Chemically Modified Graphene and Sulfonic Acid-Doped Polyaniline Nanofiber Composites: Preparation Routes, Characterization, and Comparison of Direct DNA Detection

Abstract

Recently, functional composites based on chemically modified graphenes (CMGs) and nanostructured conducting polymers have attracted wide interest in the field of electrochemical biosensing. However, comprehensive studies of the effects of various CMGs on the electrochemical properties and biosensing performance of the resulting composites are scarce. In this work, for the first time, we fabricated and deeply evaluated three composites composed of CMGs and sulfonic acid-doped polyaniline nanofiber (namely, CMG–SPAN composites). The CMGs (involving the unreduced form and reduced forms prepared by different reduction routes) were chosen to show the effects of reduction and different preparation routes on the morphologies, electrochemical properties, and DNA biosensing performances of the composites. Notably, the self-redox signals of SPAN in these composites were significantly enhanced and were used for rapid, direct, and label-free DNA detection. Moreover, a preliminary study of the capacitive characteristics of the thermally reduced graphene oxide–SPAN composite was conducted at the end of this work, owing to the potential benefits of the composite in a supercapacitor that were surprisingly observed in this research. The findings of this work will provide useful guides for better understanding of the interaction between CMG and SPAN and for the future development of high-performance functional materials for electrochemical sensors/biosensors and supercapacitors.