Related Experiment Video
Updated: Oct 17, 2025
Aptamer-Based Target Detection Facilitated by a 3-Stage G-Quadruplex Isothermal Exponential Amplification Reaction
Published on: October 6, 2022
Target-Mediated 5'-Exonuclease Digestion of DNA Aptamers with RecJ to Modulate Rolling Circle Amplification for
Roger M Bialy1, Yingfu Li1,2, John D Brennan1
1Biointerfaces Institute, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4O3, Canada.
Abstract:
We report a new method for biosensing based on the target-mediated resistance of DNA aptamers against 5'-exonuclease digestion, allowing them to act as primers for rolling circle amplification (RCA). A target-bound DNA strand containing an aptamer region on the 5'-end and a primer region on the 3'-end is protected from 5'-exonuclease digestion by RecJ exonuclease in a target-dependent manner. As the protected aptamer is at the 5'-end, the exposed primer on the 3'-end can participate in RCA in the presence of a circular template to generate a turn-on sensor. Without target, RecJ digests the primer and prevents RCA from occurring, allowing quantitative fluorescence detection of both thrombin, a protein, and ochratoxin A (OTA), a small molecule, at picomolar concentrations.
