White-Fluorescent Dual-Emission Mechanosensitive Membrane Probes that Function by Bending Rather than Twisting

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biophysics

Background:

• Mechanosensitive probes are crucial for understanding membrane dynamics.
• Existing probes often rely on twisting mechanisms.
• A novel unbending mechanism offers new possibilities for probe design.

Purpose of the Study:

• Introduce novel bent N,N -diphenyl-dihydrodibenzo[a,c]phenazine amphiphiles as mechanosensitive probes.
• Investigate their unique excited-state unbending mechanism.
• Demonstrate their utility in discriminating membrane environments and imaging.

Main Methods:

• Synthesis and characterization of novel amphiphiles.
• Spectroscopic analysis of dual emission properties.
• Confocal and two-photon excitation fluorescence (TPEF) microscopy of vesicles.

Main Results:

• The probes exhibit dual emission from bent and planarized excited states.
• This dual emission effectively differentiates between micelles, monomers, and various membrane phases (S_o, L_d).
• Vesicles engineered with these probes emit white light, encoding ratiometric information.

Conclusions:

• Bent amphiphiles operate via an unprecedented excited-state unbending mechanism.
• These probes offer a versatile platform for sensing membrane states.
• The technology enables advanced imaging of membrane domains in giant unilamellar vesicles.