The Preparation Of A New Type Of Nucleic Acid Probe Based On Quantum Dots And Its Use In IN Situ Hybridization

Quantum dots (QDs), as a new type of fluorescent labels, offer a number of unique optical properties, including broad excitation spectra, narrow luminescence bands, large Stokes shift, high resistance to photodegradation, long fluorescence lifetime and the surface can be modified, which make them have great attention during the past tween years. But there are still a lot of practical problem left unsolved. It is very important to improve the stability and biocompatibility when Quantum dots are widely used in the field of biology application at now.Gene probe is a nucleic acid sequences whose DNA sequence is known, and with a marker. It can be the entire gene, can also be a part of genes; can be DNA itself, can also be transcribed by RNA. Gene probe trace target gene by marker in molecular hybridization rule.ISHH is the short name of in situ hybridization histochemistry,which is widely used in cell genetics, breeding, medicine and other fields. The probe preparation and detection are important. However, due to the development of molecular biology, the existed detecting methods are not sensitive enough. It is meaningful to find a more appropriate detecting technique.In this thesis, based on the excellent optical properties of quantum dots and the insufficient detecting methods of ISHH, we want to choose a quantum dot to be the marker of gene probe. we discussed the stability of different quantum dots and prepared a new type of nucleic acid probe which signed by quantum dot. we used the quantum dots probe to test GAPDH gene in the muscles of the 50d Yorkshire sows. The main concents and results are listed as follows:1.we discussed the stability of different quantum dots which can be used of signing gene probe and selected stable quantum dot which can be used in PCR and stable existed in EDC/NHS solution.2. CdSe/ZnS QDs have been conjugated successfully with DNA in aqueous solution. The product was characterized by ultraviolet-visible absorption spectra and Agarose gel electrophoresis. The results indicated that the quantum dots probe has been prepared successfully.3. the biological activity and tracing function of probe which has been have been conjugated with QDs have been tested by ISHH. The results indicated that the quantum dots probe has been prepared successfully and GAPDH gene was successfully probed in muscle tissue of Yorkshire sows by this quantum dots probe.In this paper, The results show that a new type of nucleic acid probe based on quantum dots synthesize successfully, and GAPDH gene was successfully probed in muscle tissue of Yorkshire sows. Such results not only can be used as the reference of the labeled nucleic acid probes based on quantum dots, but also provides a evidence for this new type of fluorescent material in the biological field.