Synthesis of Black Elemental Selenium Peroxidase Mimic and Its Application in Green Synthesis of Water-Soluble Polypyrrole as a Photothermal Agent

Black elemental selenium (Se), which shows peroxidase mimic activity and can catalyze the redox reaction between H2O2 and tetramethylbenzidine (TMB) was prepared by a simple method. The mimetic activity was greatly influenced by pH and temperature. The black elemental Se was used to catalyze the green synthesis of water-soluble polypyrrole (PPy) in the presence of sodium poly(styrene sulfonate) (PSS) as the template. The ultraviolet–visible (UV–vis) spectra of PPy obtained at different pH and temperature were recorded to obtain the optimum conditions. The black elemental Se catalyzed PPy can convert near-infrared (NIR) light energy to heat with a photothermal efficiency of 28.4%. After exposure to 808 nm laser light irradiation for 10 min, a remarkable antitumor effect was observed for human cervical cancer (HeLa) cells cocultured with the PPy.