RNA aptazyme-tethered large gold nanoparticles for on-the-spot sensing of the aptazyme ligand.

A single-step sensing system was developed to visually detect ligands of a cleavase-like RNA aptazyme at room temperature using aptazyme-tethered gold nanoparticles, the electrosteric stability of which was adjusted by increasing their diameter. In this system, the ligand induces self-cleavage of the aptazyme on gold nanoparticles to decrease the electrosteric stability of the gold nanoparticles, which causes them to visibly aggregate. In comparison to a previous multi-step system using aptazymes and gold nanoparticles separately, the present system requires only single handling and no special equipment, making it more suitable for on-the-spot sensing.