Raman nanoparticle probes for antibody-based protein detection in tissues

Area of Science:

• Biomolecular detection
• Nanoparticle-based assays
• Optical imaging

Background:

• Surface-enhanced Raman scattering (SERS) nanoparticles offer novel optical detection methods for biomolecules.
• Formalin-fixed paraffin-embedded (FFPE) tissues are crucial for pathological analysis but present detection challenges.
• Prostate-specific antigen (PSA) is a key biomarker for prostate cancer detection.

Purpose of the Study:

• To evaluate the performance of composite organic-inorganic nanoparticles (COINs) conjugated to antibodies for detecting PSA in FFPE prostate tissue sections.
• To compare the efficacy of COIN-based detection with traditional Alexa conjugates using identical staining protocols.
• To assess spectral differences between Raman and fluorescence signatures and extract COIN probe signals.

Main Methods:

• Utilizing antibody-conjugated COINs for SERS-based detection of PSA in FFPE prostate tissue.
• Employing identical staining protocols to compare COIN-antibody conjugates with Alexa-antibody conjugates.
• Performing spectral analysis to differentiate Raman signals from background autofluorescence.
• Generating PSA expression images from extracted COIN probe signals and evaluating assay performance metrics.

Main Results:

• COINs provided signal intensities comparable to Alexa conjugates.
• COIN assays demonstrated good intra-, inter-, and lot-to-lot consistencies.
• Staining accuracy for COINs was slightly lower than Alexa due to an elevated false-negative rate.
• Spectral analysis successfully extracted COIN probe signals from background autofluorescence.

Conclusions:

• COIN and Alexa detection reagents exhibit similar overall performance in FFPE tissues.
• COINs represent a viable alternative for Raman-based biomolecular detection in FFPE samples.
• Further development of COINs is supported for enhanced accuracy in diagnostic applications.