Biocompatible surfactants for water-in-fluorocarbon emulsions

Abstract

Drops of water-in-fluorocarbon emulsions have great potential for compartmentalizing both in vitro and in vivo biological systems; however, surfactants to stabilize such emulsions are scarce. Here we present a novel class of fluorosurfactants that we synthesize by coupling oligomeric perfluorinated polyethers (PFPE) with polyethyleneglycol (PEG). We demonstrate that these block copolymer surfactants stabilize water-in-fluorocarbon oil emulsions during all necessary steps of a drop-based experiment including drop formation, incubation, and reinjection into a second microfluidic device. Furthermore, we show that aqueous drops stabilized with these surfactants can be used for in vitro translation (IVT), as well as encapsulation and incubation of single cells. The compatability of this emulsion system with both biological systems and polydimethylsiloxane (PDMS) microfluidic devices makes these surfactants ideal for a broad range of high-throughput, drop-based applications.

Osmotic-pressure-controlled concentration of colloidal particles in thin-shelled capsules

“…An aqueous solution of PVA (Mw 13,000-23,000, Sigma-Aldrich) is used as the innermost and the continuous phase of double-emulsion drops, which stabilizes interfaces between water and oil. As middle oil phases, we use one of four solutions: ETPTA (Sigma-Aldrich) containing 0.2 wt.% photoinitiator (2-hydroxy-2-methylpropiophenone, Sigma-Aldrich), polysiloxanes modified with methacrylate (SB4722, n (Z/r) ¼ 570 cSt, Evonik) containing 0.2 wt.% photoinitiator, PDMS oil (n ¼ 20 cSt, Sigma-Aldrich) containing 2 wt.% surfactant (DC749, Dow Corning) and FC oil (3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-dodecafluoro-2-trifluoromethylhexane, HFE 7500, 3 M) containing 1 wt.% surfactant (Krytox-PEG-Krytox surfactant) 33 ; to produce solid microcapsules, we use ETPTA solution, while we use SB4722 solutions to make rubber capsules. As a collection liquid for doubleemulsion drops, we use an aqueous mixture of PVA and NaCl with controlled osmolarity.…”

Single cell kinase signaling assay using pinched flow coupled droplet microfluidics

“…HFE-7500 fluorocarbon oil (3 M NovecTM, Singapore) with 2% Krytox (modified with PEG head) surfactant [40][41][42] was used to generate stable droplets. All the syringes were connected to their respective cell, oil and reagent inlet ports on the microfluidic device with 1 mm (OD) tubing and operated using Harvard PhD ULTRA syringe pumps (Harvard Apparatus, USA).…”

Versatile, cell and chip friendly method to gel alginate in microfluidic devices

“…This was the case even at higher pH (tested between pH 6.7 and 7.8) for the combination involving ZnGlycine. Fluorinated oil with biocompatible fluorosurfactant (similar to Holtze and coworkers 25 ) was used as an immiscible carrier fluid to produce monodisperse emulsions of the precursor alginate solutions prior to gelation. This carrier fluid is biocompatible, offers high oxygen solubility 26 and is compatible with PDMS microchannels.…”