Enhancing or Quenching of a Mitochondria-Targeted AIEgens-Floxuridine Sensor by the Regulation of pH-Dependent Self-assembly, Efficient Recognition of Hg2+, and Stimulated Response of GSH

by Selleckchem | Feb 03 2024

Biocompatible fluorescent probes have emerged as essential tools in life sciences for visualizing subcellular structures and detecting specific analytes. Herein, we report the synthesis and characterization of a novel fluorescent probe (TPE-FdU), incorporated with hydrophilic 2'-fluoro-substituted deoxyuridine and hydrophobic ethynyl tetraphenylethene moieties, which possessed typical aggregation-induced emission (AIE) behavior. In comparison to the TPE-FdU (pKa 7.68) treated in neutral conditions, it performed well at pH 4, exhibiting an enhanced 450 nm emission signal of approximately four times stronger. As the pH value was increased to 10, the fluorescence intensity was completely quenched. The TEM images of TPE-FdU in an acidic environment (nanospherical morphology, AIE enhance, pH = 4) and in a basic environment (microrods, fluorescence quenching, pH = 9) revealed that it was a pH-dependent self-assembled probe, which was also illustrated by the interpretation of the NMR spectrum. Furthermore, the TPE-FdU probe exhibited a specific response to trace Hg2+ ions. Interestingly, the quenched fluorescence of the TPE-FdU probe caused by Hg2+ can be recovered by the addition of GSH due to the formation of the Hg-S bond being released away. MTT assay and CLSM images demonstrated that TPE-FdU was nontoxic and selectively visualized in the intracellular mitochondria. These results contributed to the development of advanced fluorescent probes with diverse applications in cell imaging, environment protection, and biomedical research.

Comments:

That's an impressive report! It seems like the synthesis of TPE-FdU, with its dual characteristics of hydrophilicity and hydrophobicity, created a versatile probe. Its ability to exhibit aggregation-induced emission behavior under specific pH conditions, particularly its fourfold enhancement in emission at pH 4 and subsequent quenching at pH 10, indicates its potential as a pH-responsive probe.

The morphological changes observed in TEM images between acidic and basic environments, from nanospherical morphology to microrods, hint at its pH-dependent self-assembly properties. The correlation of these changes with the NMR spectrum further validates this pH-dependent behavior.

The selective response to trace Hg2+ ions and the subsequent recovery of fluorescence upon the addition of GSH due to the formation and release of the Hg-S bond is fascinating. This feature could be invaluable in environmental monitoring and bioimaging applications.

Moreover, the non-toxic nature of TPE-FdU, as evidenced by the MTT assay, coupled with its selective visualization within intracellular mitochondria observed through CLSM images, underlines its potential as a safe and specific imaging agent for biomedical research.

Overall, this multifunctional TPE-FdU probe holds promise for various applications in cell imaging, environmental protection, and biomedical studies, owing to its pH-responsive behavior, selectivity towards specific analytes, and intracellular targeting ability.