基于新型分子识别机制的电位型传感器技术研究

发布时间：2018-08-19 12:25

【摘要】：分子识别是化学及生物传感得以实现的重要过程,传统的离子选择性电极依赖离子载体实现对目标离子的高选择性检测。自上世纪六十年代开始,得益于生物化学及超分子化学的发展,多种高效的离子载体被发现、合成并用于构建聚合物膜电位型传感器。虽然上世纪九十年代低检出限离子选择性电极的发现进一步推动了该领域的发展,但是最近一二十年关于新型离子载体(尤其是阴离子载体)的报道较少。这一方面是由于该领域没有及时将超分子化学的研究成果引入造成的,另一方面是因为发展阴离子及中性分子的载体/识别体确有难度。本论文从新型的分子识别机制出发,分别利用共价键、配位键、氢键及特殊的化学反应发展了几类新型的电位型传感器:1.基于硼酸寡聚反应的电位型多元醇传感器。葡萄糖氧化酶的性质不稳定,因而酶基传感器的长期稳定性欠佳。葡萄糖本身不能引起电位信号,并且缺乏能产生电位信号的高选择性葡萄糖识别体,所以目前并没有关于高选择性电位型葡萄糖传感器的报道。通过二硼酸与葡萄糖之间的可逆共价作用,两种分子可以以首尾相接的形式形成线状或环状寡聚阴离子。利用该寡聚阴离子与聚阳离子鱼精蛋白之间的静电作用及鱼精蛋白本身的电位响应,可实现葡萄糖的检测。其它单糖因为只有一对顺式二醇结构,不会和二硼酸形成寡聚阴离子,因而不会干扰葡萄糖的检测。该方法可在没有特异性识别体的情况下实现对葡萄糖的检测,并可用于植物多酚的检测。2.基于竞争分析的电位型磷酸根传感器。可逆共价作用只发生在特定的官能团之间,因而上述方法有一定的局限性。考虑到配位作用键能较强而且存在于大多数阴离子与金属离子之间,我们利用配位作用构建了竞争型磷酸根传感器。以Cu2+-BPMP(双(2,6-二(2-吡啶基甲基)氨基甲基)-4-甲基苯酚)或Zn2+-BPMP为分子识别体,以邻巯基苯酚为指示分子,利用指示分子氧化反应过程中产生的电位信号,我们实现了磷酸根的选择性检测。通过电位滴定实验与竞争实验测定了磷酸根、指示分子与分子识别体的结合常数,进一步验证了检测原理。其它阴离子不能将指示分子从分子识别体中取代下来,因而不干扰磷酸根检测。该方法可用于矿泉水、唾液、尿液等样品中磷酸根含量的检测。3.基于阳离子及中性锑烷的电位型氟离子传感器。氟离子的水化能很强,需要发展强亲和力的载体,将其从水相有效地萃取到膜相。以电中性及阳离子锑烷为氟离子载体,通过优化离子交换剂的种类及用量,构建了高选择性氟离子电极。研究表明,这类电极对氟离子的选择性明显优于只掺杂有阴离子交换剂的聚合物膜电极。采用双层膜夹心法测定了离子载体与各种离子之间的结合常数,该结合常数反映了电极的选择性系数。基于阳离子及电中性锑烷的氟离子电极具有优良的响应性能,可用于水溶液中氟离子浓度的测试,有一定的潜在应用价值。4.电中性硫酚的电位响应及其在电化学传感中的应用。对于大部分电中性分子来说,很难利用共价键及配位键发展与其相对应的分子识别体。经典的聚合物膜电极理论认为只有带电物质才能在聚合物膜上引起电位响应。研究表明,电中性的表面活性剂、苯酚及硼酸等可以间接方式改变膜表面的电荷分布进而引起电位响应。但是,这类电中性物质能够引起电位响应的报道较少。我们发现,电中性苯硫酚可在氢键作用下在阴离子交换剂掺杂的聚合物膜上引起电位响应。通过均相的紫外滴定实验及两相萃取实验,我们研究了苯硫酚与离子交换剂在均相及两相溶液中结合性质,据此推测了它的电位响应机理。该电极可作为一种简单易行的手段检测环境污染物苯硫酚。另外,利用苯硫酚氧化反应过程中的信号变化,可发展高灵敏的电位型传感平台用于多种物质的电化学检测。5.免标记、聚合放大型自由基反应传感器。以上几种传感方法针对的都是物理化学性质比较稳定的目标物,但是对于化学性质不稳定的目标物如自由基,很难发展一种与之相对应的分子识别体。利用自由基反应聚合乙烯型及芳香型单体的性质及高灵敏聚离子电极,我们发展了针对自由基反应的电位型传感平台。我们首先考察了经RAFT反应及FRP反应产生的聚离子及其对应的单体在聚合物膜电极上的响应性能,研究发现聚离子电极对聚合物的灵敏度显著高于对单体的灵敏度。利用葡萄糖氧化酶消除溶液中的氧气,以自由基反应聚合阳离子或阴离子单体,我们实现了对自由基引发剂(如辣根过氧化物酶、G-四联体/核酸酶、Fenton反应)及猝灭剂(过氧化氢酶)的检测。基于类似的原理,该传感平台可实现多种反应及目标物的高灵敏电位检测。
[Abstract]:Molecular recognition is an important process for chemical and biological sensing. Traditional ion-selective electrodes rely on ion carriers to achieve high selective detection of target ions. Since the 1960s, thanks to the development of Biochemistry and supramolecular chemistry, a variety of efficient ion carriers have been discovered, synthesized and used to construct polymerization. Although the discovery of low detection limit ion selective electrodes in the 1990s has further promoted the development of this field, there have been few reports about new ion carriers (especially anionic carriers) in the last 20 years. This is due to the lack of timely introduction of supramolecular chemistry research results in this field. On the other hand, it is difficult to develop carriers / recognizers for anions and neutral molecules. In this paper, several novel potential sensors based on boric acid oligomerization have been developed by using covalent bonds, coordination bonds, hydrogen bonds and special chemical reactions, respectively. 1. Sensors. Glucose oxidase is unstable in nature, so the long-term stability of enzyme-based biosensors is poor. Glucose itself can not cause potential signals and lacks highly selective glucose recognizers that can produce potential signals. So there is no report on high selective potential glucose biosensors. Through boric acid and glucose Reversible covalent interactions between sugars allow the two molecules to form linear or cyclic oligomeric anions in the form of head-to-tail contact. The detection of glucose can be achieved by the electrostatic interaction between the oligomeric anion and polycationic protamine and the potential response of protamine itself. Other monosaccharides have only one pair of cis-diols, but no cis-diols. This method can be used to detect glucose without specific recognition body, and can be used to detect plant polyphenols. 