10.1021/jacs.8b10396.s001 Meihui Su Meihui Su Shuoxin Li Shuoxin Li Hao Zhang Hao Zhang Junqing Zhang Junqing Zhang Haoliang Chen Haoliang Chen Changhua Li Changhua Li Nano-Assemblies from J‑Aggregated Dyes: A Stimuli-Responsive Tool Applicable To Living Systems American Chemical Society 2018 RAW 264.7 cells activates photoinduced singlet oxygen production BODIPY photofunctional tools Living Systems Controlling core iodo-substituted boron dipyrromethene PEG peroxynitrite water-stable J-aggregated dye-templated nanoassemblies cell culture medium amphiphilic diblock copolymer nanoplate Stimuli-Responsive Tool Applicable mechanism 2018-12-14 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Nano-Assemblies_from_J_Aggregated_Dyes_A_Stimuli-Responsive_Tool_Applicable_To_Living_Systems/7526588 Controlling the packing arrangements of dyes is a facile way of tuning their photophysical and/or photochemical properties, thus enabling new sensing mechanisms for photofunctional tools. Here, we present a general and robust strategy toward water-stable J-aggregated dye-templated nanoassemblies by incorporating an amphiphilic diblock copolymer and a stimuli-responsive dye as the only two building components. An iodo-substituted boron dipyrromethene (BODIPY) was adopted as a template to direct the self-assembly of poly­(ethylene glycol)-<i>block</i>-polycaprolactone (PEG–PCL), forming a core–shell nanoplate with slip-stacked BODIPYs as core surrounded by hydrophilic PEG shell. The self-assembled nanoplate is stable in cell culture medium and possesses a built-in stimuli-responsiveness that arises from BODIPY bearing <i>meso</i>-carboxylate protecting group, which is efficiently removed upon treatment with peroxynitrite. The resulting negative charges lead to rearrangement of dyes from J-stacking to nonstacking, which activates photoinduced singlet oxygen production from the nanoassemblies. The stimuli-activatable photosensitivity has been exploited for specific photodynamic ablation of activated RAW 264.7 cells with excessive endogenous peroxynitrite. In light of the generality of the sensing mechanism, the concept described herein will significantly expand the palette of design principles to develop diverse photofunctional tools for biological research and clinical needs.