Scientists believe red blood cells' flexibility contributes to… (Don Bartletti/Los Angeles…)
One of red blood cells' remarkable characteristics, among many, is their ability to deform and squish their way through blood vessels -- even blood vessels tinier than they are -- to deliver oxygen throughout the body. Scientists believe this flexibility contributes to red blood cells' ability to circulate for an average of 120 days.
Now researchers at the University of North Carolina have synthesized red blood cell-sized and -shaped nanoparticles that mimic this flexibility and longevity. The discovery may lead to the development of better methods for delivering drugs, they reported Monday in the Proceedings of the National Academies of Science.
"We believe this study represents a real game changer for the future of nanomedicine," said Joseph DiSimone, the study's co-lead investigator, in a news release. Getting particles to continue circulating in the body for extended periods has been a challenge, he said.
Previous studies had focused on how size, shape and surface characteristics of particles affected their movement through the bloodstream, the team wrote, but flexibility's role is less well understood. To test it out, the researchers built artificial cells out of a gel material with "tunable elasticity" -- that is, the team could control how deformable the cells were.
They ran their fake cells through a battery of tests in the lab, and injected them intravenously into mice. They found that the softest cells they tested remained in the bloodstream 30 times longer than the least flexible ones did. Rigid particles lodged in the lungs, while more flexible ones wound up in the spleen, just as real red blood cells do when they begin to lose elasticity.
While the team does not yet know if their pseudo-cells can carry drugs through the body, they said that the technology could help in the production of synthetic blood, in cancer treatments or in medical imaging. Getting particles to continue circulating in the body for extended periods has been a challenge, they said.
Related: Read more in the Los Angeles Times about artificial blood.