Aqueous Synthesis Of CuInS₂ Ternary Quantum Dots Enriched With Different Active Groups On The Surface And Their Application In Fluorescent Probes

Quantum dots(QDs)are one of the most promising new materials currently released.It is a very small semiconductor nanomaterial with unique optical and electromagnetic properties,and has a very wide range of applications in biomedicine.At present,the research and application of QDs are mainly concentrated on binary QDs such as Cd S,Cd Te,Cd Se,Cd S/Zn S,Cd Se/Zn S and so on.However,it is well known that Cd²⁺is a toxic heavy metal ion.Therefore,the use of binary QDs containing Cd²⁺does not meet the current strategic requirements for environmentally friendly materials.The I-III-VI type QDs are a new type of QDs that have appeared in recent years.It overcomes the problem of environmental pollution caused by traditional quantum dots containing more heavy metal elements(cadmium or lead).It effectively reduces the biological toxicity of quantum dots and expands the application range of quantum dots.Among them,CuInS₂ quantum dots have the advantages of non-toxicity,high absorption coefficient,stable photochemical properties,etc.,and have become ideal solar cells and bio-optical imaging materials.Therefore,the research and application of CuInS₂ quantum dots can help reduce the toxicity of QDs,achieve environmental protection goals,and meet the current demand for environmentally friendly materials.To sum up,this thesis aims to exmlore a method for constructing low-toxicity water-soluble CuInS₂ ternary quantum dots with different active groums on the surface,in order to mrovide a simmle and effective way to develom new environmentally friendly QDs omtical materials.In this paper,six new CuInS₂ ternary quantum dots with different active groups on the surface were successfully synthesized by hydrothermal method.These quantum dots have good dispersibility,good fluorescence intensity and light stability.Fluorescence test results show that the type or density of the surface active groups on CuInS₂ ternary quantum dots is also a factor that affects their optical properties.The application research shows that the fluorescence of the six CuInS₂ quantum dots prepared has different response characteristics to metal ions and antibiotic-neomycin sulfate,and is expected to become a fluorescent probe material in biology.In addition,some quantum dots with excellent optical properties exhibit low cytotoxicity and achieve ideal imaging effects on tumor He La cells.The main research contents are as follows:1.Preparation of CuInS₂ ternary quantum dots rich in hydroxyl groups(-OH)on the surface and its response to metal ions and neomycin sulfateThe first part of the work uses 2-mercaptoethanol,thioglycerol,mercaptopolyvinyl alcohol(SH-PVA)as ligands,Cu Cl₂·2H₂O and In Cl₃·4H₂O as metal precursors,and thiourea as the sulfur source.Three CuInS₂ ternary quantum dots with rich hydroxyl groups on the surface.The structure and optical properties of the three water-soluble CuInS₂ QDs synthesized by IR,XRD,TEM,EDS,TG,UV,and fluorescence spectroscopy were tested.The test results show that the three CuInS₂ QDs are of cubic crystal structure,the micro-morphology has obvious quasi-spherical shape,and the size distribution is uniform,the dispersion is good,the average particle size is4.7,5.3 and 4.3 nm,indicating that the above ligands It is an effective stabilizer for preparing CuInS₂ quantum dots.The optical performance test results show that the fluorescence emission peaks of these three CuInS₂ QDs are located at 430,510 nm and450 nm,respectively,and the half-width is narrow.At the same time,the fluorescence of their aqueous solutions has temperature and p H response properties.In addition,the three CuInS₂ QDs showed selective response to different metal ions Pb²⁺,Fe³⁺and Cu²⁺.In addition,neomycin sulfate can significantly inhibit the fluorescence intensity of the three QD aqueous solutions,and has a certain linear relationship within a certain concentration range.Therefore,a fluorescence quenching method was established for the determination of neomycin in fruits and vegetables.The rapid analysis and detection of neomycin residues is expected to become a new type of multifunctional