Low-Power Biomedical Interfaces

Yazıcıoğlu, Refet Fırat; Xu, Jiawei; Mohan, Rachit; Raducanu, Bogdan; Helleputte, Nick Van; Lopez, Carolina More; Mitra, Srinjoy; Pettine, Julia; Wegberg, Roland van; Konijnenburg, Mario

doi:10.1007/978-3-319-21185-5_5

Cited by 2 publications

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“…Impedance characterization at the electrode/electrolyte interface is of great importance in the fields of impedance-based biosensing, − neuro protheses, vitro communication with electrogenic cells, rechargeble lithium-ion batteries, , and most recently in vivo energy sources to power implantable devices. , Because of the low cost, low power, noninvasive nature, and ease of miniaturization, impedance-based sensors pose many advantages for applications, where decreasing size and cost are crucial, such as in point-of-care diagnostics and biowarfare agent detection. In practical applications, microelectrodes offer many advantages compared to conventional large electrodes including minimal amounts of sample and expensive reagents, high sensitivity, and spatial resolution. − Moreover, they can be easily integrated into microfluidic platforms. − However, microelectrodes are often limited in performance at low RF frequency spectrum in biologically relevant media, which are of predominant interest in physiological research.…”

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confidence: 99%

Self-Similar Interfacial Impedance of Electrodes in High Conductivity Media

2017

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Electrode polarization (EP) happening due to accumulation of ions at the electrode/electrolyte interface is an inevitable phenomenon while measuring impedance spectrum in high conductivity buffers and at low RF spectrum. Well-characterized time scales elucidating the EP effect are important for the rational design of microfluidic devices and impedance sensors. In this Article, interfacial impedance at the electrode/electrolyte interface is investigated considering channel height and Debye length effects on characteristic time scale in a binary electrolyte solution using parallel plate electrode configuration. Experimental results reveal self-similarity of normalized electrical impedance as a function of the normalized frequency. The experimental results also match with numerical solutions obtained by finite element simulation of unsteady fully coupled Poisson-Nernst-Planck (PNP) equations. Furthermore, fractal shaped gold nanostructured electrodes are examined, and it has been proven that electric double layer (EDL) formed on porous electrode surfaces acts as a thick EDL and modifications to the characteristic time scale is necessary for porous electrodes. Finally, a constant phase element (CPE) model is proposed to account for the self-similar impedance spectrum, which can be used for different channel heights and solution conductivities.

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