Fig. 2. (a) pH-dependent DOX release profiles of DOX@M-MSN–P(NIPAM-co-MAA)-3.3 at (□) pH 5.0, (■) pH 6.5 and (Δ) pH 7.4 in the same NaCl concentration (0.15 M) at 37 °C. (2) Cell survival assay. (b) HeLa cells: (□) blank M-MSN–P (NIPAM-co-MAA)-3.3, (■) DOX@M-MSN–P(NIPAM-co-MAA)-3.3, and (Δ) free DOX. (c) HEK 293 cells exposed to blank M-MSN–P(NIPAM-co-MAA)-3.3. Adapted with permission from The Royal Society of Chemistry.⁶⁷.