Preparation Of N-Acetyl-L-Cysteine Capped Hg(ag)doped Cdse Quantum Dots And Their Biologic Applications

Using N-acetyl-L-cysteine （NAC） as a stabilizer, well water-dispersed Hg（Ag）doped CdSe quantum dots were facilely synthesized via a simple aqueous phasemethod. The as-prepared quantum dots were thoroughly characterized by fouriertransform infrared spectroscopy （FTIR）, transmission electron microscopy （TEM）,X-ray photoelectron spectroscopy （XPS）, etc. The experimental conditions forquantum dots preparation were optimized with fluorescence spectrum. Fluorescencebehaviors of bovine hemoglobin, bovine serum albumin and Cu²⁺on the NAC cappedCdHgSe quantum dots were investigated. Novel methods for hemoglobin and Cu²⁺determination were developed, and successfully used for biological sample analysis.In addition, the application of NAC capped CdAgSe quantum dots in cell imagingwas also explored, the results indicate that the as-prepared quantum dots can entercells by endocytosis and has the potential in cell imaging. The contents aresummarized as follows:1. Using N-acetyl-L-cysteine （NAC） as a stabilizer, well water-dispersed CdHgSequantum dots were facilely synthesized via a simple aqueous phase method. Theobtained quantum dots were verified by FTIR, TEM, XPS, etc.2. Fluorescence behaviors of bovine hemoglobin on the NAC capped CdHgSequantum dots were investigated, and a novel method for hemoglobin determinationwas developed. Under the optimal experimental conditions, the change offluorescence intensity （ΔI） is linearly proportional to the concentration of Hb in therange of4.0×10-9⁴.4×10-7molL-1with a detection limit of2.0×10-9molL-1. Thedeveloped method has been successfully employed to determine Hb in human urinesamples.3. The interactions between NAC capped CdHgSe quantum dots and hemoglobin,serum albumin were studied. The results indicate that the hydrogen bonds played amajor role in the binding of quantum dots and hemoglobin, and the probablequenching mechanism is initiated by dynamic collision; the electrostatic force playeda major role in the binding of quantum dots and serum albumin, and the probablequenching mechanism is initiated by static quenching.4. Fluorescence behaviors of Cu²⁺on the NAC capped CdHgSe quantum dotswere investigated, and a novel method for Cu²⁺determination was developed. Underthe optimal conditions, the change of fluorescence intensity （ΔI） is linearly proportional to the concentration of Cu²⁺in the range of1.0×10-9⁴.0×10-7mol/Lwith a detection limit of2.0×10-10mol/L （S/N=3）. The developed method has beensuccessfully employed to determine Cu²⁺in shrimp samples, and the result isconsistent with the atomic absorption method.5. Using N-acetyl-L-cysteine （NAC） as a stabilizer, well water-dispersed CdAgSequantum dots were facilely synthesized via a simple aqueous phase method. Theobtained quantum dots were verified by FTIR, TEM, XPS, etc. The as-prepared NACcapped CdAgSe quantum dots were cultured with Hela cells, the results indicate thatthe quantum dots can enter cells by endocytosis and has the potential the cell imaging.