Versatile Ratiometric Fluorescent Probe Based on the Two-Isophorone Fluorophore for Sensing Nitroxyl

Abstract

Nitroxyl (HNO) is closely linked with numerous biological processes. Fluorescent probes provide a visual tool for determining HNO. Due to fluorescence quenching by HNO-responsive recognition groups, most of the current fluorescent probes exhibit an “off-on” fluorescence response. As such, the single fluorescence signal of these probes is easily affected by external factors such as the microenvironment, sensor concentration, and photobleaching. Herein, we have developed a ratiometric fluorescent probe (CHT-P) based on our previously developed two-isophorone fluorophore. CHT-P could be used to determine HNO through ratiometric signal readouts with high selectivity and sensitivity, ensuring the accurate quantitative detection of HNO. Additionally, the probe exhibited low cytotoxicity, was cell permeable, and could be used for ratiometric imaging of HNO in cells. Finally, CHT-P-coated portable test strips were used to determine HNO using the solid-state fluorescence signal readout.

Reusable HNO Sensors Derived from Cu Cyclam: A DFT Study on the Mechanistic Origin of High Reactivity and Favorable Conformation Changes and Potential Improvements

“…Conventional HNO detection methods use analytic instruments to quantify products of HNO dimerization/dehydration or reactions with thiols, phosphine, and heme proteins. − However, most of them are indirect, time-consuming, and relatively unreliable. To overcome the limitations, direct HNO detection methods based on mass spectrometry and electrochemistry were developed. − For detections inside living cells, in vivo HNO sensors are accessible with bioimaging functions using metal complexes, − phosphines, − thiols, , or esters …”

A novel isophorone-based fluorescent probe for recognizing Al3+ and its bioimaging in plants

“…26 Therefore, it is crucial to develop novel uorescent probes for the detection of Al 3+ to overcome these drawbacks. In recent years, isophorone dyes have been used to construct uorescent probes [27][28][29] and electroluminescent (EL) materials 30 due to their ultrafast intramolecular charge transfer (ICT) 31 and large Stokes shis 32 generated by the electron donor-p-acceptor molecular structure. 27,29 However, few studies have been reported on the structure of isophoronebased Al 3+ uorescent probes.…”

“…Compared with other reported uorescent probes, 20,23,33 the malononitrile-isophorone uorescent probe was used in this study because of its relatively simple synthesis process and similar uorescence properties, which is favourable for wide application. [27][28][29] The dicyanoisophorone derivatives themselves have excellent near-infrared uorescence emission properties. 34 Upon addition of Al 3+ , the probe YT-Al complexes with it, leading to a decrease in the electron absorption capacity of the carbonyl group (C]O), which enhances the ICT effect 31 of the probe molecule and red-shis the uorescence spectrum.…”