Amine-Conjugated FRET Coumarin-Cyanine Ratiometric Probes for Sensitive Viscosity and HSA Imaging in Live Cells and Tissues

Authors

Mohamed Mahmoud, Michigan Technological UniversityFollow
Mahmood Norouzi, Michigan Technological UniversityFollow
Adonis Amoli, Michigan Technological UniversityFollow
Sheng Su, Carnegie Mellon University
Christina You, Michigan Technological University
Yan Zhang, Michigan Technological UniversityFollow
Isabelle Knighton, Michigan Technological UniversityFollow
Athar Ata, Michigan Technological UniversityFollow
Thomas Werner, Michigan Technological UniversityFollow
Haiying Liu, Michigan Technological UniversityFollow

Document Type

Data

Publication Date

3-27-2026

Abstract

We designed and synthesized two novel ratiometric near-infrared fluorescent probes, probe A and probe B, tailored for sensitive detection of intracellular viscosity and human serum albumin (HSA) dynamics. Probe A integrates a coumarin donor with a cyanine acceptor to enable ratiometric fluorescence changes upon HSA binding, exhibiting increased visible emission and decreased near-infrared fluorescence. Probe B is engineered with a hemicyanine scaffold that responds to viscosity changes by enhancing visible fluorescence and moderately increasing near-infrared emission, allowing precise ratiometric sensing of microenvironmental viscosity. Both probes show excellent selectivity against biologically relevant amino acids, metal ions, and anions, and exhibit high photostability with less than 3% fluorescence ratio decrease over two hours of continuous excitation. Cytotoxicity assays confirmed low toxicity, with HeLa cell viability remaining above 85% after 48 hours at concentrations up to 40 μM, supporting their application for long-term live-cell imaging. Using confocal microscopy, probe B sensitively detected intracellular viscosity increases induced by Monensin, Lipopolysaccharide, and Nystatin treatments in HeLa cells, with ratiometric fluorescence changes correlating with viscosity elevations. Co-localization with mitochondrial dye IR-780 confirmed mitochondrial targeting (Pearson’s coefficient 0.939). Probe B also effectively reported viscosity changes in vivo in Drosophila melanogaster larvae under similar stress conditions. Probe A enabled quantitative ratiometric imaging of HSA dynamics in live cells, with fluorescence changes strongly correlated to albumin concentration. Application of probe A to kidney tissue sections from normal and polycystic kidney disease models revealed significantly elevated fluorescence in diseased tissues, indicating increased intracellular viscosity linked to pathological remodeling.

Recommended Citation

Mahmoud, M., Norouzi, M., Amoli, A., Su, S., You, C., Zhang, Y., Knighton, I., Ata, A., Werner, T., & Liu, H. (2026). Amine-Conjugated FRET Coumarin-Cyanine Ratiometric Probes for Sensitive Viscosity and HSA Imaging in Live Cells and Tissues.
Retrieved from: https://digitalcommons.mtu.edu/all-datasets/73