A green route to water-soluble polyaniline for photothermal therapy catalyzed by iron phosphates peroxidase mimic

A green route to water-soluble polyaniline (PANI) using iron phosphates (FePOs) peroxidase mimic as a catalyst and H2O2 as an oxidant is presented. Polystyrene sulfonate (PSS) is used as a template to synthesize a conductive PANI-PSS complex. PANI samples were characterized by UV-Vis spectroscopy, FT-IR spectroscopy and bulk conductivity measurement. Results indicated that the conductivity of the PANI catalyzed by the FePOs peroxidase mimic greatly depends on the pH, temperature and molar ratios of H2O2 and aniline. Superior to natural horseradish peroxidase, the prepared FePOs demonstrated a robust catalytic ability and could catalyze the formation of PANI-PSS at much lower pH values of 1.5-2.6. The photothermal effect of the FePOs catalyzed PANI samples was investigated and a high light-to-heat conversion efficiency of 39.6% was obtained for the sample with a conductivity of 2.576 x 10(-3) S cm(-1). Excellent biocompatibility and remarkable anti-tumor effect were observed for the prepared PANI with human cervical cancer (HeLa) cells as a cell model.