Rational Design of Near-Infrared Fluorescent Probes for Accurately Tracking Lysosomal Viscosity with Allyl Snchoring Si-Rhodamine

Abstract

The abnormal microenvironment parameter, viscosity, is closely connected with various diffusion processes, signal transduction, molecule interactions, and various diseases. It is greatly significant to design viscosity-dependent near-infrared (NIR) small molecule fluorescence probes for visualizing biological processes or diagnosing diseases. Herein, through the stepwise modulating structure of the silicon−rhodamine fluorophore (SR), we report three viscosity probes with allyl or methyl group as rotors, named SR-T-Al, SR-S-Al, and SR-T-Me. Among them, SR-T-Al demonstrates better viscosity responsibility from 1.0 to 1410.4 cP of viscosity. Therefore, the probe of SR-T-Al is successfully applied to sensitively monitor lysosome microscopic viscosity changes of living cells induced by oxygen stress. What's more, based on its advantages in NIR emission (669 nm) and large Stokes shift (201 nm), we also use it to image variations of viscosity in an acute hepatitis mouse induced by carbon tetrachloride. Both time and concentration-dependent induction models display the great ability of SR-T-Al to detect viscosity alteration. All the experimental results indicated that this allyl-rotor-based NIR viscosity probe could provide a general platform to monitor abnormal physiological processes and diseases relating to viscosity.

Dual Enzyme-Locked Activation Reporter for Accurate Liver Cancer Surveillance

“…After the above preliminary cell imaging experiments, we have determined the dual-locked response of Si-NTR-LAP to NTR and LAP. Based on this, we further tested whether the probe was able to distinguish cancer cells from normal cells at the cellular level and whether the imaging signal-to-background ratio of the double-locked probe was better than that of the single-locked probe. − The screened hepatocellular carcinoma cells, HepG2, and normal liver cells, HL-7702, were used in the experiments. In order to assist in determining the reliability of the probes in recognizing normal cells and cancer cells, we used HL-7702 cells stably expressing the green fluorescent protein so that the cells would be easily distinguished by their own green fluorescent labels.…”

Mechanistic analysis of viscosity-sensitive fluorescent probes for applications in diabetes detection

“…13). 99 They synthesized three probes by varying the amount of alkylation at the nitrogen atom at the third position of rhodamine. Among these, the di-allyl substituted probe showed the most significant electron donating ability and was chosen for further study.…”

Near-Infrared Fluorescent Probe with pH- and Viscosity-Switchable Performance for the Detection of Thrombi in Live Animals and Organs

“…The absorption and emission spectra of classical rhodamine derivatives are below 600 nm, which hinder their application in live animal imaging. − As known, the emission wavelength of chromophores can be red-shifted by extending the conjugated π-bonds. The original molecular structure of rhodamine is stable enough with a high fluorescence quantum yield.…”