Structural and electrochemical studies of functionalization of reduced graphene oxide with alkoxyphenylporphyrin mono- and tetra-carboxylic acid: application to DNA sensors

Blend of graphene and pi-conjugated molecules presents a new class of material with unique mechanical, optical, and electrical properties. Here, we study the physico-chemical and electrical properties of nanomaterials that combine chemical reduced graphene oxide (CRGO) features and functionalities of tetrabutyloxyphenylporphyrins bearing a mono- or tetra-carboxylic groups. The hybrid nanomaterials are characterized by different techniques including UV-visible, FT-IR, Raman spectroscopy, MEB and SEM. Their electrochemical properties are studied by cyclic voltammetry (CV) with inner sphere and outer sphere redox markers as well as the electrochemical impedance spectroscopy (EIS). Our results support the formation of strong interactions between porphyrins and CRGO. Furthermore, we investigated the relationship between structure and electronic properties of porphyrins on the resulting blend. We demonstrated that these modified porphyrins with alkoxy and carboxyl groups not only improve the dispersion of CRGO, but also enhances the electron transfer ability. These nanocomposites open up new opportunities for the fabrication of biosensors devices. The detection of DNA demonstrated with LOD down to attomolar range and with ability to discriminate between DNA from Rpob gene of M. Tuberculosis strand and mutated in PCR sample. (C) 2020 Elsevier Ltd. All rights reserved.