A research paper by scientists at Beijing Institute of Technology and City University of Hong Kong presented a versatile electrodynamics simulation model designed to analyze the driving forces of partially filled electrodes to optimize the structural parameters of Digital microfluidic chips.
The research paper, published on Mar. 06, 2025 in the journal Cyborg and Bionic Systems, utilizes finite element analysis to determine the voltage distribution within the Digital microfluidic chip and calculates the driving force acting on the droplets using the principles of virtual work.
Digital microfluidic chips (DMCs) have shown huge potential for biochemical analysis applications due to their excellent droplet manipulation capabilities. The driving force is a critical factor for characterizing and optimizing the performance of droplet manipulation. Conducting numerical analysis of the driving force is essential for DMC design, as it helps optimize the structural parameters. "Despite advances in numerical analysis, evaluating driving forces in partially filled electrodes remains challenging." said the author Yanfeng Zhao, a researcher at Beijing Institute of Technology, "Here, we propose a versatile electrodynamics simulation model designed to analyze the driving forces of partially filled electrodes to optimize the structural parameters of DMCs."
The study first developed an electrodynamics simulation model by integrating finite element analysis with an electromechanical model to accurately calculate the voltage distribution and driving force on droplets over partially filled electrodes in digital microfluidic chips. Using this model, the researchers systematically investigated how key parameters—including the dielectric constant and thickness of the dielectric layer, as well as the dielectric constant and conductivity of the droplet, and substrate spacing—affect the droplet driving force. They validated the simulation by measuring droplet acceleration as an indicator of driving force and compared these results with the simulated trends. Finally, the optimized model was applied in biochemical experiments to demonstrate effective droplet manipulation and microscopic imaging.
By constructing an electrodynamic simulation method that combines finite element analysis and electromechanical models, this study can accurately calculate the voltage distribution and driving force of droplets on partially filled electrodes, and systematically reveal the effects of dielectric layer parameters, droplet electrical properties, and substrate spacing on droplet driving performance. The experimental verification (using droplet acceleration as an indicator) is basically consistent with the simulation results, proving the reliability of the model and demonstrating the practical application of this method in droplet manipulation and microscopic imaging in biochemical experiments. "We anticipate that the electrodynamics simulation model is capable of evaluating the driving force in partially filled electrodes within complex DMCs, offering unprecedented possibilities for future structural designs of DMCs." said Yanfeng Zhao.
Authors of the paper include Yanfeng Zhao, Zhiqiang Zheng, Jiaxin Liu, Xinyi Dong, Haotian Yang, Anping Wu, Qing Shi, and Huaping Wang.
This research was supported by the National Key Research and Development Program of China under grant 2023YFB4705400; the National Natural Science Foundation of China under grants 62222305 and U22A2064; the Beijing Natural Science Foundation under grants L242023 and 4232055; and the Postdoctoral Fellowship Program of CPSF under grant BX20230459.
The paper, "Structural Optimization of Microfluidic Chips for Enhancing Droplet Manipulation and Observation via Electrodynamics Simulation" was published in the journal Cyborg and Bionic Systems on Mar. 06, 2025, at DOI: 10.34133/cbsystems.0217.
