A cyclic enzymatic amplification method for sensitive and selective detection of nucleic acids

Based on Exonuclease III (Exo III) and displacing probes, we have developed a Cyclic Enzymatic Amplification Method (CEAM) for sensitive and selective detection of nucleic acids. In this design, the displacing probe is non-fluorescent on its own and cannot be digested by Exo III until displacement hybridization by a target sequence, leading to release of free non-quenched fluorophore. Because a single target sequence can lead to the release and digestion of numerous fluorophore strands from the displacing probe, a remarkable signal amplification is achieved. With this method, DNA can be detected in the picomolar range with a high selectivity and within less than 20 min.