Aggregation Control of Gold Nanoparticles and Surface-Enhanced Raman Scattering within Giant Unilamellar Vesicles

Area of Science:

• Nanotechnology
• Biophysics
• Analytical Chemistry

Background:

• Giant unilamellar vesicles (GUVs) are crucial models for cell membranes.
• Detecting trace molecules within GUVs is challenging.
• Surface-enhanced Raman scattering (SERS) offers high sensitivity for molecular detection.

Purpose of the Study:

• To investigate the use of SERS for detecting trace molecules within GUVs.
• To explore the role of gold nanoparticle aggregation in SERS signal enhancement.
• To develop a GUV-based biosensor for sensitive molecular detection.

Main Methods:

• Encapsulation of gold nanoparticle aggregates and bipyridine within GUVs.
• Incorporation of gramicidin into the GUV membrane to facilitate ion transport.
• Monitoring Raman spectra changes induced by gold nanoparticle aggregation.
• Utilizing Na+ ion influx to trigger gold nanoparticle aggregation.

Main Results:

• SERS signal enhancement was observed only after gold nanoparticle aggregation within GUVs.
• Gramicidin-mediated cation permeation regulated gold nanoparticle aggregation.
• The aggregation of gold nanoparticles amplified the Raman spectrum of bipyridine.
• GUVs with aggregated gold nanoparticles showed enhanced Raman signals.

Conclusions:

• Gold nanoparticle aggregation within GUVs significantly enhances SERS signals.
• Gramicidin acts as a regulator for nanoparticle aggregation via ion flux.
• This GUV-based system shows potential as a novel biosensor for intracellular trace molecule detection.