Research On The Detecting System Of QDs Labeling Tumor Markers

Progressing faster than ever, quantum dots (QDs) have become new fluorescentlabels. The unique optical properties of QDs make them to be the ideal fluorescentlabel probe marking the tumor markers, such as antigen and other activebio-substances derived from the expression process of cancer gene. With theadvantage of highly specific, easily to detect and earlier to present, tumor makers havebeen already widely applied in clinic. Furthermore, combined with diagnosticmethods, the examination of tumor markers can highly raise the early diagnostic rateof tumor.Different from traditional detecting method of tumor markers,the QDs basicallymark the fluorescence of coupling QDs by the reactant to measure the content oftumor markers,when tumor markers have immune reaction on the unique antigen ofcoupling QDs.The paper developed two detecting instrument with QDs immunochromatographytest strip and a microfluidic chip experiment platform on QDs encoding-microsphere,which were all applied to study the technology of QDs labling tumor markers, both inexperimental and clinic test. The results showed that QDs immunochromatographytest strip were cheap, faster to test, easily to conduct, and of good reproducibility,specificity and sensitivity. Hence, it is qualified to be widely applied in hospitals fortumor markers’ detect and screening.The innovations of the thesis embodied as follows:1. It constructed a liquid chip detect system based on Fiber optic spectrometer asdecoding device, to achieve mass decoding and high-throughput test on encodingmicrobeads, which also conquered the defects of flow cytometry, Luminex andother instruments providing no proper information while testing fluorescent encodingmicrobeads. The system achieves real-time location and redundancy of theencoding-beads by CCD real-time image, the real-time test decoding onfluorescence spectrum of QDs encoding-beads by optical fiber spectrometer, thereal-time test of tumor markers-antigen-QDs coulpling’s target fluorescence tocalculate the concentration of tumor markers. The thesis also studied on the detecting method of AFP. By labeling the concentration of the patients’ AFP and the workingcurve of target fluorescence intensity, the thesis detected the AFP in serum viaworking curves method, limit up to1ng/mL.2. QD barcodes of two adjacent wave length can be identified by wavelettransform technique. To obtain mass QD barcodes, the overlay peaks of fluorescenceoccur, leading to difficulties in identifying QD barcodes. Following wavelet transform,peak location remained unchanged, so the eigenvalue of spectrum of codingfluorescence was extracted. The spectrum of fluorescence mixed with DQs was split,and two QD barcodes were identified. The improved barcodes identification ofadjacent spectrum increase colors of QD barcodes, thereby enhancing codeinformation volume, which lays a foundation for detecting tumor markers.3. The paper has developed QDs immunochromatography test strip readers,which achieved fast, easily, sensitively, precisely detect on tumor markers. The paperstudied on the reaction time and sample dosing by these instruments, confirming thebest standing reaction time as10min and the Optimal dosage as50ul. The experimentresult showed that the detect limit of the instrument is1ng/mL, the repeatability errorratio is under1%. Furthermore, the thesis also studied on the method to detect AFP inserum by the instruments, labeling AFP working curves to test the AFP concentration.Meanwhile, the instrument applied standard addition method to test the concentrationof AFP, the error ratio is under5%. Besides, the two instruments were also carriedinto clinic test in three hospitals for1000patients’ AFP in serum, compared withECLIA method. The result showed the instruments have the same accuracy andsensitivity with ECLIA, which was qualified with detecting on tumor markers inclinic.4. The thesis made an primary approach to the QDs immunochromatography teststrip mass test, putting foward encoding immunochromatography QDs by color,which would develope color encoding multi-channel strip, rejecting non-specificityadsorption immune QDs fluorescence theory and algorithm in fluorescence spectrumon detection line. Hence, it ensured the accuracy of the mass test.