The ability to manipulate bioparticles is fundamental necessity and important in many modern biomedical technologies, including biosensors and biochips, tissue engineering, drug delivery and micro electro mechanical systems. Microfludic and dielectrophoretic (DEP) force method has attracted most attention due to its number of advantages. The goal of this research work is to develop Microfluidic and dielectrophoretic based miniaturized devices for pre-concentration of analytes and develop a comprehensive understanding of effects pre-concentration on electronic biosensing mechanism. These miniaturized devices have numerous advantages over others for low applied voltage, flexibility and compatibility for amalgamation into lab-on-a-chip devices. With optimized design of channel geometry, channel dimensions, electrode patterns, and properly selected operation condition, the miniaturized devices are integrated with poly-silicon nanowire field effect transistor (Poly-Si NW FET).
Good degree of DNA pre-concentration was obtained by employing negative-DEP technique. SF-100 Xpress maskless photolithography system has been employed to fabricate Poly (ethylene glycol) diacrylate (PEG-DA) based insulating DEP constriction at low cost with saving time which is especially advantageous for developing micro-electro-mechanical systems. With use of iDEP technique we achieved pre-concentration at desired sensing region and the pre-concentration of low dielectric strength biomolecules (such as DNA), was undeterred by the lower biomolecular polarizability. Furthermore, Oxygen plasma treatment resulted in significant improved performance due to passivation of Si dangling-bond defects. The pH sensitivity of the device treated with oxygen plasma was 400 mV pH-1 which is a significant improvement for chemical sensing applications. Finally, inertial focusing was employed for effective DNA pre-concentration on Poly-Si NWFET and high sensitivity is ensured even with low concentration of target DNA. These results provided important information for the future development of the Poly-Si NWFET for a variety of biological sensing experiments

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