Study On The Assay Of Nanobarcodes

Barcodes are a part of our everyday life. Fast, simple, and accurate, barcoding has become the most popular data-entry method to track the ever-exploding amount of information in the macroscopic world in the past 15 years. In the meantime, an increasing demand for tracking smaller items and for direct monitoring of individual chemical interactions has driven the exploration for novel methods of barcoding at much smaller scales. Successful demonstrations of micro- or nano-sized barcodes in molecular interaction studies, combinatorial screening, and convert tracking have opened up new opportunities for research.In this thesis, a new sort of DNA nanostructures have been synthesized by our group. We first synthesized the fluorescence-labeled short oligonucleotides, which were specifically labeled with a fluorophore and was complementary to the other long oligonucleotides. After hybridization, these oligonucleotides formed a Fluorescence -labeled DNA nanostructures. Since both dye type and dye number can be precisely controlled, multicolor fluorescenceintensity-encoded nanobarcodes could be fabricated. The decoding is based on the different ratios of different fluorescent dyes, independent of the dye positions. Consequently, the resultant DNA nanobarcodes not only had coding capacity, but also contained molecular recognition elements that could be used for molecular detection. The resultant nanobarcodes were evaluated using gel electrophoresis. Moreover, the modified gold nanoparticles by the resultant nanobarcodes were also evaluated by gel electrophoresis and by spectrofluorimeter. The results were the dependable elements for the actual application of the nanobarcodes.Gold nanopartilces have many special properties such as quantum size effects, suface effects, Optical effects and compatibility effects. With these properties, gold nanoparticles and their bioconjugates were widely used in clinical diagnostics and material field. At present, characterization of gold nanoparticles and their DNA conjugates are being relied on TEM and other techniques. But the equipments and operations are so expensive and complicated that economical and simple methods need to be developed. In this study, spectrofluorimeter and Gel electrophoresis were established for the separation of gold nanoparticles and modified gold nanoparticles.It is already found that gold nanoparticles could be separated under gel electrophoresis. Gel electrophoresis has electrostatic effects and molecule sieving effects so it's could split Au nanoparticles with different sizes precisely. Under these conditions, small particles have large electrophoresis mobility. Moreover it was found that the modified gold nanoparticles'electrophoresis mobility is differing from the unmodified. Small particles are determined to be optimal size for the surface modification and it could maximally increases the sensitivity of the DNA detection. Further experiments need to be developed to get better results.