Carbon-based electrochemical sensor: Modified electrodes and as-prepared 3D printed electrodes for simultaneous detection of purines and pyrimidines

Abstract

Abnormalities of deoxyribonucleic acid (DNA) bases include guanine (G), adenine (A), thymine (T), and cytosine (C) in organisms could cause defects or mutations in the immune system. Therefore, it makes sense to detect all four bases simultaneously. Herein, a modified Glassy carbon electrode (GCE) with the electrodeposition of carbon material and pre-treated three-dimensional (3D) printed electrode (3DPE) were developed and compared for the simultaneous detection of bases. The electrochemical techniques include cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS), and the characterizations used were field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). There is a clear separation oxidation peak between purine and pyrimidine bases at two types of electrodes. Among them, due to the synergistic effect of rGO and MWCNT on the electrodes can achieve a more favorable catalytic effect. In phosphate buffer solution (PBS, pH 7.0), the comparison results showed that 3DPE have a wider linear range (G and A: 2.50–100.00 μM, T and C: 25.00–1000.00 μM) and lower detection limits of 0.07, 0.20, 0.44 and 1.29 μM, respectively. Both electrodes had also been applied to the detection of DNA bases in saliva and human serum samples with satisfactory results. Furthermore, the 3DPE is extremely inexpensive, highly designable and can be prepared in batches.