基于石墨烯的胆固醇电化学传感器的制备与性能研究

发布时间：2018-11-24 15:09

【摘要】：血清中高胆固醇水平与糖尿病、高血压、动脉粥样硬化及冠心病等人类多发症有关,血清中胆固醇的含量已成为临床诊断的一项重要指标。传统测定方法所用仪器复杂、检测时间久、费用较高、干扰因素多,电化学传感器具有对目标物有较高的识别能力,样品用量少、响应快,成本低、体积小,便于普及的优点,开发微型化、简便化、可大批量生产的测定胆固醇含量的电化学传感器具有重要意义。石墨烯具有高的比表面积、良好的导电性、超高的机械强度及独特的电学性质,基于石墨烯的纳米复合材料在电子器件、生物材料、传感器材料和催化剂载体等领域展现优异性能,具有广阔应用前景。将石墨烯与导电聚合物材料、无机贵金属材料结合,为新型的电化学传感器和电化学生物传感器的开发提供了新的思路。本论文主要是基于石墨烯的胆固醇电化学传感器的制备与性能研究,主要研究内容如下:采用改进的Hummers方法,制备氧化石墨,用超声剥离的方法制备氧化石墨烯,然后用水合肼对其还原制备还原的石墨烯材料,对石墨烯制备工艺进行了优化。运用XRD、Raman、FTIR、SEM、TEM、AFM等手段对其进行了微观结构表征,结果表明,超声剥离13h可以合成薄的、理想的石墨烯材料。制备了石墨烯/硫堇/壳聚糖/胆固醇氧化酶/辣根过氧化物酶胆固醇生物传感器。以合成的石墨烯为载体,具有良好导电性的硫堇为导电介体,壳聚糖为粘结剂,负载胆固醇氧化酶和辣根过氧化物酶作为催化剂,制备出了基于石墨烯/硫堇的胆固醇生物传感器,检测胆固醇浓度的最佳工作条件为:测试体系的p H值取7.0,测试温度取室温。该传感器具有较低的检测限3.7×10-7M、较高的灵敏度24m AM-1cm-2、检测范围为2.0×10-6~4.6×10-4 M,且具有很强的抗干扰能力。该体系对胆固醇的检测具有较低的检测限3.7×10-7M、较高的灵敏度24m AM-1cm-2、检测范围为2.0×10-6~4.6×10-4 M,表观米氏常数KapM为4.9×10-5M,且具有很强的抗干扰能力,对葡萄糖、抗坏血酸、尿酸等干扰物质分别只产生了0.15%、1.69%、2.19%的电流变化。采用分部电化学聚合方法合成石墨烯/聚吡咯/壳聚糖/胆固醇氧化酶/辣根过氧化物酶胆固醇生物传感器,研究了恒电位法聚合聚吡咯的工艺以及筛选了循环伏安法聚石墨烯的适合的电解质溶液,又研究了酶固定过程中戊二醛交联时间对传感器性能的影响,结果表明,运用恒电位聚合法于0.75V电位下聚合180s,再用循环伏安法在含Li Cl O4为电解质的氧化石墨烯溶液中于0.2~0.9V范围内聚合18圈,最后负载酶后于0.3%wt.戊二醛溶液中交联2h为最佳制备工艺。该方法所制得的基于石墨烯/聚吡咯的胆固醇生物传感器,具有较宽的检测范围2.0×10-6~4.3×10-3 M,较低的检测限1.8×10-7M。研究了基于石墨烯/铂的无酶胆固醇传感器。采用共沉淀法,利用弱还原剂乙二醇,与氯铂酸和氧化石墨烯溶液在100℃高温下进行反应6h,使它们得到充分还原,合成石墨烯负载铂的复合材料。石墨烯为铂提供了大量的活性位点,使其均匀分散,纳米铂也使石墨烯克服了自身的卷曲和层间堆叠等不足。用0.03M氯铂酸合成的石墨烯/铂复合材料修饰到电极上,并用0.3%wt.戊二醛溶液进行交联3h,成功得制备出基于石墨烯/铂的胆固醇无酶传感器。该传感器具有更宽的检测范围2.9×10-3~6.9×10-3 M,更低的检测限8.3×10-8M。以上方法制备的基于石墨烯的胆固醇传感器,可用于血清中游离胆固醇或总胆固醇的检测,以及处理后食品中胆固醇的检测。这对胆固醇传感器的研究具有重大意义和发展前景。
[Abstract]:The high cholesterol level in the serum is related to the human multiple diseases such as diabetes, hypertension, atherosclerosis and coronary heart disease, and the content of cholesterol in the serum has become an important index of clinical diagnosis. The traditional measuring method has the advantages of complex instrument, long detection time, high cost and multiple interference factors, The electrochemical sensor capable of mass production for measuring the content of cholesterol is of great significance. The graphene has high specific surface area, good electrical conductivity, high mechanical strength and unique electrical property, and the graphene-based nano composite material has excellent performance in the fields of electronic devices, biological materials, sensor materials and catalyst carriers, and has wide application prospect. the combination of the graphene with the conductive polymer material and the inorganic noble metal material provides a new idea for the development of a novel electrochemical sensor and an electrochemical biosensor. This paper is mainly based on the preparation and performance of the graphene-based cholesterol electrochemical sensor. The main contents are as follows: the modified Hummers method is adopted to prepare the oxidized graphite, and the graphene oxide is prepared by the method of ultrasonic stripping. and then the reduced graphene material is reduced and prepared by using the water-bonding agent, and the preparation process of the graphene is optimized. The microstructural characterization was carried out by means of XRD, Raman, FTIR, SEM, TEM and AFM. The results show that the ultrasonic stripping 13h can be used to synthesize a thin, ideal graphene material. a graphene/ thiocyanate/ chitosan/ cholesterol oxidase/ horseradish peroxidase cholesterol