Since the onset of the ongoing pandemic, rapid diagnosis is getting increasing importance for not only SARS-CoV-2 diagnosis but also for other pathogens, including bacteria, fungi, and viruses. While numerous optical and electrochemical sensors have been developed and demonstrated with excellent sensitivities and detection limits, the bottleneck remains in the sample preparation for these sensors. Most diagnostic methods for bacterial pathogens still rely on culture-based methods to enrich the bacterial cells or amplify DNA for PCR-based detection. Enrichment-free approaches focus on the isolation and concentration of bacterial cells for preparing the sample for detection in a biosensor. In this work, we present different microfluidic approaches to isolate and concentrate bacterial cells that result in anywhere between 10 and 100 times the concentration of bacterial cells, which can then be introduced into an electrochemical biosensor for impedimetric detection of bacterial pathogen cells. The work also utilizes an in-house developed multistage filtration and concentration approach for isolating pathogenic microorganisms from food matrices for demonstration^1-2.

1. Ghuman, A., et al., Selective Isolation and Concentration of Foodborne Bacterial Pathogens in a Microfluidic Device, in ECS Meeting Abstracts. 2019.

2. Zhou, Y., et al., Isolation and Separation of Listeria monocytogenes Using Bacteriophage P100-Modified Magnetic Particles. Colloids and Surfaces B: Biointerfaces, 2019.