| Quantum dots(QD),with a diameter of 1-100 nanometers insize,as a specific kind of nanoparticles newly developed in recentyears,provide an extremely good fluorescent signal and then can wellbe used for fluorescent labeling , also as an ideal bioconjugatedfluorescent probe for bioanalysis,because of their unique optical andelectronic properties,such as broad excitation spectrum,narrowemission spectrum , good tune and neglectable optical bleachphenomenon etc. Although its research and application has just beenexplored,QD have attracted great attention from scientists in manyfields. Its basic knowledge and characters , synthesis , labelingapproach,recent progress and prospect in potential application to lifescience,especially to immunoassay and rapid diagnostic analysis arereviewed in part 1, chapter 1.In part 1, chapter 2, a rapid and facile method for hydrothermalsynthesis of CdTe nanocrystals under mild conditions is developed. Inthis procedure, tripeptide thiol glutathione was used as stabilizingagent, CdTe NCs with controllable photoluminescence wavelengthfrom 500 nm to 680 nmw ere prepared within two hours. Comparedwith CdTe NCs prepared with thiohydracrylic acid as stabilizing agent,as-prepared NCs show much narrower photoluminescence FWHM,more symmetrical emission peak and higher photoluminescencequantum yield. Experimental results show that as-prepared NCs havevery good biological compatibility and they are nontoxic. And theseCdTe NCs can conjugate with biological molecules for furtherbiological luminescence study. The proposed hydrothermal synthesisprocedure has the advantage of simplicity, inexpensiveness, timesaving and mild operating conditions.Semiconductor nanocrystals(NCs) attracted great attention in various academic fields in the pastdecades, especially the water-soluble semiconductor NCs with highphotoluminescence (PL) quantum yield (QY), which have been ofgreat importance for biological applications. Compared withtraditional tags, NCs have some unique chemical and physicalproperties, such as broad band excitation, narrow bandwidth emission,high photobleaching threshold, good chemical stability, readily tunablespectral properties and so on. When the reaction system is stabilizedwith GSH, the NCs not only grow much faster but also result innarrow particle size distribution and the enhancement of PL QY. Theas-prepared CdTe NCs can be directly used as biological tags withoutany post-preparative treatment. Compound with a sulfhydryl and acarboxyl, but seldom with amino function group, is usually used asstabilized reagent. Stabilizer used in this paper is a novel one, GSH,which contains all –SH, –N, and –OH groups. It can form a circularcomplex on the surface of nanoparticles, so that the nanocrystals havemany superior characteristics and make the as-prepared NCs havegood biological compatibility and almost have no toxicity. Thishydrothermal synthesis procedure has the advantage of simplicity,inexpensiveness, time saving and mild operating conditions.In part 1, chapter 3, applying studies of semiconductornanoparticles were done because of their specific optical characters.First, the method of tagging cells with quantum dots by electroporationis developed. An electroporation method is proposed to make QDspass through the membranes of K562 leukaemia cells. This method isoperated simply and facilitates the tagging experiment greatly. Thismethod brings forward some more extrusive advantages than cellendocytosis and microinjection method, and there should be a verygood foreground for further applications. Second, biodistribution ofquantum dots in rats is studied. We wish to assess not only how thesematerials distribute themselves within a living animal, but also the fateof these materials. In this chapter, the biological distribution of CdTenanocrystals in a rat was studied by means of bioanalysis and somerules were obtained. The experiment results indicate that quantum dotsare transported by blood circulatory system to liver and spleen, andcan be observed in these organs within 24 hours which emissionwavelength has a red shift. With the time passing, quantum dotsdistributed in the two organs get less and less till disappearing. Byusing quantum dots as a tagging to study the transportation,distribution and metabolizing of nanoparticles, the operation is verysimple and safe, and the results got directly. The results have muchreference and guiding value for further study of the bio-distribution ofother nano-particles and pharmacons in vivo. Third, a novel method ofsynthesizing fluorescence-encoded microspheres by dispersingpolymerization technique is reported. A series of polystyrenemicrospheres from 1μm to 5μm in diameter are attained. By thefollowing one-step swelling procedure, the different nanocrystals werecarried into the inner of Ps microspheres quantificationally. As-prepared fluorescence-encoded microspheres have the followingoutstanding advantages: the nanocrystals are not absorbed on thesurface of the microspheres but carried into the inner of microspheres,so the NCs cannot be isolated or leaked out easily. Besides, comparedwith microspheres loaded by traditional organic dyes, as-synthesizedphotoluminescent microspheres have better photostability, and it ismuch more difficult for them to be photobleached. Moreover, thismethod can be operated easily and reproducibly.In part 2, chapter 1, Some new advances in development of micro-fluidic-chip analysis systems at home and abroad are introducedsystematically. The progresses in the aspects of miniaturization ofinstrument, application to the biological analysis, micromachiningtechnology for chips and various detection techniques developed areviewed especially. And some problems faced now are presented. Flowcytometry is a general method for analyzing microparticles such ascells, bacteria and other microorganism with high efficiency,integrating optics, fluidics, electronics, and computer technology. Withthe application of all kinds of advanced technologies, flow cytometersare getting smaller, cheaper, faster, more integrated and better inperformance.In part 2, chapter 2, the microchip flow cytometer and the methodof detecting biochemical sample are studied. Applying electrokineticfocusing technology, the whole fluidic controlling system is set up on amicrochip with four electrodes in it. By using laser inducedfluorescence system, the prototype instrument is small, and theoperation is simpleIn part 2, chapter 3, a microfluidic chip is designed and fabricated,and in coupled with flow cytometry. Using Na2PO4 solution addedwith hydroxypropyl methyl cellulose (HPMC) as buffer and sheathingfluid, it solves a set of problems met during the flowing of fluorescentmicrospheres in the microchannel, so as to keep the fluidic conditionsunder more effective control. By using laser induced fluorescencesystem assembled at the lab and applying electrokinetic focusingtechnology, the counting of the microspheres is achieved. And realtime observation of their actual fluidic state through an invertedfluorescence microscope is made. The whole system is compact andeasy to be operated. The usage of reagent and sample is little and thespeed of the assay is quick. Combining microspheres and flowcytometry, the method of detecting epidemic hemorrhagic fever andnew-castle disease is developed. It also set the foundation for theresearch of detecting multiple animal diseases simultaneously. |
PDF Full Text Request