*2.6. Size Analysis by Flow Cytometry in Vitreous and Plasma Samples*

Flow cytometry (Apogee Flow Systems, Hertfordshire, UK) was used to differentiate between the liposomes and other possible porcine vitreous and human plasma components of the same size by large-angle light scattering (LALS) and by detecting the calcein fluorescence to separate the liposome population. The LALS measurements returned the relative size and coefficient of variation (CV) of the liposome population. A calibration line for the liposome size was produced by measuring liposomes of different size in buffer with DLS, as described earlier, and then measuring the same samples with Apogee flow cytometry (Figure S4A). The generated calibration line had the following equation (*R <sup>2</sup>* = 0.96):

$$\text{LHS} = \text{21.666} \times \text{DLS}(\text{nm}) - 888.11. \tag{1}$$

The flow cytometry signal from bulk vitreous and plasma without liposomes was analyzed separately, and only the liposome population was gated into the final data (Figure S4B–E, Supplementary Materials).
