Thermoresponsive DNA Tweezer as a Universal Sensing Platform for Small Molecule and Protein Detection

Rapid, simple, and sensitive detection of multiple classes of biomolecules is highly desired in broad fields including disease diagnosis, drug discovery, and biological analyses. We demonstrate a thermoresponsive DNA tweezer converting biomolecule bindings into ratiometric fluorescence responses under heating. This DNA tweezer is formed by binding an affinity protein (e.g., antibody) to a pair of small-molecule-labeled DNA arms sharing complementary sequences at the terminals, and one DNA arm is also conjugated with a fluorophore. Depending on its thermal stability, the DNA tweezer can undergo switching action from the closure state to the open state upon heating, generating increased fluorescence, which is measured in real time by microscale thermophoresis analysis. The presence of targets modulates the assembly or disassembly of the DNA tweezer, causing distinct signals. This strategy allows for the rapid and sensitive detection of protein and small-molecule targets with robust responses. This heating-responsive DNA tweezer will facilitate sensor developments and dynamic DNA nanotechnology in a wide range of applications.