SERS-Based Immunoassay for α-Fetoprotein Biomarker Detection Using an Au-Ag Nanostars Platform

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Spiky gold-silver nanostars exhibit strong plasmonic properties for enhanced Raman scattering (SERS).
• Current cancer biomarker detection methods often suffer from low sensitivity and reliance on Raman reporters.
• A need exists for improved, reporter-free SERS platforms for early cancer diagnostics.

Purpose of the Study:

• To develop and evaluate a liquid-phase SERS platform for sensitive cancer biomarker detection.
• To optimize gold-silver nanostar concentration and functionalization for enhanced SERS performance.
• To demonstrate the platform's capability for label-free detection of alpha-fetoprotein (AFP).

Main Methods:

• Gold-silver nanostars were synthesized and their concentration adjusted via centrifugation.
• SERS performance was assessed using methylene blue and mercaptopropionic acid as probe molecules.
• Nanostars were functionalized with antibodies against AFP for antigen detection, utilizing EDC/NHS chemistry.

Main Results:

• SERS signal intensity correlated with nanostar concentration, indicating sensitive detection capabilities.
• The functionalized nanostar platform detected AFP antigens within a range of 500-0 ng/mL.
• A limit of detection (LOD) of 16.73 ng/mL for AFP antigens was achieved.

Conclusions:

• The developed aqueous, surfactant-free SERS platform offers sensitive and rapid detection of cancer biomarkers.
• The platform leverages intrinsic vibrational modes, eliminating the need for Raman reporters.
• This approach holds significant potential for advancing early cancer diagnostics.