Figure 4: Fluorescence quantification of ncSi:AB brightness and liposomal encapsulation.

(a) Plot of the percentage of empty liposomes as an indication of encapsulation efficiency of the fractions. The percentage of empty liposomes was obtained by finding the fraction of the liposomes observed in the TRITC channel that did not have any nanoparticles (UV channel) at the same location below a chosen threshold. (b) Ratio of blue (ncSi:AB) to red (TRITC-labeled liposome) normalized to the quantified (Supplementary Figure 4) brightness of the naked particles as a measure of encapsulation of the various fractions. (c) EC-50 toxicity measurements of the set of 11 monodisperse ncSi:AB from batch D used in the encapsulation study in A and B. (d–f) are the red (TRITC), blue (UV illumination and 580 nm long pass emission for ncSi:AB) and a merged image of both channels respectively for the lipid control with no ncSi:AB. G, H, I and J, K, L are the same channels as those used in D, E and F, but for fractions D5 and D7, respectively. Scale bar = 30 μm. Error bars represent standard deviations from triplicate samples. Comparison of the toxicity was done using a one-way ANOVA and a subsequent post hoc Tukey’s test as previously used in Fig. 2. Fractions D5 and D7 were chosen for comparison because they differed significantly from each other.