柔性基底上石墨烯阵列的传感行为及对细胞释放物的检测
发布时间：2018-10-18 07:34
【摘要】：石墨烯是一种二维(2D)周期性蜂窝状点阵结构,平面由碳六元环组成的,通过不同的方式,如卷曲,翘曲或堆积,可以形成零维(0D)的富勒烯(fullerene),一维(1D)的碳纳米管(carbon nano-tube,CNT)或者三维(3D)的石墨(graphite)。作为一种新型2D平面碳材料,石墨烯因为具有优异力学、热学、光学、电学性能而受到外界的广泛关注。而石墨烯特殊的结构也使其在电化学领域有广泛应用。基于石墨烯衍生物——氧化石墨烯(GO)还原得到的石墨烯(rGO)具有良好的导电性,且表面含有少量功能基团,是一种理想的电化学电极材料。另外,GO易于分散、表面修饰且生物相容性良好,在细胞调控和电化学生物传感器构筑方面具有独特的优势。而为满足特殊环境和人体特殊构造测试需要,开发新型的,高品质的柔性器件越来越受到人们的关注。柔性传感器是柔性器件非常重要的组件,传感器的性能直接决定了柔性器件的性能。随着柔性器件得到越来越广泛的应用,开发出基于石墨烯的柔性传感器件,成为众多研究学者共同努力的方向。与刚性基底相比,基于石墨烯高柔韧性和机械强度,制备的石墨烯柔性电极,可以使电极与靶组织良好接触,减少电极和组织之间的机械强度的不匹配,可以减少临床应用中产生的机械损伤和免疫反应。因此受到广泛关注。本文分别采用软光刻转印技术和紫外光刻微加工技术在不同刚性基底上构筑了图案化的GO阵列和GO/rGO微阵列。探究了神经细胞PC12在不同刚性基底表面选择性粘附以及其在GO/rGO微阵列表面粘附、增殖的行为。深入研究GO/rGO圆盘阵列电极在不同弯曲曲率下的电化学特性,并对PC12细胞释放物(双氧水H2O2)进行检测。具体研究内容如下:1、利用软光刻微接触印刷技术,以表面具有微结构的聚二甲基硅氧烷(PDMS)为转移印章,在不同刚性基底表面制备图案化GO薄膜。通过调节旋涂GO溶液的次数和旋涂转速控制成膜质量。着重探究了印章表面(0.36cm2)施加不同压力(0.10N、0.20N、0.25N、0.35N、0.45N、0.50N、0.55N、1N)时对成膜质量的影响。研究结果表明,印章表面施加压力为0.5N,维持12h时得到比较均匀规整的GO图案,厚度约10nm。GO表面含有丰富的官能团,具有很好的亲水性,便于细胞粘附增殖。在不同刚性基底表面转印GO阵列并接种PC12细胞,发现神经细胞更倾向于粘附在刚度较小的GO阵列表面。2、通过微加工工艺和电化学还原技术,在柔性基底上制备了与光刻尺寸相匹配的GO/rGO微阵列。对微阵列表面形貌及微观结构进行了表征。研究不同形状、不同尺寸微图案对PC12细胞粘附、增殖行为的影响。研究发现,GO/rGO微阵列表面接种细胞后,细胞更倾向于粘附在GO表面,并沿着GO/rGO边界生长延伸。这种行为有利于细胞受到药物刺激释放的活性物质迅速扩散到电极表面。3、探究了不同曲率下微阵列电极电化学特性的变化规律。研究结果表明,借助循环伏安测试方法优选的微阵列电极的最佳尺寸为直径20μm、间距60μm的圆盘阵列。在0.6V条件下,微阵列电极表现出良好的催化氧化H2O2的性能,实现了材料表面无任何催化剂修饰不同曲率条件下对低含量H2O2的检测。实施药物刺激后,不同曲率的阵列电极对细胞释放的活性物质H2O2的响应程度不同。相同条件下,电极向内弯(曲率k0)时,随着曲率的增大,电极检测性能得到提升;而电极外弯(曲率k0)时,随曲率增加,测定结果基本相同。出现这种结果的原因是由于内弯时阵列电极附近,电势线密度增加,电场强度增强,细胞跨膜电压增大,从而提升微阵列电极的电化学催化活性。
[Abstract]:Graphene is a two-dimensional (2D) periodic honeycomb lattice structure consisting of carbon six-membered rings, such as curling, warping or stacking, can form a zero dimension (0D) fullerene, one-dimensional (1D) carbon nanotubes, cnts) or three-dimensional (3d) graphite. As a novel 2D planar carbon material, graphene is attracted to the outside world due to its excellent mechanical, thermal, optical and electrical properties. and the special structure of graphene has wide application in the field of electrochemistry. Graphene (rGO) obtained by reduction of graphene derivative _ graphene oxide (GO) has good conductivity, and a small amount of functional groups on the surface is an ideal electrochemical electrode material. In addition, GO is easy to disperse, has good surface modification and good biocompatibility, and has unique advantages in cell regulation and electrochemical biosensor construction. In order to meet the needs of special environment and special structural test of human body, the development of new and high-quality flexible devices has attracted more and more attention. A flexible sensor is a very important component of a flexible device, and the performance of the sensor directly determines the performance of the flexible device. With the more and more extensive application of flexible devices, graphene-based flexible sensor has been developed, which has become the direction of