Synthesis of cadmium sulfide ( CdS) nanoclusters and its application in an electrochemical DNA hybridization detection were described. The nanoclusters were successfully labeled to a 5'-amino group capped oligonucleotides probe that is related to the colitoxin gene. The DNA genetic sensing assay relies on the target oligonucleotides on the glassy carbon electrode (GCE) hybridized with the CdS nanocluster-oligonucleotides DNA probe. Hybridization events between the probe aid target were monitored by the release of the CdS anchored on the hybrids by oxidative dissolution and the indirect determination of the solubilized Cd~(2+) ions by sensitive anodic stripping voltammetry (ASV) . The detection limit is 10 pmol/L of the complementary target oligonucleotides.

Key words: CADMIUM SULFIDE, NANOPHASE MATERIALS, OLIGONUCLEOTIDE, VOLTAMMETRY, ESCHERICHIA COLI, ELECTROCHEMISTRY