fluorescent probe material.Finally,the biological application ability of the latter two QDs was investigated by cell imaging experiments.The results showed that these two QDs have low toxicity and good biocompatibility.Through comparative analysis of the staining effect in He La cells,SH-PVA was found QDs are more easily captured by cancer cells and exhibit ideal imaging effects on live tumor cells.1.Preparation of CuInS₂ternary quantum dots rich in carboxylic acid(-COOH)on the surface and its response to metal ions and neomycin sulfateThe second part of the work uses D-penicillamine(D-Pen),Tiopronin(TP)as ligands,Cu Cl₂·2H₂O and In Cl₃·4H₂O as metal precursors,and thiourea as the sulfur source.Two kinds of CuInS₂ ternary quantum dots rich in-COOH on the surface.The structural and optical properties of the two water-soluble CuInS₂ QDs synthesized were tested by IR,XRD,TEM,EDS,UV,and fluorescence spectroscopy.The test results show that the two CuInS₂ QDs are of cubic crystal structure,the micro-morphology has obvious quasi-spherical shape,and the size distribution is uniform,the dispersion is good,the average particle size is 4.5 and 4.2 nm,indicating that the above ligands are prepared An effective stabilizer for CuInS₂ quantum dots.The optical performance test results show that the fluorescence emission peaks of these two CuInS₂ QDs are located at 540 and 430 nm,respectively,and the half-width is narrow.And the fluorescence of their aqueous solution has temperature and p H response performance.In addition,the two CuInS₂ QDs showed selective response to metal ions Na⁺and Fe³⁺,respectively.In addition,neomycin sulfate can significantly inhibit the fluorescence intensity of the three QD aqueous solutions,and has a certain linear relationship within a certain concentration range.Therefore,a fluorescence quenching method was established for the determination of neomycin in fruits and vegetables.The rapid analysis and detection of neomycin residues is expected to become a new type of multifunctional fluorescent probe material.3.Preparation of CuInS₂ ternary quantum dots rich in amino groups(-NH₂)on the surface and their response to metal ions and neomycin sulfate and application of cell imagingThe third part of the work first uses PMA and PEI as raw materials,and undergoes hydroxyl amination under the action of EDC and NHS to synthesize mercapto PEI(SH-PEI).Then using SH-PEI as the ligand,Cu Cl₂·2H₂O and In Cl₃·4H₂O as the metal precursors,and thiourea as the sulfur source,a CuInS₂ ternary quantum dot rich in amino groups on the surface was synthesized by hydrothermal method.The structure and optical properties of the water-soluble CuInS₂ QDs synthesized by IR,XRD,TEM,EDS,TG,UV,and fluorescence spectroscopy were tested.The test results show that the CuInS₂ QDs have a cubic crystal structure,the micro-morphology has a clear quasi-spherical shape,and the size distribution is uniform,the dispersion is good,and the average particle size is 10.25 nm,indicating that the above ligands are prepared for CuInS₂ quantum dot Effective stabilizer.The optical performance test results show that the fluorescence emission peaks of these CuInS₂ QDs are located at 450 nm,respectively,and the half-width is narrow.At the same time,the fluorescence of their aqueous solutions has temperature and p H response properties.In addition,the CuInS₂QDs exhibited selective response characteristics to the metal ion Cd²⁺.In addition,neomycin sulfate can significantly inhibit the fluorescence intensity of this QD aqueous solution,and has a certain linear relationship within a certain concentration range.Therefore,a fluorescence quenching method was established for the determination of neomycin in fruits and vegetables.The rapid analysis and detection of neomycin residues is expected to become a new type of multifunctional fluorescent probe material.Finally,the biological application capabilities of quantum dots were studied through cell imaging experiments.The results show that the prepared ternary quantum dots have low toxicity and good biocompatibility.Then we analyzed the staining effect in He La cells and found that SH-PEI QD is susceptible to cancer cell capture,showing the ideal imaging effect of live tumor cells.