Nanoparticles are being tested as potential drug delivery devices for a number of different treatments, but recent research from scientists at the Norwegian Radium Hospital shows that they may, in some cases, hinder cellular function, reports Forbes' Alex Knapp. According to the Research Council of Norway, the researchers dyed nanoparticles 30 to 100 nanometers in diameter, so as to fluoresce when irradiated with a laser and to track them as they made their way through a cell. "Trials showed that a protein that transports iron into a cell is taken up in the usual way even when bound to a nanoparticle. However, while 99 percent of a protein not bound to a nanoparticle will make its way out of the cell and can be recycled, a nanoparticle-bound protein remains in the cell," the Research Council says. The nanoparticle then accumulates in endosomes, and the researchers say it interrupts the cell's normal function, including the flow of vital substances in and out of the cell. This news is troubling, Knapp says, in that it suggests that if nanoparticles are consumed in medicines for a long period of time, the accumulations could put patients at higher risk for cancer for other diseases related to interruptions in cellular function. The Norwegian team plans to continue its research, Knapp adds, including studying nanoparticles smaller than 30 nanometers, and made of different materials or in different shapes.