Preparation Of Silicon Quantum Dots And Its Research On Chemiluminescence

During the research of bioluminescence imaging, the Chemiluminescence molecules-fluorescent dyes composite nanoparticles wrapped by amphiphilic polymer could produce specific response to the reactive oxygen in vivo and has high sensitivity. But the receptor-fluorescent dyes still have some problems such as weak biocompatibility, low fluorescence quantum yield, lack of ability to resist photobleaching, low emission wavelength and short emission wavelength. As a class of photoluminescence materials at the nanoscale, semiconductor quantum dots (QDs) is used for biological imaging as a kind of new type of fluorescent probe by researchers and it has showed obvious advantages, due to their unique optical and electrical properties. Among them, silicon quantum dots have the properties of riching raw materials, non-toxic, emitting in infrared window, adjusted emission wavelength, the different hydrophilicity or hydrophobicity under different surface modification and good biocompatibility. So it has become nanomaterials with most biological imaging application value. It should be a very meaningful attempt, if we choose silicon quantum dots as energy receptor to substitute traditional organic fluorescent dyes for bioluminescence imaging.As a earlier research of chemical luminescence energy transfer-silicon quantum dot composite nanometer probe, This article conducted to prepare near-infrared, oil-soluble silicon quantum dots and synthesis luminescence molecules by hydrazinolysis at low temperature two basic research work. In addition, we also have developed a real-time and on-line monitoring nitrite in water by a chemiluminescence analytical system analytical application research work. Thesis mainly includes the following several aspects:1. Review partThis part mainly introduces the quantum dots’quantum effect, optical characteristics and its application in biomedical and expounds the principles of quantum dot; the research background and significance of silicon nanomaterials, the preparation methods of silicon quantum dots and their application in the field of biomedical imaging. Finally we introduced the research background and the content of this article. 2. Preparation of silicon quantum dotsFirst, we have prepared silicon nanowires by the method of chemical etching mono-crystalline silicon slice, providing rich raw materials for the synthesis of silicon quantum dots; Then, the silicon nanowires were converted into fragments by ultrasonic, and the fragments were converted into oil-soluble silicon quantum dots by nitric acid’s oxidation and hydrogen fluoride’s corrosion and by controlling the proportion of hydrogen fluoride and nitric acid fragments. The silicon quantum dots’optical properties were characterized by UV-Vis spectrophotometer, Fluorescence spectrophotometer and Infared spectroscopy; we also have analyzed and proposed the formation mechanism of silicon quantum dots.3. Synthesizing isoluminol by hydrazinolysis at low temperature4-Nitro phthalic acid was converted into4-nitro dimethyl phthalate through esterification reaction, then the4-nitro dimethyl phthalate was converted into chemiluminescence reagent-isoluminol with hydrazine hydrate by hydrazinolysis and reduction reaction; the isoluminol was purified by recrystallization; The intermediate product and the final product were characterized by means of mass spectrometry and nuclear magnetic resonance.4. Real-time and On-line Monitoring Nitrite in Water by a Chemiluminescence Analytical SystemA real-time chemiluminescent analytical system for on-line monitoring of NO2-in water is constructed. By sampling continuously, NO2-was converted to HOONO on-line; HOONO was delivered to react with luminol immediately, which realized an automatic and continuous detection for nitrite. This analysis system can be applied to monitoring nitrite in process of water treatment as well as to the surface water. Applications to tap water being constantly or repetitiously heated to boiling and sub-boiling provide evidence for drinking water healthy.At last we summarized the main content of this paper, in which it has pointed out the advantages and disadvantages of the research work and put forward the outlook for future work.