Pneumatically Controlled Nanofluidic Devices for Contact-Free Trapping and Manipulation of Nanoparticles

Contact-free trapping and manipulation of individual nano-objects in solution are of great scientific interest and remain one of the challenges in nanofluidics. Geometry-induced electrostatic (GIE) trapping is one powerful method that enables stable trapping of charged nano-objects smaller than 100 nm without the need of externally applied fields. However, due to the absence of external control, there is a lack of the function to actively control and manipulate the trapped objects. Here, novel trapping devices are fabricated from polydimethylsiloxane (PDMS)-based soft lithography replica molding, which simplifies fabrication and results in high-throughput and low cost production. The development and implementation of a pneumatic system is described that makes the PDMS-based GIE trapping devices capable of controlling the height of the nanofluidic channels. This setup enables fast and flexible tuning of the potential depth and trap stiffness as well as active trapping and release of the nanoparticles during the experiment, paving the way toward highthroughput manipulation of nanoparticles.