Blood compatibility of novel poly(gamma-glutamic acid)/polyvinyl alcohol hydrogels

Sodium poly(gamma-glutamic acid) (PGA), a water-soluble and biodegradable polypeptide, was reacted with polyvinyl alcohol (PVA) to form hydrogel without any chemical treatment. The gelation occurred probably due to physical cross-linking of polymer chains by interpenetrating hydrogen bonding. From the results of thermal analysis, PGA/PVA exhibited better thermal stability than native PVA. Although the swelling ratio decreased with the increase of PGA content, however, the water resistance and retention were improved. The tensile strength of the PGA/PVA hydrogel membranes was about 15-30% lower than that of the native PVA, whereas the elongation was increased 2.0-2.6 times. The amount of protein adsorbed and platelets adhered on the PGA/PVA membranes were significantly curtailed with increasing PGA content, thereby showing improved blood compatibility. The as-fabricated hydrogels were proven to be non-cytotoxic evaluated in vitro by L-929 fibroblast incubation. Overall results demonstrate that the non-cytotoxic PGA/PVA hydrogels, due to better water resistance, mechanical properties and blood compatibility could be very promising candidates for blood-contacting medical devices.