Biomolecule nanosensing

Abstract

Detection of genetically modified food through Real-Time Polymerase Chain Reaction (RT PCR) involves the use of expensive fluorescence labels. In this study, comparison between three nano-graphene oxide (GO) materials (HO Nano-400, TO SGNF, and HO PyroG) was conducted in order to find out which nano-GO material would be a more suitable candidate as electrochemical labels in place of the traditional fluorescence labels. Electrochemical characterization including X-ray photoelectron spectroscopy (XPS), cyclic voltammetry, differential pulse voltammetry, square-wave voltammetry as well as electrochemical impedance spectroscopy (EIS) was performed across varying concentrations of nano-GO. Conjugation of nano-GO materials with single-stranded DNA via covalent bonding was carried out and electrochemical characterization was repeated on the conjugated nano-GO materials. A significant electrochemical signal for all nano-GO materials was still observed after conjugation with single-stranded DNA corresponding to the DNA primer sequence. Hybridization of one of the conjugated nano-GOs (HO PyroG) with complementary strand (Sequence 1) was carried out as a preliminary study due to its better electroanalytical performance. Electrochemical characterization was also performed where a reduction of electrochemical signal of the hybrid was observed. Further characterization was performed using techniques including attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy and fluorescence were carried out on these materials to monitor if the conjugation of sequence to nano-GO materials was successful. With that, the findings in this study are essential toward finding a strategy for electrochemical PCR, in place of the traditional and thus expensive RT PCR.