Electrodeless dielectrophoretic concentrator for analyte pre-concentration on poly-silicon nanowire field effect transistor

The sensitivity of biosensors can be affected by mass transport limitations as a result of miniaturization. To enhance signal sensitivity, pre-concentration of deoxyribonucleic acid (DNA), in the vicinity of the sensing elements of n-type polycrystalline silicon nanowire field effect transistor (Poly-Si NWFET) is demonstrated using a microfluidic device based on insulator or gradient dielectrophoresis (iDEP) to overcome mass transport limitations. In insulator-based dielectrophoresis (iDEP), insulating microstructures produce non-uniform electric fields to drive dielectrophoresis (DEP) in microsystems. Fabrication of accurately controlled three-dimensional (3D) microstructure of poly (ethylene glycol) diacrylate (PEG-DA) with a narrow microchannel using maskless gray-scale lithography is described. The fabrication of three-dimensional structures at low cost with saving time is accomplished by the use of maskless exposure system. PEG-DA has been used due to its excellent biocompatibility and ease of fabrication. To enhance the stability of PEG-DA, we added another polymer pentaerythritol tetraacrylate (PETA). Electrical property of the Poly-Si NWFET is ensured by plotting I-V_G curve after the integration of iDEP micro device.