A single-cell encapsulation method based on a microfluidic multi-step droplet splitting system

Single cell analysis is of great significance to understand the physiological activity of organisms. Microfluidic droplet is an ideal analytical platform for single-cell analysis. We developed a microfluidic droplet splitting system integrated with a flow-focusing structure and multi-step splitting structures to form 8-line droplets and encapsulate single cells in the droplets. Droplet generation frequency reached 1021 Hz with the aqueous phase flow rate of 1 mu L/min and the oil phase flow rate of 15 mu L/min. Relative standard deviation of the droplet size was less than 5% in a single channel, while less than 6% in all the 8 channels. The system was used for encapsulating human whole blood cells. A single-cell encapsulation efficiency of 31% was obtained with the blood cell concentration of 2.5 x 10(4) cell/mu L, and the multicellular droplet percentage was only 1.3%. The multi-step droplet splitting system for single cell encapsulation featured simple structure and high throughput. (C) 2015 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.