Related Experiment Video
Updated: Jan 8, 2026
10:34
FRET Microscopy for Real-time Monitoring of Signaling Events in Live Cells Using Unimolecular Biosensors
Published on: August 20, 2012
23.7K
Live-cell quantitative FRET imaging made simple by autocalibration in QuanTI-FRET.
Julien Leblanc1, Alain H Lombard1, Adrien Saumureau1
1Laboratoire Interdisciplinaire de Physique (LIPhy), Université Grenoble Alpes, CNRS, 38000, Grenoble, France.
The European Physical Journal. E, Soft Matter
|December 12, 2025
Summary
We simplified quantitative fluorescence resonance energy transfer (FRET) measurements in living cells. Our new autocalibration method eliminates the need for separate calibration experiments, making FRET analysis more accessible.
Area of Science:
- Cellular and Molecular Imaging
- Biophysics
- Biotechnology
Background:
- Genetically encoded biosensors utilizing fluorescence resonance energy transfer (FRET) enable real-time monitoring of cellular biochemical activity.
- Quantitative FRET analysis is crucial for reliable biological insights but is often hindered by complex calibration procedures and dependence on experimental setup.
- Previous methods like quantitative three-image FRET (QuanTI-FRET) provided absolute FRET probabilities but required additional experimental steps for calibration.
Purpose of the Study:
- To develop a simplified protocol for quantitative FRET measurements in living cells.
- To introduce an autocalibration method for FRET biosensors that directly uses experimental data.
- To enhance the accessibility and reproducibility of quantitative FRET analysis.
Main Methods:
- Leveraging the inherent constant stoichiometry of intramolecular FRET biosensors for direct system calibration.
- Implementing autocalibration within the QuanTI-FRET framework, utilizing the robustness of the calibration process.
- Validating the autocalibration method by comparing results with standard calibration using live-cell FAK biosensor images.
Main Results:
- Demonstrated successful direct calibration of FRET biosensors using only the experimental dataset of interest.
- Showcased the robustness of the QuanTI-FRET calibration, allowing for accurate autocalibration even with varying calibration dataset quality.
- Achieved quantitative FRET measurements with a simplified experimental workflow.
Conclusions:
- The proposed autocalibration method significantly simplifies the experimental protocol for quantitative FRET analysis in living cells.
- This approach enhances the accessibility of quantitative FRET by reducing experimental complexity and reliance on external calibration standards.
- Publicly available software and a napari plug-in are provided to facilitate the adoption of this simplified quantitative FRET protocol.
