Ultra-sensitive cytometric detection of rare particle on microfluidic device

In this work, the rare bacteria-like-sized particles were detected in real-world-like sample circumstances with high concentration interfering particles and fluorescein background using cytometric fashion by simultaneously detecting their fluorescence emission and scattering light on microfluidic device to demonstrate its application of identifying the foodborne pathogens in real world food samples. Based on a polydimethylsiloxane (PDMS) microfluidic chip and compact optics configuration, the pathogenic-sized, 1.013 µm fluorescently labeled latex beads in suspension had been interrogated quantitatively in similar real-world food samples circumstances, where the targeted particles diluted at low concentration down to 100 particles/mL and mixed with various unlabeled interfering beads with different size at a high concentration up to 106 particles/mL. In order to figure out the interference of fluorescence background in cytometric detection, the same fluorescently labeled beads mixed with various concentrations fluorescein were detected as well. Taken together, these quantitative measurements prove the capability of detection and identification the foodborne pathogens on microfluidic devices in food safety inspection applications.