Nanotechnology is used to treat human body through the development of diagnostic devices, contrast agents, analytical tools, physical therapy applications and drug delivery vehicles. In most applications, nanoparticles are coated with a layer of molecules, often proteins, which determine the use of nanoparticles when they enter cells. In a wide range of cells nanoparticles are taken into inner region of cell where this essential coating is degraded to work against the disease.
Scientists have uncovered what happens to nanoparticles when they enter human cells. They found that the important proteins that make up the outer layer of these nanoparticles are degraded. But scientists have to still understand this phenomenon. Scientists at the University of Liverpool think say that they do not know what state they are in by the time they get there.
The design of any intracellular nanodevice must now take into account the possibility of cathepsin L degradation and either bypass the endosome area all together or have some built-in inhibition of the enzyme. Researchers have developed methods to measure the location and the state of the nanoparticle quickly and quantitatively.

However according to the researchers nanotechnology is an interesting area that has the potential to push all sorts of technological boundaries. Still there is promise of some useful applications in biology and some excellent results have been seen with the development of nanomagnetic technology to guide therapeutic proteins and DNA to specific sites to treat tumours.