Solar-triggered Photothermal Therapy for Tumor Ablation by Ag Nanoparticles Self-Precipitated on Structural Titanium Oxide Nanofibers

Abstract Photothermal therapy is considered to be a promising approach for minimally invasive tumor treatment. Before the clinical trial, the photo-induced heat production efficiency in tumor tissue needs improvement. Herein, we demonstrated a one-pot hydrothermal synthesis followed by calcination to prepare the Ag NPs-precipitated TiO2 photocatalysts. With calcination temperature ascending, anatase TiO2 transformed into rutile TiO2, and self-precipitated Ag NPs vanished. Besides, fibers started to sinter with adjacent fibers, transforming into the bulk form. Due to the rich Ag NPs precipitated on the surface, leading to strong surface plasma resonance, Ag doped anatase TiO2 NFs (STF) presented the superior photocatalytic activity. Under the irradiation, 10,000 ppm of STF showed significant temperature enhancement in the photothermal conversion in vitro and the photothermal therapy in vivo. The body surface temperature can be increased up to 47.96°C with an irradiation time of 5.0 min. Moreover, the tumor growth was inhibited for up to 24 days, and the survival rate of mice was extended. From the protein identification of HE and Caspase 3 stain, STF proficiently disturbed the tumor expansion and led to tumor cell apoptosis. STF triggered by xenon lamp irradiation contributed to the significant tumor ablation and showed great potential in photothermal therapy.