Dual-Analyte Fluorescent Sensor Based on [5]Helicene Derivative with Super Large Stokes Shift for the Selective Determinations of Cu2+ or Zn2+ in Buffer Solutions and Its Application in a Living Cell

A new fluorescent sensor, M201-DPA, based on [5]helicene derivative was utilized as dual-analyte sensor for determination of Cu2+ or Zn2+ in different media and different emission wavelengths. The sensor could provide selective and bifunctional determination of Cu2+ in HEPES buffer containing Triton-X100 and Zn2+ in Tris buffer/methanol without interference from each other and other ions. In HEPES buffer, M201-DPA demonstrated the selective ON–OFF fluorescence quenching at 524 nm toward Cu2+. On the other hand, in Tris buffer/methanol, M201-DPA showed the selective OFF–ON fluorescence enhancement upon the addition of Zn2+, which was specified by the hypsochromic shift at 448 nm. Additionally, M201-DPA showed extremely large Stokes shifts up to ∼150 nm. By controlling the concentration of Zn2+ and Cu2+ in a living cell, the imaging of a HepG2 cellular system was performed, in which the fluorescence of M201-DPA in the blue channel was decreased upon addition of Cu2+ and was enhanced in UV channel upon addit...