A copper(II) displacement approach for fluorescent turn-on sensing of glutathione using salicylaldehyde modified polydopamine nanoparticles

A Selective and Reversible Fluorescent Probe for Cu2+ and GSH Detection in Aqueous Environments

“…[30] PBI could form a stable complex with Cu 2 + to selectively recognize Cu 2 + in other metal cations, when PBI binding with Cu 2 + , it quenched fluorescence due to the combined effect of strengthened PET process and paramagnetic property of Cu 2 + (according to Figure 7B), closed ESPT process. [18,31] In addition, due to the strong affinity between Cu 2 + and GSH, Cu 2 + might complex with GSH and be extracted from the coordination system, which could recover the electron effect of PBI and significantly increase the fluorescence intensity. [14,15] The possible changes of the coordination mode were shown in Scheme 2.…”

“…Because the GSH with multiple donor atoms like O, S and N atoms has higher affinity towards Cu 2 + is expected to decomplex Cu 2 + from the PBI-Cu 2 + , which suppressed the photoinduced electron transfer (PET) from the electron-rich surface of PBI the paramagnetic Cu 2 + , [18] GSH showed a higher recovery rate (77 %) than Cys (38 %), indicating the complex could detect GSH specifically. Addition of GSH to PBI-Cu 2 + with other amino acids in HEPES buffer (10 mM, pH 7.4) leading to great fluorescence enhancement (> 75 %), and suggesting the PBI-Cu 2 + ensemble has an excellent potential for GSH detection in physiological environment, as shown in Figure 6B.…”

“…[12,13] For now, using Cu 2 + complexes as a fluorescent probe may be one of the most promising methods for detection of biothiols. [14][15][16][17][18] Reported excited-state intramolecular proton-transfer (ESIPT) based fluorescent probes were mainly designed based on the structures of 2-(2'-hydroxyphenyl) benzoxazole (HBO), 2-(2'-hydroxyphenyl)benzimidazole (HBI) and 2-(2'hydroxyphenyl)benzothiazole (HBT), in which the weak basic heterocyclic structures were used as hydrogen-bonded acceptors. [19] Unlike ESIPT probes, excited-state proton transfer (ESPT) of PBI assisted by a single water molecule.…”