Development of an impedimetric DNA-biosensor based on layered double hydroxide for the detection of long ssDNA sequences

DNA testing requires the development of sensitive and fast devices to measure the presence of nucleic acid sequences by DNA hybridization. In this paper, a simple and label-free DNA-biosensor has been investigated based on the detection of DNA hybridization on layered double hydroxide (LDH) nanomaterials with special emphasis on targeting long single stranded DNA sequences. First, the immobilization of a 20 bases long DNA probe on a thin layer of Mg 2AlCO 3 and Mg 3AlCO 3 LDH was studied. Then, DNA hybridization reaction was detected by means of Electrochemical Impedance Spectroscopy. The resulting biosensor showed a high sensitivity for the detection of 80 bases long DNA complementary sequences. The dynamic range was 18-270 ng/ml with a detection limit lower than 1.8 ng/ml.This work was supported by the Spanish MICINN (CTQ2010-20541), the Generalitat de Catalunya (2009/SGR/208) and CIBER-BBN. Special funds were obtained from Spanish and Tunisian government to support this work within AECID program (A/2675/05 and A/6256/06).Peer reviewe