Chitosan-Stabilized Noble Metal Nanoparticles: Study of their Shape Evolution and Post-Functionalization Properties

Area of Science:

• Materials Science
• Nanotechnology
• Plasmonics

Background:

• Noble metal anisotropic nanostructures are of significant interest due to their shape-dependent plasmonic properties.
• These properties are particularly relevant in the near-infrared region for various applications.

Purpose of the Study:

• To synthesize gold and gold-silver anisotropic nanostructures with high shape-yields.
• To investigate the role of chitosan in controlling nanoparticle morphology.
• To demonstrate the potential of these nanostructures in sensing and spectroscopic applications.

Main Methods:

• Seed-mediated wet synthesis using silver nanoparticles as seeds.
• Utilizing two types of chitosan with different properties as stabilizing agents.
• Post-functionalization with poly(10,12-pentacosadiynoic acid) (PCDA).

Main Results:

• Formation of homogeneous nanoplatelets (25-nm size, 7-nm thickness) or porous nanocages (50-nm size) depending on the chitosan used.
• Chitosan's molecular properties significantly influenced the resulting nanostructure shape.
• Synthesized nanostructures exhibited shape-dependent plasmonic features and tunable surface properties.

Conclusions:

• Chitosan plays a crucial role in directing the formation of anisotropic nanostructures.
• The synthesized gold and gold-silver nanostructures are versatile platforms for sensing and spectroscopy.
• Post-functionalization with PCDA yields chromic platforms suitable for diverse applications.