The European Physical Journal E ( IF 1.8 ) Pub Date : 2021-03-23 , DOI: 10.1140/epje/s10189-021-00008-x Tao Huang 1, 2 , Bergoi Ibarlucea 1 , Anja Caspari 3 , Alla Synytska 3, 4 , Gianaurelio Cuniberti 1 , Joost de Graaf 5 , Larysa Baraban 2
|
Abstract
Control over micromotors’ motion is of high relevance for lab-on-a-chip and biomedical engineering, wherein such particles encounter complex microenvironments. Here, we introduce an efficient way to influence Janus micromotors’ direction of motion and speed by modifying their surface properties and those of their immediate surroundings. We fabricated light-responsive Janus micromotors with positive and negative surface charge, both driven by ionic self-diffusiophoresis. These were used to observe direction-of-motion reversal in proximity to glass substrates for which we varied the surface charge. Quantitative analysis allowed us to extract the dependence of the particle velocity on the surface charge density of the substrate. This constitutes the first quantitative demonstration of the substrate’s surface charge on the motility of the light-activated diffusiophoretic motors in water. We provide qualitative understanding of these observations in terms of osmotic flow along the substrate generated through the ions released by the propulsion mechanism. Our results constitute a crucial step in moving toward practical application of self-phoretic artificial micromotors.
Graphic abstract
中文翻译：
表面电荷对光激活 Janus 微电机运动的影响
摘要
对微电机运动的控制与芯片实验室和生物医学工程高度相关，因为此类颗粒会遇到复杂的微环境。在这里，我们介绍了一种通过修改 Janus 微电机及其周围环境的表面特性来影响其运动方向和速度的有效方法。我们制造了具有正表面电荷和负表面电荷的光响应 Janus 微电机，两者均由离子自扩散电泳驱动。这些用于观察玻璃基板附近的运动方向反转，我们改变了玻璃基板的表面电荷。定量分析使我们能够提取粒子速度对基材表面电荷密度的依赖性。这是基底表面电荷对水中光激活扩散电泳马达运动性的首次定量证明。我们根据推进机制释放的离子产生的沿基底的渗透流对这些观察结果进行定性理解。我们的结果构成了自泳人造微电机实际应用的关键一步。
京公网安备 11010802027423号