XJIPC OpenIR  > 环境科学与技术研究室
Thesis Advisor袁群惠
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline材料工程
Keyword碳量子点 绿色合成 汞离子 银离子 荧光传感

碳量子点作为一种新型的纳米荧光探针材料,与有机分子荧光探针和半导体量子点荧光探针相比,具有水溶性好、化学稳定性好、毒性低、生物相容性好及抗光漂白能力强等诸多优点,近年来受到传感检测、生物成像、生物标记等领域研究者的广泛关注。针对量子点合成、性质与应用研究的新方法及新技术也逐渐成为相关研究领域的热点。本论文通过使用无毒生物分子,即DNA、胞嘧啶(C)和胸腺嘧啶(T)为前驱物,利用水热合成法,在较为温和的反应条件下成功制备出了几种碳量子点材料(Bio-dots,C-dots,T-dots),并对其微观结构、发光性质及重金属传感性能等进行了一系列的研究。研究表明,由DNA 制备得到的Bio-dots 材料不需要后修饰即可作为荧光探针检测重金属离子Hg(II)和Ag(I)。在Hg(II)或Ag(I)加入后,其荧光强度明显下降。而对于其他十余种干扰离子,其荧光响应并不明显。通过一系列的表征和分析证实,Bio-dots 对Hg(II)和Ag(I)具有良好选择性和灵敏度的决定性因素是由于Bio-dots 表面残存的T 和C 可以分别与Hg(II)和Ag(I)形成T-Hg(II)-T 和C-Ag(I)-C发卡结构(hairpin structure)。另一方面,Bio-dots 表面存在的含O、含N 基团与Hg(II)和Ag(I)间较强的特异结合作用也是该Bio-dots 材料具有选择性的重要原因。Bio-dots 应用于检测Hg(II)和Ag(I)的检测限分别约为48 nM 和0.31 μM。对于以C 或T 为前驱体制备的C-dots 或T-dots,本论文对它们的重金属离子传感性能也进行了一系列的测试,研究结果表明,以C 饱和溶液制备的C-dots 较用T制备的T-dots 具有更强的荧光。但有趣的是,我们推测的C-dots 对Ag(I)有荧光淬灭作用而T-dots 对Hg(II)有荧光淬灭作用的结果并不成立;与之相反,C-dots对Hg(II)具有较好的荧光响应,而其他干扰离子对于C-dots 的荧光性质影响较小。根据其荧光性质和其他表征结果,我们认为,与前面研究中的Bio-dots 不同的是,C-dots 和T-dots 在对于Hg(II)和Ag(I)传感中,不能够形成T-Hg(II)-T 或C-Ag(I)-C的发卡结构,其荧光淬灭的主要原因是由于表面官能团的作用。另外,C-dots 对Hg(II)的荧光检测对pH 没有要求,在弱酸弱碱条件下均可以检测,其对Hg(II)的检测限约为11 nM,且响应时间极短,可以在30 s 之内完成。

Other Abstract
As a new kind of fluorescence probe, Carbon quantum dots exhibit many advantages, such as high water solubility, robust chemical inertness, low cytoxicity, superior biocompatibility and high resistance to photobleaching. Therefore, carbon quantum dots are widely used in the field of heavy metal ions detection with absolute advantage over organic fluorescent molecules and semiconductor quantum dots. In this thesis, we synthesis three kinds of carbon quantum dots called bio-dots, C-dots and T-dots from DNA, base pairs cytosine (C) and thymine (T) under relatively mild conditions, respectively. And we have evaluate the detection performance towards heavy metal ions of these carbon quantum dots through a serious of tests. The bio-dots derived from DNA could be used as an efficient biosensor for the detection of Hg(II) and Ag(I), directly, with the estimated detection limits of 48 nM and 0.31 μM (at a signal-to-noise ratio of 3), respectively . The existence of thymine (T) and cytosine (C) residuals on the surface of bio-dots led to the feasible determinations with good selectivity and satisfying recoveries in real water sample analysis analyses. Besides, the rich oxygen/nitrogen containing groups including carboxyl and amino groups on the surface also contributed to the good sensing performance of the obtained bio-dots, due to their high affinity towards Hg(II) and Ag(I) ions. For C-dots and T-dots, we have conducted a series of tests on their detection performance. C-dots devived from the saturated solution of cytosine (C) have a stronger fluorescence compared with T-dots synthesis from the saturated solution of thymine (T). Beyond our expectation, C-dots have greater fluorescence quenching efficiency towards Hg (II) than Ag (I). It is found that pH have almost no effect to the detection of Hg(II) for C-dots, and under the condition of weak acid and weak base the detection can be realized. The detection limit is about 16 nM towards Hg (II) for C-dots. What is more, the response time is extremely short and can be completed within 30 s.
Document Type学位论文
Recommended Citation
GB/T 7714
宋婷. 荧光碳量子点绿色合成及其汞、银离子传感性能研究[D]. 北京. 中国科学院大学,2015.
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