The complex of rutin-Cu (C81H86Cu2O48, abbreviated by Cu2R3, R = rutin) was synthesized and characterized by elemental analysis and IR spectra. Cyclic voltammetry (CV) and fluorescence spectroscopy were used to investigate the interaction of Cu2R3 With salmon sperm DNA. It was revealed that Cu2R3 could interact with double-stranded DNA (dsDNA) by a major intercalation role. Using Cu2R3 as a novel electroactive indicator, an electrochemical DNA biosensor for the detection of specific DNA fragment was developed and its selectivity for the recognition with different target DNA was assessed by differential pulse voltammetry (DPV). The target DNA related to coliform virus gene could be quantified ranged from 1.62 x 10(-8) mol L-1 to 8.10 X 10(-7) mol L-1 with a good linearity (r = 0.9989) and a detection limit of 2.3 x 10(-9) mol L-1 (3 sigma, n = 7) was achieved by the constructed electrochemical DNA biosensor. (C) 2008 Elsevier Ltd. All rights reserved.