Fluorescence-DEP experiments were carried out on an upright fluorescence optical microscope (Axioskop 2 FS plus; Carl Zeiss) in reflection mode with 50 X objective focused at 200 µm x 200 µm active area. Labelled bacteria E. coli DHα5 conjugated with nano-ovals suspended in D.I water was injected into the channel to carry out DEP experiments. A filter set with an excitation wavelength of 540-552 nm and emission wavelength of 567-647 nm (filter set 20HE, Carl Zeiss) was used in connection with an Axio Cam MRm digital camera to record fluorescence videos at an exposure time of 0.7 s using a multi-dimensional acquisition mode in the Axio-vision 4.7.1 release software (Carl Zeiss MicroImaging, Inc). Two types of Raman microscopes were used. The first one was an upright Thermo Scientific™ DXR™ Raman confocal microscope equipped with 10 X objective (spot size of 3.1 μm) and 780 nm laser, with Omnic 8 software. A full spectral range scans of 3500-50 cm-1, wavenumber accuracy of ± 2 cm-1 captured with a single exposure of the CCD. Parameters like 5mW lazer power, 50 µm slit width, 1 s exposure time is kept constant for all experiments. Second portable Raman Microscope is a Pro Raman L (Enwave Optronics. Inc.) with CCD detector cooled to -60ºC with spectral range from 3,300 cm-1 to 100 cm-1. Parameters like 325 mW laser power, 1 s exposure time and 100 µm probe diameter at focus were invariable for all experiments. A function generator (Model 33120A, Hewlett Packard) is used to generate different frequencies (f) of the sinusoidal AC voltage; syringe pump (NE-1000) from New Era Pump Systems (Farmingdale, NY) is used to produce various flow velocities. Experiments with change in concentration of cells were performed at optimised freq... ... middle of paper ... ... P.; Jejelowo, A.; Li, J.; Meyyappan, M., Wafer-scale fabrication of patterned carbon nanofiber nanoelectrode arrays: A route for development of multiplexed, ultrasensitive disposable biosensors. Biosensors and Bioelectronics 2009, 24 (9), 2818-2824. 21. Bhana, S.; Chaffin, E.; Wang, Y.; Mishra, S. R.; Huang, X., Capture and detection of cancer cells in whole blood with magnetic–optical nanoovals. Nanomedicine 2013, 1-14. 22. Bonham, A. J.; Braun, G.; Pavel, I.; Moskovits, M.; Reich, N. O., Detection of Sequence-Specific Protein-DNA Interactions via Surface Enhanced Resonance Raman Scattering. Journal of the American Chemical Society 2007, 129 (47), 14572-14573. 23. Arumugam, P. U.; Chen, H.; Cassell, A. M.; Li, J., Dielectrophoretic Trapping of Single Bacteria at Carbon Nanofiber Nanoelectrode Arrays. The Journal of Physical Chemistry A 2007, 111 (49), 12772-12777.