DATE2024.08.23 #Press Releases
Successful creation of moving droplets with controllable velocity
Summary
A research group led by Associate Professor Miho Yanagisawa at the Graduate School of Arts and Sciences, University of Tokyo, and Project Assistant Professor Hiroki Sakuta at the same institution has successfully fabricated droplets that move according to the surrounding concentration gradient. In this study, an aqueous two-phase system [poly(ethylene glycol) (PEG) and dextran (DEX)] was filled within an elongated chamber to generate a constant PEG concentration gradient. The DEX droplets move down the PEG concentration gradient. By analyzing the composition inside and outside the droplets, they found that the droplet motility originates from Marangoni convection, which is caused by the difference in interfacial tension in front of and behind the moving droplet. In addition, the motile velocity is explained by the interfacial tension gradient and the dynamic viscosity of the solution. Furthermore, they control the motile velocity by adjusting the viscosity of the solution by changing the conformation of the DNA spontaneously incorporated into the droplet. This achievement is expected to contribute to applied research on the use of moving droplets as micro-robots for drug delivery systems, etc.
Figure：Motile droplet due to the concentration gradient of the surrounding solution and the change in velocity with the conformational transition of coexisting DNA.
The study was published online in the international journal ACS Applied Materials & Interfaces on August 1, 2024.
Links：Graduate School of Arts and Sciences, The University of Tokyo.（in Japanese）
Journal
-
Journal name ACS Applied Materials & InterfacesTitle of paper