Biomolecule induced nanoparticle aggregation: effect of particle size on interparticle coupling

Area of Science:

• Nanotechnology
• Materials Science
• Biochemistry

Background:

• Gold nanoparticles exhibit unique optical properties due to surface plasmon resonance.
• Biomolecule interactions can induce aggregation and alter nanoparticle optical characteristics.
• Understanding these changes is crucial for developing sensitive detection methods.

Purpose of the Study:

• To investigate the aggregation behavior of gold nanoparticles with glutathione.
• To study the impact of nanoparticle size on aggregation and optical properties.
• To explore the potential of gold nanoparticles for sensitive glutathione detection.

Main Methods:

• Preparation of gold nanoparticles using Frens' method.
• Induction of nanoparticle aggregation with glutathione under varying pH conditions.
• Characterization using UV-vis spectroscopy, FTIR, Raman, XRD, and TEM.
• Analysis of optical properties using Maxwell-Garnett effective medium theory.

Main Results:

• Gold nanoparticles form well-ordered aggregates with glutathione.
• Aggregation leads to significant changes in optical properties, including new peaks at longer wavelengths.
• The intensity and shift of these peaks depend on nanoparticle size, glutathione concentration, and pH.
• Larger gold nanoparticles demonstrate higher sensitivity for glutathione detection.

Conclusions:

• Gold nanoparticle aggregation with glutathione is size-dependent and pH-sensitive.
• Optical property changes provide a basis for sensitive glutathione detection.
• Larger gold nanoparticles offer enhanced sensitivity for detecting glutathione.