Studies Of Cu₅FeS₄ Bio-nanoparticles In Blue-green Algae Control And Cancer Theranostics

Nowadays,environmental pollution causes a problem to people's health with the rapid development of economy,especially water pollution in China.Novel nanotechnology provides some strategies aimed at blue-green algae inhibition.In the past few years,copper sulfide?CuS?nanoparticles,as a typical of sulphide,have attracted greatly attention in the applications of biomedicine and have the potential to remove blue-green algae with photothermal ablation.Utilizing its ultra-high near-infrared light absorption,copper sulfide nanoparticles are mainly used for the PTT of cancer.In order to further promote the application of copper sulfide nanoparticles in the theranostics of cancer,in this paper,based on our previous work,we doped iron into CuS nanoparticles,yielding Cu₅FeS₄ nanoparticles with high near infrared absorption and magnetic properties,for blue-green algae inhibition and multimodal imaging guided PTT treatment.The main results of this dissertation are summarized as following:Chapter 1:This chapter is an introductive overview of current status of blue-green algae inhibition,PTT and relevant nano-therapeutic agents,the application of nanotechnology in blue-green algae control and the summary of the application of contrast agents in bio-imaging.Chapter 2:Cu₅FeS₄ nanoparticles were prepared by high temperature oil phase synthesis,and a series of characterization and analysis were carried out.Polyethylene glycol?PEG?was used to modify Cu5FeS4 nanoparticles,yielding PEGylated Cu₅FeS₄nanoparticles?Cu₅FeS₄-PEG?with good biocompatibility and stability.Under 1064 nm laser irradiation,Cu₅FeS₄-PEG nanoparticles exhibited very strong photothermal conversion efficiency.In addition,the photoacoustic imaging and magnetic resonance imaging based on Cu₅FeS₄-PEG nanoparticles were also conducted.Chapter 3:Based on the synthesized Cu₅FeS₄-PEG nanoparticles,we selected Anabaena and Microcystis aeruginosa as modals and then conducted the photothermal effect for blue-green algae inhibition.Chapter 4:The potential toxicity of Cu₅FeS₄-PEG nanoparticles was systematically studied.It was found that Cu₅Fe S₄-PEG nanoparticles induced no obvious toxicity to cells.In addition,cancer cells incubated with Cu₅FeS₄-PEG nanoparticles were significantly ablated under 1064 nm irradiation at low laser power density,achieving excellent therapeutic efficiency.Chapter 5:After studying the blood circulation,biodistribution of Cu₅FeS₄-PEG,as well as multimodal imaging guided cancer PTT treatment,we found that Cu₅FeS₄-PEG exhibited long-term blood circulation and high tumor uptake after intravenous injection.Utilizing the intrinsic high near-infrared absorption and magnetic properties,the in vivo photoacoustic imaging/magnetic resonance imaging were carried out.Under the guidance of multimodal imaging,the in vivo PTT was also conducted using Cu₅Fe S₄-PEG as nano-agents,indicating excellent tumor ablation under 1064 nm laser irradiation.Cu₅FeS₄-PEG induced no obvious toxicity to treated mice as evidenced by blood biochemistry,hematological analysis,and histological examinations.In summary,we for the first time have prepared the multifunctional Cu₅Fe S₄nanoparticles with appropriate surface modification.The blue-green algae incubated with Cu₅FeS₄-PEG NPs could be completely killed under near-infrared laser irradiation.In vitro and in vivo PTT were conducted under the guidance of PA/MRI multi-modal imaging.The results showed that Cu₅FeS₄ nanoparticles exhibited ultra-effective tumor ablation at a rather low laser power density of 0.5 W/cm²,and induced no obvious toxicity to treated mice.Therefore,our results further promote the potential applications of nanomaterials in cancer therapeutics.Meanwhile,utilizing the intrinsic surface tension and photocatalysis properties,nanomaterials may also be applied in the range of environmental pollution treatment.Although the government invest much capital in inhibition of cyanobacteria,the current strategies including physics,chemistry,biology and other strategies still could not completely solve the problem of environmental pollution.Therefore,the use of the intrinsic properties of nanomaterials may bring a novel strategy for the inhibition of cyanobacteria or other harmful water plants.