SERS detection of biomolecules using lithographed nanoparticles towards a reproducible SERS biosensor

Area of Science:

• Nanotechnology
• Spectroscopy
• Biochemistry

Background:

• Surface-enhanced Raman scattering (SERS) offers high sensitivity for molecular detection.
• Gold nanostructures are effective SERS substrates due to their plasmonic properties.
• Accurate spectral detection of proteins is crucial for diagnostics and research.

Purpose of the Study:

• To develop and optimize a SERS substrate for sensitive protein detection.
• To investigate the influence of gold nanocylinder dimensions on SERS enhancement factors.
• To establish a correlation between localized surface plasmon resonance (LSPR) and SERS signal optimization.

Main Methods:

• Fabrication of gold nanocylinders using electron-beam lithography (EBL).
• Characterization of nanocylinder dimensions (100-180 nm diameter, 200 nm gap).
• SERS measurements of bovine serum albumin (BSA) and ribonuclease-A (RNase-A) at low concentrations.

Main Results:

• Achieved accurate spectral detection of BSA and RNase-A.
• Estimated high SERS enhancement factors (10^5 for BSA, 10^7 for RNase-A) at 1 mM concentration.
• Demonstrated that optimizing nanocylinder size, shape, and LSPR position is key for maximizing SERS enhancement.

Conclusions:

• Gold nanocylinder arrays fabricated by EBL are efficient for protein spectral detection.
• Optimized LSPR positioning, relative to laser excitation and Raman bands, is critical for high SERS enhancement.
• This SERS approach provides a sensitive method for analyzing proteins.