An activatable NIR turn-on fluorescent probe for copper (II) ion and live cell imaging

Abstract

Herein we have reported a fluorescent probe (MB-M) based on MB derivative for Cu 2+ ions detection. The probe was well characterized by 1 H NMR, 13 C NMR and HR-MS spectrum. Probe MB-M showed naked-eyes recognition to Cu 2+ as color change from colorless to indigo. The probe exhibited promising features such as high fluorescence and UV–vis selectivity, fast response (5 mint), workable at pH 2–7, and low limit of detection (LOD = 0.33 µM). Probe MB-M was also used for Cu 2+ ions imaging in HepG-2 cells and detection in daily life (Test Strip and lake water). Moreover, non-covalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analysis were used to study the interaction between MB-M and Cu 2+ ions. By examining the electronic characteristics of the complex using natural bond orbital (NBO), electron density difference (EDD), and frontier molecular orbital (FMO) analysis, the sensitivity of MB-M towards Cu 2+ ions were investigated. The results illustrated that the interactions between MB-M and Cu 2+ ions involved chemisorption.