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1 June 2016 Light emission from electrodes under dielectrophoresis conditions
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The use of fluorescence in microfluidic optical biodetection requires materials with low-background fluorescence to avoid influencing the desired optical signal with spurious light emission. For the same reason, spurious light emission from galvanoluminescence (GL) should be avoided when fluorescence is used in dielectrophoresis (DEP)-based biosensors. Use of non-noble metal electrodes such as indium tin oxide (ITO) in DEP devices is therefore a concern. We evaluate GL in the context of conditions typical of DEP devices. We experimentally show that use of ITO can result in GL. We also show that GL can be avoided, even with metals that demonstrate strong GL such as Al, by proper selection of operating frequency, which can be determined by measuring the impedance spectrum of the DEP device. In addition, we demonstrate that GL results in broadband emission for all of the salt solutions tested. Broadband emission implies that at least some of the light will pass through typical fluorescence filters if a device exhibits GL. We also show that Ni and Cr electrodes do not exhibit GL and may therefore be suitable as low-cost DEP electrodes.
Long-Fang Tsai, Hua Gong, Kathryn L. Dallon, Brian A. Mazzeo, and Gregory P. Nordin "Light emission from electrodes under dielectrophoresis conditions," Journal of Micro/Nanolithography, MEMS, and MOEMS 15(2), 025001 (1 June 2016).
Published: 1 June 2016

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