Rapid electrokinetic isolation of cancer-related circulating cell-free DNA directly from blood.

Background: Circulating cell-free DNA (ccf-DNA) is becoming an important biomarker for cancer diagnostics and therapy monitoring. The isolation of ccf-DNA from plasma as a "liquid biopsy" may begin to replace more invasive tissue biopsies for the detection and analysis of cancer-related mutations. Conventional methods for the isolation of ccf-DNA from plasma are costly, time-consuming, and complex, preventing the use of ccf-DNA biomarkers for point-of-care diagnostics and limiting other biomedical research applications.

Low level epifluorescent detection of nanoparticles and DNA on dielectrophoretic microarrays.

Common epifluorescent microscopy lacks the sensitivity to detect low levels of analytes directly in clinical samples, such as drug delivery nanoparticles or disease related DNA biomarkers. Advanced systems such as confocal microscopes may improve detection, but several factors limit their applications. This study now demonstrates that combining an epifluorescent microscope with a dielectrophoretic (DEP) microelectrode array device enables the detection of nanoparticles and DNA biomarkers at clinically relevant levels.

Dielectrophoretic isolation and detection of cfc-DNA nanoparticulate biomarkers and virus from blood.

Dielectrophoretic (DEP) microarray devices allow important cellular nanoparticulate biomarkers and virus to be rapidly isolated, concentrated, and detected directly from clinical and biological samples. A variety of submicron nanoparticulate entities including cell free circulating (cfc) DNA, mitochondria, and virus can be isolated into DEP high-field areas on microelectrodes, while blood cells and other micron-size entities become isolated into DEP low-field areas between the microelectrodes. The nanoparticulate entities are held in the DEP high-field areas while cells are washed away along with proteins and other small molecules that are not affected by the DEP electric fields.