Optimization of Nanosubstrates toward Molecularly Surface-Functionalized Raman Spectroscopy

Area of Science:

• Analytical Chemistry
• Materials Science
• Spectroscopy

Background:

• Reliable analytical sensors with high sensitivity and specificity are crucial for diagnostic advancements.
• Surface-enhanced Raman spectroscopy (SERS) offers high sensitivity, but requires specific analyte recognition.
• Molecular surface functionalization is key to enhancing SERS specificity for diagnostic applications.

Purpose of the Study:

• To establish a controllable molecular surface functionalization process for textured gold surfaces.
• To compare the sensitivity and specificity of different SERS platforms based on surface functionalization.
• To identify optimal substrate specifications for advanced SERS diagnostic applications.

Main Methods:

• Fabrication of textured gold surfaces with varying thicknesses and RMS roughness.
• Functionalization of gold surfaces using self-assembled benzyl-terminated and benzoboroxole-terminated monolayers.
• Analysis of SERS signal enhancement and analyte sensitivity using principal component analysis (PCA) and self-organizing maps (SOM).

Main Results:

• Optimal molecular surface functionalization was achieved at 80 ± 8 nm thickness and 7.2 ± 1.0 nm RMS roughness.
• The optimized SERS platforms exhibited a 70-fold increase in SERS signal.
• Improved sensitivity for polysaccharide detection was observed with the functionalized surfaces.

Conclusions:

• Controllable molecular surface functionalization is essential for optimizing SERS platforms.
• Specific substrate specifications (thickness and roughness) significantly impact SERS sensitivity and specificity.
• These findings provide a foundation for developing molecular imprinting techniques for SERS-based diagnostics.