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Updated: Aug 14, 2025
Microfluidic Chip Fabrication and Method to Detect Influenza
Published on: March 26, 2013
Visual detection of Cronobacter sakazakii on a microfluidic chip fabricated by a 3D molding method
Xu Chen1, Yue Ma1, Shuangyu Miao1
1Food Science College, Shenyang Agricultural University, Shenyang, China, 110866. chenxu2015@syau.edu.cn.
Insights
A new microfluidic chip assay detects Cronobacter sakazakii in infant formula. This rapid, visual test is suitable for resource-limited settings, improving food safety.
Area of Science:
- Microbiology
- Biotechnology
- Food Safety
Background:
- Cronobacter sakazakii is a pathogen linked to neonatal infections from contaminated powdered infant formula (PIF).
- Current C. sakazakii detection methods require specialized labs and trained personnel, limiting accessibility.
- Microfluidic devices coupled with isothermal amplification offer promising solutions for on-site microbial detection.
Purpose of the Study:
- To develop a rapid, visual detection method for C. sakazakii in PIF using microfluidic chips.
- To establish a multiplex competitive annealing mediated isothermal amplification (mCAMP) assay for C. sakazakii identification.
Main Methods:
- Fabrication of polydimethylsiloxane (PDMS) microfluidic chips using a 3D molding technique.
- Development of a multiplex competitive annealing mediated isothermal amplification (mCAMP) assay targeting 16S rRNA and ITS genes.
- Visual detection of C. sakazakii in powdered infant formula (PIF) samples.
Main Results:
- The developed mCAMP assay demonstrated high specificity for C. sakazakii.
- The limit of detection for the assay was determined to be 2.2 × 10^3 CFU g^-1.
- With enrichment, the assay successfully detected C. sakazakii at an initial inoculation level of 1 CFU g^-1 in spiked PIF samples.
- The assay provides naked-eye visible results, indicating suitability for rapid, on-site analysis.
Conclusions:
- A novel PDMS microfluidic chip-based mCAMP assay enables visual detection of C. sakazakii in PIF.
- This method offers a sensitive, specific, and accessible tool for food safety applications, especially in resource-limited environments.
- The pre-immobilized primers on the chip enhance its practicality for field use.
Abstract:
Cronobacter sakazakii (C. sakazakii) is a pathogenic bacterium associated with life-threatening neonatal infections that have been linked to contaminated powdered infant formula (PIF). Most C. sakazakii testing is still limited in microbiology laboratories due to the need for sophisticated equipment and professional technicians. Microfluidic chips combined with isothermal amplification analysis are shown to be one of the most attractive microbiological on-site detection platforms. In this study, PDMS microfluidic chips were fabricated by a simple 3D molding method and sealed with "PDMS glue". The chip consisted of an inlet, a microchannel, six reaction wells, and six vent holes. And based on the 16S rRNA and ITS genes of C. sakazakii, we have successfully proposed a multiplex competitive annealing mediated isothermal amplification (mCAMP) assay on the microfluidic chip for the visual detection of C. sakazakii in PIF samples. The primers were fixed in the reaction wells of the chip before detection, which can be preserved for 60 days at 4 °C. The results showed that the established mCAMP assay had high specificity, and the limit of detection was 2.2 × 103 CFU g-1. With enrichment culture, even if the initial inoculation level is 1 CFU g-1, the mCAMP assay can still detect the presence of C. sakazakii in spiked PIF samples. The test results are visible to the naked eye, which is suitable for rapid analysis in resource-limited settings.
