A 18F radiolabelled Zn(ii) sensing fluorescent probe

Abstract

A selective fluorescent probe for Zn(II), AQA-F, has been synthesized. AQA-F exhibits a ratiometric shift in emission of up to 80 nm upon binding Zn(II) ([AQA-F] = 0.1 mM, [Zn(II)Cl₂] = 0–300 μM). An enhancement of quantum yield from Φ = 4.2% to Φ = 35% is also observed. AQA-F has a binding constant, K_d = 15.2 μM with Zn(II). This probe has been shown to respond to endogenous Zn(II) levels in vitro in prostate and prostate cancer cell lines. [¹⁸F]AQA-F has been synthesized with a radiochemical yield of 8.6% and a radiochemical purity of 97% in 88 minutes. AQA-F shows the potential for a dual modal PET/fluorescence imaging probe for Zn(II).