Electric shocks manipulate cellular biofilm composition

Researchers use electrochemical signals to stimulate the proliferation of different cells in biofilms, which controls their growth.  

Biofilms are invisible communities of microscopic bacteria and can be found anywhere and everywhere there is moisture, nutrients and a surface. The ability to control biofilms would be especially valuable in areas where bacteria growth is a concern. This includes hospitals as biofilms can cause chronic infections, which is particularly problematic due to the current threat of antibiotic resistance.

Researchers from the University of California, San Diego (CA, USA) have developed a method to control biofilm growth by combining a novel microfluidic chip with a multielectrode array to send localized electric shocks to the bacterial biofilm. This device also measures the physiological response within the biofilm at a single-cell resolution.  

Biofilms are made of various specialized cell types, and the researchers manipulated the ratio of matrix-producing cells and motile cells to alter the biofilm’s physical and biological properties.

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Motile cells are essential to the formation and spread of biofilms, whereas the matrix-producing cells act as the structural glue. If there are too many matrix-producing cells, the biofilm cannot grow efficiently as it becomes too rigid, whilst if there are too many motile cells it will disintegrate as the cells swim away from each other.  

The electric stimulation from this novel device increased the rate of proliferation of motile cells only, despite motile cells and matrix-producing cells being genetically identical. “While it is known that electrical shocks can kill cells, here we show that they can cause growth of a specific sub-type of cells,” said Gürol Süel, who led the research group. “How a second-long stimulation can promote growth for hours and only of one type of cells is a great puzzle that we are eager to solve.”  

This method of controlling biofilm composition could provide a way to destabilize them in healthcare settings, preventing chronic infections.  

“Being able to modulate cell types in this way is not just important for understanding biofilms,” commented Colin Comerci, the first author of the study. “The electrochemical signals we used are similar to signals used during development in more complicated organisms like frogs, fish or even humans. Thus, our findings may offer analogies to other biological systems.”

You can find a video of the biofilm composition changing that was recorded by the Süel lab here.