5 research outputs found
Towards Bio-impedance Based Labs: A Review
In this article, some of the main contributions to BI (Bio-Impedance) parameter-based systems for medical, biological and
industrial fields, oriented to develop micro laboratory systems are summarized. These small systems are enabled by the development
of new measurement techniques and systems (labs), based on the impedance as biomarker. The electrical properties of the life mater
allow the straightforward, low cost and usually non-invasive measurement methods to define its status or value, with the possibility
to know its time evolution. This work proposes a review of bio-impedance based methods being employed to develop new LoC
(Lab-on-a-Chips) systems, and some open problems identified as main research challenges, such as, the accuracy limits of
measurements techniques, the role of the microelectrode-biological impedance modeling in measurements and system portability
specifications demanded for many applications.Spanish founded Project: TEC 2013-46242-C3-1-P: Integrated Microsystem for Cell Culture AssaysFEDE
Broadband Bioimpedance Spectroscopy Based on a Multifrequency Mixed Excitation and Nuttall Windowed FFT Algorithm
Bioimpedance spectroscopy (BIS) has become an important clinical indicator for monitoring the pathological status of biological tissues, and multifrequency simultaneous measurement of BIS may provide more accurate diagnostic information compared with the traditional frequency-sweep measurement technology. This paper proposes a BIS multifrequency simultaneous measurement method based on multifrequency mixed (MFM) signal excitation and a Nuttall windowed interpolation FFT algorithm. Firstly, the excitation source adopts the nine-frequency MFM signal f(9,t), which has excellent spectral characteristic and is very suitable for BIS measurement. On this basis, a Nuttall window is adopted to truncate sample data, and an interpolation FFT algorithm based on Nuttall window is built to perform spectral analysis, in which the parameter correction formula is provided based on polynomial approximation. A BIS measurement simulation experiment is performed on an RC three-element equivalent circuit, and results on the 9 primary harmonic frequencies ranging from 3.9 kHz to 1 MHz show a high accuracy with the impedance amplitude relative error |Ez|<0.3%, and the phase absolute error |Ep|<0.1°. This paper validates the feasibility of BIS multifrequency simultaneous measurement method and establishes an algorithm foundation for the development of practical broadband BIS measurement system
On the calculation of the D-optimal multisine excitation power spectrum for broadband impedance spectroscopy measurements
The successful application of impedance spectroscopy in daily practice requires accurate
measurements for modeling complex physiological or electrochemical phenomena in a single
frequency or several frequencies at different (or simultaneous) time instants. Nowadays, two
approaches are possible for frequency domain impedance spectroscopy measurements: (1)
using the classical technique of frequency sweep and (2) using (non-)periodic broadband
signals, i.e. multisine excitations. Both techniques share the common problem of how to
design the experimental conditions, e.g. the excitation power spectrum, in order to achieve
accuracy of maximum impedance model parameters from the impedance data modeling
process. The original contribution of this paper is the calculation and design of the D-optimal
multisine excitation power spectrum for measuring impedance systems modeled as 2R-1C
equivalent electrical circuits. The extension of the results presented for more complex
impedance models is also discussed. The influence of the multisine power spectrum on the
accuracy of the impedance model parameters is analyzed based on the Fisher information
matrix. Furthermore, the optimal measuring frequency range is given based on the properties
of the covariance matrix. Finally, simulations and experimental results are provided to validate
the theoretical aspects presented.Peer ReviewedPostprint (published version
Novel Methods for Weak Physiological Parameters Monitoring.
M.S. Thesis. University of Hawaiʻi at Mānoa 2017