Magnetic Bead Chain-Based Continuous-Flow DNA Extraction for Microfluidic PCR Detection of Salmonella

• Published in: Micromachines (Basel) Vol. 12; no. 4; p. 384
• Main Authors: Wang, Yuhe, Qi, Wuzhen, Wang, Lei, Lin, Jianhan, Liu, Yuanjie
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.04.2021; MDPI
• Subjects: 3-D printers; Acids; Bacteria; Beads; Chains; Continuous flow; continuous-flow DNA extraction; Deionization; Efficiency; Ethanol; magnetic bead chains; Magnetic fields; Magnets; Methods; microfluidic PCR; Microfluidics; Nucleic acids; Pathogens; Proteinase; Reagents; Salmonella; Salmonella detection; Serpentine; Silicon dioxide; Three dimensional printing; Water purification; United States > US; China; continuous-flow DNA extraction; Salmonella detection; microfluidic PCR; magnetic bead chains
• ISSN: 2072-666X; 2072-666X
• DOI: 10.3390/mi12040384

Nucleic acid extraction is crucial for PCR detection of pathogenic bacteria to ensure food safety. In this study, a new magnetic extraction method was developed using 3D printing and magnetic silica beads (MSBs) to extract the target DNA from a large volume of bacterial sample and combined with microfluidic PCR to determine the bacteria. After proteinase K was added into a bacterial sample to lyse the bacteria and release the DNA, it was continuous-flow injected into the serpentine channel of the extraction chip, where magnetic silica bead chains had been formed in advance using a homogeneous magnetic field generated by two concentric semicircle magnets to capture the MSBs. Then, the flowing DNA was captured by the MSB chains, washed with alcohol, dried with gas, and eluted with deionized water to obtain the purified and concentrated DNA. Finally, the extracted DNA templates were injected into a microfluidic PCR chip with lyophilized amplification reagents and determined using a commercial qPCR device. The experimental results showed that the DNA extraction efficiency was more than 90%, and the lower detection limit of was 10 CFU/mL. This new detection method is promising to provide the rapid, sensitive, and simultaneous detection of multiple foodborne pathogens.