Enhancement of the Immune Function by Titanium Dioxide Nanorods and Their Application in Cancer Immunotherapy

With the rapid development of nanotherapy, concerns surrounding the possible use of nanomaterials-mediated immunomodulation are growing. Thus, evaluating the effects of novel materials for potential application in nanotherapy is essential. Herein, we studied the effects of TiO2-nanorods (NRs) on the immune function and their potential application in immunotherapy. TiO2-NRs exerted specific immunomodulatory effects on the main immune cells. Cytokines TNF-α and IL-2, which play a key role in antitumor processes, were upregulated more significantly than other cytokines (IL-4, IL-5, IFN-γ) in the main immune cells. The cells group treated with a high dose of TiO2-NRs (50 mg/L) for 12 h produced a higher TNF-α content of 530.4 pg/mL relative to that (238.2 pg/mL) treated with saline solution only. The TNF-α content increased to 2.2- and 4.9-fold for macrophages and lymphocytes, respectively. Also, we conclude that TiO2-NRs exposure may trigger T cell proliferation and bias toward Th1 immune response and cause a long-lasting activation of lymphocytes involved in adaptive immunity rather than an innate immunity in BALB/c mice. Furthermore, we explored the potential application of TiO2-NRs in immunotherapy. At a given dose of 1 mg/kg, the inhibition rate by TiO2-NRs (26.7%) was much higher than that by DOX (13.3%).