Jönsson Mats, Welch Ken, Hamp Sven, Strømme Maria
Department of Engineering Sciences, The Angström Laboratory, Uppsala University, Sweden.
J Phys Chem B. 2006 May 25;110(20):10165-9. doi: 10.1021/jp060148q.
A method to quantify the density of viable biological cells in suspensions is presented. The method is implemented by low-frequency impedance spectroscopy and based on the finding that immobilized ions are released to move freely in the surrounding suspension when viable Escherichia coli cells are killed by a heat shock. The presented results show that an amount of ions corresponding to approximately 2 x 10(8) unit charges are released per viable bacterium killed. A micro probe station with coplanar Ti electrodes was electrically characterized and used as a measuring unit for the impedance spectroscopy recordings. This unit is compatible with common microfabrication techniques and should enable the presented method to be employed using a flow-cell device for viable bacteria counting in miniaturized on-line monitoring systems.
