Electrochemical nanoporous alumina membrane-based label-free DNA biosensor for the detection of Legionella sp

► Ultrasensitive DNA detection of Legionella pneumophila with LOD of 3.1×10−13 M. ► One and three base-pair mismatches can be distinguished from complementary target. ► Single step analysis of unlabeled DNA targets. ► Biosensor comprises DNA probe-grafted nanoporous structure on electrode. ► Signal changes when nanoporous structure is blocked upon DNA hybridization.