ESIPT-based ratiometric fluorescent probe for highly selective and sensitive sensing and bioimaging of group IIIA ions in living cancer cells and zebrafish

Gallium , aluminum , and indium belong to Group IIIA of the periodic table with similar chemical properties, which were a double-edged sword for living organisms. Therefore, it's particularly important to detect the content of Group IIIA in organisms. Obviously, the fluorescent probe method has become a mainstream method for detecting metal ions with advantages of convenience and high efficiency. Unfortunately, fluorescent probes that can simultaneously detect these three metal ions are rarely reported. 3-hydroxyflavone ( 3-HF ) is a highly focused molecule with chemical and photochemical properties and have great potential for bioimaging applications as sensors with excited-state intramolecular proton transfer (ESIPT). Here, 3-HF as ratiometric fluorescence probes have been developed for responding to Group IIIA ions including Ga(III), Al(III) and In(III) ions with ESIPT-based mechanism. 3-HF displayed highly specific sensing for Group IIIA ions over other cations with a green fluorescence transformation into blue fluorescence by the formation of 2:1 complexes. However, rapid response toward Group IIIA ions was developed using ratiometric fluorescence with wide pH range and good reversibility , and the response mechanism of 3-HF toward Group IIIA ions was annotated by density functional theory (DFT). Furthermore, the biological applicability of 3-HF has shown that 3-HF were able to detect and image Group IIIA ions in cells. Additionally, using a zebrafish model, we exhibited the capability of this 3-HF probe for detecting and imaging Group IIIA ions in zebrafish. This work achieves the detection and imaging of Group IIIA simultaneously by 3-HF probe in living cells and zebrafish and provides another example for “ESIPT OFF”.