Formation and characterization of AcetalDextran-AuNP-Micelles. (a) AcetalDextran-AuNPs and PEG-PCL were dissolved in toluene and then suspended in water to form an emulsion, driving self-assembly of AcetalDextran-AuNP-Micelles. (b) Hydrodynamic diameter of micelles determined via dynamic light scattering. The average peak hydrodynamic diameter was 146 nm. (c) Electron microscopy imaging of micelles in water via Cryo-TEM and standard TEM. (d) Hydrodynamic diameter of micelles in PBS at 4 °C, recorded immediately after suspension and at 1 hour, 1 day, 3 days, 5 days, and 7 days (average of three measurements, ± SEM). At 7 days, the sample was diluted 10-fold in water to reduce salt concentration and then imaged by TEM (inset).