本文選題：檸檬酸 + 尿素��； 參考：《西北大學》2015年碩士論文

【摘要】：近年來,隨著科學技術(shù)的發(fā)展,低維碳納米材料逐漸被人們所發(fā)現(xiàn)。尤其是從石墨中剝離出單層的二維石墨烯之后,石墨烯材料的特性及應(yīng)用很快成為各領(lǐng)域科學家們研究的熱點。準零維材料中的量子點隨著其制備技術(shù)的不斷提高,已經(jīng)被逐漸應(yīng)用于熒光探針、細胞成像等生物和醫(yī)學方面。作為一種新興的碳材料—石墨烯量子點(graphene quantum dots, GQDs),不僅具有石墨烯的導電性良好、強度大、比表面積大等優(yōu)異特性；而且結(jié)合了量子點的量子限域效應(yīng)、小尺寸效應(yīng)及邊緣效應(yīng)等優(yōu)點,表現(xiàn)出良好的生物相容性、低毒性、強水溶性、高熒光穩(wěn)定性等特性,使其在生物醫(yī)藥、傳感器、光學及電學器件等方面有潛在的應(yīng)用前景。本論文主要優(yōu)化改進制備GQDS及其氮摻雜的條件,以提高其熒光量子產(chǎn)率,通過各種手段對材料的結(jié)構(gòu)及性質(zhì)進行了詳細研究,并探究了氮摻雜石墨烯量子點(N-GQDs)在離子檢測中的應(yīng)用以及GQDs在HBV-DNA檢測中的應(yīng)用。全文主要研究內(nèi)容為以下幾部分：(1)采用熱解法,以檸檬酸為有機前驅(qū)體,制備石墨烯量子點,通過優(yōu)化反應(yīng)時間、反應(yīng)溫度、溶液酸堿度等實驗條件,探究最優(yōu)的制備條件。在最優(yōu)條件下,其熒光量子產(chǎn)率達到9%,平均粒徑為3.0 nm。并以尿素為氮源,利用水熱法對GQDs實施氮摻雜制備了富含“吡咯N”的N-GQDs,通過研究原料配比、反應(yīng)時間和反應(yīng)溫度等因素對熒光性能的影響確定了實驗優(yōu)化方案。在最優(yōu)化條件下,其熒光量子產(chǎn)率為24%,平均粒徑為7.5 nm。與此同時,GQDs (τ1=1.74 ns)和N-GQDs (τ1=7.40 ns)的熒光壽命衰變被很好的擬合成一條單指數(shù)曲線,說明二者都具有單一發(fā)色源。除此之外,我們還對GQDs及N-GQDs的形成機理進行了詳細討論。(2) N-GQDs構(gòu)建光致發(fā)光傳感器檢測Cu2+。Cu2+與N-GQDs表面的羧基進行化學螯合,使得N-GQDs發(fā)生聚集,導致能量或電子的轉(zhuǎn)移,使N-GQDs的熒光發(fā)生猝滅。Cu2+濃度與熒光強度在0～100 nM范圍內(nèi)呈線性關(guān)系,檢出限為14 nM。此檢出限比先前報道過的一些值更有意義。(3)以GQDs作為熒光供體,GO作為熒光受體構(gòu)建檢測HBV-DNA方法。研究了GO濃度、響應(yīng)時間及加入目標DNA(tDNA)后的孵化時間等因素對HBV-DNA檢測的影響。在最佳條件下,體系熒光強度的恢復比率約96.5%,檢出限達5.08 nM(S/N=3)。該檢測方法可以高效分辨完全互補序列、單堿基錯配序列和完全不互補序列,方法簡便、靈敏度高,具有極大的應(yīng)用價值。
[Abstract]:In recent years, with the development of science and technology, low-dimensional carbon nanomaterials have been gradually discovered. Especially after the removal of two-dimensional graphene from graphite, the properties and applications of graphene materials have quickly become the focus of scientists in various fields. Quantum dots in quasi-zero dimensional materials have been gradually used in biological and medical fields such as fluorescent probes cell imaging and so on with the improvement of their preparation techniques. As a new carbon material, graphene quantum Dots (GQDsN) not only have good electrical conductivity, high strength and large specific surface area of graphene, but also combine the quantum limiting effect of quantum dots. The advantages of small size effect and edge effect, such as good biocompatibility, low toxicity, strong water solubility and high fluorescence stability, make it have potential applications in biomedicine, sensors, optical and electrical devices. In order to improve the fluorescence quantum yield of GQDS and its nitrogen doping, the structure and properties of GQDS were studied in detail. The application of N-doped graphene quantum dots (N-GQDs) in ion detection and the application of GQDs in HBV-DNA detection were also discussed. The main contents of this paper are as follows: 1) the optimum preparation conditions of graphene quantum dots were investigated by optimizing the experimental conditions such as reaction time, reaction temperature and pH of the solution, using citric acid as an organic precursor. Under the optimum conditions, the fluorescence quantum yield is 9 and the average particle size is 3.0 nm. N-GQDsrich in pyrrole N were prepared by hydrothermal method with urea as nitrogen source. The optimum scheme was determined by studying the effects of raw material ratio, reaction time and reaction temperature on the fluorescence properties of N-GQDsrich in GQDs. Under the optimum conditions, the fluorescence quantum yield is 24% and the average particle size is 7.5 nm. At the same time, the fluorescence lifetime decay of GQDs (蟿 1, 1. 74 ns) and N-GQDs (蟿 1 + 7. 40 ns) were well fitted into a single exponential curve, indicating that both of them have a single chromogenic source. In addition, we also discussed the formation mechanism of GQDs and N-GQDs in detail. The photoluminescence sensor constructed by N-GQDs was used to detect the chemical chelation of Cu2. Cu2 with the carboxyl group on the surface of N-GQDs, which led to the aggregation of N-GQDs and the transfer of energy or electrons. The fluorescence quenching of N-GQDs shows a linear relationship with fluorescence intensity in the range of 0 ~ 100nM, and the detection limit is 14 nm. The detection limit is more significant than some previously reported values.) GQDs was used as a fluorescent donor and go as a fluorescent receptor to construct a method for the detection of HBV-DNA. The effects of go concentration, response time and incubation time on HBV-DNA detection were studied. Under the optimum conditions, the recovery ratio of fluorescence intensity of the system is about 96.5 and the detection limit is 5.08 NM / S / N ~ (3 +). The method is simple and sensitive and has great application value because it can efficiently distinguish complete complementary sequence, single base mismatch sequence and complete uncomplementary sequence.
【學位授予單位】：西北大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ127.11

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