5,10,15,20-tetrakis (4-carboxyl phenyl) porphyrin-functionalized urchin-like CuCo2O4 as an excellent artificial nanozyme for determination of dopamine

Urchin-like peroxidase mimics 5,10,15,20-tetrakis (4-carboxyl phenyl) porphyrin-functionalized CuCo2O4 nanospheres (Por-CuCo2O4) has been fabricated as an excellent visual biosensor. X-ray diffractometry (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) have been employed to characterize the composition, morphologies, and elemental analysis of the as-synthesized Por-CuCo2O4. The catalytic activity of Por-CuCo2O4 was evaluated by the chromogenic substrate 3,3 ',5,5 '-tetramethylbenzidine (TMB) with the aid of H2O2, which exhibited a visual blue change with an absorption maximum at 652 nm for only 10 s. The peroxidase-like behaviors of Por-CuCo2O4 conformed to the Michaelis-Menten equation. Electrochemistry, radical scavenger, and fluorescence probe experiments verified that electron transfer, center dot O-2(-) radicals, and holes (h(+)) are the important factors during the catalytic oxidation of TMB. Based on the inhibition of dopamine (DA) on TMB oxidation, the Por-CuCo2O4-based colorimetric biosensor has been successfully constructed for sensitive determination of DA witha detection limit (LOD) of 0.94 mu M. In addition, colorimetry was validated to detect DA in serum samples with high sensitivity and good selectivity.

Automated summary

The Urchin-like peroxidase mimic Por-CuCo2O4 has been fabricated as an excellent visual biosensor for sensitive detection of dopamine (DA) with high sensitivity and good selectivity in serum samples. The catalytic activity of Por-CuCo2O4 was evaluated by chromogenic substrate TMB with H2O2, showing a rapid visual blue change. Experiments confirmed that electron transfer, O-2(-) radicals, and holes (h(+)) are important factors during the catalytic oxidation process.