Superchiral Plasmonic Phase Sensitivity for Fingerprinting of Protein Interface Structure

Area of Science:

• Plasmonics
• Biophysics
• Nanotechnology
• Spectroscopy

Background:

• The structure of biomaterials, particularly proteins, at interfaces is critical for biological processes like cell membrane function, biofilm formation, and enzyme biocatalysis.
• Conventional spectroscopic methods lack the sensitivity to analyze the small quantities of biomaterials present at interfaces.
• Understanding interfacial biomolecular structure is vital for addressing challenges such as antibiotic resistance and optimizing biotechnological applications.

Purpose of the Study:

• To develop a highly sensitive method for analyzing the structure of biomolecules at interfaces.
• To overcome the limitations of conventional spectroscopic techniques in studying interfacial biomaterials.
• To demonstrate a novel bioanalytical tool for discriminating between structurally similar proteins based on their interfacial geometry.

Main Methods:

• Utilizing the interaction of proteins with superchiral fields generated by chiral plasmonic nanostructures.
• Inducing asymmetric changes in retardation phase effects of excited bright and dark modes within the nanostructure.
• Analyzing phase retardations by fitting resonance line shapes in reflectance spectra to obtain structural fingerprints.

Main Results:

• The interaction with superchiral fields generates unique interference effects, serving as incisive probes of interfacial biomolecular structure.
• Phase retardations derived from reflectance spectra provide sensitive 'fingerprints' of biomolecular conformation at interfaces.
• The method successfully discriminated between layers of structurally related proteins exhibiting different geometries.

Conclusions:

• A powerful new tool has been demonstrated for the bioanalytical toolbox, enabling sensitive analysis of interfacial biomolecular structure.
• The developed technique overcomes sensitivity limitations of conventional methods for studying biomaterials at interfaces.
• This approach holds significant potential for applications in diagnostics, drug discovery, and understanding biological interfaces.