Disposable, pressure-driven, and self-contained cartridge with pre-stored reagents for automated nucleic acid extraction

Nucleic acid extraction is vital in many applications such as molecular diagnostics, genetic engineering, and deoxyribonucleic acid (DNA) sequencing. Although recent advances in nucleic acid extraction have been made to improve the process using microfluidics, it is still necessary to make it easy for end-users by having pre-loaded reagents, eliminating pipetting between steps, and automating the process for point-of-care (POC) testing. Herein, we present a pressure-driven and self-contained cartridge with pre-stored reagents for automating nucleic acid purification. To reduce operational complexity, reagents were transferred through a microfluidic chip using pressurized air stored inside the cartridge instead of an external pump or valving system. After performing cell lysis, the cartridge was inserted into the device, and the nucleic acid was purified automatically within 3 min Escherichia coli (E. coli) O157:H7 DNA extracted by our device showed similar concentration, purity, and real-time polymerase chain reaction (qPCR) results as the conventional column-based nucleic acid extraction method. Our device achieved a detection limit of 103 CFU for E. coli DNA, which is the same as that obtained using the conventional solid-phase extraction method. This study introduces a novel approach for automating the sample preparation process, which can help in facilitating POC molecular diagnostics.

Automated summary

In this study, a pressure-driven and self-contained cartridge with pre-stored reagents was designed to automate nucleic acid purification. By using pressurized air stored inside the cartridge, reagents were transferred through a microfluidic chip, which reduced operational complexity. The device achieved similar results to the conventional column-based extraction method in terms of concentration, purity, and real-time polymerase chain reaction (qPCR) for Escherichia coli (E. coli) O157:H7 DNA. It also had a detection limit of 103 CFU, similar to the conventional solid-phase extraction method. This novel approach for automating sample preparation can facilitate point-of-care molecular diagnostics.