A fully automatic dPCR microfluidic system for detection of large-volume and low-abundance bacteria sample

• Published in: Sensors and actuators. B, Chemical Chemical, 2024-04, Vol.405, p.135110, Article 135110
• Main Authors: Hu, Kai, Yin, Weihong, Wang, Yu, Xia, Liping, Bai, Yiwen, Zhu, Qiangyuan, Yin, Juxin, Mu, Ying, Jin, Wei
• Format: Article
• Language: English
• Subjects: Digital PCR system; Fully automated workflow; Large-volume and low-abundance; Microfluidic technology
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2023.135110

Digital polymerase chain reaction (dPCR) has become a key technology for bacteria detection with superior sensitivity and accuracy, enabling in reducing the spread of waterborne disease. However, the current systems lack a complete dPCR detection workflow for low-abundance bacteria water sample in large-volume, including bacteria enrichment, nucleic acid (NA) extraction and digital arrays generation. In this work, a fully automated workflow system has been developed for dPCR detection. A preprocessing cartridge designed for single-use has been fabricated to realize the bacterial capture (∼ 98%), NA absorption (∼ 81%), mixing and heating. A PDMS-based microfluidic chip and a vacuum cover are employed for the generation of digital arrays without the pre-degas of PDMS. The proposed system exhibits a good linear relationship of Escherichia coli (E. coli) detection within the range from 2.5 × 101 CFU/mL to 2.5 × 104 CFU/mL, with a limit of detection ∼ 2.5 CFU/mL when enrich 5 mL sample. Furthermore, the dPCR detection results of four actual water samples are comparable to those obtained by the gold standard method plate counting, demonstrating its potential as a point-of-care testing (POCT) tool for accurate quantification of large-volume and low-abundance bacteria samples. •For the first time, the workflows of bacteria enrichment, nucleic acid extraction and digital arrays generation are integrated into a fully automated microfluidic system.•This system can achieve the dPCR detection of large-volume and low-abundance bacteria sample.•This system provides a good linear relationship of E. coli detection within the range from 2.5 × 101 CFU/mL to 2.5 × 104 CFU/mL, with a limit of detection ∼ 2.5 CFU/mL.•The results of four actual water samples from this system are comparable to the plate counting.