A carbon ion beam irradiated MWCNT/AuNPs composite sensor for a sensitive assay of purine-nucleosides of DNA

Abstract

Multi-walled carbon nanotube (MWCNT) and gold nanoparticle (AuNPs) composite modified glassy carbon (MWCNT/AuNPs/GC) was irradiated with a high energy carbon ion beam and the surface morphology of the irradiated sensor was analysed using Raman spectroscopy, FE-SEM and Electrochemical Impedance Spectroscopy (EIS). The irradiated MWCNT/AuNPs/GC sensor has been applied for the electrochemical investigation of deoxyguanosine (dGuo) and deoxyadenosine (dAdo) by using square wave voltammetry and cyclic voltammetry. The irradiated sensor has been found to exhibit an excellent electrocatalytic activity, leading to an enhancement in the peak currents of dGuo and dAdo. The peak potentials also shifted to less positive potentials as compared to the unirradiated MWCNT/AuNPs/GC (pristine). The peak current of dGuo and dAdo was found to be linear in the range of 1–500 μM and detection limits of 126 and 109 nM, respectively, were observed. The practical utility of the irradiated sensor has been demonstrated by the determination of dGuo and dAdo in the DNA samples extracted from herring sperm and a MCF7 cell line (human breast cancer cells). Further, the carbon beam irradiated sensor displayed high sensitivity and reproducibility and has been found to be suitable in clinical diagnosis.