Three-dimensional fluorescence lifetime imaging of a molecular rotor at complex interfaces of grease
- 1Leica Microsystems K.K., 1-29-9 Takadanobaba, Shinjuku-ku, Tokyo, Japan
- 2Kyodo Yushi Co., Ltd., 2-2-30 Tsujido-kandai, Fujisawa, Kanagawa, Japan
- 3Tohoku University, 6-6-11 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi, Japan
Abstract
Fluorescence lifetime imaging microscopy (FLIM) maps local physicochemical properties on a confocal laser-scanning microscope. Soft materials are a promising target for FLIM, given their demand for multi-scale microanalysis; of particular interest are the interfacial properties of complex fluids, which remain underexplored. Here, we demonstrate three-dimensional FLIM mapping at complex interfaces of grease as a model system. In grease, tens-of-nanometer-scale thickener fibers form a three-dimensional network in the base oil, and the extent to which fiber–oil interactions alter the local oil properties is an open question. Our bulk measurements confirm that the fluorescence lifetime of a molecular-rotor dye dissolved in the oil is coupled to the local viscosity. Three-dimensional FLIM reveals that the lifetime of the molecular rotor significantly increases at the fiber–oil interfaces. Phasor analysis and pixel-level fitting show that the interfacial state arrests the rotation of the molecular rotor, so the interface is solid-like rather than viscous. Its physicochemical origin may offer a new handle for designing grease materials. Beyond the ~200 nm resolution of our images, the lifetime-domain separation of the two states resolves their coexistence within a single diffraction-limited voxel. Three-dimensional high-resolution FLIM will broaden the mapping of interfacial properties in soft complex materials.
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BibTeX
@misc{tsurusawa2026threedimensional,
title = {{Three-dimensional fluorescence lifetime imaging of a molecular rotor at complex interfaces of grease}},
author = {Hideyo Tsurusawa and Ryo Shibata and Masaki Watanabe and Minami Soma and Takashi Nogi},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009549/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009549/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Three-dimensional fluorescence lifetime imaging of a molecular rotor at complex interfaces of grease
AU - Hideyo Tsurusawa
AU - Ryo Shibata
AU - Masaki Watanabe
AU - Minami Soma
AU - Takashi Nogi
PY - 2026
DA - 2026/09/28
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009549/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009549/v1
AB - Fluorescence lifetime imaging microscopy (FLIM) maps local physicochemical properties on a confocal laser-scanning microscope. Soft materials are a promising target for FLIM, given their demand for multi-scale microanalysis; of particular interest are the interfacial properties of complex fluids, which remain underexplored. Here, we demonstrate three-dimensional FLIM mapping at complex interfaces of grease as a model system. In grease, tens-of-nanometer-scale thickener fibers form a three-dimensional network in the base oil, and the extent to which fiber–oil interactions alter the local oil properties is an open question. Our bulk measurements confirm that the fluorescence lifetime of a molecular-rotor dye dissolved in the oil is coupled to the local viscosity. Three-dimensional FLIM reveals that the lifetime of the molecular rotor significantly increases at the fiber–oil interfaces. Phasor analysis and pixel-level fitting show that the interfacial state arrests the rotation of the molecular rotor, so the interface is solid-like rather than viscous. Its physicochemical origin may offer a new handle for designing grease materials. Beyond the ~200 nm resolution of our images, the lifetime-domain separation of the two states resolves their coexistence within a single diffraction-limited voxel. Three-dimensional high-resolution FLIM will broaden the mapping of interfacial properties in soft complex materials.
ER -