MICROANALYTICAL METHOD FOR THE SIMULTANEOUS CONCENTRATION AND SEPARATION OF MICROORGANISMS AND/OR PARTICLES BY DIELECTROPHORESIS AND ELECTRIC FIELD GRADIENTS IN MICRODEVICES.

摘要

The microanalytical method performed by dielectrophoresis and electric field gradients generated by direct current in microdevices allows the microorganisms and/or particles to be simultaneously concentrated and/or separated whereas the suspension medium is flowed. The selective and sequential elution in fractions with a higher purity is obtained from each one of the populations trapped by dielectrophoresis upon applying an electric field lower than that required by the population so as to continue trapped. Said elution is showed in a dielectropherogram from the optic detection and measure, thus allowing concentration factors to be obtained for quantifying each population. The present method may be performed in different microdevices and has the potential to be integrated to analytical methods where a non-destructive and quick microbiological analysis is required, within the minute order, which facilitates the concentration and recovery of populations free from other type of microorga nisms and/or microparticles for their subsequent process, the same being used as a method for the quantification and purification of the species present in the mixture. The microanalytical method may be applied in the detection of pollutants in food and water, in clinical or environmental samples, amongst other examples, thus providing multiple benefits over conventional methods such as the microorganism culture, the filtration and centrifugation.