Two for the price of one

Nanoparticles can simultaneously enable magnetic resonance imaging (MRI) and fluorescent imaging of living organisms for disease diagnostics, such as monitoring the progression of cancer and its response to therapy. Researchers at the Massachusetts Institute of Technology (MIT) have reported a proof of principle in which the bottlebrush polymer nanoparticles, carrying distinct sensors for fluorescence (Cy5.5) and MRI (a nitroxide contrast agent) are mixed to track vitamin C in mice. In regions of high vitamin C concentration, there is a strong fluorescent response but negligible MRI contrast. In low vitamin C conditions, the MRI signal becomes visible but the fluorescence glow is very weak.