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Synthesis, Assembly, and Characterization of Monolayer Protected Gold Nanoparticle Films for Protein Monolayer Electrochemistry
Published on: October 4, 2011
Layer-by-layer assembly of electro-active gold nanoparticle/cytochrome c multilayers.
Sebastian Markus Bonk1, Fred Lisdat
1Biosystems Technology, Wildau University of Applied Sciences, D-15745 Wildau, Bahnhofsstr. 1, Germany.
Biosensors & Bioelectronics
|September 15, 2009
Summary
Modified gold nanoparticles (GNPs) can be integrated into cytochrome c (CytC) multilayers, enabling electro-active assemblies. These assemblies, built using layer-by-layer deposition, show promising electrochemical properties for biosensor applications.
Area of Science:
- Nanotechnology
- Biochemistry
- Electrochemistry
Background:
- Cytochrome c (CytC) is a redox protein crucial for electron transport.
- Layer-by-layer (LbL) deposition is a versatile technique for creating multilayered nanostructures.
- Gold nanoparticles (GNPs) offer unique optical and electronic properties for biosensing.
Purpose of the Study:
- To investigate the incorporation of modified gold nanoparticles (GNPs) into cytochrome c (CytC) multilayer assemblies.
- To evaluate the electrochemical activity and properties of these novel multilayer structures.
- To explore the potential of GNP-CytC assemblies for biosensing applications.
Main Methods:
- Synthesis and modification of gold nanoparticles (GNPs) with mercaptopropionic acid (MPA).
- Characterization of GNPs using UV-Vis spectroscopy and transmission electron microscopy (TEM).
- Surface plasmon resonance (SPR) to study GNP binding kinetics to CytC layers.
- Fabrication of multilayer assemblies using LbL deposition on gold electrodes.
- Electrochemical measurements (cyclic voltammetry) to assess CytC electro-activity.
Main Results:
- MPA-modified GNPs exhibit efficient adsorption onto CytC layers with fast kinetics.
- CytC successfully binds to MPA-modified GNPs, forming stable assemblies.
- Polyelectrolytes in CytC multilayers can be replaced by small GNPs (5nm) or eliminated entirely.
- Fully electro-active CytC multilayers are achieved on gold electrodes, with a formal potential of -24+/-12mV vs. Ag/AgCl.
- Electrochemical response increases linearly with the number of layers, reaching 100 pmol/cm² CytC with 6 layers.
Conclusions:
- Modified GNPs are effective components for constructing electro-active CytC multilayer assemblies.
- LbL deposition allows for tunable fabrication of GNP-CytC nanostructures with controlled protein loading.
- These assemblies demonstrate significant potential for electrochemical biosensing and bioelectronic devices.
- The study provides insights into electron transfer mechanisms and particle size effects within these multilayer systems.
