Ultrasensitive Surface-Enhanced Raman Scattering Platform for Protein Detection via Active Delivery to Nanogaps as a...

Area of Science:

• Plasmonics and Nanomaterials
• Biomolecular Detection
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) offers sensitive, label-free molecular detection.
• Protein detection via SERS is challenged by protein size and delivery to hotspots.
• Existing SERS substrates lack active control over plasmonic hotspots for biomolecules.

Purpose of the Study:

• To develop an actively tunable SERS substrate for enhanced protein detection.
• To implement an active protein delivery strategy to improve SERS sensitivity.
• To achieve single-molecule level protein detection with a wide quantification range.

Main Methods:

• Fabrication of a gold nanoTriangle plate Array on Gel (AuTAG) with thermoresponsive hydrogels.
• Utilizing temperature control to tune interparticle distances and hotspot accessibility.
• Implementing a Gel Filter Trapping (GFT) method for active protein delivery to AuTAG hotspots.

Main Results:

• The AuTAG substrate demonstrated tunable plasmonic properties via temperature-controlled hydrogel volume changes.
• The GFT method effectively delivered proteins to hotspots on AuTAGs, minimizing nonspecific adsorption.
• Achieved ultrahigh SERS sensitivity for protein detection down to the single-molecule level.
• Demonstrated a wide quantification concentration range spanning 6 orders of magnitude.

Conclusions:

• The combination of AuTAG and GFT provides a powerful platform for ultrasensitive protein detection.
• This approach overcomes limitations of traditional SERS for large biomolecules.
• The tunable plasmonic device and active delivery strategy enable advanced molecular sensing applications.