Single-chain fragment variable antibody piezoimmunosensors.

Area of Science:

• Biomedical Engineering
• Immunotechnology
• Biosensor Technology

Background:

• Current biosensors often struggle with sensitivity and specificity in complex biological samples.
• Recombinant antibodies offer potential advantages over whole antibodies in biosensor design.
• Optimizing antibody immobilization is crucial for enhancing biosensor performance.

Purpose of the Study:

• To develop a novel nonlabeled biosensor for rapid and sensitive antigen detection.
• To investigate the use of engineered single-chain fragment variable (scFv) antibodies for improved biosensor performance.
• To evaluate the diagnostic potential of a piezoimmunosensor (PZ) utilizing scFv self-assembled monolayers.

Main Methods:

• Construction of a recombinant single-chain fragment variable (scFv) antibody with a cysteine linker (scFv-cys).
• Self-assembly of scFv-cys onto a gold-coated quartz crystal microbalance surface to form a dense, oriented monolayer (SAM).
• Characterization and performance evaluation of the scFv SAM piezoimmunosensor (PZ) against other antibody formats.

Main Results:

• The scFv-cys SAM formed a densely packed, rigidly oriented monolayer with significantly higher antigen-binding site density (35x) compared to whole antibodies.
• The scFv SAM PZ demonstrated superior sensitivity and specificity over Fab fragments and whole antibody PZs.
• The biosensor successfully detected low concentrations of antigens in complex biological samples with high selectivity and speed.

Conclusions:

• Engineered scFv antibodies with cysteine linkers enable the formation of highly efficient self-assembled monolayers on biosensor surfaces.
• This novel scFv SAM PZ biosensor exhibits significant advantages for rapid, sensitive, and specific antigen detection in complex samples.
• The developed biosensor holds high diagnostic potential for various applications requiring sensitive biomarker detection.