Fig. 5. Optical micrographs of (a) IR820-BSA nanogels, (b) IR820-vesicles, (c) DOX–BSA nanogels and (d) DOX-vesicles incorporated within calcite crystals. The inset on the right in (a) shows calcite crystals precipitated in the presence of IR820 only. The transparent and colorless aspect of the crystals indicates that the IR820 molecules do not incorporate within calcite on their own. The insets on the left show the loaded nanocarriers dispersed in aqueous solutions. The darker colors of the solutions and crystals occluding the loaded BSA nanogels (a and c) compared to the vesicles (b and d) demonstrate the superior performances of the BSA nanogels as nanocarriers for both DOX and IR820, compared to the vesicles.