Static imaging of cellular forces and biomechanics within the human body can be inferred using MRI and other imaging techniques. However, live images of these same forces cannot be accomplished with current technology. Stanford Materials Science and Engineering professor, Jennifer Dionne, in collaboration with Miriam B. Goodman, a professor of molecular and cellular physiology, is developing a new possible way to look at how cells move and interact with each other in real time using glowing nanoparticles.
The nanoparticles that Dionne and her lab have created glow when activated by a near-infrared laser and can change color depending on the forces acting on them. The idea that we can investigate cellular movement by watching the changing colors of the nanoparticles as they travel through the body could provide valuable information about human touch, digestion, cancer, wound healing, cellular division and differentiation, and much more.
“Altered cellular-level forces underlie many disorders, including heart disease and cancer,” says Dionne, “This would be a nanoscale readout that you could use in vitro or in vivo to detect disease at a very early stage.”
The first phase of the study involves digestion of the nanoparticles by Caenorhabditis elegans. Of course, the eventual objective is to use the nanoparticles to detect cellular forces in humans, but initially, the team is testing the technique in worms. The worms offer good insight into how the nanoparticles register forces through the worm’s digestion. The team can log the changing colors as the nanoparticles move through the worm and work to decipher what kinds of biomechanics are at play with each color.
“The color that each nanoparticle emits changes from red to orange when there is a mechanical force on the order of nanonewtons to micronewtons – a force range thought to be very relevant for intercellular forces,” said Alice Lay, a graduate student in the Dionne lab.
Because nanoparticles are so small, they have the potential to create in-depth force maps of what is happening in and around cells. Not only can the technique be used inside the body to learn more about cellular activity, but also to understand the forces involved in sensory load from the environment. For example, if we understood more about how cells registered touch, we could implement that sensory information in prosthetic development.
After mapping out the static cellular forces within the worms, the team will create a dynamic map of the particles over time to examine the change in cellular forces during processes such as digestion. Once they have information about different processes in healthy worms, they will introduce mutations to learn if gene expression plays a role in changing cellular forces.
The ultimate goal is to move the technique to human subjects. The nanoparticles are biocompatible so could be ingested or injected to understand internal processes or forces acting on a specific area within the body such as the site of a wound or tumor. The changing colors of the nanoparticles could provide an idea of the activity of the cells in that area.