biosensor is prepared. The graphene/ sulfur-based cholesterol biosensor is prepared by using the synthesized graphene as a carrier, a sulfur atom with good electrical conductivity as a conductive mediator, a chitosan as an adhesive, a load cholesterol oxidase and a horse radish peroxidase as a catalyst, The optimum working conditions for detecting the concentration of cholesterol are: the p H value of the test system is 7.0, and the test temperature is room temperature. The sensor has a low detection limit of 3. 7-10-7M, a high sensitivity of 24m AM-1cm-2, a detection range of 2.0-10-6-4. 6-10-4M, and has strong anti-interference capability. The system has a low detection limit of 3. 7-10-7M, a high sensitivity of 24m AM-1 cm-2, a high sensitivity of 24m AM-1 cm-2, a detection range of 2.0-10-6-4, 6-10-4 M, an apparent m-constant KapM of 4. 9-10-5M, and has strong anti-interference ability, The current changes of uric acid, such as uric acid, were only 0.15%, 1.69% and 2.19%, respectively. The synthesis of graphene/ poly-graphene/ chitosan/ cholesterol oxidase/ horseradish peroxidase cholesterol biosensor by a partial electrochemical polymerization method, a process for the polymerization of polygraphene by a constant potential method, and a suitable electrolyte solution for screening the polygraphene of the cyclic voltammetry, The effect of glutaraldehyde cross-linking time on the performance of the sensor was also studied. The results show that the polymerization of 180s under the potential of 0. 75V by the method of constant potential polymerization, and the cyclic voltammetry is used to polymerize the 18-ring in the range of 0. 2-0. 9V in the graphene solution containing Li-Cl _ 4 as the electrolyte. The final load of the enzyme was 0.3% by weight. and the cross-linking of the glutaraldehyde solution for 2h is the optimal preparation process. The method has the advantages of wide detection range of 2.0, 10-6-4, 3-10-3M, and low detection limit of 1. 8-10-7M. The enzyme-free cholesterol sensor based on graphene/ platinum was studied. By adopting the co-precipitation method, the weak reducing agent ethylene glycol, the chloroplatinic acid and the graphene oxide solution are reacted at a high temperature of 100 DEG C for 6h, so that they are fully reduced, and the composite material of the graphene supported platinum is synthesized. The graphene provides a large number of active sites for platinum, so that the graphene is uniformly dispersed, and the nano-platinum also overcomes the defects that the graphene overcomes the defects of the curling and the interlayer stack, and the like. The graphene/ platinum composite synthesized with 0. 03M chloroplatinic acid was modified to the electrode and used with 0.3% wt. The glutaraldehyde solution was cross-linked for 3h, and a graphene/ platinum-based cholesterol-free sensor was successfully prepared. The sensor has a wider detection range of 2. 9-10-3-6. 9-10-3M, and a lower detection limit of 8.3-10-8M. The graphene-based cholesterol sensor prepared by the method can be used for detecting the free cholesterol or total cholesterol in the serum, and detecting the cholesterol in the food after treatment. This study of cholesterol sensor is of great significance and development prospect.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O657.1;R446.11

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