Figure 4.

Cell metabolic activity assay (MTS) of the PLGA-PEG NPs and PLGA-PEG-TFA NPs loaded with NIR dye at different concentrations incubated with C28/I2 cell line. The percent of metabolic cell activity was measured at three time point. (A) 24 h, (B) 48 h, and (C) 72 h. For each assay, the positive control was obtained using DMSO 50% and the negative control was obtained with cells only. The negative controls are indicated by the black horizontal line. Asterisk indicates significant difference in Student’s t-test, * p < 0.05.