Multicomponent coassembled nanodrugs based on ovalbumin, pheophorbide a and Zn2+ for in vitro photodynamic therapy

Photodynamic therapy (PDT) has been considered as a therapeutic method based on non-invasiveness and lower side effect. However, photosensitizers (PS), as a major component of PDT, suffer from aggregation and limit reactive oxygen species (ROS) generation in the delivery process, thus causing unsatisfactory therapeutic effect of PDT. Herein, we demonstrate a multicomponent coordination coassembly strategy based on the combination of metal-binding protein (ovalbumin, OVA), metal ions (Zn²⁺) and a photosensitive drug (pheophorbide a, PheoA) for constructing supramolecular photosensitive nanodrugs towards antitumor PDT. The resulting photosensitizer nanodrugs exhibit well-defined nanorod structures, good colloidal dispersity, and high encapsulation efficiency. Most importantly, multicomponent coassembled nanorods possess favorable stability of physiological environment and on-demand release of PS in response to an acidic ambient in tumor cells. These features result in the high level of ROS generation in tumor cells, benefiting for enhanced therapeutic effect of in vitro PDT.