Multifunctional au nanoparticle dendrimer-based surface plasmon resonance biosensor and its application for improved...

Area of Science:

• Nanomaterials Science
• Biomedical Engineering
• Analytical Chemistry

Background:

• Developing sensitive and specific biosensors is crucial for early disease diagnosis.
• Nonspecific protein adsorption often hinders biosensor performance in complex biological samples.
• Gold nanoparticles (Au NPs) and dendrimers offer unique properties for biosensing applications.

Purpose of the Study:

• To synthesize and characterize a bifunctional dendrimer-encapsulated Au NP system for biosensor development.
• To create a stable, anti-fouling sensor surface for enhanced biomolecule detection.
• To establish a sensitive surface plasmon resonance (SPR) based competitive immunoassay for insulin detection.

Main Methods:

• Synthesis of fourth-generation polyamidoamine dendrimer (G4-PAMAM) encapsulated Au NPs.
• Immobilization of Au NP-dendrimer onto a mixed self-assembled monolayer (SAM)-modified gold surface.
• Functionalization of dendrimer thiol groups to hydrazide for receptor immobilization.
• Development of an SPR-based competitive immunoassay for insulin detection.

Main Results:

• The modified surface demonstrated resistance to nonspecific protein adsorption.
• The developed biosensor achieved a high sensitivity with a detection limit of 0.5 pM for insulin.
• SPR signal amplification was observed due to the coupling of localized plasmons with surface plasmon waves.
• The biosensor showed good correlation with a reference method when analyzing insulin in human serum.

Conclusions:

• The Au NP-dendrimer modified surface provides a stable and highly sensitive platform for biosensing.
• The developed SPR immunoassay offers enhanced sensitivity and specificity for insulin detection.
• This biosensing platform has significant potential for detecting various biomarkers in biological samples.