2. Potential phosphate sensors based on competitive analysis. Reversible covalent interactions occur only between specific functional groups, so that they do not interfere with glucose detection. Considering that the coordination bond is strong and exists between most anions and metal ions, a competitive phosphate sensor is constructed by using the coordination interaction. Cu2 + - BPMP (bis (2,6-bis (2-pyridylmethyl) aminomethyl) - 4-methylphenol) or Zn2 + - BPMP are used as molecular recognizers and o-mercapto-BPMP as molecular recognizers. Phenol is used as an indicator molecule, and the selective detection of phosphate is realized by using the potential signals generated during the oxidation reaction of the indicator molecule. The binding constants of phosphate are determined by potentiometric titration and competitive experiments. The detection principle is further verified by indicating the binding constants between the indicator molecule and the molecular recognition molecule. This method can be used for the determination of phosphate in mineral water, saliva, urine and other samples. 3. Potential fluoride ion sensors based on cations and neutral antimony alkanes. Fluoride ions have strong hydration energy and need to develop strong affinity carriers to effectively extract them from aqueous phase. A highly selective fluoride ion electrode was constructed using electroneutral and cationic antimony alkane as fluoride ion carrier by optimizing the type and dosage of ion exchangers. The results showed that the selectivity of this kind of electrode to fluoride ion was obviously superior to that of polymer membrane electrode only doped with anion exchanger. The binding constant between the body and various ions reflects the selectivity coefficient of the electrode. The fluoride ion electrode based on cationic and electroneutral antimony alkane has excellent response performance and can be used to measure the concentration of fluoride ions in aqueous solution. It has a certain potential application value. 4. The potential response of electroneutral Thiophenol and its electrochemical transfer. The classical theory of polymer membrane electrode holds that only charged materials can induce potential response on polymer membranes. Studies have shown that electroneutral surfactants, phenols and boric acids can be indirect. However, there are few reports that these electroneutral substances can induce potential response. We found that electroneutral thiophenol can induce potential response on anion exchanger doped polymer membranes under hydrogen bonding. Homogeneous ultraviolet titration and two-phase extraction experiments were carried out. The binding properties of Thiophenol and ion exchanger in homogeneous and two-phase solutions were studied. The potential response mechanism of Thiophenol was deduced. The electrode can be used as a simple and easy method to detect thiophenol in environmental pollution. In addition, a highly sensitive potential sensing level can be developed by using the signal changes during the oxidation of thiophenol. Electrochemical detection of a variety of substances. 5. Label-free, polymerized amplified radical reaction sensors. The above-mentioned sensing methods are aimed at relatively stable physical and chemical properties of the target, but for unstable chemical properties such as free radicals, it is difficult to develop a corresponding molecular recognition. The properties of reactive polyethylene and aromatic monomers and highly sensitive polyion electrodes have been developed for the potentiometric sensing of free radical reactions. We first investigated the response of polyions and their corresponding monomers to polymer membrane electrodes via RAFT and FRP reactions, and found that polyion electrodes react with polymer membranes. Using glucose oxidase to eliminate oxygen in solution and to polymerize cationic or anionic monomers by free radical reaction, we have successfully detected free radical initiators (such as horseradish peroxidase, G-tetrad/nuclease, Fenton reaction) and quencher (catalase) based on similarity. The sensing platform can achieve high sensitivity potential detection for various reactions and targets.
【学位授予单位】：中国科学院烟台海岸带研究所
【学位级别】：博士
【学位授予年份】：2016
【分类号】：X830;TP212

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