Liver cancer remains a significant medical problem and one promising therapeutic approach is to embolize the tumor. One emerging embolization strategy is to use thermoresponsive materials that can be injected but gel at the tumor site. It is now reported on thermoresponsive nanocomposites generated by grafting poly(N-isopropylacrylamide) chains on bacterial cellulose nanowhiskers. Chemical and physical evidences are provided for grafting and demonstrated a sol–gel transition when the temperature is increased above 34.3 °C. Cytotoxicity test in human umbilical vein endothelial cells indicates the excellent biocompatibility of these nanocomposites for use as embolic materials. These results suggest that the nanocomposites offer appropriate properties for embolization of hepatocellular carcinoma.