A New Fluorescence Turn-On Probe for Aluminum(III) with High Selectivity and Sensitivity, and its Application to Bioimaging

Abstract

The development of novel selective probes with high sensitivity for the detection of Al3+ is widely considered an important research goal due to the importance of such probes in medicine, living systems and the environment. Here, we describe a new fluorescent probe, N′-(4-diethylamino-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (1), for Al3+. Probe 1 was evaluated in a solution of acetonitrile/water (1:1 v/v). Compared with previously reported probes for Al3+, probe 1 can be synthesized easily and in high yield. A Job plot confirmed that probe 1 is able to complex Al3+ in a 1:1 ratio, and the binding constant was determined to be 4.25×108 m−1. Moreover, the detection limit was as low as 6.7×10−9 m, suggesting that probe 1 has a high sensitivity. Common coexistent metal ions, such as K+, Co2+, Ca2+, Ba2+, Ni2+, Pb2+, Hg2+, Ce2+, Zn2+, Cd2+, Fe3+, showed little or no interference in the detection of Al3+ in solution, demonstrating the high selectivity of the probe. Finally, the ability of probe 1 to act as a fluorescent probe for Al3+ in living systems was evaluated in Gram-negative bacteria, Escherichia coli, and confocal laser scanning microscopy confirmed its utility. The results of this study suggest that 1 has appropriate properties to be developed for application as a fluorescent probe of Al3+ for use in biological studies.

Self-Assembly of Amphiphilic Schiff Base and Selectively Turn on Circularly Polarized Luminescence by Al3+

“…The fluorescence intensity of compound 2 increased almost linearly to the amount of Al 3+ but remained steady when more than 1.0 equiv of Al 3+ was applied (Figure C), suggesting a 1:1 binding mode between compound 2 and Al 3+ . To further investigate the binding stoichiometry of compound 2 and Al 3+ , Job’s plot analysis , (Figure S6) based on fluorescence spectra was performed, in which the transition point for fluorescence intensity appeared at the molar fraction of 0.5, suggesting that compound 2 bound to Al 3+ with a 1:1 molar ratio. Furthermore, the 1:1 binding stoichiometry between compound 2 and Al 3+ was also verified by ESI-MS spectrum of compound 2 and compound 2 /Al 3+ .…”

Easily Accessible Schiff Base ESIPT Molecules with Tunable Solid State Fluorescence: Mechanofluorochromism and Highly Selective Co2+ Fluorescence Sensing

“…In contrast, 2 showed highly selective fluorescence quenching for Co 2+ ions (Figure , S26–27). It is noted that 2 e exhibited highly selective fluorescence enhancement for Al 3+ ions in CH 3 CN−H 2 O mixture . Co 2+ ions did not show any interference.…”

“…ESIPT fluorophores 1 – 4 were synthesized via simple Schiff base condensation reaction between HBH and different aldehydes (Scheme a, S1) . Amine precursor, HBH, was synthesized by reacting hydrazine and methyl salicylate.…”

A Highly Selective Turn-on Fluorescent Probe for the Detection of Aluminum and Its Application to Bio-Imaging

“…Fluorescent approach is the most attractive and highly sensitive method to detect low concentrations of analysts [9]. In recent years, there has been considerable progress for the detection of aluminum utilizing fluorescent chemo-sensors [10,11,12,13,14,15]. However, there are still many limitations during the application of most reported fluorescent probes, such as working well only in anhydrous systems, poor selectivity or sensitivity, and weak binding ability [13,16,17,18,19].…”