Lipids-Fluorophores Interactions Probed by Combined Nonlinear Polarized Microscopy.

Area of Science:

• Biophysics
• Membrane Biophysics
• Optical Microscopy

Background:

• Lipid membranes are crucial for cellular functions.
• Fluorescence imaging is widely used to study membrane properties.
• The impact of fluorescent probes on membrane structure is not well understood experimentally.

Purpose of the Study:

• To develop an optical microscopy method to investigate the influence of embedded fluorescent lipid probes on their surrounding lipid environment.
• To achieve a lateral resolution of a few hundred nanometers.

Main Methods:

• Development of a novel optical microscopy imaging method.
• Combination of polarized two-photon fluorescence microscopy to detect lipid probes.
• Utilized polarized coherent Raman scattering microscopy to analyze membrane lipids.
• Employed model probes TMA-DPH and di-8-ANEPPS in DPPC and DOPC lipid membranes.

Main Results:

• The developed method achieved a lateral resolution of a few hundred nanometers.
• Both TMA-DPH and di-8-ANEPPS probes induced orientational disorder in the CH-bonds of DPPC lipids.
• No significant effect on lipid CH-bonds was observed in more disordered DOPC lipid membranes.

Conclusions:

• Fluorescent lipid probes can perturb the structure of lipid membranes.
• The effect of probes depends on the lipid environment's order.
• This method provides a new way to study probe-induced effects in lipid membranes at the nanoscale.