Detecting order and lateral pressure at biomimetic interfaces using a mechanosensitive second-harmonic-generation...

Area of Science:

• Chemical Physics
• Materials Science
• Biophysics

Background:

• Molecular probes with mechanosensitive properties offer new ways to study interfaces.
• Understanding molecular behavior at biomimetic interfaces is crucial for various applications.

Purpose of the Study:

• To investigate a planarizable push-pull molecular probe at phospholipid interfaces.
• To explore the probe's response to varying surface pressure and order using surface-specific nonlinear optics.

Main Methods:

• Utilized surface-second-harmonic-generation (SSHG) spectroscopy.
• Employed quantum-chemical calculations for theoretical support.
• Conducted polarization-resolved and time-resolved SSHG measurements.

Main Results:

• Observed a significant spectral shift of the probe at liquid-ordered interfaces, dependent on surface pressure.
• Quantum-chemical calculations attributed the shift to probe planarization.
• Found probe orientation to be highly sensitive to lateral pressure and interface order.
• Noted slower probe dynamics within the more constrained phospholipid monolayer.

Conclusions:

• The study successfully demonstrates the utility of mechanosensitive probes combined with SSHG for interface analysis.
• Probe planarization and orientation are key indicators of mechanical stress at biomimetic interfaces.
• This approach offers a powerful tool for probing interfacial phenomena in complex systems.