ESIPT and CHEF based highly sensitive and selective ratiometric sensor for Al³⁺ with imaging in human blood cells

Abstract

Based on excited state intramolecular proton transfer (ESIPT) and chelation induced enhanced fluorescence (CHEF) machanisms, a new fluorescence ratiometric probe for Al 3+ was designed and synthesized and its structure was confirmed through single crystal X-ray study. This probe is capable to show excited state intramolecular proton transfer through two different pathways. Introduction of Al 3+ in the mixed aqueous solution of the probe exhibits abrupt change in the photophysical properties. A ratiometric emission profile was noticed in presence of Al 3+ . Interestingly, the presence of other metal ions (specially trivalent ions e. g. Fe 3+ , Cr 3+ , Ga 3+ and In 3+ ) do not perturb the fluorescence intensity of the probe (except Cu 2+ and Pb 2+ , slight changes were noticed). This indicates that the probe shows high affinity towards Al 3+ . The ratiometric sensing phenomenon may be explained as the presence of two different mechanism namely excited state intramolecular proton transfer and chelation induced enhanced fluorescence, showed by the probe in presence of Al 3+ in the excited state. The complexation of the probe with Al 3+ inhibits excited state intramolecular proton transfer while the chelation induced enhanced fluorescence mechanism come to play. The probe was efficient to detect the cellular uptake of Al 3+ , which is demonstrated here with human blood-cell imaging. Moreover the detection limit was found to be 6.72 × 10 -8 M.We have synthesised a probe for fluorescence ratiometric detection of Al 3+ . The probe can image Al 3+ in living cells.

MoS2‐QD‐Based Dual‐Model Photoluminescence Sensing Platform for Effective Determination of Al3+ and Fe3+ Simultaneously in Various Environment

“…Moreover, it is understood that the aluminium based drugs such as antiperspirants, antiulcer agents and antacids are more harmful to human health than that of food contaminated with Al 3+ ions . In addition, Al 3+ ions can stay inside the cells and tissues for longer time before being excreted by the body . Hence, the World Health Organization (WHO) listed the excess Al to be one of the food pollution sources and limited it to 200 μg⋅L −1 (7.41 μM) in drinking water .…”

A Phenyl Thioether‐Based Probe: Zn2+ Ion Sensor, Structure Determination and Live Cell Imaging†

“…Out of seventeen different metal ions (Na + , Zn 2+ , Cd 2+ , K + , Ca 2+ , Mg 2+ , Mn 2+ , Fe 3+ , Al 3+ , Co 2+ , Cr 3+ , Ni 2+ , Pd 2+ , Hg 2+ , Cu 2+ , Ba 2+ , Pb 2+ ) only in presence of Zn 2+ the probe shows strong emission upon excitation at 380 nm in the MeOH‐H 2 O (v/v 9:1) (HEPES buffer, 10 mM, pH 7.4) medium (Figure ) . On the incremental addition of Zn 2+ to the solution of H 2 ‐SAP the intensity of fluorescence emission increases (λ em , 560 nm) linearly and blue shifted (40 nm) and results improvement of quantum yield to 0.080 ( Figure S6) , may due to introduction of Chelation enhanced fluorescence (CHEF) and embarrassment of ESIPT (Scheme ) …”

Sugar‐Based Self‐Assembly of Hydrogel Nanotubes Manifesting ESIPT: Theoretical Insight and Application in Live Cell Imaging

“…The ‘keto‐enol’ tautomers (Scheme ) behave quite different under UV‐irradiation. In the ground state, the BTHBC present as enol form (E) and this is stabilized by the intramolecular hydrogen bonding interaction between hydrogen atom of phenolic –OH group and nitrogen atom (N T ) of HBT or imine nitrogen (N C ) of chitosan –. Upon excitation, the hydrogel in the excited‐state enol form (E*) transform to the excited‐state keto form (K*) through intramolecular proton transfer.…”