Study Of Polyxometalate-based Nanocomposites For Photothermal/Chemodynamic Therapy Of Tumors

Photothermal therapy（PTT）has received much attention as a promising treatment for cancer with fewer side effects than conventional radiotherapy,chemotherapy and surgical resection Chemodynamic therapy（CDT）is a newly developed cancer treatment that kills tumor cells through a Fenton/Fenton-like reaction that converts hydrogen peroxide（H₂O₂）into toxic hydroxyl radicals（·OH）.Therefore,PTT and CDT synergize to achieve better tumor treatment results.With the development of nanoscience and nanobiotechnology,several advances in cancer treatment have been made in the past decades.And polyoxometalates（POM）now have a good prospect as nanomaterials for biomedical applications.As a result,there is a proliferation of POM-based nanomaterials.Combining photothermal therapy and chemodynamic therapy,the synergistic treatment of both has become a new prospect for development.In this thesis,Heteropoly blue（HPB）was first synthesized,and then HPB@COF nanoparticles were synthesized by a one-pot method.Using the Schiff base structure of the covalent organic frameworks（COFs）,it breaks down at the tumor site to release HPB.The photothermal property of HPB is then used to ablate the tumor cells.It was also shown by both in vivo and in vitro results that HPB@COF nanoparticles have good tumor therapeutic effects along with good p H responsiveness.This study provides a new strategy for PTT with great potential.Secondly,tungsten carbide was used as the material to synthesize tungsten-based POM,and new polyxometalate nanomaterials（WC-POM）were synthesized according to a modified Folin-Ciocalteu assay to give both CDT and PTT therapeutic effects.In vitro and in vivo experiments confirmed the low toxicity,good biocompatibility and high tumor suppression efficiency of WC-POM nanoparticles.The tumor suppression rate was improved with the synergistic treatment of chemodynamic therapy and photothermal therapy with WC-POM.Finally,based on POM has redox properties and promotes the production of ROS to kill tumor cells.Meanwhile,in order to improve the therapeutic efficiency,tungsten carbide was used as the raw material to synthesize tungsten-based polyacid with chemodynamic therapy effect（CDT）.To enhance its therapeutic effect,the carrier polydopamine（PDA）was introduced,and finally the polymetallic oxalate nanomaterial（POM@PDA）was synthesized to utilize the redox properties of POM with the photothermal property of PDA for effective treatment.This suggests that POM@PDA has good prospects for synergistic treatment of CDT and PTT.