Confocal-based fluorescence fluctuation spectroscopy with a SPAD array detector

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Confocal laser-scanning microscopy (CLSM) coupled with fluorescence fluctuation spectroscopy (FFS) is vital for analyzing rapid, sub-resolution biomolecular dynamics in live cells.
• Existing detector arrays for CLSM-based FFS require complex data corrections and limit integration with single-photon methods like fluorescence lifetime imaging.

Purpose of the Study:

• To overcome limitations of current detector arrays in CLSM-FFS systems.
• To introduce a novel single-photon-avalanche-diode (SPAD) array detector for enhanced CLSM-FFS analysis.
• To enable simultaneous spatial and temporal data acquisition for biomolecular studies.

Main Methods:

• Integration of a novel single-photon-avalanche-diode (SPAD) array detector into a CLSM system.
• Validation using multiple FFS techniques: spot-variation fluorescence correlation spectroscopy, pair-correlation function analysis, and image-derived mean squared displacement analysis.
• Demonstration of simultaneous acquisition of multiple samples within the CLSM detection volume.

Main Results:

• The novel SPAD array detector successfully overcomes previous limitations in CLSM-FFS.
• The system allows for simplified data correction and seamless integration with single-photon techniques.
• Validated FFS analyses confirm the detector's capability for precise biomolecular process studies.

Conclusions:

• The developed CLSM system with a SPAD array detector offers a powerful and versatile tool for studying fast, sub-resolution biomolecular processes.
• This architecture provides a unique combination of spatial and temporal information, making it ideal for advanced live-cell imaging.
• The proposed method is poised to become a preferred technique for CLSM-based FFS applications.