surface can be performed by 2D-polyacrylamide gel electrophoresis. This technique allows the identification of the proteins that adsorbed onto the nanoparticle surface. To evaluate modifications of the composition of the adsorbed protein with time, a faster method based on capillary electrophoresis can also be used. Finally, the activation of the complement produced by nanoparticles can be evaluated either by a global technique or by a specific method measuring the specific activation... 

Surface shear viscosity (and modulus) may thus tell us something about conformation and thickness of adsorbed protein layers, and especially about changes with time and with composition. The latter may involve the addition of small quantities of an amphiphile, which tends to greatly reduce t]ls, or partial displacement of an adsorbed protein by another one. However, a clear and simple theory is not available combination with the... 

A polysaccharide can be added as a component in a protein system to produce a protein-polysaccharide composite structure. Tolstoguzov (2003) reviewed the main function of protein and polysaccharide in protein-polysaccharide food formulation. Generally, polysaccharides have less surface activity in comparison to proteins. This inferiority is related to their low flexibility and monotonic repetition of the monomer units in the backbone. The low surface activity of polysaccharides results in their inability to form a primary adsorbed layer in the system. The nature of interactions between polysaccharides and adsorbed proteins, as well as their influence on colloid stability, can either stabilize or destabilize the emulsions. Attractive protein-polysaccharide interactions can enhance the emulsion stability by forming a thicker and stronger steric-stabilizing layer. In contrast, the attractive interactions... 

The adsorption of plasma proteins to polymers precedes the interaction of blood cells with the surfaces, and therefore, is likely to be an important initial event in the response of blood to polymers (25, 29). At present, however, little is known about the adsorbed protein layer, even though it has been studied in some detail in recent years (30-36). Because protein adsorption from blood plasma is a competitive process, differences in the adsorbed layer on different polymer substrates could be a primary cause of differences in thrombogenicity. Previous studies of the composition of the adsorbed protein layer have employed 12oI-labeled protein added to plasma (37-39), antibody binding (34) to detect individual proteins, or electrophoretic analysis of detergent-elutable proteins (17, 33, 35). The procedure used in this study does not require the large surface areas used in previous work (35), nor does it rely on incorporation of radiolabels (36) into adsorbed protein. Instead, a staining method at least 100-fold more sensitive than these other techniques has been used. 

By the same token, the chemical composition of the substrate may play a major role in protein adsorption, since highly hydrophilic (hydrogel) surfaces tend to adsorb plasma proteins reversibly with little damage, whereas hydrophobic surfaces cause strong and partially irreversible adsorption leading to extensive damage of adsorbed proteins. 

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