Figure 1.

Schematic illustrations of visible-light-induced core cross-linked nanosized drug delivery system combined with ultrasound for effective tumor therapy. (A) a core cross-linked nanosized system was fabricated to encapsulate β-Lapachone and BDOX. Then, visible-light was used to promote the formation of core cross-linked nanosized drug delivery system via diselenide bond exchange (β-Lapachone/BDOX-CCS), endowing excellent physiological stability. (B) β-Lapachone/BDOX-CCS efficiently penetrated the tumor interstitium after ultrasound irradiation. (C) In tumor cells, β-Lapachone was first released from the β-Lapachone/BDOX-CCS and promoted reactive oxygen species (ROS) generation by overexpressing NQO1, which fed back to the diselenide bond and BDOX, thus promoting the substantial release of DOX. Moreover, the generated ROS and DOX synergistically induced tumor apoptosis. ROS levels in healthy cells were largely unchanged by β-Lapachone due to low expression of NQO1, ensuring that BDOX remained inert in these cells.