The analysis of cell free (cf) DNA and cf-RNA continue to become more widely used for cancer and other disease diagnostics and management. We have now demonstrated a dielectrophoretic (DEP) based approach that allows cf-DNA and cf-RNA biomarkers from chronic lymphocytic leukemia (CLL), solid tumor and traumatic brain injury (TBI) patients to be isolated in about 10-20 minutes directly from a small volume (25-50ul) of patient whole blood or plasma. Figure 1 shows fluorescent image analysis results for cf-DNA isolated by DEP from one normal blood sample and five CLL patient blood samples (left side), and one normal plasma sample and five CLL patient plasma samples (right side). Overall, the fluorescent cf-DNA levels were higher in most of the CLL patient samples when compared to the fluorescent DNA levels obtained from the normal blood samples. The PCR and DNA sequencing results for cf-DNA isolated from 5 CLL patient blood and plasma samples by the DEP process were exactly comparable to results obtained using conventional methods, which take several hours to complete, are more laborious (many steps) and require much larger plasma/blood samples. In the case of a solid tumors Figure 2 below shows cf-DNA which was isolated by DEP from a 50ul plasma sample from an NSC lung cancer patient. Generally, cf-DNA for “liquid biopsies” is isolated from plasma using relatively long and involved processes which are not suitable for point of care (POC) diagnostics. DEP now allows the isolation and fluorescent detection to now be carried out in less than 20 minutes. In further work related to brain cancer and TBI diagnostics, Figure 3shows the isolation of cf-RNA containing glioblastoma exosomes from human plasma samples. The new DEP devices are now being used to collect cf-DNA/RNA from a variety of other cancer (solid tumor) and TBI patient blood and plasma samples, setting the stage for “seamless sample to answer” diagnostics.
(1) Sonnenberg A, Marciniak JY, Rassenti L, Ghia EM, Skowronski EA, Manouchehri S, McCanna JP, Widhopf II GF, Kipps TJ and Heller MJ, “Dielectrophoretic Isolation and Detection of Cancer Related Circulating Cell Free DNA Biomarkers from Blood and Plasma”, Electrophoresis, V35, 12-13, pp. 1828-36, July 2014. (2) Sonnenberg A, Marciniak JY, Rassenti L, Ghia EM, Skowronski EA, Manouchehri S, McCanna JP, Widhopf II GF, Kipps TJ and Heller MJ, “Rapid Electrokinetic Isolation of Cancer-Related Circulating Cell Free DNA Directly from Blood”, Clinical Chemistry, 60:3, pp.500-509, 2014. (3) McCanna JP, Sonnenberg A, and Heller MJ, Low level epifluorescent detection of nanoparticles and DNA on dielectrophoretic microarrays, J. BioPhotonics , 1–11 (2013) / DOI 10.1002/jbio.201300046.
See more of this Group/Topical: 2015 Annual Meeting of the AES Electrophoresis Society