Scheme 2. GNPs (to scale) and the Molecules Capable of Stabilizing Each Size.

Arrows represent the span of molecules that are capable of stabilizing each GNP size, that is, all molecules can act as coatings for 20 nm GNPs, 1–4 stabilize 40 nm GNPs, and 1 and 3 are effective coatings for the 100 nm GNPs.