Automated Quantitative Phase Imaging Pipeline : for Monitoring Bacterial Cell Growth under Chemical Influence

Sammanfattning: Bacteria have a vital role in ecosystems and the human health. However, the effect of environmental pollution on them at the single-cell level are still not well understood. Label-free imaging has become increasingly important within science. It has allowed for the visualization of cells without the use of molecular tools or labels. Quadriwave lateral shearing interferometry (QLSI) is a label-free method that requires short exposure of cells to light. QLSI is a technique within Quantitative phase imaging (QPI), and the method records and stores information about the optical phase delay (OPD) as pixel values within an interferogram. These interferograms can be used to extract features of biological significance, such as dry mass. Here, an automated image analysis pipeline was developed to convert interferometric images captured with the NIS software and a commercial SID4 sC8 camera (from Phasics) from a fully automated microscope. The pipeline segments regions of interest (ROI) from the OPD images and calculates various parameters of biological significance, such as dry mass. This pipeline enables the quantification of dry-mass changes among individual cells, for multiple positions. The developed image analysis pipeline provides a powerful tool for studying bacteria at the single-cell level and has significant implications for pharmacology, ecotoxicology, and engineering.