Nano‐Titanium Oxide‐Coated Carbon Nanotubes for Photothermal Therapy in the Treatment of Colorectal Cancer

Abstract Carbon nanotubes (CNTs) display good potential in tumor photothermal therapy (PTT). In this study, it is aimed to investigate the therapeutic potential of nano‐titanium oxide‐coated multi‐walled carbon nanotubes (MCNTs) against colorectal cancer (CRC). First, TiO 2 nanosheets are modified on the surface of MCNTs to obtain nano‐TiO 2 ‐coated MCNTs. Next, cell compatibility validation is conducted on nano‐TiO 2 ‐coated MCNTs, and it is found that nano‐TiO 2 ‐coated MCNTs are safe within a certain concentration range (0–200 µg mL⁻ 1 ). Interestingly, nano‐TiO 2 ‐coated MCNTs display a good killing effect in CRC cells under near‐infrared (NIR) laser irradiation. Subsequently, nano‐TiO 2 ‐coated MCNTs markedly promote the proapoptotic effects of NIR laser irradiation and significantly inhibit the expression of cell cycle proteins CCNA1 and CCND1 in CRC cells under NIR laser irradiation, which indicates that nano‐TiO 2 ‐coated MCNTs exert anti‐CRC effects under NIR laser irradiation by regulating cell apoptosis and cell cycle. Furthermore, nano‐TiO 2 ‐coated MCNTs accelerate inhibitory effects on the AKT signaling pathway under NIR laser irradiation. Finally, a cell line‐derived xenograft model is established, and the results showed that nano‐TiO 2 ‐coated MCNTs significantly exhibit superior tumor‐killing ability under NIR laser irradiation in vivo. Collectively, these results demonstrate that nano‐TiO 2 ‐coated MCNTs with NIR laser irradiation may serve as an effective strategy for the treatment of CRC.