Pukyong National University

PKNU Research Team Develops Event-Driven Autonomous Droplet Control System

- Research Published in the Prestigious International Journal Sensors & Actuators B: Chemical

- Establishes a Foundation for a CCEP-Based Automated 3D Cell Culture Platform

A research team led by Professor Do-Jin Lim of the Department of Chemical Engineering at Pukyong National University has developed SEDAR (Self-Evolving Droplet Autonomous Regulation), an event-driven autonomous droplet control system capable of recognizing the state of microscopic droplets and automatically responding without external intervention.

Contact Charge Electrophoresis (CCEP)-based digital microfluidic technology has attracted significant attention because it enables the precise movement and manipulation of droplets, offering considerable potential for applications in cell culture, bioanalysis, and laboratory automation platforms. However, conventional systems have largely been confined to laboratory environments, relying on a range of external equipment such as high-voltage power supplies, computers, and cameras. As a result, they have faced limitations in long-term operation and full automation under practical cell-culture conditions.

The research team developed a ‘self-contained CCEP’ platform that integrates a portable battery, high-voltage boost module, Raspberry Pi？based control system, camera, and wireless communication functions into a single device. Using this platform, the researchers successfully implemented a portable system capable of operating independently without the need for external equipment and confirmed that it could function stably for extended periods even inside a cell-culture incubator. The team also verified that the system’s remote monitoring capability enables real-time observation and control of cellular conditions within droplets without opening the incubator.

Building on their previously developed L-SPAA, a universal droplet-control algorithm, the researchers implemented an event-driven routing function that recognizes the state of droplets and automatically responds accordingly. By employing image-analysis technology, the system was able to identify color changes and the presence of particles within droplets in real time and automatically alter droplet movement paths based on the detected conditions. In addition, the team successfully demonstrated the automatic sorting and collection of droplets containing spheroids, further highlighting the platform’s potential for autonomous biological and biomedical applications.

This study is significant in that it greatly expands the potential applications of digital microfluidic technology by integrating the ‘Self-contained CCEP’ platform and ‘Event-driven Routing’ technology into a single system. In particular, the platform provides a foundation for the future development of an automated three-dimensional (3D) cell culture platform based on organoids and spheroids. The researchers noted that the addition of functions such as droplet dispensing, culture medium replacement, and sample sorting and retrieval could further advance the system toward fully automated 3D cell-culture applications.

Dr. Seo-Jun Bae, the first author of the study and a postdoctoral researcher, explained, “While the previously developed L-SPAA was a control technology designed to move droplets efficiently, SEDAR is an autonomous platform capable of operating independently within an incubator and performing tasks based on the state of individual droplets.” He added, “Through this research, we have established the foundation for an integrated operational platform that connects droplet-control, culture-medium handling, and sample-recovery technologies, which had previously been developed separately. Moving forward, we plan to expand the system into a comprehensive platform capable of automating the entire process of organoid- and spheroid-based three-dimensional cell culture.”

The research findings were published in Sensors & Actuators B: Chemical (Impact Factor: 7.7), a globally recognized international journal ranked within the top 2% of the JCR category for Instruments & Instrumentation, under the title “A Self-Contained Event-Driven Autonomous Routing (SEDAR) CCEP System for Droplet 3D Cell Culture.”

The research team led by Professor Do-Jin Lim carried out this study with support from the National Research Foundation of Korea (NRF) under grant number RS-2026-25477068. <Pukyong Today>