Cryo-Transmission Electron Microscopy Confirms Controlled Synthesis of Cadmium Sulfide Nanocrystals within Lecithin Vesicles

Size-quantized CdS nanocrystals of controlled dimensions are synthesized within monodisperse egg lecithin vesicles made by detergent depletion. Cryo-transmission electron microscopy (cryo-TEM) enables imaging in situ both of the vesicle wall and of the encapsulated nanocrystal. Cryo-TEM images confirm that only one particle per vesicle forms and that nanocrystal diameter is determined by the number of Cd²⁺ ions initially encapsulated. These micrographs further show that the particles adsorb to the inner surface of the vesicle membrane, which suggests that crystal growth and particle core structure could be controlled through manipulation of vesicle bilayer chemistry.