Preparation Of Multifunctional Photothermal Nanomaterials Based On Polydopamine For Cancer Therapy

Cancer is still a major threat to human health.Treatments such as surgery,chemotherapy and radiation therapy have major adverse effects on normal cells,causing great suffering to patients.In recent years,gene therapy,immunotherapy,photodynamic therapy,photothermal therapy（PTT）and other novel therapies have become hot topics in cancer treatment research.Photothermal therapy is a method that converts the absorbed light energy into heat energy through photothermal agents to induce local temperature rise,which eventually triggers the death of cancer cells.This strategy has the advantages of high efficiency,non-invasive,precise targeting and non-invasive.However,single photothermal therapy also has some limitations,such as limited light penetration depth which can not completely eliminate deep tumors,leading to tumor recurrence and metastasis.In order to enhance the effectiveness of cancer treatment,it is necessary to develop multifunctional photothermal nanomaterials that combine photothermal therapy with other treatment modalities.Therefore,in this thesis,two multifunctional photothermal nanoparticles based on polydopamine（PDA）were designed and synthesized,and their potential applications in cancer therapy were explored.Details of the study are as follows.1.Through the force of mesoporous polydopamine（mPDA）and metal,mPDA-Ag NBs was successfully synthesized by adding silver nitrate to the synthesized mPDA nanobowls（NBs）solution.Gold nanocages（AuNCs）were formed on the surface of mPDA by metal replacement,and then modified with triphenylphosphine（TPP）to successfully synthesize mPDA-AuNC-TPP NBs capable of targeting mitochondria.DOX can be loaded in the pore space and outer surface of mPDA byπ-πsuperposition,and the mesoporous of mPDA and gold cage structure increases the drug loading capacity,and the release of DOX was found to be p H/NIR dual-responsive.In addition to the excellent photothermal conversion performance and good drug loading capacity,AuNCs shed by photothermal stimulation can also target mitochondria and further damage cancer cells under photothermal stimulation,which has good potential for chemo-photothermal therapy in cancer.2.A simple and mild method was developed to prepare mPDA-Cu₃Bi S₃ NBs with good biocompatibility.The obtained NBs can be used for photothermal therapy（PTT）in NIR-Ⅱ biowindow,which enhances the tumor penetration ability.In addition,when mPDA-Cu₃Bi S₃NBs in the weakly acidic tumor microenvironment,and the degradation-generated Cu⁺reacts with the intracellular overexpressed H₂O₂ by Fenton reaction to generate toxic hydroxyl radicals（·OH）,which promotes chemodynamic therapy.This novel NBs with PTT and CDT properties provides promising prospect for synergistic treatment of cancer.