Protein polycation-plasma

Another interesting featiu e issued from this work is the generalisation of the rapidity with which protein-polymer interaction set up since one minute of protein-polymer contact was sufficient to result in the protective effect of protein. The collection of a white pellet by centrifugation of plasma and Q-P(TDAE)ii or PLL in the absence of RBC appeared as another support to the occxurence protein-polycation complexation. 

Another approach is to use polycation complexes, which can be electrostatically attracted and adsorbed to the negatively charged cell membranes and lead to electrostatically adsorptive endocytosis [155, 156], Eor example, cationized polymer conjugates [157], proteins [158, 159], and nanoparticles [96, 160, 161] exhibit enhanced cellular intemahzations when compared with their noncationized counterparts. Cationic charges, however, can cause severe serum inhibition and rapid clearance from the plasma compartment [162-164] for instance, a cationized antibody had a 58-fold increase in the systemic clearance from the plasma compartment... 

The mechanism of RBC agglutination by polycations has been studied since 1951 , particularly by Katchalsky and coworkerswho pointed out the occurrence of hemolysis in the presence of PLL. In all these instances, authors used washed RBC in agglutination studies thus precluding the observation of any effect due to plasma proteins. Under physiological conditions, blood proteins have generally a net negative charge and can therefore form polyelectrolyte-type complexes with polycations upon intravenous administration. 

This is the reason why we decided to investigate the interactions between blood elements, namely RBC and plasma proteins, and six polycations poly(L-lysine) (PLL), poly(e-lysine) (PEL), diethylaminoethyl-dextran (DEAE-dextran), poly(dimethyldiallylammonium) chloride (PDDAC), poly[2-(dimethylamino)ethyl methacrylate] (P(DMAEMA)) and Q-P(TDAE)n. 

Based on the present understanding of polyanion-polycation complexes and given the complexity of the composition of plasma in proteins with various polyelectrolyte properties, one can consider that a synthetic polycation faces a great number of competing polyanionic systems, including RBC, when introduced in whole blood. The identification of the... 

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