Two-dimensional porphyrin-Co9S8 nanocomposites with synergistic peroxidase-like catalysis: Synthesis and application toward colorimetric biosensing of H2O2 and glutathione

Abstract

Porphyrins modified inorganic semiconductors as a platform in nanomaterials have been paid more attention, due to the fast electron transfer from synergistic effect. Two-Dimensional 5,10,15,20-tetra(4-carboxyphenyl)porphyrin-Co9S8 nanocomposites (H2TCPP-Co9S8 nanocomposites) were synthesized via a simple one-step hydrothermal method. A simple and highly sensitive method toward colorimetric biosensing of H2O2 was developed by monitoring the color change of chromogenic substrate 3,3,5,5-tetramethylbenzidine (TMB) from colorless to blue. Notably, the H2TCPP-Co9S8 nanocomposites were proved to possess the highly peroxidase-like activity, compared with that of pure Co9S8 nanosheets. Unusually, ESR data verified that the catalytic mechanism of H2TCPP-Co9S8 was firstly ascribed to production of superoxide radicals. The detection limit of H2O2 was 8.19 μM and the linear range from 10 to 200 μM. Similarly, The detection limit of glutathione is as low as 0.194 μM with a linear range of 0.3–10 μM. Furthermore, this sensor has shown high selectivity to H2O2 detection and was successfully applied in H2O2 detection in contact lens fluid samples with satisfying results.