Study On The Preparation Of Functional Graphene And The Application Of Resonance Energy Transfer Of Graphene In Biochemical Analysis

As a result of special structure, mechanical, electronics and chemical properties, graphene have been importantly used in the fields of field effect transistors, sensors, clean energy devices and graphene-polymer nanocomposites since their discovery in 2004. In this paper, we prepared graphene oxide, and applied to analyse of HIV DNA detection in the foundation of using graphene oxide as the resonance energy transfer acceptor. At the same time, we prepared the graphene and photoluminescent graphene by the new methods, and investigated the physical and chemical properties of them, and then explored the properties of them as resonance energy transfer acceptor or donor. The main content is as follows:1. By introducing graphene oxide as signal-to-background ratio enhancer, a simple long range resonance energy transfer strategy for short DNA target with its sequence related to the human immunodeficiency virus type 1 is explored. In the absence of target ssDNA, both probe ssDNA and SG I dye are adsorbed on the surface of GO, and the fluorescence of SG I is quenched by GO following long range resonance energy transfer process. In the presence of target DNA, however, a double-stranded structure of DNA gets formed, and thus SG I dye can bind with double-standed DNA in the mode of intercalation and minor groove binding, keeping away from graphene oxide surface owing to the reduction of the interaction between the rings of the nucleotide bases and the honeycomb surface of GO. As a result, fluorescence emission from SG I dye gets enhanced with high signal-to-background. It was found that a detection limit of 0.31 nM could be achievable, and single-base-pair mismatches are easily detected. The strategy for sequence-specific DNA detection has sensitivity, simplicity, high specificity and anti-interference properties. 2. The preparation of folic-modified graphene was demonstrated using graphene oxide as carbon source and folic acid as reducing agent. It was noteworthy that folic acid is not only the reductant, but also stabilizer, and the folic-acid modified graphene can disperse in water for more than four months. Furthermore, ultraviolet-visible absorption spectroscopy, X-ray powder diffraction, fourier transform infrared spectrum, raman spectroscopy, transmission electron microscope pattern, thermal stability and cell toxicity was investigated, and the synthetic materials has good properties compared with other graphene. Simulanteously, compared with graphene oxide, the prepared folic-modified graphene quenched the fluorescein dye as resonance energy transfer acceptor is much better.3. A simple hydro thermal method was developed for preparation of photoluminescent graphene using surfactant PEG-600 as passivation reagent. Owning to a great quantity of hydroxyl group in the PEG-600 molecules, the prepared photolumineccent graphene can disperse in water for more than five months, and show good salt resistance and anti-photobleaching. The fluorescence intensity is stable during the pH 2.0-12.0.