Sensitive plasma protein analysis by microparticle-based proximity ligation assays

Area of Science:

• Biochemistry
• Immunology
• Analytical Chemistry

Background:

• Detecting disease-specific proteins in blood is crucial for early diagnosis and therapy monitoring.
• Current protein biomarker assays struggle with sensitivity and specificity in complex biological fluids.
• Trace-level protein detection remains a significant challenge in clinical diagnostics.

Purpose of the Study:

• To develop a highly sensitive and specific assay for detecting rare proteins in biological samples.
• To overcome the limitations of existing protein detection methods.
• To validate a new assay for broad application in clinical diagnostics.

Main Methods:

• Development of a microparticle-based solid-phase proximity ligation assay (PLA).
• Utilizing simultaneous recognition of target proteins by three antibodies for enhanced specificity.
• Comparison with state-of-the-art sandwich ELISAs using vascular endothelial growth factor, interleukin-8, and interleukin-6.

Main Results:

• The developed PLA demonstrated superior dynamic range and sensitivity compared to sandwich ELISAs.
• The assay successfully detected rare protein molecules in undiluted plasma, serum, and whole blood.
• Consistent performance was observed across nine different antigens, highlighting assay robustness.

Conclusions:

• Solid-phase proximity ligation assay is a powerful tool for sensitive and specific protein biomarker detection.
• The assay is suitable for validating a wide range of protein biomarkers in clinical samples.
• This method advances the potential for early disease detection and personalized medicine.