Title: An Integrated Droplet Manipulation Platform with Photodeformable Microfluidic Channels

Author: Quan Liu, Guodong Yu, Chongyu Zhu, Bo Peng, Ruohan Li, Tao Yi, Yanlei Yu*

Journal: Small Methods, 2021, 5(12), 2100969

Abstract:

Manipulating droplets by light in microscale allows precise control of microfluidics, liquid delivery, micromachines, and so on. Among these applications, microfluidic technology is of particular interest for miniaturization of the portable analysis systems, which require the integration of various liquid operations in one device. Here, a photodeformable microfluidic platform is constructed by combining Laplace pressure and capillary condensation to integrate the transportation, fusion, separation, and mixing of liquid slugs in one chip. The Laplace pressure, attributed to the photodeformation of the liquid crystal polymers, is generated to propel the slug. The capillary condensation is introduced by the delicate design of the fluid channels, allowing the fusion and separation of slugs without any connected microvalves. Catalytic oxidation reaction and protein detection processes are realized in the platform, which are amenable to a variety of miniaturized bio-medical applications, such as portable analysis and point of care testing.

Fulltext Link: https://onlinelibrary.wiley.com/doi/10.1002/smtd.202100969

In this work, the actuation layer photo-deformable liquid crystal polymer material is combined with PMMA substrate with a microchannel structure to construct an all-light-control microfluidic chip: 1) The asymmetric deformation of the microchannel is used to generate Laplace pressure to drive the droplet transportation in the channel; 2) at the same time, the capillary condensation effect is introduced by the delicate design of the fluid channels to realize the fusion and separation of the droplets under the light drive; 3) the capillary action is used to cause the droplet vortex to promote the stirring and mixing of the sample in the transportation process.