Preparation of aldehyde-, amino-, and hydrazide-functionalized polymer particles for direct immobilization of the sugars

The reaction of poly(vinyl alcohol) with glutaraldehyde (GA) at different molar ratio was systematically studied. By this reaction, white particles functionalized with aldehyde groups were obtained and their diameters were found to be between 50 and 150 nm. The amount of free ---CHO groups on the surface of the particles reached more than 1.6 mmol/g by adjusting the ratio of n(GA)/n(---OH). The free ---CHO groups were then converted into alkyl amino, aromatic amino, and hydrazide groups by coupling with hexamethylene diamine, m-phenylene diamine, and adipic dihydrazide, respectively, and the length of the spacer was also prolonged. Finally, a series of sugar-particle conjugates were prepared by directly coating the functionalized particles with maltose, D-(+)-glucosamine, and heparin. The anticoagulant experiments show that the heparin immobilized on the aldehyde- and hydrazide-functionalized particles is still biologically active.