Ag supraparticles with 3D hot spots to actively capture molecules for sensitive detection by surface enhanced Raman...

Area of Science:

• Materials Science
• Spectroscopy
• Nanotechnology

Background:

• Surface-enhanced Raman spectroscopy (SERS) requires substrates with high hot spot density for sensitive detection.
• Steric hindrance from surfactants and ligands can limit target molecule access to hot spots on SERS substrates.

Purpose of the Study:

• To fabricate non-close-packed 3D supraparticles that actively capture molecules for enhanced SERS detection.
• To overcome limitations of steric hindrance in traditional SERS substrate designs.

Main Methods:

• Fabrication of non-close-packed 3D supraparticles through droplet contraction and free energy minimization.
• Utilizing capillary forces within supraparticle capillaries to drive target molecule entry into hot spots.
• Evaluating SERS enhancement of 3D supraparticles with various target molecules, including antimicrobial agents and drugs.

Main Results:

• 3D supraparticles exhibit high-density hot spots and actively capture target molecules.
• Capillary action within the non-close-packed structure facilitates molecule entry into hot spots.
• SERS enhancement of 3D supraparticles is over an order of magnitude greater than multi-layered nanoparticle structures.
• Demonstrated SERS performance with diverse analytes, including drugs and antimicrobial agents.

Conclusions:

• Non-close-packed 3D supraparticles offer a promising strategy for sensitive SERS detection.
• The capillary-induced molecule capture mechanism enhances SERS performance.
• This approach provides a novel method for preparing advanced SERS substrates.