【作者】 王胜；

【导师】 时康；

【作者基本信息】 厦门大学 ， 物理化学， 2008， 硕士

【摘要】 生物活性物种在电极表面的固定和性质表达是生物电化学研究中两个主要的研究内容。在具有独特物理、化学性质的生物膜的界面上构建具有生物活性的分子识别体系被认为是一条行之有效的研究路线。通常构建生物功能性膜主要采用聚合和自组装两种方法,其中,聚合以物理方法为主,而自组装则在开路条件下完成。由于物理方法常使用极端的聚合条件,因而生物物种的活性在成膜时很难充分维系,开路条件下的自组装则不易达到人工调控表面的目的。电化学方法作为一种简单可控的手段,可在保持生物物种活性的温和条件下在电极表面成膜,因此,通过电化学方法构建生物功能性膜并应用于生物物种的检测是生物电化学研究中重要的研究领域。本论文系统探索了在金电极表面通过电化学手段调控自组装以及聚合生成生物膜的方法。采用电化学控电位方法自组装修饰生成巯基硼酸衍生物膜;采用电化学氧化聚合方法聚合成聚3-噻吩硼酸膜;采用电化学还原诱导聚合方法聚合得到了甲基丙烯酸凝胶膜。论文首先调查了多晶金电极表面经不同预处理步骤后表面的性质变化。实验发现金电极仅依次经过机械抛光、电化学极化两处理步骤后可得到较为清洁的表面;但依次经机械抛光、化学氧化抛光、电化学极化、化学还原四个处理步骤后可获到最佳的适宜修饰的表面。随后调查了采用电化学控电位方法在金电极表面自组装巯基硼酸衍生物单层膜,相应内容描叙在第四章中。实验以Fe（CN）₆^3-/4-氧化还原电对为分子探针,表征了硼酸衍生物单层膜在不同pH溶液中与糖类物质（含邻羟基物质）选择性发生脂化可逆反应的性质,结果表明在最佳电位0.4～0.5 V范围内的控电位自组装可使巯基硼酸衍生物键合在金表面,与开路条件下的自组装相比,有一定的优越性。巯基硼酸衍生物单层膜可应用于手性酒石酸的分析,实验发现在中性和弱碱性溶液中,单层膜对L型酒石酸脂化反应的选择性高于D型酒石酸。另外,单层膜可与多巴胺（DA）发生选择性较高的可逆的脂化反应,采用预富集方法可高选择性地检测DA,并不受抗坏血酸（AA）的干扰;巯基硼酸衍生物膜的链长对DA的检测下线和线性范围有一定的影响。线性检测范围为10～300μmol/L,检测下限为1μmol/L。在论文的第五章中,探索了在三氟化硼乙醚溶液中通过电化学氧化聚合生成3-噻吩硼酸聚合膜的成膜方法,而在水溶液中3-噻吩硼酸通常不易发生聚合。实验表明获得的聚合膜中的硼酸基团在中性条件下,仍可与多巴胺（DA）发生选择性极高的可逆的酯化反应。修饰电极可用于预富集方法定量分析多巴胺（DA）,当检测溶液中同时含有1 mmol/L抗坏血酸（AA）、1 mmol/L尿酸（UA）和2mmol/L葡萄糖（GO）对多巴胺（DA）的定量检测无显著的干扰。在论文的第六章中,发展了一种在可保持生物物种活性的条件下可发生的、新的电化学聚合成膜方法,即在室温、中性pH水溶液中,通过电化学还原过硫酸根产生稳定的自由基方法,诱导甲基丙烯酸在金电极表面聚合生成膜。AFM等表征实验结果表明诱导聚合的膜是一种三维多孔膜,与金表面有良好的附着力;当室温、中性pH的聚合水溶液中含有生物活性物种葡萄糖氧化酶时,三维多孔膜在形成时可将葡萄糖氧化酶有效地、高通量地包裹固定在膜内;制得的葡萄糖氧化酶电极具有较高的生物活性,对葡萄糖（β-D glucose）的检测具有响应快、灵敏度高、稳定性好等优点;实验进一步探索了获得固定葡萄糖氧化酶的最佳条件;在最佳的条件下对β-D glucose的检测下限可达为0.05 mmol/L。论文最后对以上三种生物功能性膜构建方法进行了对比总结。电化学还原诱导聚合成膜作为一种室温条件下、中性pH值水溶液中温和的成膜方式,可实现生物活性酶的有效固定,是需进一步探索研究的新方法。更多还原

