Protein-Assisted Nanoscale Combined Photothermal Ablation And Radionuclide For Anaplastic Thyroid Carcinoma Nanotheranostics

Objective and contentAs the lowest incidence of thyroid cancer pathological type,undifferentiated thyroid carcinoma has the characteristics of high mortality and less survival time than other types.Clinically,traditional surgery,radiotherapy and chemotherapy are difficult to achieve ideal therapeutic effects,so there is an urgent need to develop new treatments to improve the clinical situation.In recent years,the development of nanomedicine brings new opportunities and challenges to clinical medicine.Photosensitizers exert the effect of photothermal therapy（PTT）by converting light energy in near infrared into heat energy to kill tumor cells.Photothermal therapy has been widely studied because of its convenience,economy and cheapness.In this study,by simulating biomineralization,we designed and constructed a protein-based nanoparticle with simple synthesis and good biocompatibility,and realized the combination of PTT,radionuclide therapy and SPECT/CT imaging.In this study,bovine serum albumin（BSA）was used as a biological template to carry copper sulfide（Cu S）nanoparticles with photothermal properties,and then labeled with ¹³¹I to complete the construction of bimodal therapy and imaging platform.Method1.By hot bath method,BSA as the biocompatibility template,BSA-encapsulated Cu S nanomaterials were formed with chemical bond interaction between S-Cu.¹³¹I was labeled on the benzene ring of BSA tyrosine with chloramine T method,thus the nano-therapy system ¹³¹I-BSA@Cu S was prepared.The size,morphology,Zeta potential and stability of the nanoparticles in solution were investigated by dynamic light scattering（DLS）and transmission electron microscope（TEM）.The chemical bonds in the nanomaterials were investigated by Fourier transform infrared（FT-IR）to determine the composition of the materials.UV spectrophotometer was used to investigate the absorption of the materials in the near-infrared to determine the photothermal absorption ability.In the in vitro experiment,the photothermal heating performance,photothermal stability and photothermal conversion efficiency of the materials were investigated.2.At cellular level,the toxicity of BSA@Cu S material to undifferentiated thyroid cancer cell line ARO was evaluated by MTT method,then the photothermal therapeutic ability of BSA@Cu S on ARO cells was evaluated with different material concentration and laser power density,and the killing effect of photothermal combined with ¹³¹I radionuclide on tumor cells was also investigated.Finally,the killing effect of cells in different treatment groups was evaluated by dead and living cell staining.3.At animal level,after the subcutaneous implanted tumor model of undifferentiated thyroid carcinoma were established,the tumor-bearing mice were treated by intratumoral injection,then scanned by SPECT/CT at several time points.The tumor-bearing mice were randomly divided into groups and treated with different therapeutic agents.Irradiated by near-infrared laser immediately after intratumoral injection,the tumor sites were photographed to monitor the local temperature by thermal camera.Then,the body weight and tumor volume of tumor-bearing mice were measured every two days,and the change curve was drawn.4.The body weight of healthy mice were weighted after intravenous injection.Blood was obtained for quantitative analysis of the main indexes of liver and kidney function in each group.The main organ slices of mice were stained with hematoxylin-eosin and histological pathological analysis to evaluate the systemic toxicity and organ toxicity of nanomaterials.Results1.We successfully prepared ¹³¹I-BSA@Cu S nanoscale therapy system,which showed regular morphology and uniform size at TEM and DLS.The result of Zeta potential not only proved the material had the component of BSA,but also had good water solubility and stability in solution,confirming the successful synthesis of material.The successful synthesis and good optical absorption properties of the materials were verified by Fourier transform infrared（FT-IR）and ultraviolet spectrometer respectively.In terms of photothermal properties,in vitro tests confirmed that the material had good near-infrared absorbance and photothermal conversion efficiency（28.07%）.2.Cellular experiments showed that the toxicity of synthesized BSA@Cu S nanomaterials to cells can be negligible within a certain concentration range.After laser irradiated,killing ability was related to material concentration and light power density.In the ¹³¹I-BSA@Cu S combined with laser irradiation group,the cell survival rate was significantly lower than only photothermal therapy.The staining test of dead and living cells displayed same results as above.3.In the SPECT/CT imaging experiment of subcutaneous transplanted tumor,the images were collected at several time points after intratumoral injection.Compared with the ¹³¹I group,the radioactivity in the ¹³¹I-BSA@Cu S group lasted longer,the excretions were slower,and the retention effects were better.¹³¹I-BSA@Cu S could stay for a longer time.In the treatment experiment of subcutaneous implant tumor,compared with other single treatment groups,¹³¹I-BSA@Cu S combined with laser irradiation showed no significant enlargement in tumor volume,tumor weight was the smallest.4.In the in vivo toxicity experiment,with high dose nanomaterials injected into the tail vein,body weight,liver and kidney function indexes,and histological pathological analysis were not significantly abnormal compared with the control group,indicating the low toxicity and good biocompatibility of prepared nanomaterials.ConclusionIn this study,we successfully constructed ¹³¹I-BSA@Cu S nanoparticles for photothermal combined radionuclide ablation of tumors.The precursors used in this synthesis are cheap and easy to prepare.The prepared nanomaterials not only have uniform morphology,appropriate size and good stability,but also show excellent photothermal properties in vitro,achiev long-term retention in the tumor site.Combined therapy can significantly inhibit tumor growth compared with single therapy.In addition,the prepared protein nanoparticles have low toxicity and biocompatibility.Our study provides a new idea and potential for the development of clinical treatment for undifferentiated thyroid carcinoma.