Increasing PCR sensitivity by removal of polymerase inhibitors in environmental samples by using dielectrophoresis

Dielectrophoresis (DEP) is a powerful tool to manipulate cells and molecules in microfluidic chips. However, few practical applications using DEP exist. An immediate practical application of a carbon-electrode DEP system, in removing PCR inhibitors from a sample, is reported in this work. We use a high throughput carbon-electrode DEP system to trap yeast cells from a natural sample (fermented grape must) and then in situ remove contaminants that interfere with PCR analysis. Retrieval of this enriched and purified yeast population from the DEP system then allows for a significant increase of sensitivity during PCR analysis. Furthermore, the fact that DEP can discriminate between viable and non-viable cells minimizes the number of false positives commonly obtained when using PCR alone. Experimental results provide clear evidence that the carbon-electrode DEP-based sample preparation step can readily and effectively clean environmental samples from natural contaminants and improve PCR sensitivity.

► Saccharomyces trapping and recovery from a carbon-dielectrophoresis (DEP) chip. ► Electrical parameters of the DEP purification process have been optimized. ► Determination of chip throughput. ► PCR detection of yeast cells trapped in the DEP chip. ► Improvement of yeast PCR detection in natural samples by using the carbon-DEP chip.