Figure 5.

Linker–gemcitabineTNM–linker–gemcitabine has minimal cytotoxicity compared to free gemcitabine. Cultured tumor cells (MDA-MB-231) were treated for 30 min with linker–gemcitabineTNM–linker–gemcitabine (A) or free gemcitabine (B) at different concentrations as indicated. Treatment concentrations were adjusted to reflect an equimolar amount of gemcitabine. After treatment, cells were washed and cultured in fresh medium for two days. At the endpoint, cell cultures were examined and imaged under a light microscope (A,B), and cell proliferation rates were evaluated by CCK-8 proliferation assay (C). Scale bar = 200 µm. p ≤ 0.05 was considered significant. **: p ≤ 0.01; ***: p ≤ 0.001 (Student’s t-test).