Label-Free Dynamic Single-Molecule Sensing of Alpha-2-Macroglobulin in Complex Matrices

Area of Science:

• Biomarker Discovery
• Analytical Chemistry
• Molecular Diagnostics

Background:

• Alpha-2-macroglobulin (A2M) is a key biomarker in inflammation, immunity, coagulation, and diseases like fibrosis, neurodegeneration, and cancer.
• Accurate A2M quantification is challenging due to its dynamic nature, low abundance variations, and interference from other plasma proteins.

Purpose of the Study:

• To introduce a novel label-free dynamic single-molecule sensing (LFDSMS) strategy for sensitive and specific A2M detection.
• To overcome the limitations of existing methods for A2M quantification in complex biological fluids.

Main Methods:

• Utilized a label-free dynamic single-molecule sensing (LFDSMS) platform monitoring real-time, reversible antibody-A2M interactions.
• Optimized buffer ionic strength to enhance binding-dissociation kinetics for signal amplification.
• Employed surface-immobilized antibodies for specific capture and detection of A2M.

Main Results:

• Achieved a limit of detection of 25 ± 2 ng/mL in undiluted serum and 29 ± 4 ng/mL in cell culture medium.
• Demonstrated high specificity for A2M detection even in complex biological matrices.
• Showed excellent correlation with ELISA (R² = 0.988), confirming method's reliability.

Conclusions:

• LFDSMS provides a sensitive, specific, and robust method for A2M quantification.
• This technique holds significant potential for quantitative biomarker profiling in clinical settings.
• The optimized LFDSMS platform addresses current challenges in A2M measurement.