Platelet adhesion and activation on an amphoteric chitosan derivative bearing sulfonate groups

To improve blood compatibility of chitosan, a linear cationic polymer of D-glucosamine,;ye have synthesized an amphoteric derivative containing sulfonate functional groups. Unlike chitosan wh-ch is soluble only in acidic pH (<5.0), the sulfonated derivative was soluble over a wide pH range. Elemental ans,lysis of N-sulfofurfuryl chitosan showed 5.20% sulfur content and the degree of substitution analysis confirmed 23.4% sulfofurfuryl substitution. Wide-scan electron spectroscope for chemical analysis (ESCA) showed the presence of sulfur (3.30%) and sodium (6.00%) on N-sulfofurfuryl chitosan surface. High resolution S2p spectra was entirely due to the -(S) under bar-O-functional moiety of the sulfonate residues. As compared with an average of more than 73.0 platelets per 25 000 mu m(2) on unmodified chitosan, only 4.50 platelets were present on the sulfonated chitosan derivative. The extent of platelet activation was also significantly reduced on the N-sulfofurfuryl chitosan surface. N-sulfofurfuryl chitosan, an amphoteric water-soluble derivative, does appear to possess non-thrombogenic properties and may be suitable for some blood-contacting applications. (C) 1998 Elsevier Science B.V.