Development of Acridine‐Derived “Turn On” Al³⁺ Fluorescent Sensors and Their Imaging in Living Cells

Abstract

Two novel highly selective fluorescent sensors L‐1 and L‐2 for the determination of Al3+ ion were synthesized and characterized. The sensors acridine‐4,5‐diylbismethyl(bis(oxy))bis(2,1‐phenylene))bis‐(methylene))bis(azanediyl))bis(3‐phenylpropan‐1‐ol) (L‐1) and 2,2′‐acridine‐4,5‐diylbis(methylene(bis(oxy))bis(2,1‐phenylene))bis‐(methylene))bis(azanediyl))bis(propan‐1‐ol) (L‐2) showed “turn on” fluorescence response in the presence of Al3+ ion in DMSO/tris‐HCl (1:1, v:v, pH=7.2) buffer solution. Other cations viz. Li+, Na+, K+, Mg2+, Ca2+, Fe2+, Co2+, Ni2+, Cd2+, Cu2+, Zn2+, Mn2+, Ba2+, Pb2+, Hg2+, Fe3+ and Eu3+ ions showed no appreciable change in fluorescence spectrum. The detection limits of L‐1 and L‐2 for Al3+ ion were at the parts per billion level. In addition, possible utilization of sensors as bio‐imaging fluorescent sensors to detect Al3+ in human cervical HeLa cells was also investigated by confocal fluorescence microscopy.

Fluorescence Sensors for Fe3+ Ion with High Selectivity and Sensitivity and Bioimaging in Living Cells

“…(Figure a). The association constant for L1 with Fe 3+ ion was calculated to be 8.00×10 4 using a Benesi–Hildebrand plot (Figure b) ,. These results suggested formation of the 1:1 complex between sensor L1 and Fe 3+ ion.…”

“…In comparison with previously reported fluorescence sensors for Fe 3+ detection, both L1 and L2 displayed superior sensitivities in terms of detection limit, high selectivity and applicability in live cell imaging. As shown in Table , each sensor had certain advantages, such as rare interference,,,,,, low detection limits,,, single‐step synthesis, and applicability in live cell imaging ,,,,,. Another advantage of these sensors was that they could be used in aqueous media without interference from other ions, which led us to achieve the fluorescence detection of Fe 3+ in living cells at micromolar level.…”