Development Of Immunochromatography Strips And Matched Analyzer Based On Quantum Dots-labeling

Immunochromatography technology is developing rapidly since 1990s with the advantages of rapidness, simplicity, economy and single-test. Therefore, it has been used in medical test, quality monitor of food, poison detection, supervision of environment and so on. Today, immunochromatography is developed towards for the higher sensitivity, quantitative and multiplex detection, and may become the effective, sensitive, early screening and diagnostic mode for pathogens, malignant tumors and cardiovascular diseases, so on. However, the sensitivity of traditional colloidal gold-based lateral flow test is too low to be satisfied with the early detection of some biomarkers with very low concentration in samples.As the nanotechnology advances rapidly, many novel nanomaterials are fabricated endlessly, and applied to immunoassays, which brings new chance for developing new generation of diagnostic kit. Quantum dots is one kind of very important functional nanomaterials, its diameter is about 1-10 nanometer. Because of Size effects and Quantum Effects, quantum dots displayed unique photoluminascent property. These synthesized quantum dots have significant advantages over traditional fluorescent dyes, including better stability, stronger fluorescent intensity, and different colors, which are adjusted by controlling the size of the dots, narrow emission wave-length, big Stocks shifts, high quantum products, etc. Because of its width absorbent spectra, it can be excitated by single wave length laser as light source, and realize multi-colour biolabelling, and is specifically suitable for live cell imaging and multi-component simultaneous detection.Based on the reasons mentioned above, we developed quantum dots labeled lateral flow test and matched analyzer.Analyzer design: we chose the LED circular ultraviolent cold light source as the excitation light source, combined the CCD analog camera with the image capture card to gain the fluorescence signals and shrinkage sharply the bulk of the biological immunochromatography analyzer, which laid the foundation of developing portable and accurate detector controlled by SCM. We established the matched software by Borland Delphi and achieve these functions as follows: image capture, image process, rapidly automatic diagnosis, the detective areas adjusting and report printing in time, as well as building a thorough patients'information database to do some input, query and statistics about patients'information.Lateral flow test: we activated CdTe QDs prepared by our lab with EDC and then coupled SPA to gain immune QDs with favorable dispersity, whose partical size was about 2.5 nm. After these work, we established immunochromatography test strips to detect HIV-1 gp41 antibody. Compared with colloidal gold test strips, we found that our QDs-labeled strips perform better on chromatography speed, sensitivity and ageing. Moreover, QDs emit fluorescence under ultraviolent but hemoglobin would not, so our method would not be influenced by the color of hemoglobin when detecting serum samples, not like the colloidal gold method. The analyzer detective limit was 1 ng/mL with good stability within batch and the mistake between batches was under control.