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

Abstract

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 × 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.