Probing contaminant bioavailability by multi-endpoint lab-on-chip Whole Cell Arrays (WeCelA)
To date, the biological availability and effects of pollutants in exposed organisms cannot be assessed in-situ. Toxicity tests are currently conducted in-vitro under highly controlled conditions, which rarely reflect the complexity of real biological systems. Therefore, this research project aims at developing and testing a multi-endpoint lab-on-chip cell array to enable the in-situ determination of the biological availability and effects of various contaminants to aquatic microorganisms in realistic systems. With our Whole Cell Array (WeCelA), we attempt to provide a new, powerful tool for an integral assessment of environmental pollutants and seek to significantly advance the development of biosensors and biomonitoring methodology. This new, integrative tool is being developed in collaboration with Prof. O. Velev of the Chemical Engineering Department of North Carolina State University, USA. The principle of WeCelA is based on (i) the selective capture of living microorganisms, e.g. phytoplanktonic cells, in on-chip micropatterned electrodes; and (ii) the measurement of biological responses and their modifications reflected by changes induced in a cell’s autofluorescence or the fluorescence of specific dyes for biological responses in cells. We will develop and test cell arrays of the largest and ecologically most significant groups of microorganisms. The biological endpoints for the WeCelA will be chosen on the basis of preliminary, flow cytometric data. Furthermore, we will determine different lethal and sub-lethal cellular responses at various periods of exposure, by assembling several series of cell arrays and testing them in parallel. Fluorescent detection of cellular responses to ionic concentrations in the arrays will provide multi-endpoint information about the cellular status. Finally, our goal is to explore the effects of toxic metals and nanoparticle exposure on cell metabolic activity to obtain further insight on the mechanisms of toxicity at the cellular level.