A bidirectional immuno-microfluidic chip for detecting autoantibodies based on an indirect assay

Area of Science:

• Biomedical Engineering
• Immunology
• Analytical Chemistry

Background:

• Autoantibodies are crucial biomarkers for disease prediction and treatment monitoring.
• Current autoantibody detection methods face challenges with long assay times and complex procedures.
• There is a need for rapid, sensitive, and robust autoantibody detection platforms.

Purpose of the Study:

• To develop and validate a bidirectional microfluidic platform for enhanced autoantibody detection.
• To improve the speed, sensitivity, and anti-interference capabilities of microfluidic diagnostic devices.
• To demonstrate the platform's utility in diagnosing autoimmune diseases using anti-citrullinated peptide antibodies (ACPA) as a model.

Main Methods:

• A bidirectional lateral-flow microfluidic chip (BiLFMC) with a "double inlet" and "waste outlet" structure was designed and fabricated.
• Optimization of the BiLFMC involved adjusting inlet-outlet distances, waste outlet diameter, and absorbent materials.
• Performance was evaluated by comparing unidirectional and bidirectional modes, assessing detection limits, precision, and consistency with ELISA.

Main Results:

• The bidirectional microfluidic chip demonstrated significantly enhanced anti-interference capabilities compared to unidirectional modes.
• ACPA detection required only 10 μL of serum (1:100 dilution) with results available in 8 minutes.
• The platform showed good precision (CVs 7.04–14.49%), a limit of quantitation of 3.951 RU/mL, and high consistency with ELISA (0.8302).

Conclusions:

• The developed bidirectional microfluidic chip offers a rapid and efficient platform for autoantibody detection.
• The BiLFMC system provides superior anti-interference performance, crucial for reliable autoimmune disease diagnosis.
• This technology holds promise for improving the clinical management of autoimmune conditions through faster and more accurate diagnostics.