DNA-Dye Assembly Based Single-Molecule Fluorescence Lifetime Imaging Probes

Disclosed are nucleic acid-chromophores and nucleic acid assembly containing the nucleic acid-chromophores. The nucleic acid-chromophore contains a nucleic acid strand and two or more adjacent chromophores. The two or more adjacent chromophores can be covalently incorporated in the backbone of the nucleic acid strand. One or more photophysical properties of the adjacent chromophores can be altered by a change in the nucleic acid assembly. In some forms, the nucleic acid assembly can contain a nucleic acid scaffold. In these forms, the change in the nucleic acid assembly can be a change in the length of a nucleic acid hybrid in the nucleic acid scaffold that is opposite the adjacent chromophores. Typically, the nucleic acid hybrid does not contain any chromophore. The nucleic acid-chromophores can serve as molecular fluorophores with emission properties that are highly sensitive to local geometry and the chemical environment.