Gold nanoparticle-paper as a three-dimensional surface enhanced Raman scattering substrate

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Paper's porous, 3D structure influences nanoparticle adsorption and aggregation.
• Controlling nanoparticle distribution is crucial for optimizing Surface-Enhanced Raman Scattering (SERS) properties.
• Gold nanoparticles (AuNPs) are effective for SERS signal amplification.

Purpose of the Study:

• Investigate the impact of AuNP concentration on paper's SERS signal amplification.
• Examine how the spatial distribution of AuNPs on different substrates affects SERS activity.
• Determine the potential of AuNP-functionalized paper as a low-cost, sensitive bioassay platform.

Main Methods:

• Depositing AuNPs onto paper substrates via dipping in solutions of varying concentrations.
• Evaluating SERS performance using 4-aminothiophenol (4-ATP) as a Raman probe.
• Comparing SERS signals from AuNPs on paper, silicon, and hydrophobized paper with constant nanoparticle numbers.

Main Results:

• AuNP surface coverage on paper scales linearly with solution concentration, maintaining aggregation levels.
• SERS intensity from AuNP-treated paper increases linearly with AuNP concentration.
• Paper substrates yield higher Raman enhancement factors (EF) than silicon due to more uniform AuNP adsorption.
• Constant AuNP droplet volume on paper results in the most reproducible and sensitive SERS signals, attributed to 3D multilayer distribution and plasmon coupling.

Conclusions:

• The 3D distribution and adsorption of AuNPs on paper significantly enhance SERS activity.
• Controlling AuNP distribution within the paper substrate is critical for optimizing SERS performance.
• AuNP-functionalized paper offers a promising, cost-effective platform for highly sensitive bioassays.