Investigating biological and synthetic nanoscopic species in liquids, at the ultimate resolution of single entity, is important in diverse fields^1,2,3,4,5. Progress has been made^6,7,8,9,10, but significant barriers need to be overcome such as the need for intense fields, the lack of versatility in operating conditions and the limited functionality in solutions of high ionic strength for biological applications. Here, we demonstrate switchable electrokinetic nanovalving able to confine and guide single nano-objects, including macromolecules, with sizes down to around 10 nanometres, in a lab-on-chip environment. The nanovalves are based on spatiotemporal tailoring of the potential energy landscape of nano-objects using an electric field, modulated collaboratively by wall nanotopography and by embedded electrodes in a nanochannel system. We combine nanovalves to isolate single entities from an ensemble, and demonstrate their guiding, confining, releasing and sorting. We show on-demand motion control of single immunoglobulin G molecules, quantum dots, adenoviruses, lipid vesicles, dielectric and metallic particles, suspended in electrolytes with a broad range of ionic strengths, up to biological levels. Such systems can enable nanofluidic, large-scale integration and individual handling of multiple entities in applications ranging from single species characterization and screening to in situ chemical or biochemical synthesis in continuous on-chip processes.

在单个实体的最终分辨率下，研究液体中的生物和合成纳米级物种在各个领域^1,2,3,4,5中都很重要。^6,7,8,9,10取得了进展，但需要克服重大障碍，例如需要强磁场，在操作条件下缺乏通用性以及在生物应用中需要高离子强度的溶液中功能有限。在这里，我们演示了可切换的电动纳米阀，它可以在芯片实验室环境中限制和引导单个纳米物体，包括尺寸大至10纳米左右的大分子。纳米阀基于使用电场对纳米物体的势能景观进行时空剪裁，该电场通过壁纳米形貌和纳米通道系统中的嵌入式电极协同调节。我们结合了纳米阀，以将单个实体与整体分离，并演示了它们的引导，限定，释放和分类。我们显示了按需运动控制的单个免疫球蛋白G分子，量子点，腺病毒，脂质囊泡，电介质和金属颗粒，悬浮在具有广泛离子强度的电解质中，直至生物学水平。这样的系统可以实现纳米流体的大规模集成，并可以在从单个物种表征和筛选到连续片上工艺中的原位化学或生化合成的应用中对多个实体进行单独处理。