Simultaneous positioning and orientation of a single nano-object by flow control: theory and simulations

In this paper, we theoretically describe a method to simultaneously control both the position and orientation of single nano-objects in fluids by precisely controlling the flow around them. We develop and simulate a control law that uses electro-osmotic flow (EOF) actuation to translate and rotate rigid nano-objects in two spatial dimensions. Using EOF to control nano-objects offers advantages as compared to other approaches: a wide class of objects can be manipulated (no magnetic or electric dipole moments are needed), the object can be controlled over a long range (>100μm) with sub-micrometer accuracy, and control may be achieved with simple polydimethylsiloxane (PDMS) devices. We demonstrate the theory and numerical solutions that will enable deterministic control of the position and orientation of a nano-object in solution, which can be used, for example, to integrate nanostructures in circuits and orient sensors to probe living cells. S Online supplementary data available from stacks.iop.org/NJP/13/013027/ mmedia 4 Author to whom any correspondence should be addressed. 5 PPM is in joint appointment with CNST, NIST, Gaithersburg, MD, USA and Institute of Research in Electronics and Applied Physics, UMD, College Park, USA. New Journal of Physics 13 (2011) 013027 1367-2630/11/013027+27$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft