ISOLATION OF PATHOGENIC LISTERIA

Diagnostic approaches providing identification of phenotypes of pathogens directly from biofluids with improved figures of merit (fast, accurate (selective, sensitive), simple, low power, and cost-effective) is needed. As innovative microfluidic strategy that can contribute to this goal is presented here. The system promises to rapidly and selectively separate, isolate and concentrate pathogens from biofluids for direct identification or further assessments (immuno- or geno-recognition). The strategy is based on DC insulator gradient dielectrophoresis (DC-iGDEP) which provides not only the advantage of truly unique and non-linear separation of bioparticles, but also can remove unwanted components that are often present in complex biological samples and interfere with subsequent assays. The approach can fuse location to identification via electric field manipulation of bioparticles, thus avoiding a number of issues with current methods that require prior molecular recognition elements and commonly cold- chain reagents. The basis for the approach is a combination of dielectrophoretic and electrokinetic forces in a single channel. To understand if this is a general approach, isolation and concentration of pathogenic versus non-pathogenic Listeria in the presence of background flora and matrix will be attempted. The long-term objective is to integrate DC-iGDEP into a simple, cost effective, reliable sensor that will be a component of a diagnostic platform that can be used in the clinical laboratory and ideally, amenable for surveillance and diagnosis in developing countries. The goal is to isolate/concentrate/separate pathogen particles from typical biofluids. Once developed, the approach can be modified for a broad range of medically important pathogens.