In solution SERS sensing using mesoporous silica-coated gold nanorods

Area of Science:

• Nanotechnology
• Materials Science
• Analytical Chemistry

Background:

• Gold nanorods coated with mesoporous silica (AuNR@MS) provide a stable platform for sensing applications.
• The mesoporous silica shell offers tunable pore sizes, enabling size-selective analyte access.
• Surface-enhanced Raman scattering (SERS) is a sensitive technique for molecular detection.

Purpose of the Study:

• To investigate the performance of AuNR@MS as a SERS sensing platform.
• To determine the analyte size limitations for detection using this platform.
• To evaluate the influence of molecular size on transport through mesoporous silica.

Main Methods:

• Synthesis of AuNR@MS core-shell nanostructures.
• Functionalization with thiolated Raman-active molecules.
• SERS measurements to assess sensing capabilities.
• Analysis of molecular transport through mesopores based on size.

Main Results:

• AuNR@MS demonstrated high colloidal stability, crucial for reliable sensing.
• Analyte transport through the mesopores was significantly dependent on molecular size.
• The platform, with ~4 nm pores, successfully sensed analytes smaller than 1.5 nm.
• High SERS sensitivity was achieved for suitable analytes.

Conclusions:

• AuNR@MS is a promising SERS sensing platform with an intrinsic analyte size cutoff.
• The mesoporous silica shell's pore size dictates the detection limit based on molecular dimensions.
• This stable and selective platform has potential applications in complex media analysis.