Researchers use revolutionary electronic technology to modify the demographics of the bacterial community

UC San Diego scientists developed a new technology that specifically targets one type of cell among genetically identical bacteria that live in the same microenvironment. They discovered that a second-long shock emitted by an electrode (dark circle in the center), preferentially causes growth of (orange) motile cells, rather than (blue) matrix-producing cells, thereby changing the ratio of cell types in the community. Credit: Süel Lab, UC San Diego

All around us, clusters of microscopic microbes exist. These invisible communities, dubbed biofilms, are found in a variety of habitats, from human skin to sewer pipes, and serve critical roles in a variety of situations, from healthcare to agriculture.

Molecular biologists and physicists at the University of California, San Diego have collaborated to develop a unique way for controlling the formation of bacterial communities using electrical shocks. Their findings, which were achieved using a newly created method, have major medical implications. Biofilms can cause persistent infections in environments where bacteria growth is a concern, particularly in settings such as hospitals where antibiotic resistance is a major health threat.

Biofilms, like other multicellular creatures, are made of a variety of cell types that each perform a unique function. For instance, matrix-producing cells act as the structural “glue” that keeps the bacterial population together, whereas motile cells contribute to the production and spread of biofilms. The balance of these two cell types determines the biofilm’s physical and biological features, as well as its evolution. If the biofilm contains an excessive number of matrix-producing cells, it becomes stiff and unable to proliferate efficiently. If the biofilm contains an excessive number of motile cells, the biofilm disintegrates as the cells swim away. Thus, manipulating the ratio of these two cell types provides a precise way for biofilm control.

As described in the journal Cell Systems on May 4, 2022, a team at UC San Diego led by postdoctoral scholar Colin Comerci and colleagues in Professor Gürol Süel’s laboratory in the Department of Molecular Biology, in collaboration with colleagues in the Department of Physics, developed a novel microfluidic device and combined it with a multi-electrode array to deliver localised electric shocks to a growing biofilm.

To their amazement, electrical stimulation induced the proliferation of motile cells, despite the fact that all cells in the biofilm are genetically identical.

“While it is well established that electrical shocks can kill cells, we demonstrate here that they can stimulate the growth of a specific subtype of cells,” said Süel, a Biological Sciences professor affiliated with the San Diego Center for Systems Biology, the BioCircuits Institute, and the Center for Microbiome Innovation. “How a second-long stimulation may encourage proliferation of a single type of cell over hours is an intriguing issue that we are keen to answer.”

“The ability to manipulate cell kinds in this way is critical for understanding biofilms,” Comerci explained. “Our electrochemical signals are analogous to those used during development in more complex species such as frogs, fish, and even humans. As a result, our findings may be applicable to different biological systems.”

A biofilm (orange) is a population of bacteria that grows on a microelectrode array (black circles). This newly created device enables the stimulation of a single type of bacterial cell in the vicinity of a microelectrode (green track). Credit: UC San Diego’s Süel Lab

Why electrical stimulation increases the population of one cell type but not another is a puzzle that the Süel laboratory continues to investigate. According to the researchers, this type of effect allows for greater control over the composition and evolution of the biofilm and may provide a new tool for destabilising biofilms in healthcare and agriculture contexts.

Colin Comerci, Alan Gillman, Leticia Galera-Laporta, Edgar Gutierrez, Alex Groisman, Joseph Larkin, Jordi Garcia-Ojalvo, and Gürol Süel are all listed as authors on the publication.

Further information: Gürol M. Süel, Localized electrical stimulation triggers cell-type-specific proliferation in biofilms, Cell Systems (2022). DOI: 10.1016/j.cels.2022.04.001. www.cell.com/cell-systems/full … 2405-4712(22)00166-1

Journal information: Cell Systems

Source: University of California – San Diego