DNA biosensor for rapid detection of genotoxic compounds in soil samples

An electrochemical DNA-based biosensor is proposed as a fast and easy screening method for the detection of genotoxic compounds in soil samples. The biosensor was assembled by immobilising double stranded Calf thymus DNA on screen-printed electrodes. The interactions between DNA and environmental pollutants can cause variations of the electrochemical proprieties of DNA when they cause a DNA damage. Preliminary studies were performed using benzene, naphthalene and anthracene derivatives as model compounds. The effect of these compounds on the surface-confined DNA was found to be linearly related to their concentration in solution. On the other hand, the objective was to optimise the ultrasonic extraction conditions of these compounds from artificially spiked soil samples. Then, the applicability of such a biosensor was evaluated by analysing soil samples from an Italian region with ecological risk (ACNA of Cengio, SV). DNA biosensor for qualitative analysis of soil presented a good correlation with a semi-quantitative method for aromatic ring systems determination as fixed wavelength fluorescence and interestingly, according results were found also with other bioassays. This kind of biosensors represent a new, easy and fast way of analysis of polluted sites, therefore they can be used as early warnings devices in areas with ecological risk as in situ measurement.