[A comparative study on cytocompatibility of medical PVA and intelligent PVA-g-NIPAAm hydrogels]

"Intelligent" Polymers which resonse with large property changes to small physical or chemical stimuli are attracting more and more attention in the field of medical science. One trend in the area is to modify some conventional medical polymers to form intelligent biomaterials. This investigation was designed to evaluate and compare in vitro cytocompatibility of PVA hydrogel, which could be used as a kind of solid support with good biomcompatibility, and PVA-g-NIPAAm, which was produced by irradiation grafting of NIPAAm onto the said PVA hydrogel support. Cytotoxicity test was carried out with a modified Cell Relative Growth Rate test (RGR test). On the day 2, day 4 and day 7, the RGRs of the PVA hydrogel were 82%, 90% and 102% respectively while the RGRs of the PVA-g-NIPAAm were 77%, 86% and 100%. The grades of the cytotoxicity of the PVA and PVA-g-NIPAAm hydrogels were 0, so they had no cytotoxicity as judged by our tests. After 24 hours, cells in direct contact with the two kinds of samples were observed morphologically through the Olympus inverted microscope and had a normal development. The conclusion suggests that irradiation grafting is a good way to modify conventional medical polymers to produce intelligent biomaterials.