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Dual-Color Fluorescence Cross-Correlation Spectroscopy to Study Protein-Protein Interaction and Protein Dynamics in Live Cells

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Published on: December 11, 2021

Inverse-fluorescence correlation spectroscopy.

Stefan Wennmalm¹, Per Thyberg, Lei Xu

¹Department of Applied Physics, Experimental Biomolecular Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden. stewen@kth.se

Analytical Chemistry

|October 29, 2009

Summary

This study introduces a novel fluorescence correlation spectroscopy method analyzing surrounding medium signals, enabling unlabeled particle and biomolecule analysis. Experiments with polystyrene beads demonstrate its potential for detecting smaller entities.

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Area of Science:

Biophysics
Spectroscopy
Nanotechnology

Background:

Fluorescence Correlation Spectroscopy (FCS) traditionally analyzes signals from labeled particles.
Analyzing unlabeled particles or biomolecules using FCS remains a challenge.

Purpose of the Study:

To present an alternative fluorescence correlation spectroscopy (FCS) approach.
To enable the analysis of unlabeled particles and potentially biomolecules.

Main Methods:

Developed an alternative FCS technique analyzing the signal from the medium surrounding particles.
Conducted experiments using polystyrene beads (100-800 nm) in an aqueous solution with Alexa 488 fluorophores.

Main Results:

Demonstrated the feasibility of analyzing unlabeled particles via their surrounding medium's fluorescence signal.
The method shows promise for detecting smaller particles and biomolecules with optimized detectors or reduced volumes.

Conclusions:

The presented alternative FCS method offers a new pathway for analyzing unlabeled samples.
Further advancements in photodetectors and detection volumes could extend this technique to biomolecular analysis.