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

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-Co 9 S 8 nanocomposites (H 2 TCPP-Co 9 S 8 nanocomposites) were synthesized via a simple one-step hydrothermal method . A simple and highly sensitive method toward colorimetric biosensing of H 2 O 2 was developed by monitoring the color change of chromogenic substrate 3,3,5,5-tetramethylbenzidine (TMB) from colorless to blue. Notably, the H 2 TCPP-Co 9 S 8 nanocomposites were proved to possess the highly peroxidase-like activity, compared with that of pure Co 9 S 8 nanosheets . Unusually, ESR data verified that the catalytic mechanism of H 2 TCPP-Co 9 S 8 was firstly ascribed to production of superoxide radicals. The detection limit of H 2 O 2 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 H 2 O 2 detection and was successfully applied in H 2 O 2 detection in contact lens fluid samples with satisfying results.