A smartphone-based fluorescent sensor for rapid detection of multiple pathogenic bacteria

In this study, we developed a fluorescent sensor for the sensitive detection of multiple pathogenic bacteria based on magnetic separation, fluorescent probes, and smartphone image processing. A microchannel device was assembled using high-transparency resin and 3D printing technology. This device was combined with a smartphone and an external lens to develop a fluorescent sensor for autonomous detection of multiple pathogenic bacteria. Three fluorescence probes with different fluorescence were synthesized from highly specific aptamers and tetraphenylethylene derivatives. These fluorescent probes can make Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa emit different colors of fluorescence. Using the enrichment performance of molecularly imprinted materials, separation and detection of bacteria can be achieved simultaneously. Finally, with the Red-Green-Blue (RGB) analysis functionality of a smartphone, real-time field detection was realized with a sensitivity of 10² CFU/mL and a detection time of 40 min. This work provides a simple, inexpensive, and real-time sensor for the detection of multiple pathogens in medical diagnostics, food testing, and environmental analyses.