{"id":35350,"date":"2026-02-02T00:05:32","date_gmt":"2026-02-01T18:20:32","guid":{"rendered":"https:\/\/www.revoscience.com\/en\/?p=35350"},"modified":"2026-02-02T00:05:34","modified_gmt":"2026-02-01T18:20:34","slug":"physics-defying-discovery-sheds-new-light-on-how-cells-move","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/physics-defying-discovery-sheds-new-light-on-how-cells-move\/","title":{"rendered":"Physics-defying discovery sheds new light on how cells move"},"content":{"rendered":"\n
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IMAGE: Joel Hallberg \/ UW\u2013Madison<\/sup><\/em><\/figcaption><\/figure>\n\n\n\n

MADISON \u2014 The cells in our bodies move in groups during biological processes such as wound healing and tissue development \u2014 but because of resistance, or viscosity, those cells can’t just neatly glide past each other.  <\/p>\n\n\n\n

Or can they?<\/p>\n\n\n\n

Using a pioneering method they developed to directly measure viscosity in a group of cells, University of Wisconsin\u2013Madison engineers have made a surprising discovery that upends understanding of how cells move.<\/p>\n\n\n\n

It’s called “negative viscosity,” and it propels cells, rather than impedes them.<\/p>\n\n\n\n

\u201cThis advance can enable researchers to develop better models for cell motion, which could lead to future applications for human health, such as ways to speed up wound healing or facilitate essential processes in tissue development,\u201d says Jacob Notbohm, an associate professor of mechanical engineering who led the research with PhD student Molly McCord. <\/p>\n\n\n\n

Notbohm and McCord detailed their findings in a paper published Dec. 4, 2025, in the journal PRX Life<\/a>. <\/em><\/p>\n\n\n\n

Cells generate forces that cause them to move, but how the forces balance among groups of cells to create motion is not clear. That\u2019s why McCord and Notbohm wanted to find a way to measure the viscosity in the system; the magnitude of the viscosity was a missing part of the equation for understanding collective cell motion.<\/p>\n\n\n\n

In experiments, the researchers used optical imaging to analyze how a single layer of epithelial cells deformed a soft gel surface as they migrated across it. This allowed them to calculate how much force the cells produced.<\/p>\n\n\n\n

Then McCord developed a new approach for analyzing the data that involved looking at various multicellular regions, or cell groups. Her analysis revealed there were regions of cells where the viscosity, unexpectedly, was negative. <\/p>\n\n\n\n

\u201cThis surprising discovery of negative effective viscosity implies injection \u2014 rather than dissipation \u2014 of energy into the flow,\u201d Notbohm says. \u201cFor example, if you were driving a car and the air had a negative viscosity, the air resistance would be propelling the car forward instead of resisting it, which goes against standard physical rules.\u201d<\/p>\n\n\n\n

However, Notbohm says negative viscosity is possible for systems with an energy source \u2014 like cells that convert nutrients into energy. And he and McCord did find that regions of cells with negative viscosity had elevated metabolic activity \u2014 reflecting an increased energy demand in these cells. <\/p>\n\n\n\n

\u201cWhen we started this project, our question was how big is the number for viscosity,\u201d says Notbohm. \u201cBut we\u2019ve now learned that we should be asking a different question: Is this number positive \u2014 or negative? This discovery reframes the problem and shows that it\u2019s meaningful to treat this viscosity as being either positive or negative, which hadn\u2019t been considered before.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

MADISON \u2014 The cells in our bodies move in groups during biological processes such as wound healing and tissue development \u2014 but because of resistance, or viscosity, those cells can’t just neatly glide past each other.\u00a0\u00a0<\/p>\n","protected":false},"author":2,"featured_media":35351,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[121],"tags":[],"class_list":["post-35350","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-physics"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab-.avif",1024,576,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--200x200.avif",200,200,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--675x380.avif",675,380,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--768x432.avif",750,422,true],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab-.avif",750,422,false],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab-.avif",1024,576,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab-.avif",1024,576,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab-.avif",1024,576,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--870x570.avif",870,570,true],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--600x576.avif",600,576,true],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--600x576.avif",600,576,true],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--760x490.avif",760,490,true],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--550x360.avif",550,360,true],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--95x65.avif",95,65,true],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--640x576.avif",640,576,true],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--96x96.avif",96,96,true],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2026\/02\/notbohm_lab--150x84.avif",150,84,true]},"author_info":{"info":["RevoScience"]},"category_info":"Physics<\/a>","tag_info":"Physics","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/35350","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=35350"}],"version-history":[{"count":1,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/35350\/revisions"}],"predecessor-version":[{"id":35352,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/35350\/revisions\/35352"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/35351"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=35350"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=35350"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=35350"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}