NYU Arts & Science
Soft Condensed Matter Seminars
November 20, 2017 Monday 3:00 PM  +
726 Broadway, room 871
Soft Condensed Matter Seminars (csmr)

Dave Philips
University of Exeter, UK

Hydrodynamic Micro-Manipulation

Optical tweezers have proven to be an extremely versatile tool to manipulate microscopic particles and investigate the mechanics of biological systems at the nanoscale. However, any object manipulated using optical tweezers is necessarily immersed in high intensity laser light, which places constraints on what materials can be manipulated, and can be potentially damaging to living cells. Here I will describe the development a new kind of micro-manipulation system based on locally generated fluid flow. The motion of optically trapped ‘actuator particles’ is orchestrated to engineer complex time-varying flow fields - enabling precise control of the trajectory of nearby free-floating particles (‘targets’). The actuator motion is driven using feedback based on measurement of the recent positions of target particles, combined with real-time multi-particle flowfield prediction. We demonstrate the suppression of Brownian motion and the targeted manipulation of multiple free-floating particles simultaneously, using only the indirect forces of the surrounding fluid. This technique removes material constraints over particles that can be ‘tweezed’, and may be useful for manipulation of delicate biological specimens and light sensitive cells.