Body-clearable Chromium Nitride Nanoparticles For The Synergetic Photothermal And Photodynamic Treatment

Cancer is a generic name of a group of diseases characterized by the uncontrollable growth of neoplastic cells.In comparison with chemotherapy or radiotherapy,photodynamic therapy(PDT)and photothermal therapy(PTT)have many benefits,for instance,deeper penetration,minimal damage,and high specificity.The integration of PTT and PDT has many advantages.Although great advances have been made in phototherapy,there are some problems there must be solved,for instance,the long-term in vivo risk as most materials are non-biodegradable and the integration of both therapies with a single-matter material.In this work,Chromium Nitride(Cr₂N)was chosen as a single-matter material that produces synergetic photothermal and photodynamic therapy.Moreover,Cr₂N showed body-clearable properties.TEM characterization disclosed a sheet-like structure with dimensions in the range of 30 to 100 nm,HR-TEM and XRD exhibited high crystallinity,and hexagonal Cr₂N crystal nature,XPS spectra showed that the spin-orbit coupling doublet of Cr 2p^3/2and Cr 2p^1/2were seen at binding energies of 575.7 and 585.8 e V,which are consistent with the typical character of Cr₂N species.As well,it revealed a broad-spectra near-infrared(NIR)absorbent in both powder and aqueous dispersion,making this material reach a high and fast temperature elevation even in small concentrations when it is irradiated with NIR,giving a photothermal conversion efficiency of 43.4%,which is higher than most of the previously reported inorganic materials.The photosensitizer properties conducted by DPBF degradation resulted in an absorbance loss,indicating a massive ROS production,as well the intracellular ROS generation tested by H2DCFDA probe showed a green fluorescence under a fluorescent microscope,indicating good photosensitizer properties of Cr₂N.Furthermore,in this study,the ROS quenches properties of Vitamin C were further investigated.The in vitro studies showed great biocompatibility of Cr₂N NPs in both HepG2(liver hepatocellular)and HUVEC(Human Umbilical Vein Endothelial Cells)cell lines,also photothermal efficiency investigated in HepG2 cell line indicates that synergetic therapy is more efficient than individual PTT or PDT.Moreover,disclosed that dual therapy PTT/PDT could be achieved by this single matter.In vivo assays realized in female BALC/C nude mice,and in which HepG2-tumor model was established,demonstrated limited cytotoxicity,hematotoxicity,and tissue toxicity of Cr₂N,their histopathological and hematological analysis were taken.In addition,major organs,feces,and urine tested by ICP-OES disclosed that a massive amount of chromium nitride is dropped by feces and urine,proving the bio-clearable properties of the materials.In fact,the Simulated Body Fluid(SBF)suggested that Cr₂N NPs are degraded into trivalent chromium ions Cr³⁺,which is a beneficial element for the human body,and it plays a vital role in the metabolism of glucose insulin,and lipid.Hence,this thesis presents a new idea for precise and low side-effect phototherapy modality.