Programmable activation of berbamine and photosensitizers for enhanced photodynamic therapy using emission-switchable upconversion nanoparticles.

Photodynamic therapy (PDT) shows great potential in precision tumor treatment. However, its efficacy is inhibited by the antioxidant defense capacities of tumor cells. To address this challenge, a near-infrared light-controlled nanosystem (UCNPs@mSiO@Azo@ZnPc&BBM, PB@UA) was developed using emission-switchable upconversion nanoparticles (UCNPs) to independently and precisely control the release of berbamine (BBM) and activation of photosensitizer for enhanced PDT in deep tissues. Firstly, BBM release was triggered by exciting PB@UA at 980 nm. The BBM could inhibit the activities of antioxidant enzymes and disrupt calcium ion regulation, making the tumor cells more susceptible to ROS-induced cell death in the following PDT treatment. The PDT was initiated by irradiating the photosensitizers of ZnPc on PB@UA at 808 nm and achieved a tumor inhibition rate of 80.91 % in vivo, which is significantly higher than that of unique PDT (31.78 %) or BBM (11.29 %) treatment and demonstrates the potential of our strategy for improved cancer treatment.