Nanoparticles in Biological Systems

Understanding the behavior of nanoparticles in biological systems opens up new directions for medical treatments and is essential for the development of safe nanotechnology. This Review discusses molecules and nanoparticles when in contact with cells or whole organisms, with a focus on inorganic materials. The interaction of particles with biology unravels a series of new mechanisms not found for molecules: altered biodistribution, chemically reactive interfaces, and the combination of solid-state properties and mobility. Externally guided movement of medicaments by using functional nanomagnets brings mechanics into drug design. In subsequent sections, the role of inertness and bioaccumulation is discussed in regard to the long-term safety of nanoparticles. Particles in motion: Nanoparticles combine the properties of a traditional solid (magnetic, optic, mechanic, radiation) with the mobility of molecules, including the ability to diffuse inside an organism. This combination opens up fascinating opportunities for medical treatments, industrial processes, and improved consumer products-but the environmental aspects must also be considered. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.