CO-Signaling Molecule-Responsive Nanoparticles Formed from Palladium-Containing Block Copolymers.

The overproduction of cell-signaling molecules causes various human diseases. This intrinsic feature offers a biochemical basis to design biosignal-responsive nanocarriers for cell-selective therapy. Here we develop a new palladium-containing block copolymer, which can chemoselectively respond to carbon monoxide (CO)-a crucial gaseous signaling molecule in cells-while inhibiting disturbances from other endogenous analogues. Palladium is introduced into polymer for the first time, and such an organopalladium-connected chain can be cleaved by a CO-induced cascade insertion-elimination reaction, triggering a desirable disassembly of their self-assembling micelles. The micellar dissociation rate depends on the dose of CO stimulus. We envisage that this polymer model would enrich the repertoire of metallopolymers and provide a new platform for designing signaling molecule-responsive macromolecular systems.