A fully automatic and high-throughput centrifugal microsystem for rapid nucleic acid purification with a direct collection via detachable microtube interface

The application of microfluidic technologies in medical diagnostics is rapidly increasing, particularly in nucleic acid (NA) diagnostics. High-speed and high-purity NA extraction is crucial for producing genetic analysis results with considerable precision and sensitivity. This study proposed a high-throughput (HTP) centrifugal microfluidic chip integrated with an automatic pipetting system for NA purification. The centrifugal microfluidic chip was designed with 10 units and a zigzag structure to automatically aliquot the solution in a single injection. Two glass fiber filter (GF/F) papers were used as the NA extraction matrix, and advanced passive valves prevented buffer overflow into adjacent chambers during injection. The innovative feature of the chip was the incorporation of collection screw tubes, which facilitated the easy collection of extracted NA and could be securely attached and detached from the chip for downstream applications. Moreover, we constructed an automatic pipetting system including a 3D-printed control board box, a liquid handling station, and a high-speed rotating unit. The system effectively isolated respiratory syncytial virus A (RSV A) from 10 clinical patient samples at a time, and the whole procedure could be performed with minimal manual operation. The combination of the collection screw tubes allowed us to easily recover the purified NA from the chip without contamination issue. The proposed NA extraction system composed of the HTP centrifugal microfluidic chip and the automatic pipetting system enables us to complete the extraction process for 10 samples within 20 min.