The Apt-HAuNS-Dox selectively killed lymphoma cells, but had no effect on the growth of off-target cells in the same cultures. The cell mixtures, composed of paired lymphoma cells and control cells at a 1:1 ratio, were treated with vehicle alone (no treatment) (a), the free DOX (b), or the Apt-HAuNS-Dox (c), respectively. After culture for 48 h, the cells were harvested and stained with CD30 antibody. Viable lymphoma cells and control cells in the same cultures were then simultaneously counted by flow cytometry analysis. The relative cell counts of each cell population were calculated by using total cells as 100%.