Rapid Isolation and Detection of Cell Free Circulating DNA and Other Disease Biomarkers Directly from Whole Blood
The ability to rapidly detect cell free circulating (cfc) DNA biomarkers and drug delivery nanoparticles directly in blood is a major challenge for early disease detection and nanomedicine. We now show that a microarray dielectrophoretic (DEP) device can be used to rapidly isolate and detect high molecular weight (hmw) DNA nanoparticulates and nanoparticles directly from whole blood. At DEP frequencies of 5–10 kHz both fluorescent-stained hmw-DNA and 40 nm fluorescent nanoparticles separate from the blood and become highly concentrated at specific DEP high field regions over the microelectrodes, while blood cells move to the DEP low field regions. The blood cells can then be removed by a simple fluidic wash while the hmw-DNA and nanoparticles remain highly concentrated. The hmw-DNA could be detected at a level of <260 ng/ml, and the nanoparticles at <9.5 × 109 particles/ml, detection levels that are well within the range for viable clinical diagnostics and drug nanoparticle monitoring. Some initial work now indicates the presence of possible cfc-DNA in CLL patient blood samples.
KeywordsCancer Biomarkers Cell free circulating DNA Diagnostic dielectrophoresis Nanomedicine Nanoparticles Whole blood
Cell free circulating DNA
High conductance dielectrophoresis
High molecular weight DNA
Polymerase chain reaction
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We would like to acknowledge David J. Charlot, Roy B. Lefkowitz, Amy L. Hsieh, Jason Steiner, Dr. Dietrich Dehlinger, Robert Littlefield and Jennifer M. Singelyn for their generous help in creating this paper. We would also like to thank Dr. Andrew McCulloch and Dr. Karen Christman and their labs for helping us obtain the whole rat blood, and Dr. Robert Kipps (UCSD Moores Cancer Center) for providing CLL blood samples. This work was supported by the NIH NCI NanoTumor Center Grant (U54-CA119335).
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