A Contracted Channel Droplet Reinjection Chip-Based Simple Integrated ddpcr System for SARS-CoV-2 and H1N1 Detection

Fengyi Liu; Anle Ge; Xixian Wang; Fei Wu; Jian Xu; Bo Ma

doi:10.1021/acs.analchem.4c05201

A Contracted Channel Droplet Reinjection Chip-Based Simple Integrated ddpcr System for SARS-CoV-2 and H1N1 Detection

Anal Chem. 2025 Jan 23. doi: 10.1021/acs.analchem.4c05201. Online ahead of print.

Authors

Fengyi Liu^{1

2

3

4}, Anle Ge^{1

2

3

4}, Xixian Wang^{1

2

3

4}, Fei Wu^{1

2

3}, Jian Xu^{1

2

3

4}, Bo Ma^{1

2

3

4}

Affiliations

¹ CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.
² Shandong Energy Institute, Qingdao, Shandong 266101, China.
³ Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China.
⁴ College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China.

PMID: 39846371
DOI: 10.1021/acs.analchem.4c05201

Abstract

Droplet microfluidics is a powerful method for digital droplet polymerase chain reaction (ddPCR) applications. However, precise droplet control, bulky peripherals, and multistep operation usually required in droplet detection process hinder the broad application of ddPCR. Here, a contracted channel droplet reinjection chip is presented, where droplets can be self-separated and detected one by one at intervals. Based on that, a Simple Integrated ddPCR (SI-ddPCR) system is established, including surface-wetting-based droplet generation, tube heating, and droplet signal detection. To assess the system's performance, we quantified SARS-CoV-2 and H1N1 simultaneously using duplex-ddPCR. The results exhibited a good linearity (R² = 0.999) at concentrations ranging from 10¹ to 10⁴ copies/μL. By employing the SI-ddPCR system, we detected SARS-CoV-2 and H1N1 in clinical samples isolated from 20 swab specimens with an accuracy of 97.5%. Thus, the developed SI-ddPCR system offers simple droplet detection, eliminates complicated peripherals and multistep operations, and promises to be a portable, low-cost, and easy-to-deploy toolbox for high-accuracy ddPCR.