Synthesis Of Green And Environmentally Friendly Dissolved AgInS₂ Ternary Quantum Dots Based On Hydrothermal Method And Its Application In Live Cell Imaging

Quantum dots(QDs)are a new type of semiconductor nanomaterials,which have unique optics properties such as strong luminous brightness,adjustable emission spectrum,long fluorescence lifetime,and good photobleaching resistance.They are used in LEDs,solar cells,especially biomedicine fields have broad application prospects.At present,the research on QDs is mainly focused on binary quantum dots such as Cd S and Cd Te.Due to the high toxicity of Cd²⁺,its application is greatly limited.Recently,due to the demand for environmental protection and the strategic requirements for environmentally friendly materials,the materials containing heavy metals such as Cd²⁺are gradually being eliminated.Therefore,research and development of novel green and environmentally friendly QDs is of great significance.Under this background,ternary QDs which are mainly composed of elements of group I-?-VI are applied.As a new type of semiconductor nanomaterial,it overcomes the high toxicity of traditional QDs to the environment and biological systems,and meet the current environmental protection requirements.Among them,Ag In S₂QDs has the advantages of non-toxicity,high absorption coefficient,stable optical performance,and fluorescence wavelength covering the visible light region to the near-infrared region.It can be used as a better biological optical imaging material.Therefore,in this thesis,three new green and environmentally friendly water-soluble Ag In S₂QDs bioluminescent nanoprobes were synthesized by hydrothermal method to achieve the goal of reducing toxicity and environmental protection,and to meet the current strategic requirements for environmentally friendly materials.The research content of this paper is mainly divided into three parts.The design,synthesis and bio-fluorescence imaging application of the three green and environmentally friendly water-soluble Ag In S₂QDs with water-soluble thioglycerol(TG),mercapto-glucosamine(GLU)and mercapto-polyvinyl alcohol(PVA)as ligands.The microscopic morphology,fluorescence performance,cytotoxicity and fluorescence imaging ability of tumor cells were systematically studied.The main research contents of this paper are as follows:1.Synthesis of green and environmentally friendly water-soluble Ag In S₂QDs based on thioglycerol and its application in cell imaging.Firstly,thioglycerol(TG)is used as the ligand,Ag NO₃and In(NO₃)₃·4H₂O are the metal precursors,and thiourea is the sulfur source.The synthesis of water-soluble Ag In S₂-TG QDs via hydrothermal method at a temperature of 150?,p H=9,Ag:In:S:TG=1:1:2:12 as the optimal reaction conditions.The research results show that Ag In S₂-TG QDs have an average particle size of 3.9 nm and emit strong green fluorescence near 507 nm.The aqueous solution of the quantum dots exhibits responsiveness to temperature,p H,and metal ions,especially Pb²⁺,Co²⁺and Ag⁺.Subsequently,the cell imaging experiments show that the quantum dots have low toxicity and good cell imaging effects,and are expected to be an ideal green and environmentally friendly biological fluorescent probe.2.Synthesis of green and environmentally friendly synthesis Ag In S₂QDs based on bio-glycosyl molecule glucose and its application in cell imaging.Firstly,sulfhydryl glucosamine(GLU),and then use it as a ligand,Ag NO₃and In(NO₃)₃·4H₂O are metal precursors,and thiourea is a sulfur source.The synthesis of water-soluble Ag In S₂-GLU QDs via hydrothermal method at a temperature of 150?,p H=10,Ag:In:S:GLU=1:1:2:12 as the optimal reaction conditions.Studies have shown that Ag In S₂-GLU QDs have a uniform size distribution,with an average particle size of 4.0 nm.It emits strong green fluorescence near 500 nm.The aqueous solution of the quantum dots exhibits responsiveness to temperature,p H,and metal ions,especially Fe³⁺,Ag⁺.Subsequently,the cell imaging experiments show that the quantum dots have low toxicity and good cell imaging effects,and are expected to be an ideal green and environmentally friendly biological fluorescent probe.3.Synthesis of green and environmentally friendly water-soluble Ag In S₂QDs based on polyvinyl alcohol(PVA)and its application in cell imaging.Firstly,thioglycolic acid(SH-CH₂COOH)and PVA were used to synthesize mercapto polyvinyl alcohol(SH-PVA)under acidic conditions and used it as a ligand.Ag NO₃and In(NO₃)₃·4H₂O were metal precursors,and thiourea as a sulfur source.The synthesis of water-soluble Ag In S₂-PVA QDs via hydrothermal method at a temperature of 150?,p H=10,Ag:In:S:PVA=1:1:2:12 as the optimal reaction conditions.Studies have shown that Ag In S₂-PVA QDs have a uniform size distribution,with an average particle size of4.2 nm.It emits green fluorescence near 488 nm.The aqueous solution of the quantum dots exhibits responsiveness to temperature,p H,and metal ions,especially Pb²⁺,Co²⁺and Ag⁺.Subsequently,the cell imaging experiments show that the quantum dots have low toxicity and good cell imaging effects,and are expected to be an ideal green and environmentally friendly biological fluorescent probe.In summary,the hydrothermal synthesis method used in this study avoids the use of organic solvents throughout the process,and the reaction conditions are relatively mild,easy to operate,and overcome the preparation disadvantages of traditional quantum dot that are relatively toxic to the environment and biological systems.In addition,the water-soluble Ag In S₂QDs was synthesized in the thesis have excellent luminescence properties and good cell imaging capabilities,especially the realization of reversible two-color fluorescence imaging of organisms by fluorescent probes.Therefore,this research provides a theoretical basis for the extensive application of Ag In S₂QDs in the field of biomedicine,and lays a foundation for the biological application of intelligent QDs.