Design of a millifluidic device for the evaluation of blue-light disinfection on Pseudomonas aeruginosa PA01 biofilm

Abstract

Significance: For the first time to our knowledge, a millifluidic device has been designed to observe the effects of blue-light irradiation in Pseudomonas aeruginosa PA01 bacterial biofilm. Approach: A bacterial biofilm is formed under controlled flow of nutrients in microfabricated channels settled on a microscope stage. The setup is devised to apply defined irradiation and evaluate the photo-killing efficiency in situ using video-microscopy and fluorescent probes. Results: We investigated bacterial survival after delivering a precise, controlled and spatially defined blue light dose upon growing biofilm. We demonstrate in this report that the combined use of constitutive GFP and propidium iodide in a millifluidic setup enables to evidence light-induced mortality at the single cell and community level. Conclusions: Real-time monitoring of a bacterial biofilm growing in a millifluidic device after irradiation opens an avenue for a better understanding of the biofilm community response to blue-light, permitting researchers to approach photokilling efficiency of biofilm as a dynamic process.