Switchable and selective detection of Zn²⁺ or Cd²⁺ in living cells based on 3′-O-substituted arrangement of benzoxazole-derived fluorescent probes

Abstract

Two benzoxazole-derived ESIPT fluorescent sensors and show highly selective detection of Zn(2+) and Cd(2+), respectively, in aqueous solution and living cells. The selectivity switching from Zn(2+) to Cd(2+) is attributed to the different binding mode which is dependent on the 3'-O-substituted arrangement.

Zinc binding with l-dopa peptides

“…Fitting of the spectrophotometric titration data with a 1:1 binding stoichiometry gave binding constants for the peptide:zinc complex, Table 3. All DopaXxx peptides effectively bind to zinc and are consistent with other catechol based binding agents [48,49]. Notably, DopaGly has the weakest observed assocation; all peptides with an aromatic cross strand partner bind zinc more tightly.…”

A Ga3+self-assembled fluorescent probe for ATP imaging in vivo

“…ATP, GTP and GaCl 3 were purchased from J&K Scientific Ltd. (Beijing, China). DHBO was synthesized according to our previous work (Xu et al, 2014). Absorption and emission spectra were collected by using a Shimadzu 1750 UV-visible spectrometer and a RF-5301 fluorescence spectrometer (Japan), respectively.…”

“…Ga 3 þ ions were found to easily coordinate with oxygen atoms of hydroxyphenyl segments (Hastings et al, 2014;McKinlay et al, 2005McKinlay et al, , 2006. DHBO ligand is a typical fluorophore known for its excited state intramolecular proton transfer (ESIPT) characteristic (Xu et al, 2014). In water solution, it is envisaged that a coordination scaffold assembled from DHBO and Ga 3 þ would establish (Scheme 1).…”

“…Herein, we present a Ga 3 þ self-assembled fluorescent sensor based on the ligand of 2-(2′,3′-dihydroxyphenyl)benzoxazole (DHBO) (Xu et al, 2014), which shows significant fluorescence enhancement only with ATP among structurally similar nucleoside triphosphates under physiological conditions. The turn-on fluorescence signal can effectively discriminate ATP from ADP and adenosine 5′-monophosphate (AMP).…”

Synthesis, crystal structure and remote allosteric binding properties of cone thiacalix[4]pseudocrown receptors bearing anthraquinone function and different arms

“…The design of receptors that offer high Zn 2+ /Cd 2+ selectivity is one of the current challenges in cation recognition chemistry. [48][49][50] Thus, the ability to optically recognize Zn 2+ in the presence of Cd 2+ is an interesting feature of this thiacalix [4]pseudocrown receptor.…”