Continuous-Flow Microfluidic Devices for Detection of Bacterial Endospores

Using non-lithographic fabrication methods developed in our laboratory, we prepared continuous-flow microfluidic analyzers. We tested these devices in experiments involving detection of bacterial endospores. The detection was based on the enhancement of the fluorescence of a cationic dye, 3,3′-diethylthiacyanine iodide (THIA), in the presence of spores. We were able to detect as few as ~10⁵ spores when injected in a device. The measurements with the micro-fluidic devices manifested significantly higher sensitivity for bacterial spores than for vegetative bacteria. Such distinction between spores and vegetative bacteria could not be achieved with THIA using steady-state emission measurements.