Integrated Printed Circuit Board Device for Cell Lysis and Nucleic Acid Extraction

Preparation of raw, untreated biological samples remains a major challenge in microfluidics. We present a novel microfluidic device based on the integration of printed circuit boards and an isotachophoresis assay for sample preparation of nucleic acids from biological samples. The device has integrated resistive heaters and temperature sensors as well as a 70 mu m X 300 mu m X 31 cm microfluidic channel connecting two 15 mu L reservoirs. We demonstrated this device by extracting pathogenic nucleic acids from 1 mu L dispensed volume of whole blood spiked with Plasmodium falciparum. We dispensed whole blood directly onto an on chip reservoir, and the system's integrated heaters simultaneously lysed and mixed the sample. We used isotachophoresis to extract the nucleic acids into a secondary buffer via isotachophoresis. We analyzed the convective mixing action with micro particle image velocimetry (micro Ply) and verified the purity and amount of extracted nucleic acids using off-chip quantitative polymerase chain reaction (PCR). We achieved a clinically relevant limit of detection of 500 parasites per microliter. The system has no moving parts, and the process is potentially compatible with a wide range of on-chip hybridization or amplification assays.