Atom-scale depth localization of biologically important chemical elements in molecular layers

Area of Science:

• Soft Matter Physics
• Biophysics
• Materials Science

Background:

• Biomolecules form functional thin layers in biological membranes and biotechnological interfaces.
• Understanding the structure of these biomolecular layers is crucial for biological and biotechnological applications.
• Current methods often require artificial heavy atom labels, limiting broader applications.

Purpose of the Study:

• To develop a label-free method for high-resolution structural investigation of biomolecular layers.
• To localize light chemical elements (sulfur and phosphorus) within these layers with near-Ångstrom precision.

Main Methods:

• Utilized standing-wave X-ray fluorescence (SWXF) for elemental localization.
• Applied SWXF to solid-supported lipid and protein layers.
• Demonstrated precise localization of light elements (S and P) without heavy atom labels.

Main Results:

• Achieved near-Ångstrom precision in localizing chemical elements within biomolecular layers.
• Successfully determined the positions of sulfur and phosphorus, key elements in abundant biomolecules.
• Overcame the limitation of requiring artificial heavy atom labels for high-resolution SWXF.

Conclusions:

• SWXF enables label-free, element-specific structural analysis of complex biomolecular layers.
• This technique provides a powerful tool for investigating biological surfaces and soft matter.
• Advances the understanding of interfacial architectures in biological and biotechnological systems.