Laser-direct-write creation of three-dimensional OREST microcages for contact-free trapping, handling and transfer of small polarizable neutral objects in solution

Contact-free handling, trapping and precise transfer of small polarizable neutral objects in solution based on dielectrophoresis is demonstrated. Laser-direct-write-created concentric aluminum ring electrode microcages are generated coaxially on top of a glass capillary that enables the direct, fast and precise transfer of specimens to and from the cage's trapping region. In this way, aggregates of pre-selected and desired size can be formed as demonstrated for pairs, triples and also larger clusters. Using a combination of two traps, which can freely be positioned with respect to each other, pairs of objects can be separated, keeping one of the constituents trapped.