Ferrofluid Microdroplet Splitting for Population‐Based Microfluidics and Interfacial Tensiometry

Latikka, Mika; Backholm, Matilda; Baidya, Avijit; Ballesio, Alberto; Serve, Amandine; Beaune, Grégory; Timonen, Jaakko V. I.; Pradeep, Thalappil; Ras, Robin H. A.

doi:10.1002/advs.202000359

Cited by 30 publications

(48 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[ 24 ] We created populations of small magnetic droplets with large surface area using a magnetic‐field‐induced instability. [ 25,26 ] The oil‐based ferrofluid was pipetted in a container with a glass bottom filled with phosphate‐buffered saline (PBS) solution. The magnetic field was created by a cylindrical permanent magnet below the container.…”

Section: Resultsmentioning

confidence: 99%

Functional Magnetic Microdroplets for Antibody Extraction

Al-Terke

Latikka

Timonen

et al. 2021

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

Antibodies play an essential role in modern medicine for diagnostic and therapeutic applications. Even though the production of antibodies is the fastest growing pharmaceutical industry area, the cost of antibodies remains high, which limits access to antibody‐based medicine both in developing and developed countries. The bottleneck and major cost factor in the production is purification of the antibody. Here, a proof‐of‐concept is presented for antibody extraction using ferrofluid microdroplets. An external magnetic field splits oil‐based ferrofluid droplets into an array of daughter microdroplets, which serve as a magnetically tunable, hydrophobic, liquid substrate with a relatively large surface area. A fusion protein (HFBI‐Protein A), added to the solution surrounding the magnetic droplets, adsorbs strongly at the liquid‐liquid interface by the hydrophobin HFBI moiety, creating a bifunctional monolayer that can catch antibody molecules. After adsorption at the liquid‐liquid interface, these antibody molecules can be released by decreasing the pH of the solution. The antibody extraction process is investigated using confocal microscopy and gel electrophoresis. In addition, the effect of HFBI on the field‐induced ferrofluid droplet splitting is examined. This study provides a proof of concept for utilizing liquid‐liquid instead of a solid‐liquid system in antibody handling.

show abstract

Section: Resultsmentioning

confidence: 99%

Functional Magnetic Microdroplets for Antibody Extraction

Al-Terke

Latikka

Timonen

et al. 2021

Adv Materials Inter

Self Cite

View full text Add to dashboard Cite

show abstract

“…satellite droplets to be created when a larger droplet pinches off [5,6]. A reason to believe this possibility is that the small bumps do not exhibit a well-defined critical wavelength, as might be expected from a Rayleigh-Plateau type of instability in non-self-similar coordinates, and the small droplets decrease in size the closer they are to the main pinch-off location.…”

Section: Discussionmentioning

confidence: 99%

“…Both numerical simulations and experiments indicate that universal self-similarity plays a crucial role near pinch-off. However, the dynamics near pinch-off can be complex, including iterated structures and break-up into droplets of multiple sizes [4,5]. The nature of the selfsimilarity depends on the relative importance of effects such as the inertia and the viscosity of the ambient fluid.…”

Section: Introductionmentioning

confidence: 99%

Stability of similarity solutions of viscous thread pinch-off

Dallaston,

Zhao,

Sprittles

et al. 2021

Preprint

View full text Add to dashboard Cite

In this paper we compute the linear stability of similarity solutions of the breakup of viscous liquid threads, in which the viscosity and inertia of the liquid are in balance with the surface tension. The stability of the similarity solution is determined using numerical continuation to find the dominant eigenvalue of the correction problem. Stability of the first two solutions identified in Brenner et al.[1] are considered. We find that the primary similarity solution, which is that seen in experiments and simulations, is linearly stable with a complex nontrivial eigenvalue, which could explain the phenomenon of break-up producing sequences of small satellite droplets of decreasing radius near a main pinch-off point. The second solution is seen to be linearly unstable. These linear stability results compare favorably to numerical simulations for the stable similarity solution, while a profile starting near the unstable similarity solution is shown to very rapidly leave the linear regime.

show abstract

“…Two liquid phases seem more promising since it is possible to go down to 0.1 mN/m tuning the strenght of the interface with proper surfactants but even smaller values would be desired. 19 In this article, we demonstrate a ferrofluidic system where we can go several orders of magnitude smaller in the interfacial tensions than the classical systems. The presented system is based on the so called Aqueous Two Phase Systems (ATPS).…”

mentioning

confidence: 86%

Ferrofluidic aqueous two-phase system with ultralow interfacial tension, instabilities and pattern formation

Rigoni,

Harnist,

Beaune

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Ferrofluids are strongly magnetic fluids consisting of magnetic nanoparticles dispersed in a carrier fluid. Besides their technological applications, they have a tendency to form beautiful and intriguing patterns when subjected to external static and dynamic magnetic fields. Most of the patterns occur in systems consisting of two fluids: one ferrofluidic and one non-magnetic (oil, air, etc.), wherein the fluid-fluid interface deforms as a response to magnetic fields. Usually, the fluids are completely immiscible and so the interfacial energy in this systems is very large. Here we show that it is possible to design a fully aqueous ferrofluid system by using phase separation of incompatible polymers. This continuous aqueous system allows an ultralow interfacial tension (down to 1 µN/m) and nearly vanishing pinning at three phase contact lines. We demonstrate the normal-field instability with the system and focus on the miniaturization of the pattern length from the typical ∼10 mm size down to ∼200 µm. The normal-field instability is characterized in glass capillaries of thickness comparable to the pattern length. This system paves way towards interesting physics such as the interaction between magnetic instabilities and thermal capillary waves and offers a way to evaluate extremely small interfacial tensions.

show abstract

Ferrofluid Microdroplet Splitting for Population‐Based Microfluidics and Interfacial Tensiometry

Cited by 30 publications

References 33 publications

Functional Magnetic Microdroplets for Antibody Extraction

Functional Magnetic Microdroplets for Antibody Extraction

Stability of similarity solutions of viscous thread pinch-off

Ferrofluidic aqueous two-phase system with ultralow interfacial tension, instabilities and pattern formation

Contact Info

Product

Resources

About