Document Detail

Electrical impedance spectroscopy for detection of bacterial cells in suspensions using interdigitated microelectrodes.
MedLine Citation:
PMID:  18371827     Owner:  NLM     Status:  MEDLINE    
In this study, we present a new, simple and rapid impedance method to detect bacterial cells by making use of the impedance properties of bacterial cell suspensions using interdigitated microelectrodes. It was found that bacterial cell suspensions in deionized (DI) water with different cell concentrations could generate different electrical impedance spectral responses, whereas cell suspensions in phosphate buffered saline (PBS) solution could not produce any significant differences in impedance spectra in response to different cell concentrations. In DI water suspensions, impedance at 1 kHz decreased with the increasing cell concentrations in the suspensions. The impedance of cell suspensions in DI water was discussed and found that it was resulted from the cell wall charges and the release of ions or other osmolytes from the cells. A linear relationship between the impedance and the logarithmic value of the cell concentration was found in the cell concentration range from 10(6) to 10(10)cfu/ml, which can be expressed by a regression equation of Z(k Omega)=-2.06 logC (cells/20 microl)+5.23 with R(2)=0.98. The detection limit was calculated to be 3.45 x 10(6)cfu/ml, which is comparable with many label-free immunosensors for detection of pathogenic bacteria reported in the literature. To achieve the selectivity of this method, we also demonstrated the feasibility of integrating magnetic separation to this impedance method. This study has demonstrated that bacterial cell concentration can be inferred by measuring the impedance of cell suspensions in DI water. This new detection mechanism could be an alternative to current impedance methods that have been reported for the detection of bacterial cells, e.g. impedance microbiology and electrical/electrochemical impedance biosensors.
Liju Yang
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Publication Detail:
Type:  Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-10-18
Journal Detail:
Title:  Talanta     Volume:  74     ISSN:  1873-3573     ISO Abbreviation:  Talanta     Publication Date:  2008 Feb 
Date Detail:
Created Date:  2008-03-28     Completed Date:  2008-04-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2984816R     Medline TA:  Talanta     Country:  England    
Other Details:
Languages:  eng     Pagination:  1621-9     Citation Subset:  IM    
Biomanufacturing Research Institute & Technology Enterprise (BRITE), and Department of Pharmaceutical Sciences, North Carolina Central University, Durham, NC 27707, USA.
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MeSH Terms
Bacteria / isolation & purification*
Biosensing Techniques / instrumentation,  methods*,  standards
Electric Impedance*
Microelectrodes / standards*
Spectrum Analysis

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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