Microfludic devices with integrated electrical detection will enable fast, low-cost or portable sensing and processing of biological and chemical samples. As an inherent property of microfabrication, microelectrical impedance spectroscopy detectors can take advantage of AC electrokinetics for particle manipulation, leading to enhanced sensitivity. Preliminary experiments on particle detection w...

This study demonstrates the application feasibility of electrochemical impedance spectroscopy (EIS) in measuring estrogen (17β-estradiol) in gas phase. The present biosensor gives a linear response (R2 = 0.999) for 17β-estradiol vapor concentration from 3.7 ng/L to 3.7 × 10-4 ng/L with a limit of detection (3.7 × 10-4 ng/L). The results show that the fabricated biosensor demonstrates better det...

We studied the behaviour of Li/Li(4)Ti(5)O(12) cells by electrochemical impedance spectroscopy to gain insight into the changes at the electrode/electrolyte interfaces during extensive cycling. A simple equivalent-circuit model is able to describe the impedance of the complete battery as a function of both state-of-charge and state-of-degradation. The formation of the solid-electrolyte interfac...

Multiple multi-frequency impedance measurements during the computer controlled passage of a probe through the M. longissimus dorsi in pork and beef were applied. It was expected that the variability in impedance would correlate with the intramuscular fat (IMF) due to the inhomogeneous distribution of electrolytes and fat. We conducted our experiments in pig carcasses at different, well defined ...

Non-invasive, label-free assessment of membrane potential of living cells is still a challenging task. The theory linking membrane potential to the low frequency α dispersion exhibited by suspensions of spherical shelled particles (presenting a net charge distribution on the inner side of the shell) has been pioneered in our previous studies with emphasis on the permittivity spectra. Whereas α ...

In biomedical applications such as the electroencephalogram, electrocardiogram and electromyogram, usually conductive hydrogels are applied to the skin providing a skin–electrode layer, with the aim of lowering contact impedance and improving the signal/noise ratio. It is important to know the electrical behavior of these materials, obtaining reliable values of their conductivity. It can be ext...

A series of animal experiments was conducted to characterize changes in the complex impedance of chronically implanted electrodes in neural tissue. Consistent trends in impedance changes were observed across all animals, characterized as a general increase in the measured impedance magnitude at 1 kHz. Impedance changes reach a peak approximately 7 days post-implant. Reactive responses around in...

A numerical method for simulating the frequency-dependent impedance response of multi-phase composite materials has been developed. The algorithm takes as input 1) a digital image of a microstructure, in two or three dimensions, of any specified composite material, and 2) the frequency-dependent electrical properties of the individual phases of the composite. Art impedance spectrum of any frequ...

A philosophy for electrochemical impedance spectroscopy is presented which integrates experimental observation, model development, and error analysis. This approach is differentiated from the usual sequential model development for given impedance spectra by its emphasis on obtaining supporting observations to guide model selection, use of error analysis to guide regression strategies and experi...

A device for continuous differential impedance analysis of single cells held by a hydrodynamic cell trapping is presented. Measurements are accomplished by recording the current from two closely-situated electrode pairs, one empty (reference) and one containing a cell. We demonstrate time-dependent measurement of single cell impedance produced in response to dynamic chemical perturbations. Firs...