TMB-assembly as nanosubstrate construction colorimetric kit for highly sensitive and selective detection of H₂O₂ and monoamine oxidase-A based on Fenton reaction

Detection of H₂O₂ is significant for the applications in environmental protection, pharmaceutical industries, food production, and clinical control. Current colorimetric kit of H₂O₂ based on enzyme or nanomaterials always needs TMB or other peroxidases substrate as coloration species. Herein, we report a simple hydrothermal method to synthesize of TMB dot as the nanosubstrate construction colorimetric kit for highly selective and sensitive detection of H₂O₂ based on Fenton reaction. Compared with TMB as the substrate, the synthesized TMB dots (TMBDs) show higher reaction activity in the presence of the same low-level Fe²⁺ and H₂O₂, resulting in highly sensitive sensing H₂O₂ down to 0.8 nM. Additionally, the obtained TMBDs can well disperse in solution, while generally TMB as substrate needs to be dissolved in organic solvents such as DMF and DMSO. Furthermore, the developed colorimetric kit is applied in detection of Mao-A, due to the reaction between epinephrine and Mao-A producing H₂O₂. More importantly, the proposed method has been successfully applied to the analysis of Mao-A in spiked human serum Hence, the TMBDs as the nanosubstrate provide an efficient, fast and sensitive approach for colorimetric kit of H₂O₂ and Mao-A, promoting more extensive application in early diagnosis of disease and drug discovery.