Abstract:

Bacterial biofilms are communities that consist of a single type or different colonies of bacterial cells. These cells are embedded in thick extracellular polymeric substances (EPS) that play key structural and functional roles relative to the specific properties of biofilms. 1 In addition to the internal bacteria and EPS, the bacterial membrane also has some signaling molecules that act as messengers for communication between bacteria and adjust the expression of bacteria-related genes to adapt to environmental changes, which is called quorum sensing (QS).2 Biofilms have heterogeneous populations, due to microenvironmental gradients caused by nutrients, oxygen, and self-generated signal molecules. As the microenvironment varies, the life state of bacteria changes with signaling molecules.

However, the distribution of these molecules in biofilms are still unknown. Moreover, though it was believed the signal molecules play key roles in biofilm development, the detail functions of them remain explored. 

To this end, we established a Mass Imaging method to reveal the 3-D distribution and changes over time of the signal molecules. In addition, a microfluidic device was designed to perform a gradient regent concentration for biofilm growth and treatment. Combined with MALDI MSI, the signal or metabolic molecules changes under the action of growth irritant with a continuous concentration in the biofilm can be shown on vision. 

1. Flemming, H. C.;  Wingender, J.;  Szewzyk, U.;  Steinberg, P.;  Rice, S. A.; Kjelleberg, S. Nat Rev Microbiol 2016, 14 (9), 563-75.
2. Frederick, M. R.;  Kuttler, C.;  Hense, B. A.; Eberl, H. J.Theoretical Biology and Medical Modelling 2011, 8 (1), 1-29.