22. Name Size Composition Details Quantum Dots 2-10 nm Colloidal fluorescent semiconductor nanocrystals. Central core consists of elements from groups II - VI of the periodic table Dendrimers <15 nm Highly branched synthetic polymers with a layered architecture - consisting of a central core, an internal region, and several terminal groups Magnetic nanoparticles 10-20 nm Spherical nanocrystals with Fe 2+ and Fe 3+ core surrounded by dextran or PEG (polyethelene glycol) molecules Gold nanoparticles <50 nm Can be prepared into different geometries - nanospheres, nanoshells, nanorods, or nanocages Carbon Nanotubes (CNT) <100 nm Coaxial graphite sheets