Microfabricated Gate-Modulated Electrochemical Ion Spectroscopy Sensor
ABSTRACT Flow-through field effect transistor structures are utilized as tunable, electrochemical ion- selective sensors to analyze the ionic content of channel fluids from drain-source current measurements and gate conductance spectroscopy. Compared to ion-selective electrodes in a flowFET its gate region acts as a programmable membrane determined by the gate potential. DC measurement results using aqueous solutions of NaCl and CuSO4 in the 10-4-10-7 molar range are discussed.
Full-textDOI: · Available from: Massood Tabib, May 07, 2014
SourceAvailable from: Senol Mutlu[Show abstract] [Hide abstract]
ABSTRACT: We have previously demonstrated that polymer plugs with sub-micron pores can suppress unwanted pressure-driven flow and enhance electro-osmotic flow in a microchannel. This paper presents two separate concepts related to electrode placement and biasing strategy that further abate generation of bubbles in the main flow. In the first concept the drive signal is applied to a main EOF porous plug through high flow resistance porous bridges present outside the main flow. In the second approach, metal electrodes are located within the main channel across a series of dielectrically isolated narrow channels. Bubble generation is suppressed with a high-frequency square wave drive, and net unidirectional flow is achieved by modulation of the zeta potential on the narrow channel surfaces. Flow velocities of 10-66 μm/sec in 20-μm high channels have been achieved by these two methods.Micro Electro Mechanical Systems, 2004. 17th IEEE International Conference on. (MEMS); 02/2004
[Show abstract] [Hide abstract]
ABSTRACT: The magnitude and direction of the electro-osmotic flow (EOF) inside a microfabricated fluid channel can be controlled by a perpendicular electric field of 1.5 megavolts per centimeter generated by a voltage of only 50 volts. A microdevice called a "flowFET," with functionality comparable to that of a field-effect transistor (FET) in microelectronics, has been realized. Two flowFETs integrated with a channel junction have been used to generate opposite flows inside a single EOF-pumped channel, thus illustrating the potential of the flowFET as a controlling and switching element in microfluidic networks.Science 11/1999; 286(5441):942-5. DOI:10.1126/science.286.5441.942 · 31.48 Impact Factor
Pumping MEMS 2004 3EN5. 176..