Biocompatible, pump-free microfluidic actuation is a challenging task for optically integrated lab-on-chips. Herein, photovoltaic actuation of aqueous microdroplets is demonstrated inside the oil-infused PDMS channels fabricated on a c-cut LiNbO₃:Fe (LN:Fe) substrate. This photovoltaic actuation is based on the repulsive response of aqueous microdroplets to laser illumination, and its “nonlocal” feature can avoid the direct laser illumination on aqueous microdroplets containing fragile biochemical targets. Both the direct electrostatic force acting on the aqueous microdroplet and the repulsive force induced by the compressed convection flow of infused oil are found contributing to this “nonlocal” feature. Due to the transition of electrostatic action from the dielectrophoretic (DEP) to electrophoretic (EP) mechanism, the maximal velocity of photovoltaic actuation in the straight-line channel exhibits a pronounced threshold effect on the laser illumination intensity. Thanking to the strong EP action, the aqueous microdroplet can be actuated to squeeze through a narrow pass in the right-angle channel. Precipitation and chromogenic chemical microreactions as well as mortal reactions of a single paramecium using the photovoltaic actuation are demonstrated for the future on-chip biochemical applications.

生物相容的无泵微流体驱动是光学集成芯片实验室的一项具有挑战性的任务。在此，在 c-cut LiNbO ₃上制造的注入油的 PDMS 通道内展示了水性微滴的光伏驱动:Fe (LN:Fe) 基板。这种光伏驱动基于水性微滴对激光照射的排斥反应，其“非局部”特征可以避免激光直接照射含有脆弱生化目标的水性微滴。发现作用在水性微滴上的直接静电力和注入油的压缩对流引起的排斥力都有助于这种“非局部”特征。由于静电作用从介电泳 (DEP) 到电泳 (EP) 机制的转变，直线通道中光伏驱动的最大速度对激光照射强度表现出明显的阈值效应。感谢强大的EP行动，水性微滴可以被驱动挤过直角通道中的狭窄通道。沉淀和显色化学微反应以及单一的致死反应使用光伏驱动的草履虫被证明用于未来的片上生化应用。