Cyclodextrin-Based Metal-Organic Nanotube as Fluorescent Probe for Selective Turn-On Detection of Hydrogen Sulfide in Living Cells Based on H(2)S-Involved Coordination Mechanism

Hydrogen sulfide (H(2)S) has been considered as the third biologically gaseous messenger (gasotransmitter) after nitric oxide (NO) and carbon monoxide (CO). Fluorescent detection of H(2)S in living cells is very important to human health because it has been found that the abnormal levels of H(2)S in human body can cause Alzheimer’s disease, cancers and diabetes. Herein, we develop a cyclodextrin-based metal-organic nanotube, CD-MONT-2, possessing a {Pb(14)} metallamacrocycle for efficient detection of H(2)S. CD-MONT-2′ (the guest-free form of CD-MONT-2) exhibits turn-on detection of H(2)S with high selectivity and moderate sensitivity when the material was dissolved in DMSO solution. Significantly, CD-MONT-2′ can act as a fluorescent turn-on probe for highly selective detection of H(2)S in living cells. The sensing mechanism in the present work is based on the coordination of H(2)S as the auxochromic group to the central Pb(II) ion to enhance the fluorescence intensity, which is studied for the first time.