Catalytic activity of biomimetic model of cytochrome P450 in oxidation of dopamine.

The introduction of electron-withdrawing group into porphyrin molecule as cytochrome P450 model can tune the energy level and have an effect on the electronic structure. In this work, linking with the strong electron-withdrawing fluorine atoms, a starburst dendritic molecule, 5,10,15,20-tetrakis(pentafluorophenyl)−21H,23H-porphyrin iron (III) chloride (FeTFPP), containing a saddle-shaped porphyrin as the central core and four pentafluorophenyl rings as the peripheral functional groups was successfully synthesized. Subsequently, the macrocyclic conjugate polymer film of FeTFPP was achieved via a low-cost electrochemical method and exploited as an efficient mimetic enzyme. Furthermore, a biomimetic sensor was constructed by the poly(FeTFPP) film and graphene (rGO) sheet (rGO-poly(FeTFPP)) for selective and sensitive detection of dopamine (DA). Here, the FeTFPP polymer performs three functions: electrochemical recognition (owing to the hydrogen bonding between the strongly electronegative fluorine atoms and DA), biomimetic microenvironment (owing to interaction between porphyrin core and DA), electrocatalysis (owing to remarkable catalytic ability of iron (III) ion). Under optimum conditions, the response to DA was linear in the concentration range between 0.05 to 300μM, and the detection limit was 0.023μM. In addition, we applied the rGO-poly(FeTFPP) film to detect DA in real samples and the results implied its feasibility for practical application. As a result, it is believed that the rGO-poly(FeTFPP) film is one of the promising biomimetic catalysts for electrocatalysis and relevant fields.