A New Ratiometric Design Strategy Based on Modulation of π-Conjugation Unit for Developing Fluorescent Probe and Imaging of Cellular Peroxynitrite

Abstract

Ratiometric fluorescent probes could effectively offset the changes of the autofluorescence and compartmental localization. FRET, ICT, etc. are the common strategies to design probes for biosensing, but these strategies have some deficiencies. Here, we proposed a new design strategy based on π-conjugation modulation, giving two different emission bands in the absence and presence of the target. The new fluorescence probe named Rhod-DCM-B was rationally designed and synthesized, which displayed a fluorescence emission peak at 670 nm because the electron cloud focuses on the conjugated DCM unit. With the addition of ONOO − , the fluorescence emission at 570 nm increased, accompanied by the decrease of fluorescence emission at 670 nm, showing a ratiometric signal change attributed to the opened spirane structure making the electron cloud concentrated on the xanthene core. The mechanism is well confirmed by MS and DFT calculations. Rhod-DCM-B exhibited outstanding sensitivity and excellent selectivity toward ONOO − . Moreover, Rhod-DCM-B was effectively employed to determine endogenous and exogenous ONOO − in living cells. As a marker for inflammation and drug-induced liver injury (DILI) process, ONOO − in vivo was successfully monitored by Rhod-DCM-B and presented a dramatic ratiometric response.

FRET Luminescent Probe for the Ratiometric Imaging of Peroxynitrite in Rat Brain Models of Epilepsy-Based on Organic Dye-Conjugated Iridium(III) Complex

“…Given the estimated concentration of ONOO − in the normal brain to be approximately 300 nM, these results highlight the considerable potential of the Ir-CBM probe for detecting ONOO − in the brains of epileptic rats. 4,5 Regarding the extremely short lifetime of ONOO − (half-life < 1 s), 6,27,52 the development of luminescent probes for quick response to ONOO − is more favorable. Subsequently, the changes of red emission at 633 nm of the probe reacted with ONOO − were recorded (Figure 1C).…”

Fluorescent dyes based on rhodamine derivatives for bioimaging and therapeutics: recent progress, challenges, and prospects

“…39). 283 Rhod-DCM-B produced a fluorescence intensity peak at 670 nm owing to the concentration of the electron cloud on the conjugated DCM group. In the presence of ONOO − , a new fluorescence peak appeared at 570 nm and the fluorescent intensity increased, whereas light emission intensity at 670 nm decreased, showing a ratiometric signal shift that may be ascribed to the expanded spirane frame, which resulted in the concentration of the electron cloud on the xanthene core.…”

Vision for Ratiometric Nanoprobes: In Vivo Noninvasive Visualization and Readout of Physiological Hallmarks

“…, 1000–1700 nm) region transmitted within human tissues encounter minimized scattering and absorption . Therefore, although developing NIR-I emissive optical- and photoacoustic-based RNPs is still actively ongoing, ,,− constructing NIR-II sensors is more favorable for high-performance in vivo imaging from deep-seated organs.…”