Photocatalytic TiO2 Nanoparticles for Tumor Therapy

Despite advances in treatments for head and neck cancers, patient survival rates have only slightly increased over the last decades [1]. Thus, novel therapy strategies need to be developed to enhance current standard... [ view full abstract ]

Despite advances in treatments for head and neck cancers, patient survival rates have only slightly increased over the last decades [1]. Thus, novel therapy strategies need to be developed to enhance current standard treatments like surgery, radiation or chemotherapy. Photocatalytic nanoparticles (NPs) are a serious candidate as they may combine their function as a therapeutic agent with surfaces that can be functionalized to mediate cellular uptake, carry drugs or molecules for diagnostic.
In this study, TiO2 (anatase) NPs with diameters of 10 nm were synthesized via hydrothermal treatment. The NPs and their in situ grafted organic surface groups were characterized by XRD, TEM, zeta potential, dynamic light scattering (DLS), thermogravimetric analysis, photocatalytic activity measurements and IR-spectroscopy. Stabilization of the synthesized NPs in cell culture media was examined via sedimentation studies (absorption spectroscopy, DLS). Cytotoxicity tests and tumor treatment experiments were carried out in a human tumor cell line (FaDu) and human bone marrow-derived mesenchymal stem cells with the help of the MTT colorimetric staining method.
After complete characterization of the synthesized TiO2 NPs, they were stabilized in cell culture media using a polycarboxylate ether as a novel stabilization agent. A perfect stability over at least one day and agglomerate sizes less than 100 nm were achieved [2]. Within this research the biocompatibility of non-activated NPs was demonstrated. For the treatment of tumor cells a novel concept was developed; the photocatalytic NPs were activated by UV light which modified their surface groups. Hereupon, NPs exhibited dose-dependent cytotoxic properties in FaDu while non-malignant cells were significantly less affected.
In summary, the novel NPs are attractive for the treatment of superficial mucosa malignancies of the head and neck due to their cancer specific toxicity and since they can be activated prior to cell exposure. This allows tumor therapy without UV irradiation of cells avoiding UV-induced DNA damages in non-targeted cells. Furthermore, pre-treatment UV activation allows the NP application in deeper cancer formations.
[1] R. Siegel et al. CA Cancer J. Clin. 65 (2015) 5–29.
[2] S. Koch et al. Colloids Surf. B: Biointerfaces 143 (2016) 7-14.