DNA Carbon-Nanodots based Electrochemical Biosensor for Detection of Mutagenic Nitrosamines.

Mutagenic and Carcinogenic substances are a threat to any living organism, and its detection is of paramount importance. In this work, we fabricate for the first time a DNA-carbon dots based electrochemical biosensor for sensitive and selective detection of mutagenic nitrosamines like N-nitrosodimethylamine (NDMA) and N-nitrosodiethanolamine (NDEA). At first, on the glassy carbon electrode (GCE), chitosan carbon dot was deposited, then, DNA was electro-statically immobilizing on the surface of carbon dots to fabricate the sensing electrode (DNA/chiCD/GCE modified electrode). In the presence of NDMA and NDEA, in differential pulse voltammetry technique, the absolute peak current increases, and thus it can detect NDMA and NDEA. The system DNA/chiCD/GCE modified electrode is highly selective and sensitive toward NDMA and NDEA. The detection limit was determined to be 9.9 × 10-9 M and 9.6 × 10-9 M, respectively. The possible reason for DNA/chiCD/GCE modified electrode showing such electrochemical selectivity toward nitrosamines is investigated and discussed.