Discrimination between protein glycoforms using lectin-functionalised gold nanoparticles as signal enhancers

Area of Science:

• Biotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Protein glycoforms, or specific sugar structures attached to proteins, are critical indicators of disease states.
• Current antibody-based assays often fail to distinguish between different glycoforms of the same protein.
• Developing tools to accurately detect and quantify protein glycosylation status is essential for advancing diagnostics.

Purpose of the Study:

• To develop a novel 'sandwich' bio-assay for sensitive and specific detection of protein glycoforms.
• To enhance signal detection using gold nanoparticles functionalized with lectins.
• To demonstrate the assay's potential in distinguishing disease states using prostate-specific antigen as a model biomarker.

Main Methods:

• Utilized biolayer interferometry sensors with immobilized antibodies to capture target proteins.
• Employed gold nanoparticles functionalized with lectins for specific glycoform identification and signal amplification.
• Validated the assay's performance using prostate-specific antigen (PSA) in buffer and for distinguishing cancerous from non-cancerous states.

Main Results:

• Achieved glycoform-specific detection sensitivity as low as 0.04 μg mL⁻¹ (1.4 nM).
• Demonstrated significant signal enhancement compared to using lectins alone.
• Successfully differentiated between cancerous and non-cancerous states of prostate cancer using PSA glycoform analysis.

Conclusions:

• The developed 'sandwich' bio-assay enables sensitive and specific glycoform detection.
• This automated, enrichment-free method offers a promising tool for disease diagnostics.
• Glycoform analysis, unlike total protein measurement, can provide crucial insights into disease status.