Development of a rapid bacterial counting method based on photothermal assembling

We developed a rapid bacterial counting method based on the photothermal assembling (PTA). Based on the laser-induced PTA in fluid medium, an initial bacterial concentration was estimated from the number of assembled bacteria. The measuring time of our method is 90 s, which is more rapid than the conventional cultivation method requiring several days at longest. Furthermore, the difference between the estimated concentrations by our method and by the cultivation method is less than 10%, which sufficiently guarantees the availability. The clarified principle will pave the way to a rapid and high throughput bacterial assay useful for medical care and food safety. (C) 2016 Optical Society of America