Effect of electrode geometry on the impedance evaluation of tissue and cell culture

Rahman, Abdur; Price, Dorielle T.; Bhansali, Shekhar

doi:10.1016/j.snb.2007.07.038

Cited by 66 publications

(47 citation statements)

References 18 publications

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“…The microlithographically fabricated interdigitated microsensor electrode (IME) or interdigitated array (IDA) has emerged as the platform of choice in the development of in-vitro and implantable conductimetric and impedimetric biosensors and biochips (Rahman et al 2007). These familiar comb electrodes have been extensively used in generator-collector electrochemistry, in polymer materials characterization (dielectometry), and as sensors in polymer cure monitoring.…”

Section: Introductionmentioning

confidence: 99%

Design considerations in the use of interdigitated microsensor electrode arrays (IMEs) for impedimetric characterization of biomimetic hydrogels

Yang

Guiseppi-Wilson²,

Guiseppi‐Elie

2010

Biomed Microdevices

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Microlithographically fabricated interdigitated microsensor electrodes (IMEs) were cleaned, surface activated, chemically functionalized (amine) and derivatized with an Acrloyl-PEG-NHS to receive a spun-applied monomer cocktail of UV polymerizable monomer. IMEs were 2050.5, 1550.5, 1050.5 and 0550.5 possessing lines and spaces that were 20, 15, 10, and 5 μm respectively; 5 mm line lengths and were 50 lines on each opposing bus. Bioactive hydrogels were synthesized from spun-applied and UV-crosslinked tetraethyleneglycol diacrylate (TEGDA) (crosslinker), 2-hydroxyethylmethacrylate (HEMA), polyethyleneglycol(200) monomethacrylate (PEGMA), N-[tris(hydroxymethyl)methyl]-acrylamide (HMMA) and poly(HEMA) (MW 60,000) (viscosity modifier) and 2,2-dimethoxy-2-phenylacetophenone (DMPA) (photoinitiator) to produce a 5 μm thick p(HEMA-co-PEGMA-co-HMMA) hydrogel membrane on the IMEs. Unmodified and hydrogel coated IMEs where characterized by AC electrical impedance spectroscopy using 50 mV p-t-p over the frequency range from 10 Hz to 100 kHz in aqueous PBS 7.4 buffer and in buffer containing 50 mM [Fe(CN)(6)](3-/4- ) solution at RT. Impedimetric responses were found to scale with the device geometric parameters. Equivalent circuit modeling revealed deviations from ideality at lower device dimensions suggesting an implication of the substrate surface charge on the double layer capacitance of the electrodes. Diffusion coefficients derived from the Warburg component are in accord with literature values.

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Section: Introductionmentioning

confidence: 99%

Design considerations in the use of interdigitated microsensor electrode arrays (IMEs) for impedimetric characterization of biomimetic hydrogels

Yang

Guiseppi-Wilson²,

Guiseppi‐Elie

2010

Biomed Microdevices

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“…Hence a direct comparison between the Q parameter of the CPE and C dl is not appropriate. The n factor of the CPE, which represents the extent of departure from ideal capacitance behavior, was found to be 0.9, which is expected for smooth metal surfaces (Abdur Rahman et al 2007). The numerical quantities of C dl and Q of CPE are comparable in magnitude.…”

Section: Capacitance Determination By Lpr and Ac Impedancementioning

confidence: 77%

Towards an implantable biochip for glucose and lactate monitoring using microdisc electrode arrays (MDEAs)

Rahman

Justin

Guiseppi‐Elie

2008

Biomed Microdevices

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A complete electrochemical cell-on-a-chip that uses the MicroDisc Electrode Array (MDEA) working electrode (WE) design was evaluated for eventual intramuscular implantation for the continuous amperometric monitoring of glucose and lactate in an animal trauma model. The microfabricated ECC MDEA5037 comprises two discrete electrochemical cells-on-a-chip (ECCs), each with a reference, counter, and MDEA working electrode. Each MDEA comprises 37 microdiscs (diameter = 50 microm) arranged in a Hexagonal Closed Packed (HCP) arrangement with a center to center distance (d) of 100 microm. Cyclic Voltammetry (CV) and Electrical Impendence Spectroscopy (EIS) reveals that this device scales in its interfacial properties with a corresponding MDEA 050 device that comprises 5,184 microdiscs. Parallel development of miniaturized mixed-signal integrated electronics for wireless reprogramming, data acquisition and communication addresses the key issues involved in developing measurement electronics, AD/DA processing, power management and telemetry for implantable amperometric biosensors. A generalized electronics platform based on the Texas Instruments TI NC01101 chip has been developed that may be readily applied to many types of biotransducers with minor modifications.

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“…The CPE represents the non-ideal capacitive behavior induced by the fractal nature of the electrode surface, surface roughness, and non-uniform current distribution. 35 In reality, as shown in Fig. 2, the needle has randomly distributed surface defects such as scratches and craters; thus, the CPE was placed facing the electrodes in the equivalent circuit.…”

Section: -6mentioning

confidence: 99%

Micro electrical impedance spectroscopy on a needle for ex vivo discrimination between human normal and cancer renal tissues

et al. 2016

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The ex-vivo discrimination between human normal and cancer renal tissues was confirmed using lEoN (micro electrical impedance spectroscopy-on-a-needle) by measuring and comparing the electrical impedances in the frequency domain. To quantify the extent of discrimination between dissimilar tissues and to determine the optimal frequency at which the discrimination capability is at a maximum, discrimination index (DI) was employed for both magnitude and phase. The highest values of DI for the magnitude and phase were 5.15 at 1 MHz and 3.57 at 1 kHz, respectively. The mean magnitude and phase measured at the optimal frequency for normal tissues were 5013.40 6 94.39 X and À68.54 6 0.72 , respectively; those for cancer tissues were 4165.19 6 70.32 X and À64.10 6 0.52 , respectively. A statistically significant difference (p< 0.05) between the two tissues was observed at all the investigated frequencies. To extract the electrical properties (resistance and capacitance) of these bio-tissues through curve fitting with experimental results, an equivalent circuit was proposed based on the lEoN structure on the condition that the lEoN was immersed in the bio-tissues. The average and standard deviation of the extracted resistance and capacitance for the normal tissues were 6.22 6 0.24 kX and 280.21 6 32.25 pF, respectively, and those for the cancer tissues were 5.45 6 0.22 kX and 376.32 6 34.14 pF, respectively. The electrical impedance was higher in the normal tissues compared with the cancer tissues. The lEoN could clearly discriminate between normal and cancer tissues by comparing the results at the optimal frequency (magnitude and phase) and those of the curve fitting (extracted resistance and capacitance). Published by AIP Publishing.

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Effect of electrode geometry on the impedance evaluation of tissue and cell culture

Cited by 66 publications

References 18 publications

Design considerations in the use of interdigitated microsensor electrode arrays (IMEs) for impedimetric characterization of biomimetic hydrogels

Design considerations in the use of interdigitated microsensor electrode arrays (IMEs) for impedimetric characterization of biomimetic hydrogels

Towards an implantable biochip for glucose and lactate monitoring using microdisc electrode arrays (MDEAs)

Micro electrical impedance spectroscopy on a needle for ex vivo discrimination between human normal and cancer renal tissues

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