Iridium-based probe for luminescent nitric oxide monitoring in live cells

Chun Wu,Ke-Jia Wu,Jin-Biao Liu,Chung-Hang Leung,Dik-Lung Ma,Hui-Min David Wang,Tian-Shu Kang

doi:10.1038/s41598-018-30991-9

Abstract

Nitric oxide (NO) is an intra- and extracellular messenger with important functions during human physiology process. A long-lived luminescent iridium(III) complex probe 1 has been designed and synthesized for the monitoring of NO controllably released from sodium nitroprusside (SNP). Probe 1 displayed a 15-fold switch-on luminescence in the presence of SNP at 580 nm. The probe exhibited a linear response towards SNP between 5 to 25 μM with detection limit at 0.18 μM. Importantly, the luminescent switch-on detection of NO in HeLa cells was demonstrated. Overall, complex 1 has the potential to be applied for NO tracing in complicated cellular environment.

Highlights

Nitric oxide (NO) plays an irreplaceable role in multiple processes of various physiology and pathology pathways, such as regulating vasodilatation, relaxation and immunization response, as well as the cardiovascular, peripheral and central nervous systems[1,2,3,4,5,6,7]
A frequently-used moiety for trapping NO is the electron-rich o-diaminophenyl functionality, as it is an effective quencher of fluorescence via photoinduced electron transfer (PET)
High resolution mass spectrometry (HRMS) and 1H, 13C NMR spectroscopy were employed for the characterization of complex 1 (Fig. S2)

Summary

Introduction

Nitric oxide (NO) plays an irreplaceable role in multiple processes of various physiology and pathology pathways, such as regulating vasodilatation, relaxation and immunization response, as well as the cardiovascular, peripheral and central nervous systems[1,2,3,4,5,6,7]. A number of NO fluorescent organic probes have been developed for bioimaging[11,12,13], including a number of o-phenylenediamine-based probes by the group of Nagano (Table S1)[14,15,16]. The Lippard group has developed several Cu(II)-based NO probes[24,25,26] The mechanism of these Cu(II)-based probes relies on the generation of a diamagnetic Cu(I) species triggered by NO reduction, which abolishes the fluorescence quenching accompanied with the paramagnetic Cu(II) center. We envisioned that 1 could act as a NO probe through the reaction of the o-diamino groups with NO to form the triazole 2 This reaction would inhibit the PET quenching effect from the o-diamino groups, leading to an increased switch-on response in the presence of NO (Fig. 1)

Methods

Results

Conclusion