Sulfur Doped Graphitic Carbon Nitride Nanosheets for the Electrochemical Detection of DNA Bases

Sulfur doped graphitic carbon nitride (S-g-C3N4) was prepared by a thermal polymerization method using thiourea as a precursor. The as-prepared S-g-C3N4 was characterized by various surface probing techniques and employed as a platform for the electrochemical detection of DNA bases guanine (G), adenine (A), thymine (T), and cytosine (C). Effect of various buffers and pH essential for the selective and sensitive detection of all the DNA bases were also investigated. From the results, it was evident that PBS (pH 9.0) buffer is the best suitable medium for the DNA detection. A limit of detection of 13.22, 13.1, 37.7, and 14.61 mu M (S/N = 3) and sensitivity of 1.76, 2.41, 0.68 and 2.38 mu A cm-2 mu M-1corresponding to G, A, T and C respectively were noticed. Further, the proposed sensor was found to be linear in the range of 5-35 mu M (G), 5-35 mu M (A), 25-175 mu M (T) and 25-175 mu M (C). The proposed S-g-C3N4 modified electrode also exhibited a stable, selective and sensitive performance towards the detection of individual DNA base in the presence of other DNA bases.