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Paredes J.,University of California at Berkeley | Paredes J.,Berkeley Sensors and Actuators Center | Paredes J.,University of Navarra | Fink K.D.,University of California at Berkeley | And 6 more authors.
Sensors and Actuators, B: Chemical | Year: 2015

Abstract Microfluidic devices play an increasingly important role in healthcare-related fields, but integration of electrodes and electronic components has been restricted at the prototyping stage of product development by a limited range of fabrication methods. In this work a new fabrication methodology is presented for embedding metallic microelectrodes in thermoplastic microfluidic devices. Microelectrodes are fabricated on steel wafers by means of photolithographic patterning and electrodeposition and then transferred to a thermoplastic sheet using hot embossing, resulting in embedded metal electrodes flush with the polymer surface. The unique shape of the microelectrodes provides an anchoring mechanism that ensures structural stability and reliability of the devices. A wide variety of thermoplastics can be used in this process including polycarbonate, polymethylmethacrylate (PMMA), and cyclic olefin copolymer (COC). Devices are assembled by a solvent-assisted bonding process, after drilling the inlets and outlets. This method allows for rapid fabrication of robust embedded electrodes and wiring connections from a broad range of metals for thermoplastic microfluidic devices. Finally, embedded interdigitated microelectrodes are used to measure conductivity within a microchannel via impedance spectroscopy analysis. The use of this technology is relevant to a wide range of analytical applications. © 2015 Elsevier B.V. All rights reserved.

Iyer V.,Berkeley Sensors and Actuators Center | Murali P.,Berkeley Sensors and Actuators Center | Paredes J.,University of Navarra | Liepmann D.,Berkeley Sensors and Actuators Center | Boser B.,Berkeley Sensors and Actuators Center
2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2015 | Year: 2015

A method for fabricating thermoplastic cartridges encapsulating integrated circuits, electrodes, and microfluidic channels using hot embossing is described for the application of a point of care magnetic label flow cytometer. Finished devices with a microchannel depth of 86 μm and RMS surface roughness of 1.6 μm are capable of operating at pressures of up to 227 kPa without leaks. The device was used to evaluate the efficiency of an on chip magnetic focusing structure which successfully focused 98% of the 4.5 μm Dynabeads® to a 30 μm target region using 100 mA of current and a 4 mT external field. © 2015 IEEE.

Paredes J.,University of Navarra | Chooljian M.,University of California at Berkeley | Fink K.D.,University of California at Berkeley | Liepmann D.,University of California at Berkeley | Liepmann D.,Berkeley Sensors and Actuators Center
18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014 | Year: 2014

Methods of fabricating microfluidic devices that are scalable, simple, and inexpensive are necessary to ease the transition of microfluidics from an academic to an industrial discipline. Here we present a method for rapid prototyping of microfluidic devices with embedded electrodes in plastic based on electroplating and hot embossing techniques. We then discuss its applicability to electroporation and lysis, two of many potential applications that could benefit from this manufacturing method. © 14CBMS.

Aran K.,University of California at Berkeley | Aran K.,Berkeley Sensors and Actuators Center | Parades J.,University of California at Berkeley | Parades J.,Berkeley Sensors and Actuators Center | And 8 more authors.
Advanced Materials | Year: 2015

A digital point-of-care biosensor for measuring reactive oxygen species is presented based on novel reactive oxygen species responsive polymer-based electrodes. The biosensor is able to detect a drug-induced liver injury by monitoring the oxidative stress in the blood. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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