Interface-Engineered Janus Au@CeO₂ Nanostructures for Ultrasensitive Ratiometric SERS Platforms.

Area of Science:

• Nanotechnology
• Materials Science
• Analytical Chemistry

Background:

• Monolayer noble metal nanoparticle (NP) arrays are promising for surface-enhanced Raman scattering (SERS) substrates.
• Controlling hotspot intensity and density is crucial for practical SERS applications.

Purpose of the Study:

• To develop a SERS substrate with precisely regulated hotspots using Janus-structure NPs.
• To enhance SERS performance and enable sensitive bacterial detection.

Main Methods:

• Fabrication of Janus nanostructures by depositing cerium oxide (CeO2) onto gold nanorods (Au NRs).
• Utilizing 4-mercaptophenylboronic acid (MPBA) as a multifunctional ligand for interparticle spacing regulation and recognition.
• Construction of a SERS sensor for Escherichia coli detection.

Main Results:

• Janus NP arrays provide accessible metal-semiconductor interface hotspots and tunable nanogaps (~1 nm).
• SERS enhancement factor increased over 11 times compared to conventional Au NR arrays.
• Developed a SERS sensor with an ultralow detection limit of ~1.1 CFU/μL for E. coli.

Conclusions:

• Janus NP arrays offer a versatile strategy for next-generation SERS substrates.
• The developed substrate demonstrates high sensitivity and specificity for bacterial detection.