Nematodes, microscopic worms, are making engineers look twice at their ability to exhibit the "Cheerios effect" when they move in a collective motion.
These parasites will actually stick together like Cheerios swimming in milk in a cereal bowl after a chance encounter "due to capillary force." This observation has made Virginia Tech engineers speculate about the possible impacts on the study of biolocomotion.
Their work appears in the journal, Soft Matter, a publication of the Royal Society of Chemistry, the week of Feb. 7. Soft Matter is the premier journal in the ongoing multidisciplinary work between physics, material science, and biology.
Two Harvard physicists first defined the Cheerios effect. In 2005, Dominic Vella and Lakshminarayanan Mahadevan wrote an article on this activity, defined by scientists as relating to fluid mechanics, in the Journal of Physics. They cited its usefulness in the study of self-assembly of small structures. Self-assembly is used in the science of nanotechnology.
Dominic Vella who now teaches at the University of Oxford, United Kingdom, collaborated with Sunghwan "Sunny" Jung, an assistant professor of engineering science and mechanics at Virginia Tech, and his student, Sean Gart, of Salem, Va., a senior in engineering science and mechanics, and authored the new paper, "The collective motion of nematodes in a thin liquid layer."
Gart has been working in Virginia Tech's Biologically Inspired Fluids Laboratory directed by Jung since last summer. Gart found that the nematodes did not crawl faster or more efficiently while stuck together.
"This is an interesting behavior that has not been studied very widely in the biolocomotion field," Jung said. "The result implies that nematodes gain neither a mechanical advantage nor disadvantage by being grouped together. The capillary forces merely keep them together after a chance encounter. This result also extends a better understanding of capillary effects in colloidal particles in engineering systems such as pickering emulsions. These emulsions are stabilized by solid particles. An example would be homogenized milk."
Contact: Lynn Nystrom email@example.com 540-231-4371 Virginia Tech