SPR Biosensing in crude serum using ultralow fouling binary patterned peptide SAM

Area of Science:

• Biomolecular Engineering
• Biosensor Technology
• Analytical Chemistry

Background:

• Matrix metalloproteinase-3 (MMP-3) is a clinically relevant biomarker for various pathologies, including cancer.
• Accurate and direct detection of MMP-3 in complex biological matrices like serum is challenging due to non-specific adsorption and the need for extensive sample preparation.
• Existing biosensing methods often require secondary detection or signal amplification, increasing complexity and cost.

Purpose of the Study:

• To develop near-zero fouling peptide monolayers for direct, label-free detection of MMP-3.
• To evaluate the efficacy of binary patterned peptides in Surface Plasmon Resonance (SPR) biosensing.
• To demonstrate the capability of these peptide monolayers for MMP-3 quantification in undiluted biological samples.

Main Methods:

• Synthesis and characterization of binary patterned peptides, including 3-mercaptopropionic acid (3-MPA)-capped peptides with varying amino acid compositions (His, Asp, Ser, Leu).
• Immobilization of peptides onto SPR sensor chips to create functionalized monolayers.
• Testing peptide resistance to non-specific adsorption using bovine serum and quantifying MMP-3 using SPR.

Main Results:

• Binary patterned peptides, particularly 3-MPA-HHHDD-OH, exhibited excellent resistance to non-specific adsorption in crude bovine serum, achieving near-zero fouling.
• An IgG biosensor demonstrated the efficiency of these peptides in SPR, with a detection limit of 1-10 pM in PBS.
• MMP-3 was accurately quantified at low nanomolar levels in undiluted bovine serum, with a limit of detection (LOD) of 0.14 nM and linearity up to 50 nM in PBS, showing statistically similar SPR response to PBS.

Conclusions:

• Binary patterned peptides offer a robust platform for creating highly stable, fouling-resistant monolayers suitable for direct biosensing.
• The developed peptide-based SPR biosensor enables sensitive and specific detection of MMP-3 directly in complex biological matrices without pretreatment.
• This approach significantly simplifies biosensing protocols and holds promise for clinical diagnostics and biomarker monitoring.