DNA displacement assay integrated into microfluidic channels

This paper describes the development of a unique fluorescence-based DNA diagnostic microfluidic assay that does not require labeling of the target sequence prior to analysis. The assay is based on the displacement of a short sacrificial fluorescent-tagged indicator oligomer by a longer untagged target sequence as it is electrophoresed through a DNA-containing hydrogel plug immobilized in a microfluidic channel. The distinct advantages of this assay are the short sensing times, as a result of directed electrophoretic transport of target DNA to the sensing element, combined with the ability to detect nonlabeled target DNA.