A Ti₃C₂-MXene-functionalized LRSPR biosensor based on sandwich amplification for human IgG detection

Area of Science:

• Biosensing and Immunoassay
• Nanomaterials Science
• Surface Plasmon Resonance Technology

Background:

• Conventional surface plasmon resonance (cSPR) faces limitations in sensitivity and accuracy for biosensing applications.
• Emerging two-dimensional (2D) materials like Ti3C2-MXene offer unique properties for enhanced biosensing platforms.
• Polydopamine (PDA) coatings provide excellent surface area and binding sites for biomolecules.

Purpose of the Study:

• To develop and characterize a novel long-range surface plasmon resonance (LRSPR) biosensor for sensitive detection of human IgG.
• To investigate the efficacy of a PDA/Ti3C2-MXene/PDA-gold film substrate combined with gold nanoparticle (AuNP) enhancers.
• To evaluate the performance of the developed biosensor in terms of detection range and limit of detection (LOD).

Main Methods:

• Fabrication of a multi-layered sensing substrate comprising PDA, Ti3C2-MXene, and a gold film.
• Immobilization of rabbit anti-human IgG (Ab1) onto the sensing substrate for primary antigen capture.
• Application of a sandwich amplification strategy using AuNPs/staphylococcal protein A (SPA)/mouse anti-human IgG (Ab2) composites as enhancers.

Main Results:

• The LRSPR biosensor successfully detected human IgG over a wide concentration range (0.075–40 μg mL−1).
• The limit of detection (LOD) achieved was approximately 20 times lower than that of cSPR biosensors.
• The biosensor demonstrated high sensitivity and accuracy in immune sensing applications.

Conclusions:

• The novel LRSPR biosensor platform based on PDA/Ti3C2-MXene demonstrates superior performance for immune sensing.
• The combination of LRSPR, MXene, and AuNP enhancers significantly improves sensitivity and lowers the detection limit.
• This advanced biosensing platform holds potential for broad applications in various biological detection fields.