| Carbon dots(CDs)as a novel type of zero-dimensional fluorescent nano-material have shown huge application prospects in the field of tumor theranostic due to their attractive characteristics such as adjustable optical performance,easy functionalization,good biocompatibility,low toxicity,and photothermal/photodynamic therapeutic functions.However,the small size of CDs makes it difficult for them to accumulate at tumor site efficiently,ultimately affecting the imaging and treatment effects of carbon dots.In addition,the treatment function of carbon dots mainly comes from the light-induced treatment mode,and the treatment effect is hindered to a certain extent by the limited light penetration depth.In this thesis,the strategy for solving the above problems is to prepare the carbon dot-metal ion composites.The thesis focuses on the preparation of carbon dot-metal ion nanocomposites and their applications in tumor theranostic.The main research contents are summarized as follows:(1)Red emissive carbon dots(RCDs)and ferrocenedicarboxylic acid(Fc)are used as structural units to prepare composite nanoparticles(abbreviated as Fc-RCDs)with the properties of fluorescence imaging and dual-modal synergistic therapy(including photothermal therapy(PTT)and CDT)a through cross-linking reactions.According to the red emissive property and broad absorption extending into the near infrared region,RCDs can be used as fluorescence imaging center and photothermal therapy agent.Fc can provide a chemodynamic therapy mode for composites based on its unique Fenton reaction activity.However,this work does not explore the main factors that affect the construction of composite systems.The second part analyzes the main factors that affect the construction of composite systems in details.(2)In order to adjust the morphology and size of the carbon dot-metal ion composites more flexibly and endow them with synergistic treatment function for improving therapeutic efficacy.Based on the previous work,functionally modified carbon dots and iron ions(Fe3+)are used as structural units to prepare composite nanoparticles(abbreviated as Fe-Ce6-RCDs)with the properties of fluorescence imaging and tri-modal synergistic anticancer treatment(including PTT,photodynamic therapy(PDT)and CDT)by assembly rather than crosslinking reactions.Among them,carbon dots with red light emission and broad absorption capabilities extending into the near-infrared region can beused as centers for fluorescence imaging and photothermal therapy,and play corresponding diagnostic and therapeutic functions.In addition,the abundant amino groups on the surface of the carbon dots provide good binding sites for the subsequent modification process,which can realize the coupling with the photosensitizer chlorin e6(Ce6)through a one-step amide bonding reaction,giving functional carbon dot(abbreviated as: Ce6-RCDs)the potential of photodynamic therapy.Fe3+can provide a chemodynamic therapy mode for composites based on its unique Fenton reaction activity.This work analyzes the main factors that affect the construction of the composite system on the basis of the preparation of multifunctional theranostic materials,which provides a certain basis for the development of such materials. |
