Direct detection of a target nucleic acid on a surface by spraying DNA-nano-tweezers-based biosensing molecules

We propose a new concept to detect a target molecule on a solid surface directly by spraying biosensing molecules. First, a filter paper as a model of a solid surface was spotted with a target nucleic acid. Then, the biosensing molecule, a DNA-nano-tweezers-structure that exhibits a peroxidase activity recognizing the target, was sprayed with hemin as a cofactor, followed by a second spray containing luminol as a substrate for a light-glowing signal. Finally, an image was recorded using a smartphone. The images revealed that only the places where the corresponding targets were spotted glowed a blue light.