A method for characterizing adsorption of flowing solutes to microfluidic device surfaces

Area of Science:

• Microfluidics
• Surface Science
• Analytical Chemistry

Background:

• Solute adsorption in microfluidic devices can significantly impact experimental outcomes.
• Characterizing adsorption is challenging due to varying device materials, designs, and operational parameters.
• Distinguishing between long-lived and transient adsorption is critical for reliable microfluidic applications.

Purpose of the Study:

• To present a versatile method for characterizing solute adsorption in microfluidic devices.
• To assess the method's sensitivity to both long-lived and transient adsorption phenomena.
• To validate the method using known non-fouling strategies.

Main Methods:

• Characterization of adsorption for highly adsorbing molecules (FITC-labeled bovine serum albumin (BSA), rhodamine B) and low adsorbing species (FITC-labeled dextran, fluorescein).
• Application of the method across diverse microfluidic device materials, designs, fabrication methods, and operational parameters.
• Validation using polyethylene oxide (PEO)-like surface coatings and unlabeled BSA blocking.

Main Results:

• The method successfully characterized adsorption of both high and low adsorbing molecules.
• Results demonstrated sensitivity to different adsorption behaviors.
• Non-fouling strategies effectively eliminated characteristic BSA adsorption, validating the method.

Conclusions:

• The presented method offers a robust approach for characterizing solute adsorption in microfluidics.
• It is adaptable to various realistic experimental conditions.
• The findings support the development of more reliable microfluidic systems by understanding and mitigating adsorption.