The optical emission properties of eFluor Nanocrystals are primarily dictated by their size, as discussed in the next section.  There are at least two aspects to consider when discussing the "size" of a quantum dot: the physical size of the semiconductor structure, and the size of the entire quantum dot moiety including the associated ligands and hydrophilic coating.  The size of the semiconductor structure is tabulated below, and reflects the diameter of the spherical quantum dot without ligands.  eFluor Nanocrystals are rendered water-dispersable with a patented poly-ethylene glycol (PEG) lipid layer that functions as both a protective hydrophilic coating around the quantum dot, as well as reducing non-specific binding  By dynamic light scattering measurements, the hydrodynamic radius of all eFluor Nanocrystals ranges from 10 to 13nm.