Polyaniline Nanovesicles for Photoacoustic Imaging-Guided Photothermal-Chemo Synergistic Therapy in the Second Near-Infrared Window.

Photoacoustic imaging-guided photothermal therapy in the second near-infrared (NIR-II) window shows promise for clinical deep-penetrating tumor phototheranostics. However, ideal photothermal agents in the NIR-II window are still rare. Here, the emeraldine salt of polyaniline (PANI-ES), especially synthesized by a one-pot enzymatic reaction on sodium bis(2-ethylhexyl) sulfosuccinate (AOT) vesicle surface (PANI-ES@AOT, λmax  ≈ 1000 nm), exhibits excellent dispersion in physiological environment and remarkable photothermal ability at pH 6.5 (photothermal conversion efficiency of 43.9%). As a consequence of the enhanced permeability and retention effect of tumors and the doping-induced photothermal effect of PANI-ES@AOT, this pH-sensitive NIR-II photothermal agent allows tumor acidity phototheranostics with minimized pseudosignal readout and subdued normal tissue damage. Moreover, the enhanced fluidity of vesicle membrane triggered by heating is beneficial for drug release and allows precise synergistic therapy for an improved therapeutic effect. This study highlights the potential of template-oriented (or interface-confined) enzymatic polymerization reactions for the construction of conjugated polymers with desired biomedical applications.