(372b) Electrokinetic Differentiation of Microorganisms in Glass Microchannels

Microscale electrokinetic techniques have a great potential for the separation and sorting of microorganisms, and could solve the need for rapid and early detection of pathogens in medical diagnostics and microbial contamination of food items and water. In this work we present the application of micro particle image velocimetry for the characterization of electrokinetic transport of three types of microorganisms in a glass microchannel: Escherichia coli, Ankistrodesmus sp., and Saccharomyces cerevisiae. The electrokinetic behavior of these three types of microorganisms was characterized employing a straight glass microchannel and direct current electric fields (50-300 V/cm). The effects of microorganism type and size, electric field magnitude, pH (5-8) and conductivity (25-100 µS/cm) of the suspending medium were analyzed. Additionally, electrokinetic differentiation was achieved when a sample containing a mixture of the three types of microorganisms was analyzed by performing fluorescence measurements at the outlet of the microchannel and generating electropherograms in 1-2 minutes. It was demonstrated that this simple system allowed identifying that three different species were present. These results demonstrate that fast and effective differentiation of intact microorganisms can be achieved employing microscale electrokinetic techniques.