Integrated Study Of Diagnosis And Treatment Of Esophageal Cancer Based On Black Titanium Dioxide Composite Nanomaterials

Esophageal squamous cell carcinoma（ESCC）is one of the most aggressive squamous cell carcinomas in Asia,which with high malignancy and low therapeutic efficiency.Current diagnosis and treatment technologies cannot meet the needs of clinical diagnosis and treatment of esophageal cancer.Based on the excellent photothermal properties of black titanium dioxide and the T1-weighted magnetic resonance imaging performance of gadolinium oxide,the applicant constructed a novel diagnostic integrated composite nanoprobe and carried out an application study in the model of esophageal cancer.The research contents are as follows:（1）B-Ti O₂ was prepared by solid phase reduction reaction using P25 and Na BH₄ as raw materials.Then,by adjusting the ratio of Gd/Ti,a novel first near-infrared（NIR-I）window probe（Gd₂O₃-b-Ti O₂）with different ratios was prepared through the polyol method.The morphology and element content of the probe were characterized by means of TEM,ICP-OES and so on.The MRI performance and the photothermal performance of the probe under 808nm laser irradiation were studied.The photothermal mechanism of the probe was preliminarily discussed.（2）A novel second near-infrared（NIR-II）window probe（Gd₂O₃-b-Ti O₂-PDA）with core-shell structure was prepared by taking advantage of the self-aggregation property of dopamine hydrochloride（DA·HCl）based on the Gd₂O₃-b-Ti O₂（Gd/Ti=1/2.5）.The morphology,structure,particle size,potential,element valence state,spectral absorption and element content of the probe were characterized by TEM,HRTEM,XRD,Zeta,DLS,XPS,UV-Vis and ICP-OES.The MRI performance and the photothermal performance of the probe under1064 nm laser irradiation were investigated.（3）The constructed NIR-II window diagnosis and treatment probe was applied in animals.Including the biocompatibility of the probe,the ability of cells to take up the probe,the metabolic distribution of the probe in vivo,the MRI and photothermal therapeutic properties of the probe in vitro and in vivo.In summary,this paper successfully constructed a novel NIR-II window diagnosis and treatment probe,which achieved the goal of safe and efficient diagnosis and treatment of esophageal cancer.The photothermal conversion efficiency of the probe reach 64.9%and the photothermal treatment performance is remarkable.At the same time,based on the energy band structure of the probe,it is found that the excellent photothermal performance of the probe is attributed to the narrowing of the band gap caused by the change of the energy band structure.In addition,the limited photothermal treatment efficiency caused by the insufficient penetration depth and the limited maximum allowable exposure of the NIR-I window laser is overcome.At the same time,Gd₂O₃ not only has excellent T1-weighted MRI performance（R1=7.05）,but also has good biocompatibility which is difficult for ordinary ionic contrast agents to have.