Impedance microflow cytometry for viability studies of microorganisms

Berardino, Marco Di; Hebeisen, Monika; Hessler, T.; Ziswiler, Adrian; Largiadèr, Stephanie; Schade, Grit

doi:10.1117/12.883954

Cited by 2 publications

(1 citation statement)

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“…The majority of IFC related work has focused on characterization of larger cells such as red blood cells, yeast, and other eukaryotic cells. − Less work has gone into investigating bacteria and other smaller particles, likely because it is difficult to achieve sufficient signal-to-noise ratios for smaller cells. Multiple studies have tried to suggest changes to the design and fabrication of the detection electrodes meant to improve the sensitivity of the technology. − However, the bacteria studies that have been done have focused on simple detection and differentiation from nonbiological particles, − and on the assessment of the viability of the bacteria. − …”

Section: Introductionmentioning

confidence: 99%

Using Impedance Flow Cytometry for Rapid Viability Classification of Heat-Treated Bacteria

Bertelsen

Skands²,

Díaz³

et al. 2023

ACS Omega

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In the future, rapid electrical characterization of cells with impedance flow cytometry promises to be a fast and accurate method for the evaluation of cell properties. In this paper, we investigate how the conductivity of the suspending medium along with the heat exposure time affects the viability classification of heat-treated E. coli. Using a theoretical model, we show that perforation of the bacteria membrane during heat exposure changes the impedance of the bacterial cell from effectively less conducting than the suspension medium to effectively more conducting. Consequently, this results in a shift in the differential argument of the complex electrical current that can be measured with impedance flow cytometry. We observe this shift experimentally through measurements on E. coli samples with varying medium conductivity and heat exposure times. We show that increased exposure time and lower medium conductivity results in improved classification between untreated and heat-treated bacteria. The best classification was achieved with a medium conductivity of 0.045 S/m after 30 min of heat exposure.

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