Figure 1: A: Macroscopic analysis of the investigated empty and fluorescent dye containing nanoparticle formulations. B: Bright and dark field photographic analysis of the effect of serial dilution (with poloxamer 188, 2.5% w/w) of SLN-P80 on the general aspect (i.e. milkiness) of the formulation. The total lipid content of the shown formulations is 56 (1), 28 (2), 14 (3), 7 (4) 3.5 (5) mM, for comparison images of liposomal suspensions constituted of phospahtidylcholine/cholesterol 36/3.6 (6) and 9/0.9 (7) mM are also reported. For nanoparticle identification codes, composition and preparation procedure, please refer to Table 1 and experimental section.