Gold Superparticles Functionalized with Azobenzene Derivatives: SERS Nanotags with Strong Signals

Area of Science:

• Nanotechnology
• Spectroscopy
• Biochemistry

Background:

• Surface-enhanced Raman spectroscopy (SERS) nanotags are alternatives to fluorescent dyes for biosensing.
• Previous SERS nanotags suffered from weak signals and poor reproducibility, limiting their use.

Purpose of the Study:

• To develop highly sensitive and reproducible SERS nanotags.
• To overcome limitations of existing SERS nanotags for improved imaging and biosensing.

Main Methods:

• Fabrication of gold superparticles (AuSPs) through one-pot formation and self-assembly of gold nanoparticles (Au NPs).
• Synthesis of an azobenzene-carrying Raman reporter with a large Raman cross-section and multiple bands.
• Self-assembly of the Raman reporter onto AuSPs to create SERS nanotags.

Main Results:

• The synthesized AuSPs provided high SERS enhancement.
• The self-assembled nanotags exhibited intense signals due to the reporter's properties.
• A specific SERS nanotag with boronic acid and azobenzene groups showed six distinct bands.
• The nanotag demonstrated high sensitivity for glycoprotein detection via aggregation-induced enhancement.
• The nanotag served as an effective antibody substitute in glycoprotein immunoassay.

Conclusions:

• The novel strategy successfully created SERS nanotags with intense signals and high reproducibility.
• These SERS nanotags show significant potential for sensitive glycoprotein detection and immunoassays.
• The developed nanotags offer a promising alternative to traditional fluorescent probes.