Biomolecular Interaction Analysis Quantification with a Low-Volume Microfluidic Chip and Particle Diffusometry.

Area of Science:

• Biomolecular analysis
• Microfluidics
• Protein-protein interactions

Background:

• Microfluidic assays often require large reagent volumes due to "dead volume" in syringes and tubing, increasing costs.
• Reducing reagent consumption is crucial for making biomolecular analysis more affordable and accessible.

Purpose of the Study:

• To design a novel microfluidic chip for low-volume protein-protein interaction analysis.
• To demonstrate real-time measurement of binding kinetics using minimal reagent volumes.

Main Methods:

• Utilized a microfluidic chip with air/aqueous two-phase droplet flow and on-chip rapid mixing.
• Employed particle diffusometry (PD) for nonintrusive optical detection of microparticle diffusion.
• Analyzed human immunodeficiency virus p24 antibody-antigen binding kinetics.

Main Results:

• The developed chip requires only 2 μL of reagent solution.
• Accurate on-chip characterization of protein binding kinetics was achieved.
• Measured association (k_on) and dissociation (k_off) rate constants agreed with independent methods.

Conclusions:

• The novel microfluidic chip effectively reduces reagent volume and cost for protein-protein interaction analysis.
• The demonstrated method provides accurate and real-time kinetic measurements.
• This approach has broad applicability in various fields requiring low-volume, high-precision analysis.