【Abstract】 The immobility and qualitative expression of active biological species at electrode surface are important research area in biological electrochemistry.The molecular recognition system constructed on the base of the biological film possessing particular physical and chemical properties is considered as an effective research road.The traditional biological functional film usually is constructed by either self-assembling(SA) or polymerization method.The self-assembling mothd is offen mainly oprated at the condition of open circuit potential,which might lead to an uncontrolable surface.The physical polymerization usually preforms under an extramine physical condition,which can damage the activation of biological species. Electrochemical method is a simple,smoth and effective means to keep the activtion of biological species during the prepare procedure of the biological funtional film.How to develope valuable electorchemistry construction method for the biological funtional film is an research area needed to be deeply expolred in biological electrochemistry.In this thesis,the optimum procedure for preparing the biological funtional film at the surface of polycrystalline Au electrode was been expolred,systemly.The self-assebling monolayer film of mercapto boric acid ramification(MBAR) was devepled at the Au surface under the controlled-potential condition.3-Thiopheneboronic acid(3-THB) polymerzation was obtained by electrochemical oxidation.The new method of electrochemically induced free-radical polymerization(EIRP) was firstly investigated and the poly(Methacrylic acid) film was successfully constructed at the Au electrode surface.Firstly,the polycrystalline Au electrode surfaces prepared by different pretreatment procedures were investigated in sulfuric acid by cyclic voltammetry.The experiment results showed the clear surface for polymerization can be obtained by mechanical mechanical polishing and chemical oxidation prodedures,but the best active surface for modification could be obtained after mechanical polishing,chemical oxidation,electrochemical polaration and chemical reduction procedures.Secodly,the self-assembling monolyaer of MBARs prepared by the controlled-potential method was analyzed by the cyclic voltammetry in ferricyanide potassium solution.It was found that the optimum controlled-potential for self-assembling was within the range of 0.4～0.5 V.The controlled-potential method made the charactersof the self-assembled monolayer better than that without one.The monolayer of monosaccharides could recognize the enantiomeric tartaric acids since L-tartaric acid more easily reacted with the monolayer than D-tartaric acid in neutral and weak acid solution.On the other hand,the monolayer of monosaccharides also could be applied in the selective detection of dopamine(DA) after preconcentration.Moreover,the longer chain MBAR detection response was more sensitive than the short one’s.The former’s liner response range was within 10～300μmol/L and the detection limit was down to 1μmol/L,while the latter’s were 30～100μmol/L and 9μmol/L.Thirdly,the poly(3-THB) film obtained by electrochemcial oxidation had many boric acid functional groups possessing negative charge in neutral solution condition,which could enhance the response of DA in the formation of rigonal and tetrahedral esters and electrostatic repulsion. Meanwhile,The poly(3-THB) film could selective detect DA in the presence of 1 mmol/L Vitamine C(AA),1 mmol/L Uric acid(UA) or 1～2 mmol/L Glucose(GO).A new electrochemical polymerization method was explored in the last charper of this thesis. Under the conditions of neutral pH adquene and room temperature,the electrochemical reduction of potassium persulfate would offer steady free-radical,which could induce the polymerzation of methacrylic acid at Au electrode.AFM and other experimental results identified that polymerization film was a three-dimensional porous stucture excellectly adhesing on Au surface. When the polymerzation solution contained glucose oxidase(GOD),the film could effectively immobilize glucose oxidase(GOD) with highly active.Corresponding GOD enmyzer electrode could quickly,sensitivity and stabilitly response forβ-D glucose in solution.Under the optimal conditions,the detection limit was down to 0.5μmol/LFinally,after constrated the three films above,the EIRP method should be the newest construction way under the conditions of neutral pH adquene and room temperature to keep the activation of biological speies.Meanwhile,lots of affects still needs to be made along this way.更多还原