A series of poly (N-isopropylacrylamide-co-glycyrrhetinic acid) (P(NIPAAm-co-GA)) microgels were prepared by dispersion copolymerization. The morphologies of the microgels were observed by field scanning electron microscopy (FE-SEM) and transmission electron microscope (TEM). The temperature sensitivity of microgels was examined by measuring the optical transmittance of the microgel aqueous solution. Cytotoxicity of the microgels was investigated by MTT assay. The results indicated that microgel particles had a regular spherical shape of about 500 nm with narrow size distributions. Moreover, P(NIPAAm-co-GA) microgels exhibited good temperature sensitivity and low toxicity. This novel microgel could be expected as good candidate for controlled growth factor release.Intorduction