Label-Free and Ultrasensitive Detection of Hg2+ Based on Structure Switching of Aptamer and Rolling Circle Amplification (RCA)

Mercury ions (Hg2+), a heavy metal contaminant of strong biotoxicity, pose a serious threat to ecosystems and human health in aquatic environments. Developing highly sensitive and specific detection methods is therefore of great importance. This study presents a novel label-free fluorescent biosensor for Hg2+ by ingeniously coupling target-induced aptamer switching with rolling circle amplification (RCA). Upon Hg2+ binding, the conformational change releases a sequestered primer to initiate RCA,