Related Experiment Video
Updated: Jul 16, 2026
14:12
Dual-Color Fluorescence Cross-Correlation Spectroscopy to Study Protein-Protein Interaction and Protein Dynamics in Live Cells
Published on: December 11, 2021
Dye-exchange dynamics in micellar solutions studied by fluorescence correlation spectroscopy
Mercedes Novo1, Suren Felekyan, Claus A M Seidel
1Departamento de Química Física, Facultade de Ciencias, Universidade de Santiago de Compostela, E-27002 Lugo, Spain. mnovo@lugo.usc.es
The Journal of Physical Chemistry. B
|March 29, 2007
Summary
Rhodamine 123 (R123) dye quickly exchanges between aqueous solutions and micelles, acting as soft supramolecular cages. This dye-micelle interaction is diffusion-controlled, with binding stability depending on the surfactant type.
Area of Science:
- Supramolecular Chemistry
- Physical Chemistry
- Biophysical Chemistry
Background:
- Membrane mimetic systems are crucial for understanding biological processes.
- Rhodamine 123 (R123) is a fluorescent dye used to probe mitochondrial function.
- Micelles serve as model systems for cell membranes.
Purpose of the Study:
- To investigate the dye-exchange dynamics of R123 with neutral micelles.
- To characterize the photophysical properties of R123 bound to micelles.
- To compare micellar behavior to other supramolecular cavities.
Main Methods:
- Fluorescence Correlation Spectroscopy (FCS) for single-molecule dynamics.
- Single-molecule multiparameter fluorescence detection (MFD) for fluorescence properties.
- Utilizing Triton X-100 and Brij 35 as neutral micelle systems.
Main Results:
- R123 partitions into micelles, causing spectral red shifts.
- Dye entry into micelles is diffusion-controlled.
- Micelles act as soft supramolecular cages, unlike rigid cyclodextrins.
Conclusions:
- Micelles exhibit fast dye-exchange dynamics.
- Dye-micelle binding stability is surfactant-dependent.
- FCS and MFD provide complementary single-molecule insights into these systems.
