Gao Zuoxuan, Yan Jinghui, Shi Lihong, Liu Xiaohu, Wang Mengtong, Li Chenyu, Huai Zechao, Wang Cheng, Wang Xuan, Zhang Lina, Yan Wenbo
State Key Laboratory of Reliability and Intelligence of Electrical Equipment, School of Materials Science and Engineering, Hebei University of Technology, Tianjin, 300130, China.
Hebei Engineering Laboratory of Photoelectronic Functional Crystals School of Materials Science and Engineering, Hebei University of Technology, Tianjin, 300130, China.
Adv Mater. 2023 Dec;35(49):e2304081. doi: 10.1002/adma.202304081. Epub 2023 Nov 5.
The electrodeless biocompatible manipulation of femtoliter-scale aqueous microdroplets remains challenging. The appropriate isolation of electrostatic charges from femtoliter-scale aqueous microdroplets is crucial for electrodeless optoelectronic manipulation based on space-charge-density modulation. Here, surfactant-mediated photovoltaic manipulation is proposed, where the surfactant layers self-assembled at the water-oil and oil-Lithium niobate interfaces are employed to isolate photovoltaic charges. The reduced electrostatic attenuation, remarkable hydrophobicity, and strong electrical breakdown suppression of the surfactant layers enable the stable and swift manipulation of femtoliter-scale aqueous microdroplets using µW-level laser in oil media. By virtue of the surfactant-mediated photovoltaic manipulation, a controllable merging/touching/detaching switch of aqueous microdroplets by adjusting the laser illumination intensity and position is realized and the cascading biochemical operations and microreactions of aqueous microdroplets and microdroplet strings are demonstrated. To demonstrate its potential in photonic Micro-Electro-Mechanical-System assemblies, the end coupling of a focused-laser-beam into a ZnO microrod leveraging the refraction effect occurring at the water/oil interface is demonstrated. Moreover, because of the selective permeability of the droplet-interface-bilayer developed between the touching microdroplets, in situ adjustment of the size of the microdroplets and the fluorescent solute contained in the microdroplets are achieved, aiming at constructing multicomponent fluorescent microdroplets with tunable whispering-gallery-mode characteristics.
对飞升级水相微滴进行无电极生物相容性操控仍然具有挑战性。从飞升级水相微滴中适当分离静电荷对于基于空间电荷密度调制的无电极光电操控至关重要。在此，提出了表面活性剂介导的光伏操控，其中在水-油和油-铌酸锂界面自组装的表面活性剂层用于分离光伏电荷。表面活性剂层降低的静电衰减、显著的疏水性和强大的电击穿抑制能力，使得能够在油介质中使用微瓦级激光对飞升级水相微滴进行稳定且快速的操控。借助表面活性剂介导的光伏操控，通过调节激光照射强度和位置实现了水相微滴可控的合并/接触/分离切换，并展示了水相微滴和微滴串的级联生化操作和微反应。为了证明其在光子微机电系统组件中的潜力，展示了利用水/油界面处发生的折射效应将聚焦激光束端耦合到ZnO微棒中。此外，由于在接触微滴之间形成的液滴界面双层的选择性渗透性，实现了对微滴尺寸和微滴中所含荧光溶质的原位调节，旨在构建具有可调谐回音壁模式特性的多组分荧光微滴。
