Fluorescent probe based on acyclic cucurbituril to detect Fe3+ ions in living cells

Fe3+ is an essential element for human body, misregulation of which in cell are concerned with serious diseases. It is very meaningful to detect Fe3+ in living cells. Here, a novel fluorescent probe (Py-ACB) based on acyclic cucurbituril and pyrene was synthesized. Py-ACB exhibits high selectivity and sensitivity to Fe3+, Fe3+ is coordinated with the carbonyl groups and oxygen atoms of Py-ACB, resulting in reverse photo-induced electron transfer (reverse PET) from pyrene unit to the carbonyl oxygen atoms to induce fluorescence quenching. The binding constant and detection limits of Fe3+ recognized by Py-ACB are 9.26 × 104 M−1 and 2.51 × 10−8 M, respectively, and Py-ACB showed high response speed to Fe3+. More importantly, the probe Py-ACB showed strong fluorescence emission in living cell, which allowed the detection of Fe3+ in live cells by bioimaging.