Detection and Automation Technologies for the Mass Production of Droplet Biomicrofluidics

Droplet microfluidics utilizes two immiscible flows to generate small droplets with the diameter of a few to a few hundred micrometers. These droplets are promising tools for biomedical engineering because of the high throughput and the ease to finely tune the microenvironments. In addition to the great success of droplet biomicrofluidics in the proof-of-concept biosensing, regenerative medicine, and drug delivery, few droplet biomicrofluidic devices have a transformative impact on the industrial and clinical applications. The main issues are the low volume throughput and the lack of proper methods for quality control and automation. This review covers the methodologies for the mass production, detection, and automation of droplet generators. Recent advances in droplet mass production using parallelized devices and modified junction structures are discussed. Detection techniques, including optical and electrical detection methods, are comprehensively reviewed in detail. Newly emerged droplet closed-loop control systems are surveyed to highlight the progress in system integration and automation. Overall, with the advances in parallel droplet generation, highly sensitive detection, and robust closed-loop regulation, it is anticipated that the productivity and reliability of droplet biomicrofluidics will be significantly improved to meet the industrial and clinical needs.