Digital Optofluidics: LED-Gated Transport and Fusion of Microliter-Sized Organic Droplets for Chemical Synthesis

Microdroplet-based organic syntheses have been developed as a valuable alternative to traditional bulk-based methods. However, unlike their water counterparts, organic microdroplets can prove challenging to manipulate. Here, we describe the first optical manipulation of discrete, nanoliter- to microliter-sized apolar droplets floating on a liquid surface to induce on-demand droplet fusion for organic synthesis. We demonstrate droplet transport on centimeter-scale distances at speeds of 0.1 to 1 mm·s–1 with well-programmable, sequential or parallel, fusion events. Because our strategy is compatible with most usual hydrocarbon solvents, such droplets can be used as microcompartments for reagents. Organic reactions readily occur upon droplet fusion, as demonstrated with an ene reaction. With an LED as the sole power source, and without any fabrication step, optical setup, pump or electrode implementation, our method provides a robust and versatile way to place digital organic chemistry under optical control.

基于微液滴的有机合成已成为传统本体合成方法的极具价值的替代方案。然而，与水相微液滴不同，有机微液滴的操控往往颇具挑战性。本文首次报道了漂浮于液面上的离散纳升至微升级非极性液滴的光操控技术，可按需触发液滴融合以开展有机合成。我们实现了液滴以0.1至1 mm·s⁻¹的速度在厘米级距离内的输运，并可实现可编程的顺序或并行融合操作。由于该策略兼容绝大多数常用烃类溶剂，此类液滴可作为试剂的微反应隔间。液滴融合后可顺利发生有机反应，我们以烯反应验证了这一点。本方法仅以LED作为唯一电源，无需任何制备步骤、光学装置、泵浦或电极部署，为实现数字化有机合成的光控操作提供了一种稳健且通用的途径。