Opt Lett. 2020 Mar 1;45(5):1164-1167. doi: 10.1364/OL.383770.
The generation and manipulation of small aqueous droplets is an important issue for nano- and biotechnology, particularly, when using microfluidic devices. The production of very small droplets has been frequently carried out by applying intense local electric fields to the fluid, which requires power supplies and metallic electrodes. This procedure complicates the device and reduces its versatility. In this work, we present a novel and flexible, to the best of our knowledge, electrodeless optoelectronic method for the production of tiny droplets of biologically friendly aqueous fluids. Our method takes advantage of the photoinduced electric fields generated by the bulk photovoltaic effect in iron-doped lithium niobate crystals. Two substrate configurations, presenting the polar ferroelectric axis either parallel or perpendicular to the active surface, have been successfully tested. In both crystal geometries, small droplets on the femtoliter scale have been obtained, although with a different spatial distributions correlated with the symmetry of the photovoltaic fields. The overall results demonstrate the effectiveness of the optoelectronic method to produce femtoliter droplets, both with pure water and with aqueous solutions containing biological material.
当使用微流控设备时，小水相液滴的产生和操控是纳米技术和生物技术的一个重要问题。非常小液滴的产生通常通过向流体施加强局部电场来实现，这需要电源和金属电极。这个过程使设备复杂化，并降低了其通用性。在这项工作中，我们提出了一种新颖的、灵活的、据我们所知的无电极光电方法，用于产生生物友好的水相流体的微小液滴。我们的方法利用了掺杂铁的铌酸锂晶体中的体光伏效应产生的光致电场。已经成功测试了两种具有平行或垂直于活性表面的铁电轴的基底配置。在两种晶体几何形状中，都获得了皮升级别的小液滴，尽管它们的空间分布与光伏场的对称性有关。总体结果表明，光电方法在产生皮升级别的液滴方面是有效的，无论是纯水还是含有生物材料的水溶液。
