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Updated: Jun 12, 2026
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Tracking Electrochemistry on Single Nanoparticles with Surface-Enhanced Raman Scattering Spectroscopy and Microscopy
Published on: May 12, 2023
Multi-layer electron transfer across nanostructured Ag-SAM-Au-SAM junctions probed by surface enhanced Raman
Murat Sezer1, Jiu-Ju Feng, H Khoa Ly
1Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin, Germany.
Physical Chemistry Chemical Physics : PCCP
|June 15, 2010
Summary
A new layered gold-silver electrode enables studying protein electron transfer using surface-enhanced resonance Raman spectroscopy (SERRS). Covalent attachment of cytochrome c enhanced SERRS signals, while electrostatic attachment maintained protein integrity and showed efficient electron transfer.
Area of Science:
- Electrochemistry
- Spectroscopy
- Biomaterials
Background:
- Studying interfacial electron transfer is crucial for understanding biological processes.
- Developing advanced electrode materials is key to improving spectroscopic analysis of biomolecules.
- Surface-enhanced resonance Raman spectroscopy (SERRS) offers high sensitivity for molecular detection.
Purpose of the Study:
- To develop and characterize a novel layered gold-silver (Au-Ag) electrode for studying interfacial electron transfer.
- To investigate the performance of the Au-Ag electrode for analyzing redox-active proteins using SERRS.
- To compare protein immobilization strategies (electrostatic vs. covalent) and their impact on electron transfer and SERRS signals.
Main Methods:
- Fabrication of a nanostructured silver (Ag) support coated with a gold (Au) film separated by a self-assembled monolayer (SAM).
- Utilizing stationary and time-resolved SERRS spectroscopy to analyze interfacial electron transfer.
- Employing the heme protein cytochrome c (Cyt-c) as a benchmark for electrode performance evaluation.
Main Results:
- The layered Au-Ag electrode demonstrated effective SERRS signal enhancement for cytochrome c.
- Covalent attachment of Cyt-c to the Au surface yielded a 25-fold increase in SERRS intensity compared to electrostatic attachment.
- Electrostatic immobilization preserved the native state of Cyt-c and exhibited near-ideal Nernstian electron transfer kinetics.
- Covalent attachment led to altered redox transitions and partial protein denaturation.
Conclusions:
- The developed layered Au-Ag electrode is a promising platform for sensitive interfacial electron transfer studies of proteins.
- Immobilization strategy significantly impacts protein behavior, redox activity, and spectroscopic signal.
- Long-distance electron transfer through the multilayer is feasible, with SAMs acting as potential rate-limiting barriers.
