LAUSR

In this study we constructed spherical photo‐responsive microcapsules composed of three photo‐switchable DNA strands. These strands first formed a three‐way junction (TWJ) motif that further self‐assembled to form microspheres through hybridization of the sticky‐end regions of each branch. To serve as the photo‐switch, multiple unmodified azobenzene (Azo) or 2,6‐dimethyl‐4‐(methylthio)azobenzene (SDM‐Azo) were introduced into the sticky‐end regions via a d‐threoninol linker. The DNA capsule structure deformed upon trans‐to‐cis isomerization of Azo or SDM‐Azo induced by specific light irradiation. In addition, photo‐triggered release of encapsulated small molecules from the DNA microcapsule was successfully achieved. Moreover, we demonstrated that photo‐triggered release of doxorubicin caused cytotoxicity to cultured cells. This biocompatible photo‐responsive microcapsule has potential application as a photo‐controlled drug‐release system.