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Microfluidic Droplet Stabilization via SPAAC Promoted Antibody Conjugation at the Water/Oil Interface
Robin Dufossez1, Marie-Pierre Krafft2, Sylvain Ursuegui3
1Bio-Functional Chemistry (UMR 7199), LabEx Medalis, University of Strasbourg, 74 Route du Rhin, 67400 Illkirch-Graffenstaden, France.
ACS Applied Materials & Interfaces
|September 13, 2023
Summary
Researchers optimized droplet-based microfluidics for sensitive protein detection by functionalizing the oil-water interface with custom surfactants and antibodies. An intermediate linker length on the surfactant balanced antibody grafting efficiency and droplet stability for improved assays.
Area of Science:
- Biotechnology
- Chemical Engineering
- Analytical Chemistry
Background:
- Droplet-based microfluidics enables miniaturized, rapid, and sensitive protein detection assays.
- Enzyme-linked immunosorbent assays (ELISAs) are central to protein detection but require functionalized surfaces for analyte capture.
- The oil-water interface within droplets offers a novel platform for assay functionalization.
Purpose of the Study:
- To investigate the impact of surfactant hydrophilic head structure on click chemistry functionalization efficiency.
- To determine how antibody grafting onto the droplet interface affects microfluidic droplet stability.
- To optimize surfactant design for enhanced performance in droplet-based immunoassays.
Main Methods:
- Synthesis of custom perfluorinated fluorosurfactants with azide-containing polar groups.
- Spontaneous surface-initiated cycloaddition-prevents-strain-alkyne-cycloaddition (SPAAC) functionalization with alkyne-modified antibodies.
- Analysis of linker length effects on SPAAC efficiency and droplet stability.
- Investigation of antibody surface coverage impact on droplet stability.
Main Results:
- Surfactant linker length critically influences the balance between antibody grafting efficiency and droplet stability.
- Short linkers maximized grafting efficiency, while long linkers enhanced droplet stability.
- An optimal intermediate linker length (PEG4) was identified for balancing both parameters.
- Increased antibody surface coverage was found to significantly improve droplet stability.
Conclusions:
- Custom fluorosurfactants with tailored hydrophilic heads enable efficient in situ functionalization of droplet interfaces.
- The developed bi-partite system allows for the creation of novel interface structures and enhanced droplet functionality for microfluidic assays.
- This approach advances the development of sensitive and stable droplet-based immunoassays.
