Poly(ionic liquid)-Gated CuCo2S4 for pH-/Thermo-Triggered Drug Release and Photoacoustic Imaging.A novel hybrid drug nanocarrier is developed with CuCo2S4 nanoparticles as the core to be encapsulated by poly(ionic liquid) (PIL), that is, poly(tetrabutylphosphonium styrenesulfonate) (P[P4,4,4,4][SS]), as the shell.  pH- and thermal-responsive characteristics of P[P4,4,4,4][SS] endow the multifunctional hybrid nanocarrier system DOX-CuCo2S4@PIL with sensitive dual-stimuli-triggered drug release behaviors.  The CuCo2S4 core converts near-infrared (NIR) irradiation into thermal energy to trigger the shrinkage of the PIL shell, which subsequently promotes drug release, and the pH-responsive release of DOX involves pH-sensitive electrostatic interaction of the PIL shell with DOX.  A favorable controlled release of 90.5% is achieved under pH/thermo dual stimuli. 
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