Label-free biomarker assay in a microresistive pulse sensor via immunoaggregation

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Biosensing Technology

Background:

• Accurate and rapid biomarker detection is crucial for early disease diagnosis and monitoring.
• Existing methods often require labels, complex sample preparation, or expensive equipment.
• There is a need for simple, label-free, and quantitative biomarker detection techniques.

Purpose of the Study:

• To develop and validate a novel label-free biomarker detection method using immunoaggregation and resistive pulse sensing.
• To demonstrate the quantitative measurement of human ferritin concentration in various media.
• To explore the adaptability of the method for detecting other macromolecular biomarkers.

Main Methods:

• Immunoaggregation: mixing target biomarkers with antibody-functionalized microparticles to form aggregates.
• Resistive Pulse Sensing: measuring the size and counting aggregates to determine biomarker concentration.
• Method Validation: testing with human ferritin in phosphate-buffered saline (PBS) and fetal bovine serum (FBS).

Main Results:

• The volume fraction of biomarker-microparticle aggregates directly correlated with biomarker concentration.
• Successful detection of human ferritin in a concentration range of 0.1 to 208 ng/mL.
• Demonstrated ability to adjust the detection range by altering microparticle concentrations.

Conclusions:

• The developed method is label-free, rapid, and quantitative for biomarker detection.
• The technique is versatile and applicable to any macromolecular biomarker with a corresponding antibody.
• Simple setup and sample preparation make this method suitable for various diagnostic applications.