Study On Application Of Two-dimensional Palladium-based Nanomaterials In Different Pathological Models And Design Of Related Diagnosis And Treatment Systems

In recent years,although it has entered the stage of highly developed medical technology,there are still some intractable diseases that threatening human health,such as cancer and a series of major diseases caused by pathogens.Population of cancer-induced death and infectious diseases every year have already accumulated to an enormous amount,however many traditional methods do not achieve a good healing effect.Increasingly,nanomaterials(NMs),especially in biomedical applications,have exhibited great values in the treatment of those diseases mentioned above.Owing to their tunable and uniform sizes,NMs are facile to be modified and be ideal platforms for biomedical applications.This paper focuses on the applications of nanomaterials in cancer therapy and antibacterial fields.By preparing different nanomaterials and modifying them with proper methods,the application of them in the treatment of tumors and bacterial inflammations were explored.The details of each chapter are as followsChapter 1:A brief summary for some biomedical applications of nanomaterials,which mainly focuses on the two studies of diagnosis and treatment of cancer or inflammation.Firstly,applications of nanomaterials in biomedical fields were summarized.Secondly,the research progress and applications of nanomaterials in cancer diagnosis and treatment,especially in photothermal and radiation therapy,were introduced.Then the research progress of nanomaterials in inflammation therapy,particularly sonodynamic therapy also was presented.Finally,the significance and research contents of this thesis were describedChapter 2:In the second chapter,we have successfully synthesized two-dimensional core-shell Pd@Au nanoplates,which have well-defined shape and controlled size.The core-shell Pd@Au nanoplates showed strong NIR absorption,radiosensitization ability and excellent stability.By modifying their surface with thiol-polyethylene glycol(SH-PEG),the prepared PEGylated Pd@Au nanoplates showed the favorable blood circulation in vivo and high tumor accumulation.Experiments showed that our Pd@Au nanoplates could eradicate tumors by radio/photothermal synergistic therapy.The Pd@Au nanoplates have been successfully applied in mouse tumor models.Chapter 3:It was mentioned that Pd@Au nanomaterials showed high tumor accumulation in the second chapter,which made us think whether palladium-based nanomaterials could show high inflammatory accumulation.Then,different sizes of palladium nanosheets(NSs)and Pd@Pt nanoplates were selected as the basis for research.The palladium-based nanomaterials were inj ected in vivo through the tail vein to investigate their inflammation accumulation.It was found that both Pd NSs and Pd@Pt nanoplates had good inflammatory accumulation efficiency.Considering that Pd@Pt nanoplates had higher catalase-like activity and could improve hypoxic microenvironment,subsequently,we designed and synthesized a new nano-inflammation diagnosis and treatment platform,the Pd@Pt-PEG-T790 nanocomposite,which was prepared by covalently linking the sonosensitizer meso-tetra(4-carboxyphenyl)-porphine(T790),with Pd@Pt-PEG-NH2.The enhanced sonodynamic treatment of the Pd@Pt-PEG-T790 nanocomposite,which possessed antibacterial by generating reactive oxygen species through acoustic power,,was demonstrated.Further bacterial infectious inflammation treatment needs to be explored.Chapter 4:Graphene oxide(GO)-based materials have recently received increasing attention in antibacterial field due to their unique two-dimensional structure,high specific surface area,water solubility,easy functionality and low cost etc.However,if GO have antimicrobial properties still is a controversial issue.In this work,the antibacterial abilities of GO solution and GO film were first evaluated against several Gram-negative and Gram-positive bacteria,such as Escherichia coli(E.coli),Bacillus and methicillin-resistant Staphylococcus aureus(MRSA).It was found that GO and GO film had no obvious impact on the growth of bacteria.Based on the similarity in the use of GO film and "Band-Aid",it is easy to apply GO film to the bacterial infection of wounds.We prepared Ag nanoparticles loaded GO film in attempt to kill bacteria.The feasibility of using the generated GO-Ag film as an antimicrobial agent was confirmed by its effective treatment of the wound infection caused by MRSA resisted bacteria.Therefore,GO-Ag film holds great promise for application in wound dressings and antimicrobial surface coatings.Chapter 5:Summarize the research work of this paper and make a prospect for the follow-up research work.