Figure 4.

Tb³⁺ binding to the DNA 4WJ measured by luminescence. Titration of TbCl₃ into 10 µM junction leads to an increase in Tb³⁺ luminescence at 543 nm. Excitation was done at 294 nm to excite the DNA and the luminescence peak at 543 nm is only observed in the presence of Tb³⁺ and junction. (Inset) Excitation and emission spectra of the Tb luminescence; the ⁵D₄→⁷F₅ transition at 543 nm is highlighted.