Fig. 4

Drug loading and release properties of Apt-NS and targeted drug delivery by Apt-NS-DOX in A549 cells. A Fluorescence intensity alterations of DOX as the increase of Apt-NS. B Zeta potentials assay of Apt-NS and Apt-NS-DOX. C Fluorescence signals detection of DOX released from Apt-NS-DOX. Black line indicated the changing trends of fluorescence signals of Apt-NS-DOX treated with DNase I enzyme. Red line indicated the changing trends of fluorescence signals of Apt-NS-DOX treated with the buffer without adding DNase I enzyme. D Confocal images showing the time-dependent cellular uptake of free DOX by A549 cells. Red fluorescence represented the free DOX. E Confocal images showing the time-dependent cellular uptake of Apt-NS-DOX by A549 cells. Red fluorescence represented the DOX released from Apt-NS-DOX; green fluorescence represented Cy5 labeled nanomaterials. Scale bar is 25 μm