Multifunctional Nanomaterials For Image-guided Tumor Therapy

In nowadays society,cancer is still one of the main killers of people's health.The morbidity rate of death is increasing year by year.Photothermal therapy is a highly effective tumor treatment method.Photothermal materials absorb laser light to convert light energy into heat energy,which can effectively ablate tumor cells.However,there are still problems: If the tumor area cannot be precisely located,it will cause damage to normal tissues around the tumor.Radiotherapy is one of the most widely used cancer treatment methods in clinical practice,however,because of its poor therapeutic effect on hypoxic tumors,it has limited its therapeutic effect.In order to solve the first problem,we developed an acid-sensitive MRI-guided tumor photothermotherapy nanosystem.First,polydopamine nanoparticles were prepared.The nanoparticles not only acted as a photothermal core,but also had a reducing group hydroxyl and amine groups on the surface to reduce potassium permanganate to manganese dioxide in situ.This method was simple and easy to prepare.Manganese oxide-coated polydopamine nanoparticles,under the condition of weak acid in the tumor,the outer shell of manganese dioxide was acid-explained to emit diamagnetic manganese ions with magnetic resonance imaging properties,whereas in the normal body fluid conditions,manganese dioxide is stable and does not have Magnetic resonance imaging performance,this method can accurately distinguish the tumor area and normal tissue,provide accurate imaging guidance for tumor photothermal therapy.In order to solve the second problem,in the second work,we prepared nano Na_xMnWO₃ nanoparticles with both diagnostic and therapeutic functions,and the material has good water solubility and biocompatibility through the modification of polyethylene glycol.In terms of tumor therapy,the material not only has good light-heat conversion performance but also can be used as a radiation sensitizer for tumors.In terms of imaging,the material has three imaging modalities: magnetic resonance imaging,CT imaging,and photoacoustic imaging.Cell experiments confirmed that nanomaterials can effectively kill cancer cells under the irradiation of a 980-nm laser,and can effectively damage the DNA of cancer cells under X-ray irradiation.The mouse tumor treatment experiment has confirmed that low-temperature photothermal assisted radiation therapy can effectively improve the hypoxic environment of the tumor and greatly enhance the efficacy of radiotherapy.In the above two works,we have provided accurate imaging guidance for photothermic therapy and provided new approach for solving the problem of poor curative effect of radiotherapy on hypoxic tumors through reasonable material design.