Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2017 Sep 20;7:12022. doi: 10.1038/s41598-017-12363-x

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© The Author(s) 2017

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

PMC Copyright notice

Two-surfactant system to control droplet interfacial tension and cell-droplet interactions. (A) Sketch of a droplet and the two-surfactant system used to stabilize and functionalize the droplets. Droplets contain a non-ionic fluorosurfactant (Krytox-PEG) and are coated with a biotinylated surfactant (DSPE-PEG-biotin). The functional biotin group in DSPE-PEG-biotin enables subsequent coatings of the droplets with fluorescent streptavidin conjugates. A biotinylated ligand to control cell-droplet interactions is linked to the streptavidin molecules at the droplet surface. (B) Equilibrium interfacial tension of water-fluorocarbon oil (Fluorinert FC43 (black), Novec 7700 (blue) and Novec 7300 (red)) for varying fluorosurfactant concentrations (C_FS). Fitting the data at low (dilute) fluorosurfactant concentrations (Methods), yields values of interfacial tension in the absence of surfactants (γ _o = 37.9, 48.3, and 53.5 mN/m for Novec 7300, Novec 7700 and Fluorinert FC43, respectively), the saturating surfactant concentration at the interface (Γ_∞ = 3.51, 4.36, and 4.46 μmol/m² for Novec 7300, Novec 7700 and Fluorinert FC43, respectively), and the Langmuir constant (a_L = 6.35, 5.31 and 3.44 μM for Novec 7300, Novec 7700 and Fluorinert FC43, respectively). Linear fits were performed for data in the saturating regime (non-dilute regime), when the interfacial tension saturates to its minimal value. Saturating surface concentrations of fluorosurfactant (2% w/w; gray bar) were used in all other experiments. (C) Interfacial tension of Novec 7700 and water, in the presence of 2% (w/w) concentration of fluorosurfactant and varying concentrations (C_NaCl) of sodium chloride (left) and in cell culture media (right). These values are compared to the value of γ in deionized water (gray line). (D) Equilibrium γ values of fluorocarbon oil (same color code as in B) in water with fluorosurfactant alone (2% w/w) and in the presence of fluorosurfactant in the oil and DSPE-PEG-biotin in the water phase. The interfacial tension of the fluorocarbon oil (Novec 7700), containing fluorosurfactant and coated with DSPE-PEG-biotin, in cell culture media is also shown.