Particle and cell counting is used for a variety of applications including routine cell culture, hematological analysis, and industrial controls(1-5). A critical breakthrough in cell/particle counting technologies was the development of the Coulter technique by Wallace Coulter over 50 years ago. The technique involves the application of an electric field across a micron-sized aperture and hydrodynamically focusing single particles through the aperture.
View Article and Find Full Text PDFSingle-cell electric impedance topography (sceTopo), a technique introduced here, maps the spatial distribution of capacitance (i.e. displacement current) associated with the membranes of isolated, living cells.
View Article and Find Full Text PDFThe fabrication and characterization of a microchamber electrode array for electrical and electrochemical studies of individual biological cells are presented. The geometry was tailored specifically for measurements from sensory hair cells isolated from the cochlea of the mammalian inner ear. Conventional microelectromechanical system (MEMS) fabrication techniques were combined with a heat-sealing technique and polydimethylsiloxane micromolding to achieve a multilayered microfluidic system that facilitates cell manipulation and selection.
View Article and Find Full Text PDFOur results demonstrate high-frequency electrical resonances in outer hair cells (OHCs) exhibiting features analogous to classical piezoelectric transducers. The fundamental (first) resonance frequency averaged f(n) approximately 13 kHz (Q approximately 1.7).
View Article and Find Full Text PDFMeas Sci Technol
August 2003
Microfluidic devices with channel cross sections measuring 4 × 10 μm(2) instrumented with gold microelectrodes were used to sense flow rates of ionic solutions on the basis of electric impedance (EI) measured perpendicular to the flow. Negative pressures were applied to access ports of the microdevices to generate flow of saline solutions (physiologic concentrations 0.9%) through the micro-EI recording zone with flow rates between 2.
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