Processing Large Volume Samples Using a Silicon Pillar Chip

PCR and antibody-based devices are currently the primary platforms for bioagent detection. PCR offers high sensitivity and specificity, but has limited effectiveness for toxins (detects residual DNA, if any, in toxin preparations) and requires thermal cycling equipment, extensive sample preparation, and complex reagents. Antibodies, which utilize relatively simple chemistry, are effective for both microbes and toxins, but provide moderate sensitivity and specificity. Therefore, both antibodies and PCR methods will remain important tools for bioagent detection. Much of our attention has been focused on developing automated PCR instrumentation using microfluidics with embedded modular components, such as a minisonicator for cell/spore lysis and a micropillar chip for nucleic acid purification and concentration. For the proposed effort, the micropillar chip, which has an extremely high surface area within a few square millimeters and a liquid volume of only 10 ul, will be derivatized with capture antibodies to rapidly extract microbes and toxins from large volume (>20 ml) samples and concentrate these into small volumes (>0.1 ml). Concentrated agents are then available for both PCR and antibody-based testing.