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Capillary-based Centrifugal Microfluidic Device for Size-controllable Formation of Monodisperse Microdroplets
Published on: February 22, 2016
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Volumeless reagent delivery: a liquid handling method for adding reagents to microscale droplets without increasing
Duane S Juang1, Joshua M Lang2, David J Beebe1,3
1Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53705, USA. djbeebe@wisc.edu.
Lab on a Chip
|December 13, 2021
Summary
A novel volume-less reagent delivery (VRD) technique for digital microfluidic (DMF) systems avoids analyte dilution by reconstituting dried reagents without increasing droplet volume. This method utilizes exclusive liquid repellency (ELR) for versatile reagent addition in microfluidic assays.
Area of Science:
- Microfluidics
- Biotechnology
- Materials Science
Background:
- Traditional digital microfluidic (DMF) systems face challenges with reagent addition, often leading to significant droplet volume increases and analyte dilution through merging droplets.
- This dilution effect complicates multi-step assays and can compromise the accuracy and sensitivity of results.
Purpose of the Study:
- To introduce and validate a new method for reagent addition in microfluidic systems that circumvents the issue of volume increase and analyte dilution.
- To demonstrate the versatility and effectiveness of this technique across various reagent types.
Main Methods:
- Development of a volume-less reagent delivery (VRD) technique based on exclusive liquid repellency (ELR), a phenomenon where an aqueous phase is fully repelled from a specific solid surface (contact angle ~180°).
- Reagents are dried onto the ELR surface, immersed in oil, and then reconstituted by an aqueous droplet dragged over the dried reagent spot.
- Paramagnetic particles or physical sliding walls are used to manipulate the aqueous droplet for reagent reconstitution.
Main Results:
- VRD successfully delivers reagents to aqueous droplets without significant volume increase, preserving analyte concentration.
- The technique was validated for a wide array of reagents, including sugars, proteins (antibodies), nucleic acids (DNA), antibiotics, and complex enzyme mixtures.
- The ELR surface is restored to its repellent state after reagent reconstitution, allowing for repeated use.
Conclusions:
- Volume-less reagent delivery (VRD) offers a significant advancement for microfluidic assays, particularly in digital microfluidic (DMF) platforms.
- This technique enables the development of more compact, efficient, and sensitive self-contained multi-step assays.
- VRD's flexibility with diverse reagents positions it as a key innovation for future microfluidic applications.
