State Key Laboratory of Robotics and System, Harbin Institute of Technology, West Da-zhi Street 92, Harbin, Heilongjiang 150001, People's Republic of China.
School of Engineering and Applied Sciences and Department of Physics Harvard University, 9 Oxford Street, Cambridge, MA 02138, USA.
Soft Matter. 2022 Jan 19;18(3):609-616. doi: 10.1039/d1sm01550h.
The heart beating phenomenon of room temperature liquid metal (LM) mercury has attracted much attention in the past years, but its research and application are limited because of the low vapor pressure and high toxicity. Here, a fundamental scientific finding is reported that the non-toxic eutectic gallium indium (EGaIn) alloy droplets beat periodically at a certain frequency based on a floating electrode under the stimulation of the direct current (DC) field. The essential characteristics of heart beating are the displacement and the projected area change of the LM droplet. The mechanism of this phenomenon is the self-regulation of interfacial tension caused by chemical oxidation, chemical corrosion, and continuous electrowetting. In this article, a series of experiments are also carried out to examine the effects of different factors on the heartbeat, such as voltage, the volume of the droplet, the droplet immersion depth, the electrolyte solution concentration, the distance of electrodes, and the type of floating electrode. Finally, the heartbeat state and application boundary of the LM droplet under different conditions are summarized by imitating the human life process. The periodic changes of the LM droplet under an external DC electric field provide a new method to simulate the beating of the heart artificially, and can be applied to the research of organ chip fluid pumping in the future.
室温液态金属（LM）汞的跳动现象在过去几年中引起了广泛关注，但由于其蒸气压低和毒性高，其研究和应用受到限制。在这里，我们报道了一个基础科学发现，即在直流（DC）场的刺激下，基于浮置电极，无毒的共晶镓铟（EGaIn）合金液滴会以一定的频率周期性地跳动。LM 液滴跳动的基本特征是其位移和投影面积的变化。这种现象的机制是化学氧化、化学腐蚀和连续电润湿引起的界面张力的自我调节。在本文中，还进行了一系列实验来研究不同因素对心跳的影响，如电压、液滴体积、液滴浸深、电解质溶液浓度、电极距离和浮置电极的类型。最后，通过模拟人体生命过程，总结了不同条件下 LM 液滴的心跳状态和应用边界。在外加直流电场下 LM 液滴的周期性变化为人工模拟心脏跳动提供了一种新方法，并可应用于未来器官芯片流体泵送的研究。
