Enzyme-free and amplified fluorescence DNA detection using bimolecular beacons.

In this work, we propose a simple and enzyme-free strategy for sensitive and selective DNA detection by using two different types of molecular beacons (MBs), MB1 and MB2. In this method, the target DNA binds with and restores the fluorescence of MB1 first. Then, MB2 hybridizes with MB1 and free the target, which is used to trigger another reaction cycle. The cycling use of the target and the employment of bi-MBs amplify the fluorescence intensity for sensitive DNA detection. The detection limit of this method was obtained as 10 pM, which is about 2 orders of magnitude sensitive than the conventional MB-based approaches.