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Updated: Apr 17, 2026
Fluorescence Lifetime Imaging of Molecular Rotors in Living Cells
Published on: February 9, 2012
Mapping live cell viscosity with an aggregation-induced emission fluorogen by means of two-photon fluorescence
Sijie Chen1, Yuning Hong, Yan Zeng
1Division of Biomedical Engineering, Department of Chemistry, Institute for Advanced Study, Division of Life Science, State Key Laboratory of Molecular Neuroscience, Institute of Molecular Functional Materials, Hong Kong University of Science & Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong (China).
Abstract:
Intracellular viscosity is a crucial parameter that indicates the functioning of cells. In this work, we demonstrate the utility of TPE-Cy, a cell-permeable dye with aggregation-induced emission (AIE) property, in mapping the viscosity inside live cells. Owing to the AIE characteristics, both the fluorescence intensity and lifetime of this dye are increased along with an increase in viscosity. Fluorescence lifetime imaging of live cells stained with TPE-Cy reveals that the lifetime in lipid droplets is much shorter than that from the general cytoplasmic region. The loose packing of the lipids in a lipid droplet results in low viscosity and thus shorter lifetime of TPE-Cy in this region. It demonstrates that the AIE dye could provide good resolution in intracellular viscosity sensing. This is also the first work in which AIE molecules are applied in fluorescence lifetime imaging and intracellular viscosity sensing.
