Inorganic nanoparticles offer great opportunities in biomedicine, for example, serving as contrast agents for imaging, hyperthermia agents and drug delivery vehicles. A critical factor limiting the applications of nanoparticles for therapeutic and diagnostic purposes is their short circulation time in vivo due to clearance by the body's reticuloendothelial system. One of the most efficient strategies to confer stealthiness to nanoparticles is the use of a polymer “cloak” which inhibits plasma protein adsorption and recognition by the immune system. This review describes some of the polymers which are suitable for these applications, and the strategies which can be employed to functionalize inorganic nanoparticles with such polymers.
