Saturation-compensated measurements for fluorescence lifetime imaging microscopy.

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Physical Chemistry

Background:

• Fluorophore saturation is a primary limitation in fluorescence lifetime imaging microscopy (FLIM).
• High excitation powers in conventional frequency-domain FLIM lead to inaccurate lifetime measurements due to saturation.
• Expanding the excitation range and improving speed in FLIM are critical for advanced biological and materials science applications.

Purpose of the Study:

• To develop an analytical theoretical description of fluorophore saturation errors in FLIM.
• To present a novel method for compensating these saturation errors.
• To validate the compensation method through simulations and experimental data.

Main Methods:

• Developed an analytical theoretical model for fluorophore saturation in FLIM.
• Implemented algorithms for error compensation in frequency-domain FLIM.
• Conducted simulations to assess the method's performance.
• Performed experiments on existing FLIM setups to validate the approach.

Main Results:

• The theoretical model accurately describes fluorophore saturation effects.
• The compensation method successfully extracts correct lifetime measurements even at high excitation powers.
• Simulations demonstrated a 13.2× increase in the effective excitation range.
• Experiments confirmed a 2.6× increase in the excitation range.

Conclusions:

• The developed method effectively overcomes fluorophore saturation limitations in FLIM.
• This approach significantly enhances the excitation range and accuracy of FLIM measurements.
• The algorithms are readily implementable on existing FLIM instrumentation, offering broad applicability.