A narrow-bandgap RuI nanoplatform to synergize radiotherapy, photothermal therapy, and thermoelectric dynamic therapy for tumor eradication.

Therapeutic resistance is an essential challenge for nanotherapeutics. Herein, a narrow bandgap RuI nanoplatform has been constructed firstly to synergize radiotherapy (RT), photothermal therapy (PTT), and thermoelectric dynamic therapy (TEDT) for tumor eradication. Specifically, the photothermal performance of RuI can ablate tumor cells while inducing TEDT. Noteworthy, the thermoelectric effect is found firstly in RuI, which can spontaneously generate an electric field under the temperature gradient, prompting carrier separation and triggering massive ROS generation, thus aggravating oxidative stress level and effectively inhibiting HSP-90 expression. Moreover, RuI greatly enhances X-ray deposition owing to its high X-ray attenuation capacity, resulting in a pronounced computed tomography imaging contrast and DNA damage. In addition, RuI possesses both catalase-like and glutathione peroxidase-like properties, which alleviate tumor hypoxia and reduce antioxidant resistance, further exacerbating O production during RT and TEDT. This integrated therapy platform combining PTT, TEDT, and RT significantly inhibits tumor growth. STATEMENT OF SIGNIFICANCE: RuI nanoparticles were synthesized for the first time. RuI exhibited the highest photothermal properties among iodides, and the photothermal conversion efficiency was 53.38 %. RuI was found to have a thermoelectric effect, and the power factor could be comparable to that of most conventional thermoelectric materials. RuI possessed both catalase-like and glutathione peroxidase-like properties, which contributed to enhancing the effect of radiotherapy.