AIE fluorescent probe based on tetraphenylethylene and morpholine-thiourea structures for detection of HClO

Abstract

As an important signal molecule in the living body, hypochlorous acid (HClO) participates in various physiological processes. However, excessive hypochlorous acid will cause some oxidative damage. The organic aggregation-induced emission luminogens (AIEgens) based on tetraphenylethylene (TPE) structures have recently become research hotspots as fluorescent probe materials. In this paper, a kind of water-soluble fluorescent probe TPE-M based on TPE and morpholine-thiourea structures were designed and synthesized for the detection of HClO. Due to the introduction of morpholine structures, the TPE-M showed excellent water solubility. The fluorescence properties of the TPE-M were strongly affected by the polarity of the solvent. Besides, the cation-anion and reactive oxygen species recognition experiments indicated that the fluorescent probe TPE-M displayed a single recognition characteristic for HClO because of the existence of thiourea structures. The limit of detection for HClO was calculated to be 0.25 μM. The particle size distribution measurement under the water phase revealed that the particle size of the TPE-M was mainly centered at 150 nm. The recognition mechanism of HClO by the probe TPE-M was proposed and explained by mass spectra and Gaussian calculation. Furthermore, a cell imaging experiment proved that the TPE-M probe successfully detected HClO in Hela cells.