Self-synchronization of reinjected droplets for highefficiency droplet pairing and merging  

作　　者：Lang Nan Tianjiao Mao Ho Cheung Shum 

机构地区：[1]Advanced Biomedical Instrumentation Centre,Hong Kong Science Park,Shatin,New Territories,Hong Kong,China [2]Department of Mechanical Engineering,The University of Hong Kong,Pokfulam Road,Hong Kong,China

出　　处：《Microsystems & Nanoengineering》2023年第2期181-192,共12页微系统与纳米工程（英文）

基　　金：the financial support provided by the General Research Fund(Nos.17307919);the Research Grants Council of Hong Kong and the Excellent Young Scientists Fund(Hong Kong and Macao)(21922816)from the National Natural Science Foundation of China.

摘　　要：Droplet merging serves as a powerful tool to add reagents to moving droplets for biological and chemical reactions.However,unsynchronized droplet pairing impedes high-effciency merging.Here,we develop a microfluidic design for the self-synchronization of reinjected droplets.A periodic increase in the hydrodynamic resistance caused by droplet blocking a T-junction enables automatic pairing of droplets.After inducing spacing,the paired droplets merge downstream under an electric field.The blockage-based design can achieve a 100%synchronization efficiency even when the mismatch rate of droplet frequencies reaches 10%.Over 98%of the droplets can still be synchronized at nonuniform droplet sizes and fluctuating reinjection flow rates.Moreover,the droplet pairing ratio can be adjusted flexibly for on-demand sample addition.Using this system,we merge two groups of droplets encapsulating enzyme/substrate,demonstrating its capacity to conduct multi-step reactions.We also combine droplet sorting and merging to coencapsulate single cells and single beads,providing a basis for high-efficiency single-cell sequencing.We expect that this system can be integrated with other droplet manipulation systems for a broad range of chemical and biological applications.

关 键 词：field MERGE SPACING 

分 类 号：O35[理学—流体力学]