Defect engineering endows NiTi stents with photothermal-enhanced catalytic activity for high-efficiency tumor therapy

Abstract

NiTi stents are widely used in clinic for palliative care to relieve obstruction caused by Gastrointestinal (GI) cancers, which have high morbidity and mortality rates. However, tumor invasion and tumor overgrowth around the stent after surgery may lead to re-obstruction of the lumen. Thus, it is urgent to endow NiTi stents with excellent tumor suppressive ability and good biocompatibility. In this study, Ce-BTC was firstly prepared on the surface of NiTi pretreated by alkaline heat, followed by pyrolysis in Ar atmosphere at 450 °C. Then, a composite coating consisting of defective cerium oxide and black Ni-Ti hydroxide/oxide was constructed on NiTi surface, which exhibited tumor microenvironment-response and hyperthermia-enhanced catalytic ability. Under near-infrared light irradiation, the photothermal performance of black Ni-Ti hydroxide/oxide and hyperthermia-enhanced catalytic activity of defective cerium oxide can achieve a synergistic effect of photothermal therapy and tumor catalytic therapy. Thereafter, defective cerium oxide can sustainably inhibit the proliferation of residual tumor cells by the generation of reactive oxygen species. Moreover, the composite coating has no obvious cytotoxicity to normal cells. This work provides a new insight for the preparation of stimulus-responsive antitumor stents for palliative treatment of gastrointestinal cancer.