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Plasmonic aptasensor with antifouling dual-functional surface layer for lysozyme detection in food
Noemi Bellassai1, Roberta D'Agata1, Giuseppe Spoto1
1Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale Andrea Doria 6, I-95125, Catania, Italy; Consorzio Interuniversitario "Istituto Nazionale Biostrutture e Biosistemi", c/o Dipartimento di Scienze Chimiche, Università di Catania, Viale Andrea Doria 6, Catania, Italy.
A novel poly-l-lysine (PLL)-based antifouling coating enables direct detection of the allergen lysozyme in food using surface plasmon resonance. This dual-functional aptasensor achieves sensitive quantification without complex sample pre-treatment.
Area of Science:
- Biosensor Technology
- Surface Chemistry
- Food Safety Analytics
Background:
- Antifouling coatings are crucial for optical biosensors, preventing non-specific adsorption in complex biological and food matrices.
- Existing antifouling plasmonic surfaces primarily target clinical biomarkers, with limited development for direct food analysis.
- Direct detection of analytes in food requires robust surfaces that prevent fouling and selectively capture targets.
Purpose of the Study:
- To develop a low-fouling surface layer for the direct detection of lysozyme in food matrices using surface plasmon resonance (SPR).
- To create a dual-functional surface combining antifouling properties with specific analyte capture capabilities.
- To demonstrate the utility of the developed aptasensor for quantifying lysozyme in real food samples without pre-treatment.
Main Methods:
- Fabrication of a poly-l-lysine (PLL)-based surface layer with immobilized anionic oligopeptide side chains for antifouling.
- Immobilization of aptamer probes onto the PLL surface for selective capture of lysozyme.
- Optimization of surface layer fabrication conditions and testing of the dual-functional surface's performance.
- Detection of lysozyme in food matrices using surface plasmon resonance (SPR) analysis.
Main Results:
- The developed PLL-based surface effectively repelled non-specific adsorption of undesired molecules.
- The aptasensor achieved a limit of detection (LOD) of 0.04 μg mL⁻¹ (2.95 nM) and a limit of quantification (LOQ) of 0.13 μg mL⁻¹ (8.95 nM) for lysozyme.
- Lysozyme was successfully quantified in milk samples, demonstrating the aptasensor's capability for direct analysis without sample pre-treatment.
Conclusions:
- The proposed poly-l-lysine (PLL)-based surface provides an effective dual-functional platform for antifouling and specific analyte detection in complex food samples.
- This plasmonic dual-functional aptasensor enables sensitive and selective quantification of allergen proteins like lysozyme directly in food matrices.
- The developed approach significantly advances the potential for rapid, on-site food quality control and safety assessment.
