Real-Time Imaging Tracking of a Dual Fluorescent Vaccine Delivery System Based on Ovalbumin Loaded Zinc Phthalocyanine-Incorporated Copolymer Nanoparticles

The vaccine delivery process plays a significant role for antigen-specific immune responses, which directly determines the effect of immunotherapy. It is crucial to reveal the real-time process of the vaccine release and the status of the implanted carrier in vivo. Herein, a dual fluorescent vaccine delivery system was monitored with the rhodamine-ovalbumin loaded zinc phthalocyanine conjugated nanoparticles (PHA-OVA NPs) to explore the vaccine delivery process. The PHA-OVA NPs showed a sustained release of ovalbumin in vitro and could significantly enhance the uptake of antigen by dendritic cells (DCs). The PHA-OVA NPs could also upregulate the levels of costimulatory molecules on the surface of DCs, suggesting an enhanced ability of the antigen delivery system to promote antigen presentation to antigen-special T cells compared to soluble antigen. The fates of the ovalbumin and the PHA NPs were tracked simultaneously in vivo using the multispectral fluorescence imaging system and the results showed that the antigen was carried to the lymphoid organs by the delivery vehicle. The multispectral fluorescence imaging provided an innovative method to track the vaccine delivery process simultaneously.