A device that can herd groups of cells like sheep, precisely directing the cells’ movements by manipulating electric fields, opens new possibilities to heal wounds, repair blood vessels or sculpt tissues.
The new system, assembled from inexpensive and readily available parts, enables researchers to control cellular movements within engineered tissues in a reliable and repeatable way. It does this by exploiting a phenomenon known as electrotaxis, in which electrochemical signals within the body can influence the migration, growth and development of cells.
Previous systems for studying cells’ responses to electric fields have been bespoke or handmade, raising issues of reproducibility, or required fabrication facilities that make them expensive and inaccessible.
The team calls the device SCHEEPDOG, for Spatiotemporal Cellular HErding with Electrochemical Potentials to Dynamically Orient Galvanotaxis (galvanotaxis is another term for electrotaxis). The device contains two separate pairs of electrodes that are used to generate electric fields along horizontal and vertical axes (akin to an Etch A Sketch), as well as recording probes to measure voltage and integrated materials to separate the cells from chemical byproducts of the electrodes. The voltage level is similar to that of an AA battery concentrated over the several centimeter-wide chamber containing the cells.
The team tested SCHEEPDOG using layers of mammalian skin cells and epithelial cells from the lining of the kidney, which are often used to study cells’ collective movements. By adjusting the electric field, the researchers could cause the cells to migrate in any direction or pattern. The team is expanding their studies to different cell types and contexts aimed at eventual applications like regenerating skin, blood vessels and nerve cells in damaged tissue, and has recently doubled the healing speed of cultured skin layers. They are working towards the development of next-generation bioelectric devices, such as e-Band-aids and electrically controlled immunotherapy.
"This device gives us an amazing level of control over cells that we wouldn’t have expected to be possible, especially with thousands of neighboring cells executing these maneuvers on command.”
– Daniel Cohen
Daniel Cohen, Assistant Professor of Mechanical and Aerospace Engineering
Tom Zajdel, former Postdoctoral Research Fellow, now Assistant Professor at Carnegie Mellon University
Gawoon Shim, Graduate Student in Mechanical and Aerospace Engineering
Danelle Devenport, Associate Professor of Molecular Biology; Eszter Posfai, Assistant Professor of Molecular Biology
Isaac Breinyn, Graduate Student in the Lewis-Sigler Institute for Integrative Genomics; Irving Miramontes, Graduate Student in Molecular Biology
Patent protection is pending. Princeton is seeking outside interest for the development of this technology.
National Institutes of Health, National Science Foundation, Princeton Catalysis Initiative