Preparation of porphyrin modified CO9S8 nanocomposites and application for colorimetric biosensing of H2O2

Abstract

Hydrogen peroxide detection has been widely applied in the fields of biology, medicine, and chemistry. Colorimetric detection of hydrogen peroxide has proven to be a fast and convenient method. In this work, 5,10,15,20-tetrakis(4-chlorophenyl) porphyrin modified Co[Formula: see text]S[Formula: see text] nanocomposites (H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] were prepared via a facile one-step hydrothermal method. H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] nanocomposites were demonstrated to possess an enhanced mimetic peroxidase activity toward the substrate, 3,3[Formula: see text],5,5[Formula: see text]-tetramethylbenzidine (TMB), which can be oxidized to oxTMB (oxidized TMB) in a buffer solution of hydrogen peroxide with a color change from colorless to blue. The catalytic activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] was further analyzed by steady-state kinetics, and H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] had high affinity towards both TMB and H[Formula: see text]O[Formula: see text]. Furthermore, fluorescence and ESR data revealed that the catalytic mechanism of the peroxidase activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] is due to hydroxyl radicals generated from decomposition of H[Formula: see text]O[Formula: see text]. Based on the catalytic activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text], a sensitive colorimetric sensor of H[Formula: see text]O[Formula: see text] with a detection limit of 6.803 [Formula: see text]M as well as a range of 7–100 [Formula: see text]M was designed.