Micro-electro-mechanical systems are now used in a wide variety of applications ranging from biodetection to the healthcare industry. Electrokinetic techniques such as dielectrophoresis and electroosmosis are frequently used for the manipulation of cells, molecules, and spores. In this paper, we show that dielectrophoresis can be used to manipulate allergens and bacteria in a wide variety of microfluidic devices. We have found that allergens such as Penicillium brevicompactum demonstrate positive dielectrophoresis and moves toward high field gradient regions while the non-biological latex beads move towards the low electric field gradient regions. Microfluidic devices equipped with dielectrophoretic gates arranged perpendicular to the flow were designed and fabricated at Sandia National Laboratories. Experiments were conducted on flowing suspensions over a broad range of flow and electric field parameters to investigate how these characteristics affect the concentration and separation of particles. Trapping using the dielectrophoretic gating device as well as the design, experimental results, and analysis of devices for particle filtration are presented. Some of the devices were fabricated using Sandia’s (SwIFT™) process while other devices were fabricated using polymers and traditional photolithography methods. We present both methods used in the fabrication of devices. The long-term goal is to develop complete hand held Lab-on-a-Chip microsystems for biodetection. The ability to manipulate and concentrate minute particles can allow for advances in the medical field as well as the future detection of biological warfare agents such as anthrax. In order to analyze biological analytes, it is first necessary to develop a method for positioning and detecting the analyte of interest. Concentrating biological particles such as the allergen Penicillium brevicompactum (PBC), Bacillus globigii (BG) spores, an anthrax stimulant, and Staphylococcus Aureus (Staph Cells), a type of food bacteria, is done using the principle of dielectrophoresis. Microfluidic devices which we use to test the suspensions were fabricated using the SwIFT™ process developed by Sandia National Laboratories. In addition, electrode designs were also fabricated using a process that we have developed in-house at the University of Maryland Baltimore County (UMBC) using polydimethysiloxane, PDMS, to make the channels and the deposition of gold, Au, as the material for the electrodes fabricated with the low pressure chemical vapor deposition method (LPCVD).

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