Study For The Auxin Fluorescence Biosensors Base On DNA Terminal Protection And Graphene Oxide

Besides indole-3-acetic acid (IAA) and other similar phytohormone, Auxin includs2,4-D and other synthetic auxin. Phytohormone indole-3-acetic acid (IAA) is a trace organic substance, synthesized in plants, and regulates the processes of plant growth and development.2,4-D is a synthetic auxin analogs, which is widely used in the fields of agricultural production as a herbicide. Some existing detection methods and techniques for Auxin have certain disadvantages, such as being unable to detect in real-time and in situ. Furthermore, the repeatability and stability of these detection methods can not be guaranteed.In order to explore some more effective method in detection of auxin, this paper tries to develop a IAA fluorescent biosensor based on DNA terminal protection and a2,4-D fluorescence biosensor based on graphene oxide (GO) for detection, the results obtained are as follows:(1) A fluorescent biosensor based on DNA terminal protection was developed to quantify small target molecules IAA. the screening scheme is based on the design of IAA-linked DNA hybrid, when adding target molecule sample, the free IAA can bind to the anti-IAA antibody protein by pre-incubating in a solution, inhibiting the formation of antibody/IAA-labeled probe/assembling probe complex in the subsequence step. In this case, the restriction endonuclease Fok I will produce shear activity through repeated shear on the fluorescence probe amplification of fluorescence signalresponse.(2) The optimal conditions for IAA detection were determined as follows. Labeling IAA to NH2-Modified Oligonucleotides and Purification of it by semipreparative high performance liquid chromatography (HPLC).50μg/mL mouse anti-IAA antibody is the optimal condition in this system.(3) The IAA were measured quantitatively by fluorescence biosensor DNA terminal protection. The results indieated that this sensor had satisfaetory linearity with the content of IAA in the range of0.1ng/mL-20ng/mL. The lowest concentration of IAA was detected in0.1ng/mL.(4) A method based on Graphene Oxide (GO) was described to quantify small target molecules2,4-D. the screening scheme is based on the design of2,4-D-linked GO, which is a good receptor in Fluorescence Resonance Energy Transfer.when adding target molecule sample, the free2,4-D can bind to the Fluorescence-labled anti-2,4-D antibody protein in a solution, Fluorescence-labled anti-2,4-D antibody protein depart from graphene oxide surface, so we can detect the fluorescence signal.(5) The optimal conditions for2,4-D detection were determined as follows.Optimized the best concentration of fluorescein labeled antibodies is0.5μg/mL, the optimal concentration of graphene oxide derivative is0.6mg/mL.(6) Based On the above conditions, we obtained the curve relationship between2,4-D concentration andfluorescence intensity of2,4-D fluorescence biosensor through detecting the concentration of2,4-D range froml ng/mL to100ng/mL, the lowest concentration accorded with the national standard limit was1ng/mL...