We propose Dielectrophoresis (DEP) as a rapid way to agglutinate targeted T. brucei strains. DEP is an electric-field technique that can induce motion on only selected targets, which will increase the specificity of the test. We use DEP to rapidly segregate T. brucei from its surroundings and agglutinate it on specific spots to facilitate its detection. To this end, we use microelectrodes made of either titanium or carbon. In particular, we postulate the use of carbon electrodes to enable DEP of T. brucei and thus inexpensive, rapid and specific agglutination assays.
The experimental setup includes a microfluidics chip featuring multiple rows of intercalated carbon or titanium electrodes (Martinez-Duarte, 2011). Experimental samples of the animal strain T. brucei brucei were pipetted onto a single electrode array, which was polarized using sinusoidal signals with frequencies between 1kHz to 10 MHz at 1-10 Vpp. The array was monitored to characterize the movement of the parasite around the electrodes. Images taken of the experiments were analyzed to assess the velocity of attachment to the electrode array.
Our initial results with both titanium and carbon electrode arrays showed parasite attachment in the range 750 kHz to 2 MHz. By implementing numerical modeling of the electric field of the device, the electric field gradient was simulated as strongest along the curve of the semicircle. This simulation corresponds to the observed location of attraction.
Ongoing work is to further characterize specificity of T. brucei movement and to investigate new carbon electrode geometries that will increase the speed of parasitic attachment. Our goal is to eventually create a DEP device with an operational protocol similar to that currently used. We aim to create an inexpensive DEP device that only require batteries for operation.
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