Poly , platelet retention

Another study [114] on the role of protonated amine of HA copolymers in platelet retention showed that minimum retention was again observed on the surface of the copolymer containing N+ in 0.1 0.3 wt%. In other words, cell attachment scarcely takes place on the surface of HA2, in contrast to poly-HEMA, on the surface of which more than 90 percent cell attachment was observed. 

Several polymers were evaluated in the form of a surface coating on glass beads packed in columns to determine their ability to retain platelets when whole human blood passes over the surface. This ability was measured as the platelet retention index p, the fraction of platelets retained on the column. Lowest values of p were found for poly(ethylene oxide), polypropylene oxide), poly(tetramethylene oxide) (in the form of polyurethanes), and polydimethylsiloxane. Highest values (around 0.8) were found for cross-linked poly(vinyl alcohol) and the copolymers of ethylenediamine with diisocyanates. Intermediate values were found for polystyrene and its copolymers with methyl acrylate, for polyacrylate, and for poly(methyl methacrylate). The results are interpreted in terms of possible hydrophobic and hydrogen bonding interactions with plasma proteins. 

Fig. 9. Retention behavior of blood cells on poly(HEMA co[jV-methyl-/V-(4-vinylphenethyl) ethylenediamine (HAV) (pH 7.2, 23 °C flow rate, 0.4 ml/min flow time, 3,5 min). Open circles, lymphocytes closed squares, platelets open triangles, erythrocytes AVEMA, N-methyl- V-(4-vinyl-phenethyl)ethylenediamine [Ref. 115]...

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