Ethiodized Oil Emulsion for Sustained Release of Anti-PD-L1 Antibodies

To develop and assess an ethiodized oil (Lipiodol) Pickering emulsion containing anti-programmed cell death ligand 1 (PD-L1) antibodies through in vitro experiments.

The emulsion was created by combining ethiodized oil with poly (lactic-co-glycolic acid) (PLGA) nanoparticles and anti-PD-L1 antibodies. Confocal laser microscopy was used to evaluate the encapsulation of the antibodies within the Pickering emulsion. To assess the stability, the emulsion was visually examined, and droplet sizes were measured under a light microscope. For the sustained release evaluation, the emulsion was introduced into saline and incubated in a shaking bath, after which the supernatant was collected over time. The concentration of anti-PD-L1 antibodies in the supernatant was determined using a bicinchoninic acid assay. Western blotting and flow cytometry were employed to confirm the functionality of the released antibodies. A conventional ethiodized oil emulsion was used as a control for comparison.

The anti-PD-L1 antibodies were encapsulated within the layer of PLGA nanoparticles, positioned at the interface between the water and oil phases, as confirmed by confocal laser microscopy. The ethiodized oil Pickering emulsion demonstrated long-term stability with significantly smaller droplet sizes (P < .001). Moreover, the emulsion facilitated a gradual and sustained release of the anti-PD-L1 antibodies over an 8-week period (P < .001). The antibodies released from the emulsion specifically targeted PD-L1.

This study demonstrated that ethiodized oil Pickering emulsions effectively encapsulate anti-PD-L1 antibodies and enable their sustained release, highlighting their potential as a therapeutic agent for primary and secondary liver cancers.