Glutathione immunosensing platform based on total internal reflection ellipsometry enhanced by functionalized gold...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Developing sensitive detection methods for small molecules like glutathione (GSH) is crucial.
• Traditional methods often struggle with sensitivity for low-concentration analytes.
• Surface Plasmon Resonance (SPR) and ellipsometry offer label-free detection but can lack sensitivity for small molecules.

Purpose of the Study:

• To develop a highly sensitive immunosensor for detecting glutathione (GSH).
• To enhance the sensitivity of ellipsometry-based SPR for small molecule detection.
• To utilize gold nanoparticles (AuNPs) as signal amplifiers in an immunosensor.

Main Methods:

• Combined ellipsometry with Kretschmann-based Surface Plasmon Resonance (SPR).
• Functionalized a gold (Au) thin film with anti-GSH antibodies for specific GSH binding.
• Employed anti-GSH antibody-functionalized Au thin films and anti-GSH antibody-functionalized gold nanoparticles (AuNPs) for enhanced detection.

Main Results:

• Low concentrations of GSH induced negligible shifts in plasmon resonant energy.
• Functionalized AuNPs significantly amplified the antigen-antibody interaction signal.
• A linear shift in resonant energy was observed with increasing free GSH concentration.
• Achieved a detection limit for free GSH in the nanomolar range.

Conclusions:

• Gold nanoparticles effectively enhance the sensitivity of immunosensors based on total internal reflection ellipsometry.
• The developed immunosensor demonstrates high sensitivity and effectiveness for detecting small molecules like GSH.
• This approach offers a promising platform for sensitive small molecule detection in various applications.