A. S. Johnson

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The use of microchip devices to study cellular systems is a rapidly growing research area. There are numerous advantages of using on-chip integrated electrodes to monitor various cellular processes. The purpose of this review is to give examples of advancements in microchip-based cellular analysis, specifically where electrochemistry is used for the(More)
In Part II of this series describing the use of polystyrene (PS) devices for microfluidic-based cellular assays: various cellular types and detection strategies are employed to determine three fundamental assays often associated with cells. Specifically, using either integrated electrochemical sensing or optical measurements with a standard multi-well plate(More)
In Part I of a two-part series, we describe a simple and inexpensive approach to fabricate polystyrene devices that is based upon melting polystyrene (from either a Petri dish or powder form) against PDMS molds or around electrode materials. The ability to incorporate microchannels in polystyrene and integrate the resulting device with standard laboratory(More)
A new method of fabricating electrodes for microchip devices that involves the use of Teflon molds and a commercially available epoxy to embed electrodes of various sizes and compositions is described. The resulting epoxy base can be polished to generate a fresh electrode and sealed against poly(dimethylsiloxane) (PDMS)-based fluidic structures.(More)
In this work, a polystyrene (PS)-polydimethylsiloxane (PDMS) hybrid device was developed to enable the integration of cell culture with analysis by microchip electrophoresis and electrochemical detection. It is shown that this approach combines the fundamental advantages of PDMS devices (the ability to integrate pumps and valves) and PS devices (the ability(More)
This paper describes the use of epoxy-encapsulated electrodes to integrate microchip-based electrophoresis with electrochemical detection. Devices with various electrode combinations can easily be developed. This includes a palladium decoupler with a downstream working electrode material of either gold, mercury/gold, platinum, glassy carbon, or a carbon(More)
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