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

Abstract

Hydrogen sulfide (H ₂S) has been considered as the third biologically gaseous messenger (gasotransmitter) after nitric oxide (NO) and carbon monoxide (CO). Fluorescent detection of H ₂S in living cells is very important to human health because it has been found that the abnormal levels of H ₂S 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 ₂S. CD-MONT-2′ (the guest-free form of CD-MONT-2) exhibits turn-on detection of H ₂S 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 ₂S in living cells. The sensing mechanism in the present work is based on the coordination of H ₂S as the auxochromic group to the central Pb(II) ion to enhance the fluorescence intensity, which is studied for the first time.