Rapid, automated nucleic acid probe assays using silicon microstructures for nucleic acid concentration

A system for rapid point-of-use nucleic acid (NA) analysis based on PCR tec hniques is described. The extraction and concentration of DNA from test sam ples has been accomplished utilizing silicon fluidic microchips with high s urface-area-to-volume ratios. Short (500 bp) and medium size (48,000 bp) DN A have been captured, washed, and eluted using the silicon dioxide surfaces of these chips. Chaotropic (GuHCl) salt solutions were used as binding age nts. Wash and elution agents consisted of ethanol-based solutions and water , respectively. DNA quantities approaching 40 ng/cm(2) of binding area were captured from input solutions in the 100-1000 ng/mL concentration range. F or dilute samples of interest for pathogen detection, PCR and gel electroph oresis were used to demonstrate extraction efficiencies of about 50 percent , and concentration factors of about 10x using bacteriophage lambda DNA as the target Rapid, multichannel PCR thermal cycling modules with integrated solid-state detection components have also been demonstrated. These results confirm the viability of utilizing these components as elements of a compa ct, disposable cartridge system for the detection of NA in applications suc h as clinical diagnostics, biowarfare agent detection, food quality control , and environmental monitoring.