Study On The Synthesis Of Prussian Blue-based Nanocomposites And Their Application In Multifunctional Theranostics

Cancer has become one of the deadliest human diseases in the world.Millions of people in the world die of cancer every year.However,the early cancer diagnosis and therapies still remain big challenges for the world.In recent years,various types of functional materials,especially functional nanomaterials,which have been extensively studied and widely used,can provide more opportunities for the early detection,diagnosis and treatment of cancer.For example,magnetic resonance imaging(MRI)contrast agents(CA),which are based on molecular imaging technology,can enhance the contrast between tumor tissues and normal tissues,making the lesions area clearer and more precise.In addition,the development of multi-functional nanomaterials to integration of diagnosis and therapies not only enhance the single function of traditional contrast agents or cancer therapeutic drugs but also realize visualization functions and real-time monitoring functions in the clinical cancer treatment.Therefore,designing and preparing multifunctional nanomaterials combined molecular imaging function with cancer therapeutic and studying its application in the field of cancer medicine are of great importance to the development of biomedicine.Based on these,in one hand,in the second chapter of this work,the Mn²⁺-doped prussian blue nanoparticles(Mn PB-25%and Mn PB-50%)with regularized manganese content were prepared simply and conveniently by microwave assisted solvothermal method.UV-visible-Infrared absorption spectrum of Mn PB NPs exhibits a high absorption peak in the near-infrared region(750 nm-1100 nm),indicating that Mn PB NPs have strong light absorption ability in the near-infrared light(NIR)region,and it is promising to be utilized as a photothermal conversion material.The photothermal effect experiment also confirmed this view,during exposing to an 808 nm laser for 10min,Mn PB NPs aqueous showed a rapid temperature increase from room temperature upto 55.3°C,reaching the thermal lethal critical temperature of tumor cells(40°C).In addition,the MRI properties of Mn PB NPs were tested using a clinically used 3.0 T magnetic resonance scanner,it demonstrated that Mn PB NPs exhibited a signal enhancement in T1-weighted MR.In another hand,in the second chapter of this work,biocompatible core-shell structured nanoparticles(Mn PB@PPy NPs)was simply fabricated by in-situ polymerization of pyrrole(Py)in the presence of Mn²⁺-doped prussian blue nanoparticles(Mn PB NPs).After coating with polypyrrole(PPy),the characteristic peak of Mn PB NPs exhibited a red shift and an enhanced absorption in the near infrared region,indicating the possibility of Mn PB@PPy NPs as efficient photothermal agent.Moreover,the PPy coating also endowed the nanoplatform with the ability to act as an effective drug carrier to load anticancer drug doxorubicin(DOX)via?-?stacking interaction.Noteworthy,the loaded drug molecules could not only be triggered to release due to the photothermal effect,but also showed a H₂O₂-responsive drug release property since the PPy coating could be gradually degraded under an ultralow concentration of hydrogen peroxide(H₂O₂),thus leading to an improved synergistic chemo/photothermal cancer therapy.Furthermore,the Mn PB@PPy NPs could be an excellent magnetic resonance imaging(MRI)contrast agent with a high longitudinal relaxivity value(r₁=10.54 m M^-1 s^-1)for the detection of tumor site and monitor of the treatment progress.