Guwahati based Institute of Advanced Study in Science and Technology has developed an electrochemical sensing platform for detecting carcinogenic or mutagenic compound N-nitrosodimethylamine (NDMA) and N-nitrosodiethanolamine (NDEA).
These are sometimes found in food items like cured meat, bacon, some cheese, and low-fat milk. It was achieved by developing a modified electrode by immobilizing carbon nanomaterials (carbon dots) in DNA.
People are exposed to harmful chemicals belonging to Nitrosamine family in cured meats, bacon, some cheese, low-fat dry milk, and fish.
Such chemicals include carcinogenic ones like NDMA and NDEA, which may also alter the chemical composition of DNA. Hence it is important to develop detection techniques to detect them.
The detection limit was determined to be 9.9×10-9 M and 9.6×10-9 M for NDMA and NDEA, respectively.
The electrochemical sensor, the electrode was developed by depositing carbon dots (carbon nanoparticles) and then immobilizing bacterial DNA on them.
The new electrode system measures the current peak. Both NDMA and NDEA alters the chemical structure of DNA present in the electrode, making it more conducting. This will result in an increased current peak.
In the presence of NDMA, guanine is modified to 6-Omethylguanine or 7-methyl guanine and with NDEA guanine changes to 8-oxoguanine to form DNA adducts.
The DNA adducts thus formed remain electrochemically active. This leads to an increase in peak current in electrochemical set-up, helping in the detection of the chemicals.