Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Talanta. 2020 Mar 1;209:120571. doi: 10.1016/j.talanta.2019.120571. Epub 2019 Nov 19.
Single-cell detection methods are already of great significance for many bioanalysis applications, and droplet microfluidics technology is understood as particularly a powerful tool. Salmonella infection is a major hygienic problem worldwide that causes major public health and economic damage, and preventing Salmonella outbreaks requires detection food-borne detection methods that are rapid, portable, and reliable, ideally without the need for complicated pre-treatment protocol steps. Herein, we present a single-cell-level analysis method based on droplet microfluidics that can sensitively and rapidly detect Salmonella directly from food samples. Specifically, this method achieves single-cell encapsulation of Salmonella in droplets of a growth medium with resazurin that enables fluorescence-based detection of pathogens within 5 h. The ratio of positive droplets in a Poisson Distribution is used for quantitation, and the detection limit of our system determined to be 50 CFU/mL, a value lower than conventional analytical methods for assessing Salmonella contamination. Our experimental results demonstrate the precise and highly sensitive performance of a single-cell-precision, droplet-based microfluidic chip analytical method for monitoring pathogenic bacteria in food. Beyond our example case of Salmonella detection from milk samples, our work lays the foundation for a new generation of microfluidics-based analytical technologies for both public health and food safety applications which can undoubtedly benefit from increases in the sensitivity and rapidity of food-borne pathogen detection.
单细胞检测方法对于许多生物分析应用已经非常重要，而液滴微流控技术被认为是一种特别强大的工具。沙门氏菌感染是全球范围内的一个主要卫生问题，会造成重大的公共卫生和经济损失，预防沙门氏菌爆发需要快速、便携和可靠的食源性检测方法，理想情况下无需复杂的预处理协议步骤。在此，我们提出了一种基于液滴微流控的单细胞水平分析方法，可直接从食物样本中灵敏、快速地检测沙门氏菌。具体来说，该方法通过在含有 Resazurin 的生长培养基中实现沙门氏菌的单细胞包封，从而能够在 5 小时内实现基于荧光的病原体检测。泊松分布中阳性液滴的比例用于定量，我们的系统检测限确定为 50 CFU/mL，低于评估沙门氏菌污染的传统分析方法。我们的实验结果证明了单细胞精度、基于液滴的微流控芯片分析方法在监测食物中致病菌方面的精确和高度敏感性能。除了我们从牛奶样本中检测沙门氏菌的示例案例外，我们的工作为新一代基于微流控的分析技术奠定了基础，这些技术可用于公共卫生和食品安全应用，无疑将受益于食源性病原体检测的灵敏度和速度的提高。
