Magnetic Genes
Genetically ­engineered cells make their own nano magnets, providing clear MRI images

Source: “MagA is sufficient for producing magnetic nanoparticles in mammalian cells, making it an MRI reporter”
Xiaoping P. Hu and Anthony W. S. Chan
Magnetic Resonance in Medicine 59: 1225-1231

Results: Scientists genetically engineered mammalian cells to produce magnetic particles three to five nanometers in diameter. The particles can be detected with magnetic resonance imaging (MRI), which could give scientists a novel way to track cells in the body.

Why it matters: Scientists typically use fluorescent markers to track specific cell types. But fluorescent signals can’t travel very far through animal tissue, so the approach is of limited use in live studies. Cellular labels detectable with MRI, which can see deep into the body, could allow scientists to observe a range of biological processes as they unfold in live animals.

Methods: From a pond-­dwelling bacterium, scientists isolated a gene for producing magnetic particles, which the bacterium uses like a compass. They inserted the gene into human cells and injected the cells into the brains of live mice. The mouse cells began to produce their own magnetic particles and could be seen clearly with MRI.

Next steps: The researchers will further assess how the nanoparticles could be used with MRI by better characterizing them and measuring their effect on cells–determining, for ­example, whether they are toxic or whether they alter cellular functions in living animals.