(179g) Actuated Tweezers for Electrokinetic Sample Separation

The isolation of specific particle by means of filtration is a crucial step towards the analysis of target species within a heterogeneous input sample. There is a need for a method of targeted filtration that minimizes strain on the sample particle. Currently, conventional methods of separation and filtration, such as centrifugation and fluidic techniques, can exert potentially harmful forces on the sample resulting in the loss or damage of desired species. To address these concerns a device has been developed that can perform “stress-free” separation on a given sample. This Electrokinetic Tweezer’s device utilizes a precise rail system to actuate electrode “tweezers” through a sample to selectively collect targets for removal. The device utilizes the phenomenon of dielectrophoresis to allow for selective collection by applying a non-uniform sinusoidal electric field ranging between 0 – 10 Vpp and 0 – 10 MHz. The result is an applied force on the desired particles drawing them towards the electrodes for removal. As opposed to traditional dielectrophoretic separation techniques the electrokinetic tweezers allow for a stationary sample with actuated electrodes eliminating the stress attributed to the motion associated with centrifugal forces or fluidics. The device was tested on a sample of red blood cell phantoms with comparable dielectric properties to red blood cells in human blood plasma and demonstrated a rate of removal near 200,000 targets/min. The desktop device is versatile with a modular design allowing for the exchange of different electrode designs, channel geometries, and applied electric field. It also easily interfaces with standard infusion pumps for automated sample loading. The electrokinetic tweezer’s shows promise in a variety of fields such as plasmapheresis and cell sorting giving it the potential to become a low-cost and robust multipurpose clinical tool.