Size really does matter, folks! Ask any scientist about the potential uses for nanoparticles, and you’ll quickly agree that these tiny little suckers deserve a spot at your dinner table, complete with cute nano-plates and nano-forks. Today’s image is from a paper describing a clever use of nanoparticles to systematically monitor how cells respond to force.
A cell encounters force from its entire environment. A cell responds to mechanical force by regulating signals, development, and migration, among other things. Biologists have been trying to understand how cells respond to force for years, and clever techniques have included manipulation by optical tweezers, micropipettes, and atomic force microscopy. These techniques, however, have been limited by their ability to monitor one cell at a time. A recent paper describes a technique in which many cells respond to uniform forces on the cortex. In this study, Tseng and colleagues plated cells on micropatterned magnetic substrates. Magnetic nanoparticles within the cells were then manipulated by a magnetic field in order to apply a uniform mechanical force on the cell cortex. By monitoring large numbers of individual cells under these forces, Tseng and colleagues developed a way for biologists to have higher control and accuracy in understanding how force affects cells. The images above show representative images of cells under varying amounts of force. The dose of nanoparticles (blue) in each cell (increasing from bottom to top) and strength of the magnetic field (increasing from left to right) both affect the response from cells. A higher nanoparticle dose and magnetic field gradient caused cells to produce more filopodial membrane extensions from cells (actin is in green) from the region where the force was applied.
Tseng, P., Judy, J., & Di Carlo, D. (2012). Magnetic nanoparticle–mediated massively parallel mechanical modulation of single-cell behavior Nature Methods, 9 (11), 1113-1119 DOI: 10.1038/nmeth.2210
Adapted by permission from Macmillan Publishers Ltd, copyright ©2012