Microscreening toxicity system based on living magnetic yeast and gradient chips
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There is an increasing demand for easy and cost-effective methods to screen the toxicological impact of the growing number of chemical mixtures being generated by industry. Such a screening method has been developed using viable, genetically modified green fluorescent protein (GFP) reporter yeast that was magnetically functionalised and held within a microfluidic device. The GFP reporter yeast was used to detect genotoxicity by monitoring the exposure of the cells to a well-known genotoxic chemical (methyl methane sulfonate, MMS). The cells were magnetised using biocompatible positively charged PAH-stabilised magnetic nanoparticles with diameters around 15 nm. Gradient mixing was utilised to simultaneously expose yeast to a range of concentrations of toxins, and the effective fluorescence emitted from the produced GFP was measured. The magnetically enhanced retention of the yeast cells, with their facile subsequent removal and reloading, allowed for very convenient and rapid toxicity screening of a wide range of chemicals. This is the first report showing magnetic yeast within microfluidic devices in a simple bioassay, with potential applications to other types of fluorescent reporter yeast in toxicological and biomedical research. The microfluidic chip offers a simple and low-cost screening test that can be automated to allow multiple uses (adapted to different cell types) of the device on a wide range of chemicals and concentrations.
KeywordsToxicity screening GFP reporter yeast Magnetic retention Microfluidic devices
We thank Dr. Andrew Knight Gentronix® for kindly supplying the yeast cells, Mr. Stephen Clark for technical support and Mrs. A. Lowry for the technical assistance with TEM. This work was funded by the European Commission, TESS COLL-CT-2006 project. The support by the Government of the Republic of Tatarstan (Algarish Grantlar Programmasi) is gratefully acknowledged by R.F.F.
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