Microfluidic on-demand engineering of longitudinal dynamic self-assembly of particles.

The lack of a simple operable method for on-demand engineering of longitudinal dynamic self-assembly of particles is one of the main problems in employing particle manipulation in biomedical research studies. Herein, a viscoelasticity-induced self-assembling microfluidic system is proposed to increase the maneuverability and orderliness of longitudinal dynamic self-assembly of particles, and achieve the on-demand control of interparticle spacings and frequencies of particles passing through an outlet. In our microfluidic system, two kinds of functional microstructures and a side-channel were designed to preprocess randomly distributed particles allowing them not to aggregate but rather to evenly distribute, and realize the on-demand control of the particle volume concentration.