A Direct Immunoassay Based on Surface-Enhanced Spectroscopy Using AuNP/PS-b-P2VP Nanocomposites

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Accurate detection of biomarkers like human immunoglobulin G (IgG) and adenosine triphosphate (ATP) is crucial for diagnostics.
• Existing detection methods may lack sensitivity, selectivity, or require complex procedures.

Purpose of the Study:

• To develop a stable and reproducible biosensor for direct detection of human IgG and ATP.
• To utilize gold nanoparticles/polystyrene-b-poly(2-vinylpyridine) (AuNP/PS-b-P2VP) nanocomposites for enhanced sensing capabilities.

Main Methods:

• Fabrication of AuNP/PS-b-P2VP nanocomposite substrates.
• Functionalization of substrates with carboxylic acid groups for covalent antibody binding.
• Characterization using Scanning Electron Microscopy (SEM), UV-Visible spectroscopy, and Surface-Enhanced Raman Spectroscopy (SERS).
• Detection assays for IgG and ATP using specific antibodies and Principal Component Analysis (PCA) for data analysis.

Main Results:

• SEM confirmed uniform adsorption of AuNP clusters on the porous nanocomposite film.
• UV-VIS and SERS demonstrated successful substrate functionalization and specific antibody-analyte interactions.
• The biosensor achieved a limit-of-detection (LOD) of 1 μg/mL for both IgG and ATP.
• High selectivity for IgG was confirmed against IgM, and the platform showed versatility for detecting other biomolecules.

Conclusions:

• The developed AuNP/PS-b-P2VP nanocomposite platform is a sensitive and selective biosensor for IgG and ATP detection.
• The platform's stability, reproducibility, and adaptability make it promising for detecting various biomolecules.
• This biosensor offers a valuable tool for biochemical analysis and potential diagnostic applications.