Possible Harmful Effects of Nanoparticles

Alongside every application, the book stresses that research into nanotechnology's harmful effects is equally important and equally fast-developing. The core concern is dimensional: nanoparticles happen to share the same size scale as biological molecules such as proteins, so they can easily get adsorbed onto the surface of living organisms and, from there, enter the tissues and fluids of the body. That same adsorbing behaviour is a double-edged property. Because it depends on the surface characteristics of the nanoparticle, it can be deliberately engineered -- designing a nanoparticle's surface so that it adsorbs specifically onto the surface of one target cell is exactly what makes targeted drug delivery to a specific site in the body possible. But the same size dependence works against control: nanoparticles only a few nanometres across can reach well inside biomolecules in a way that larger nanoparticles simply cannot, and they can cross cell membranes freely. Inhaled nanoparticles are known to be able to reach the bloodstream, and from there other organs such as the liver, the heart, or blood cells generally. Because of this, researchers are actively trying to understand how living organisms respond to nanoparticles of varying size, shape, chemical composition and surface characteristics, since none of these variables can be assumed safe just because the particle is 'nano'. An accompanying enrichment diagram, explicitly marked 'Not for examination', catalogues disease associations by exposure route: ingestion through the gastro-intestinal system with Crohn's disease and colon cancer; orthopedic-implant wear debris with auto-immune diseases, dermatitis, urticaria and vasculitis; inhalation through the lungs and circulatory system with asthm …