Responsive Fluorescence Probe for Selective and Sensitive Detection of Hypochlorous Acid in Live Cells and Animals

Abstract

The development of effective bioanalytical methods for rapid, sensitive and specific detection of HOCl in vitro and in vivo plays a key role for better understanding the roles of this molecule in normal and diseased conditions, but remains challenging due to the highly reactive nature of HOCl and the complicated biological conditions. In this work, a new fluorescence probe, PQI, was developed for monitoring of the HOCl level in biological samples. PQI was easily synthesized by a one-step condensation reaction. Upon addition of HOCl, significant changes in the absorption spectra and the color of the solution were noticed, facilitating the "naked eye" detection of HOCl in PBS buffer. The fluorescence of PQI was found to be significantly increased within a few seconds, leading to "OFF-ON" fluorescence response towards HOCl. The sensing mechanism, oxidation of thioether by HOCl, was confirmed by HRMS titration analysis. PQI features a large Stokes shift, high sensitivity and selectivity, and rapid fluorescence response towards HOCl. Quantitative detection of HOCl in single live cells was demonstrated through fluorescence imaging and flow cytometry analysis. PQI was then successfully used in visualisation of HOCl in live zebrafish and nude mice.

A Redox-Switchable Colorimetric Probe for “Naked-Eye” Detection of Hypochlorous Acid and Glutathione

“…1-Ethyl-2-methylquinolinium iodide was prepared according to our reported methods [48,49]. 2-Methylquinoline, iodoethane, 2-hydroxy-5-methoxy benzaldehyde were purchased from Aladdin reagent Co. (Shanghai, China).…”

Imaging of Hypochlorous Acid by Fluorescence and Applications in Biological Systems

“…The Zhang group in 2018 developed a probe for the selective detection of HOCl . The probe was synthesized by a “one‐step” condensation reaction; upon addition of HOCl, sulfur was oxidized to form sulfoxide and afforded an emission increase centered at 588 nm (Scheme ).…”

A Reaction‐Based Fluorescent Probe for Imaging of Native Hypochlorous Acid

“…[10][11][12][13][14] Synthetic small molecular fluorescent probesh ave been confirmed that were superior tools for trackingH OCl due to their high sensitivity,s electivity and easy manipulation. [15][16][17][18][19][20][21][22][23][24][25][26][27] Fluorescence imaging has been considered to be ah igh biocompatible imaging technique andh as been widely used ford etection of specific speciesa tt he cellular level for its noninvasive, realtime visualization, and high spatiala nd temporal resolution. [28][29][30][31][32][33] The conjunction of fluorescent probe and fluorescence imaging could provide us powerful tools for visualization of biologically relevant species.H ence, the fluorescent probesw ith high selectivity and sensitivity would able to trace the endogenousH OCl in living organisms.…”

“…Due to the highly reactive and short‐lived, dynamic monitoring of HOCl activity in living systems is requirement and that is the motivators for the development of novel methods for the detecting HOCl in various biological systems . Synthetic small molecular fluorescent probes have been confirmed that were superior tools for tracking HOCl due to their high sensitivity, selectivity and easy manipulation . Fluorescence imaging has been considered to be a high biocompatible imaging technique and has been widely used for detection of specific species at the cellular level for its noninvasive, real‐time visualization, and high spatial and temporal resolution .…”