Boosting sensitivity in electrochemically driven bilayered plasmonic platforms for optical redox detection.

Area of Science:

• Electrochemistry
• Surface Plasmon Resonance (SPR)
• Biomolecular Assemblies

Background:

• Conventional SPR struggles with weak optical signals from low-concentration redox processes.
• Detecting redox changes in molecular assemblies requires enhanced sensitivity and robustness.

Purpose of the Study:

• To develop an electrochemical SPR technique for improved detection of redox processes.
• To optimize SPR signal readout for low-concentration biomolecular assemblies.

Main Methods:

• Combined cyclic voltammetry with wavelength/angle-tuned SPR.
• Utilized a silver/gold bilayer electrode for enhanced signal.
• Employed cytochrome c as a model redox probe.
• Performed polarized angular reflectance and transfer-matrix calculations.

Main Results:

• Optimized SPR detection sensitivity by tuning excitation wavelength and refractive index.
• Identified optimal detection within the SPR response linear region and at the redox probe's absorption band.
• Achieved accurate, wavelength-dependent optical constants (552-785 nm).

Conclusions:

• The developed electrochemical SPR method enables highly sensitive detection of biomolecular assemblies.
• Facilitates real-time probing of interfacial redox processes with enhanced sensitivity and electrochemical robustness.