Functional TiO₂ nanocoral architecture for light-activated cancer chemotherapy

To achieve light-triggered drug release in cancer chemotherapy, we developed multimodal titanium dioxide (TiO₂) nanocorals modified with methoxy polyethylene glycol (mPEG). TiO₂ nanocoral-like structures were synthesized by optimizing a solvothermal method. The developed nanocoral structures were efficiently conjugated with chemotherapeutic drugs on the surfaces of the TiO₂ nanoparticles. The mPEG on the surfaces of the multifunctional nanocorals effectively conjugated the drug and improved the biocompatibility of the nanocorals. Following UV light irradiation, the TiO₂ nanocorals produce free radicals (˙OH and ˙O₂ ^-) and are effective for drug release in cancer cells. Importantly, the amount of drug released from the multimodal TiO₂ nanocorals can be regulated by UV-light irradiation time, which allows for further control of the anti-cancer effect. The multimodal TiO₂ nanocorals exhibit a combination of light-activated, stimuli-triggered drug release for killing of cancer cell. The cytotoxicity, cellular uptake, and intracellular location of the formulations were evaluated in MCF7 cells. Our results showed that nanocoral-DOX complexes exhibited a greater cytotoxicity toward MCF7 cells than free DOX. Our work demonstrates that the therapeutic efficacy of DOX-loaded TiO₂ nanocorals is strongly dependent on their loading mode and the chemotherapeutic effect is improved under UV light illumination, which provides a significant breakthrough for future applications of TiO₂ as a light activated drug carrier in cancer chemotherapy.