Nano-Assemblies from J‑Aggregated Dyes: A Stimuli-Responsive Tool Applicable To Living Systems
2018-12-14T00:00:00Z (GMT)
by
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)-block-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 meso-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.
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CC BY-NC 4.0