Serum proteins, adsorption

When cells are suspended in a biological fluid or culture medium, both serum proteins and cells interact with the surface substrate. Serum protein adsorption behavior on SAMs has been examined with various analytical methods, including SPR [58-61], ellipsometry [13, 62, 63], and quartz QCM [64—66]. These methods allow in situ, highly sensitive detection of protein adsorption without any fluorescence or radioisotope labeling. SPR and QCM are compatible with SAMs that comprise alkanethiols. In our laboratory, we employed SPR to monitor protein adsorption on SAMs. 

FIGURE40.il Serum protein adsorption on PE wettability chemogradient surface (1 h adsorption). n = i. 

Farokhzad et al. reported the immnnological characterization of lipid-polymer hybrid nanoparticles and proposed a method to control the levels of complement activation induced by these nanoparticles. In this method, the nanoparticle snrface was modified by attaching methoxyl, carboxyl, and amine groups. It was found that the snrface chemistry significantly affects human plasma and serum protein adsorption patterns. ... 

M. Lord, B. Cousins, P. Doherty, J. Whitelock, A. Sinunons, R. Williams, B. Milthotpe, The effect of sihea nanoparticulate coatings on serum protein adsorption and cellular response, Biomaterials 27 (2006) 4856-4862. 

Both oral and parenteral uptake of colloidal carrier systems have been found to depend on the nature of the carrier as such. In the latter case, the RES uptake of colloidal drug carriers depends on a number of factors, notably the surface properties of the carrier (see above). This is related to the adsorption of certain serum proteins (opsonins) at the carrier surface, which initiates various biological responses. For example, it is known that macrophages, major components in the RES system, have Fc receptors at their surfaces, which means that carriers with adsorbed IgG are more likely to be captured by these cells (52). By reducing the adsorption of the opsonins at the carrier surface, e.g. by surface treatment using PEO derivatives, a very low serum protein adsorption can be reached, thereby prolonging the bloodstream circulation time and obtaining a more uniform tissue distribution (see above). 

A perfusion microbioreactor has been developed based on mass transport simulation to find out reasonable culture scales with relatively low chemical gradients [10]. Here a PDMS surface is treated with surfactant solution to reduce nonspecific serum protein adsorption, which keeps the culture conditions steady. As described above, to achieve physiologically meaningful functions in vitro, a culture with a larger number of cells and higher density must be obtained. 

Effect of Precontamination on PLL(375)-g[5.6]-PEG-(5) Adsorption. Metal oxide surfaces that exhibited large amounts of hydrocarbon surface contamination nevertheless adsorbed a layer of PLL(375)-g[5.6]-PEG(5) that suppressed subsequent serum adsorption. Titanium dioxide waveguides that were not cleaned according to the procedure described in section 1.4.1 exhibited substantial hydrocarbon surface contamination (see Tables 2 and 3 and Figure 2). However, these XPS data also indicate that an additional layer of PLL(375)-g[5.6]-PEG-(5) does, indeed, adsorb onto this contaminated surface. Furthermore, OWLS experiments showed that the typical adsorbed areal density of 120 ng/cm forms on contaminated titanium dioxide waveguides and that this adsorbed layer of polymer suppresses subsequent serum protein adsorption by about 95%. That is, the adsorption and performance characteristics of PLL(375)-g[5.6]-PEG(5) are identical in the case of both contaminated and cleaned titanium dioxide surfaces. 

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