An Ac Electrokinetic Microarray Device For Isolation Of Cell Circulating Free Nucleic Acid From The Blood Of Cancer Patients

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Circulating cell-free (ccf) DNA is becoming a biomarker of interest for cancer diagnosis and monitoring. The isolation of ccf-DNA from plasma may be used as a “liquid biopsy” and could replace more invasive tissue biopsies for analysis of cancer-related mutations. Conventional methods for isolation of ccf-DNA from plasma are costly, time-consuming, and require a significant amount of sample processing, which could result in loss of important biomarkers. An AC electrokinetic microarray device has been developed to reduce the time and cost needed for sample processing. In an earlier study, this microarray device was used to rapidly (15 minutes) isolate ccf-DNA from 25 μL of unprocessed blood from 15 chronic lymphocytic leukemia (CLL) patients to compare PCR and sequencing results with classical ccf-DNA isolation processes and gold standard isolation of DNA directly from lymphocytes. Our objective now is to determine if there is a correlation between the on-chip fluorescence imaging data of the ccf-DNA with the lymphocyte cell counts. Blood was collected from CLL patients in lithium heparin collection tubes. SYBR Green was added to the CLL blood sample to label the ds-DNA. A 25 μL aliquot of the CLL blood was inserted into the AC electrokinetic microarray device. A 10 kHz sinusoidal waveform was applied at 11 volts peak-to-peak for three minutes without fluid flow. With the field still on, the chip was washed for five minutes with 1x TE at a rate of 100 µL/min to remove other blood components. Once the wash was complete, a fluorescence image was taken for analysis. The white blood cell counts and % lymphocyte data were used to calculate the concentration of lymphocytes in each patient sample, and the fluorescence images were analyzed for average fluorescence in a defined region of interest. The preliminary data shows some correlation between the number of lymphocytes in the patient blood and the fluorescence calculated from the images. It is important to note that while the sample size was small, the data shows promise and calls for a larger study. Citation Format: Jennifer Marciniak, Avery Sonnenberg, Laura Rassenti, Emanuela Ghia, George Widhopf, Elaine Skowronski, Sareh Manouchehri, Thomas J. Kipps, Michael J. Heller, David J. Charlot, Rajaram Krishnan. An AC electrokinetic microarray device for isolation of cell circulating free nucleic acid from the blood of cancer patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1514. doi:10.1158/1538-7445.AM2014-1514