In Vivo Metabolism Of Ultrasmall Copper Selenide Nanoprobes

Nanoscale copper chalcogenides have been widely used in nanomedicine,such as photoacoustic(PA)imaging,photothermal therapy(PTT),photodynamic therapy(PDT),and chemodynamic therapy(CDT),however,their pharmacokinetics,degradation,and biological effects of the released copper ions are usually overlooked and have not been investigated,which are crucial for their future clinical translation.As an essential trace element in all living organisms,changes in the homeostasis of copper ions are closely related with different types of diseases,such as inflammation,neurodegeneration,cancer and metabolic disorders.The excess copper ions can generate reactive oxygen species(ROS),like singlet oxygen(1O2),hydroxyl radicals(·OH)and peroxides(R-O-O·)via Haber-Weiss cycle and Fenton-like reactions,which could lead to oxidative damage to tissues.The deficiency in copper may cause neurological problems and hematological manifestations.Objective:The aim of this thesis is to investigate the pharmacokinetics,degradation,and biological effects of polyvinylpyrrolidone(PVP)functionalized ultrasmall copper selenide(Cu2-xSe)theranostic nanoparticles.Methods:In this thesis,PVP functionalized ultrasmall copper selenide(Cu2-xSe)nanoparticles and Cu2+-specific fluorescence molecule(NCM),reactting with copper ions quickly and specifically to enhance near infrared fluorescence almost 300 times,were synthesized.The progress of copper ions metabolism of ultrasmall biodegradable theranostic Cu2-xSe nanoparticles have been investigated in vitro by inductively coupled plasma mass spectrometry(ICP-MS).After cultured with RAW 264.7 murine macrophages,the cell uptake of Cu2-xSe nanoparticles and the release of copper ions were assessed by fluorescence molecule(NCM).We also demonstrate the distribution,degradation,and the metabolism of ultrasmall Cu2-xSe nanoparticles by the in vivo fluorescence imaging,the blood routine test,blood biochemistry and histology analysis,and the characterization of copper transport and binding proteins such as copper transporter 1 protein 1(CTR1),Copper-transporting ATPase 2 ATP7B,metallothioneins(MTs),and copper chaperone for superoxide dismutase(CCS).Results:(1)The results show that ultrasmall Cu2-xSe nanoparticles are gradually releasing copper ions in vitro and in vivo.(2)The results of bio-distribution,in vivo fluorescence imaging and rubeanic acid(RA)staining show that ultrasmall Cu2-xSe nanoparticles can be mainly eliminated through feces and urine from the body within 72 h after intravenous injection,and this process did not cause severe toxicity.Concolution:The release of copper ions and low toxicity of Cu2-xSe nanoparticles suggest their great potential in serving as a copper-supplying agent.