A novel method for the continuous separation of microorganisms based on electrical properties

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 101-103).Increased throughput in the techniques used to engineer new metabolic pathways in unicellular organisms demands similarly high throughput tools for measuring the effects of these pathways on phenotype. For example, the metabolic engineer is often faced with the challenge of selecting the one genomic perturbation that produces a desired result out of tens of thousands of possibilities. This thesis proposes a separation method - iso-dielectric separation, or IDS - which separates microorganisms continuously based on their dielectric properties. This technology would enable high throughput screening of cells based upon electrically distinguishable phenotypes. Iso-dielectric separation uses dielectrophoresis (DEP) and media with spatially varying conductivity to separate cells based upon their effective conductivity. Our target application is the separation of Escherichia coli based upon the amount of the intracellular polymer poly(hydroxybutyrate) that each cell contains. This thesis discusses the modeling, design, fabrication, and testing of an IDS device.by Michael D. Vahey.S.M

Predictive control of a micro bead's trajectory in a dielectrophoresis-based device

International audienceMicro and nano-particles can be trapped by a non uniform electric field through the effect of the dielectrophoretic force. Dielectrophoresis (DEP) is used to separate, manipulate and sense micro particles in several domains, such as in biological or Carbon Nano-Tubes (CNTs) manipulations. This paper tackles the creation of a closed loop strategy in order to control, using DEP, the trajectory of micro objects using vision feedback. A modeling of the dielectrophoresis force is presented to illustrate the non linearity of the system and the high dynamics of the object under dielectrophoresis . A control strategy based on the generalized predictive control method is proposed with the aim of controlling the trajectory, taking advantage of the high dynamics despite the non linearity. Simulated results are shown to evaluate our control strategy