Fig. 4

In vitro cytotoxicity of CD38pep- and CD138pep-targeted nanoparticles loaded with a chemotherapeutic. Nanoparticles targeted with 1% peptide density of CD38pep or CD138pep were prepared loaded with doxorubicin prodrug, and their cytotoxicity was tested versus that of nontargeted nanoparticles as well as free doxorubicin. Cells were dosed with either 5 µM (a) or 10 µM (b) of carfilzomib and allowed to incubate for 1, 3, 6, or 12 h. At this point, the cells were washed to remove all free drug and nanoparticles from the well, fresh media were added, and the cells were incubated for the rest of a 48-h time span at which cell viability was tested with CCK8. All experiments were done in triplicate. Data represent means (± s.d.)