Microfluidic cell surface antigen expression analysis using a single antibody type.

Area of Science:

• Biotechnology
• Cell Biology
• Analytical Chemistry

Background:

• Antigen expression is crucial for disease diagnosis, monitoring, and cell phenotype analysis.
• Distinguishing cells based on subtle antigen expression differences presents a challenge in biological and clinical studies.

Purpose of the Study:

• To develop an affinity capture method for isolating cells based on differential antigen expression using a single microfluidic chip.
• To quantify antigen expression differences between cell populations with high specificity and efficiency.

Main Methods:

• Designed a microfluidic chip with dual affinity regions utilizing varying antibody concentrations for differential cell capture.
• Employed herringbone-modified capture channels to enhance cell-surface interactions under continuous-flow conditions.
• Validated the method by analyzing Ramos B lymphocytes and HuT 78 T lymphocytes and spiking cells into blood samples.

Main Results:

• Achieved 95% separation purity and 15% capture efficiency in microfluidic chip experiments.
• Demonstrated a strong correlation (R^2 = 0.94) between cell capture ratios and CD71 antigen expression levels.
• Validated performance in complex blood samples, showing consistent expression ratio measurements and 9.5x sample enrichment.

Conclusions:

• The developed microfluidic affinity capture system robustly measures antigen expression differences between cells.
• This method enables the distinction of cells even without unique surface antigens, provided sufficient expression level differences.
• The technology offers a valuable tool for cell analysis in clinical studies, pathology, and biological research.