High-frequency, dielectric spectroscopy for the detection of electrophysiological/biophysical differences in different bacteria types and concentrations.

High-frequency, dielectric spectroscopy for the detection of electrophysiological/biophysical differences in different bacteria types and concentrations.
Anal Chim Acta. 2018 Oct 22;1028:86-95
Authors: Russel M, Sophocleous M, JiaJia S, Xu W, Xiao L, Maskow T, Alam M, Georgiou J
Abstract
This paper describes a novel technique to quantify and identify bacterial cultures of Bacillus Subtilis (2.10-1.30 × 109 CFU mL-1) and Escherichia Coli (1.60-1.00 × 109 CFU mL-1), in corn oil using dielectric spectroscopy at elevated frequencies of 0.0100-20.0 GHz. This technique is using the electrophysiological/biophysical differences (e.g. gram positive and gram negative) between various bacteria types, as a basis to distinguish between bacteria concentrations and bacteria types. A close-ended, coaxial probe of 20.0 mm long sample-holder was developed and used to calculate the dielectric constant from the measured S parameters of the bacterial cultures, using the Nicolson-Ross-Weir method. This technique shows a linear relationship (r2 ≥ 0.999) between the dielectric constant and the cell concentration, at 16.0 GHz. The sensitivity of the technique is 0.177 × 109 (CFU mL-1)-1 for B. Subtilis (with a size of 10.0 × 1.00 μm), 0.322 × 109 (CFU mL-1)-1 for E. Coli (with a size of 2.00 × 0.500 μm) and 0.913 × 109 (CFU mL-1) -1 for their 1:1 mixture, while the response time is 60.0s. The dep...

Source: Analytica Chimica Acta - June 11, 2018 Category: Chemistry Authors: Russel M, Sophocleous M, JiaJia S, Xu W, Xiao L, Maskow T, Alam M, Georgiou J Tags: Anal Chim Acta Source Type: research