Delivery of minimally dispersed liquid interfaces for sequential surface chemistry

Area of Science:

• Microfluidics
• Biochemistry
• Analytical Chemistry

Background:

• Sequential reagent delivery is crucial for multi-step assays but often suffers from interface dispersion.
• Controlling reagent delivery at the microscale is challenging, impacting assay accuracy and automation.

Purpose of the Study:

• To develop a method for sequential reagent delivery with minimal dispersion.
• To enable contact-free interaction with biological samples for dynamic response studies.
• To facilitate highly automated multi-step assays.

Main Methods:

• Utilizing segmented flow to encapsulate reagents as droplets, confining dispersion.
• Employing a passive array of microstructures for oil phase removal near the reaction surface.
• Implementing a vertical microfluidic probe for open-surface, contact-free sample interaction.

Main Results:

• Demonstrated minimal dispersion between reagent plugs during transport.
• Achieved a reagent transition time of 560 ms over a 60 cm distance.
• Successfully implemented assays for receptor-ligand kinetics and GFP fluorescence response to pH variations.

Conclusions:

• The developed method enables precise, sequential reagent delivery crucial for studying dynamic cellular and protein responses.
• This technique supports automated multi-step assays and contact-free biological sample analysis.
• The findings have implications for advancing biochemical assays and understanding biological system dynamics.