pH-controlled reversible assembly of peptide-functionalized gold nanoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Biochemistry

Background:

• Gold nanoparticles (GNPs) are widely used in various applications.
• Peptide functionalization offers unique properties to nanoparticles.
• Understanding nanoparticle assembly is crucial for controlling their behavior.

Purpose of the Study:

• To investigate the pH-dependent assembly and disassembly of carboxylated peptide-functionalized gold nanoparticles (peptide-GNPs).
• To determine the optimal pH conditions for controlled nanoparticle assembly.
• To elucidate the mechanism driving the assembly process.

Main Methods:

• UV-vis spectroscopy for monitoring assembly/disassembly.
• Transmission Electron Microscopy (TEM) for structural analysis.
• Fourier-Transform Infrared (FTIR) spectroscopy for confirming intermolecular interactions.

Main Results:

• Uncontrolled 3D assembly at pH 2.5.
• Controlled 1D chain formation at pH 4.
• Mixed 1D and 2D nanostructures between pH 2.5 and 4.
• Reversible disassembly at pH 10.
• Assembly driven by intermolecular H-bonding between peptide carboxyl groups.

Conclusions:

• The pH significantly influences the assembly and disassembly of peptide-GNPs.
• Controlled 1D nanostructures can be formed at specific pH values.
• Intermolecular hydrogen bonding is the primary mechanism for peptide-GNP assembly.