joint efforts of many researchers. Compared with the rigid substrate, the graphene flexible electrode prepared based on the high flexibility and mechanical strength of the graphene can make the electrode contact with the target tissue in good contact, so that the mismatching of mechanical strength between the electrode and the tissue can be reduced, and mechanical damage and immune reaction generated in clinical application can be reduced. As a result, extensive attention has been given. In this paper, a patterned GO array and GO/ rGO micro-array were constructed on different rigid substrates by soft lithography transfer and UV lithography. The selective adhesion of PC12 cells on different rigid substrates and the adhesion and proliferation of PC12 cells on the surface of GO/ rGO microarray were investigated. The electrochemical properties of GO/ rGO disk array electrodes under different bending curvature were studied, and the release of PC12 cells (H2O2) was investigated. The specific research contents are as follows: 1. Using soft lithography micro-contact printing technology, a patterned GO film is prepared on different rigid substrate surfaces by using polydimethylsiloxane (PDMS) with micro structure as transfer seal. The film forming quality is controlled by adjusting the number of spin coating GO solutions and the spin coating speed. The influences of different pressures (0. 10N, 0. 20N, 0. 25N, 0. 35N, 0. 45N, 0. 50N, 0. 55N, 1N) on the film forming quality were investigated. The results show that the pressure on the surface of the seal is 0. 5N. When maintaining 12h, the uniform and regular GO pattern is obtained. The thickness is about 10nm. The GO surface contains rich functional groups, has good hydrophilicity, and is convenient for cell adhesion and proliferation. After the transfer of GO arrays on the surface of different rigid substrates and inoculation of PC12 cells, it was found that nerve cells were more likely to adhere to the lower stiffness GO array surface. 2. The GO/ rGO microarray matching the lithography dimension was prepared on the flexible substrate by micro-processing and electrochemical reduction techniques. The surface morphology and microstructure of microarray were characterized. The effects of different shapes and micro patterns on adhesion and proliferation of PC12 cells were studied. It was found that after inoculation of cells on the surface of GO/ rGO microarray, cells tended to adhere to the GO surface and extend along the GO/ rGO boundary. This behavior is beneficial to the rapid diffusion of the active substance released by drug stimulation to the surface of the electrode. The results show that the optimal size of the microarray electrode is 20. m u.m in diameter and 60. m u.m in pitch by means of cyclic voltammetry. Under the condition of 0. 6V, the microarray electrode showed good catalytic oxidation of H2O2 and realized the detection of low content of H2O2 under different curvature conditions without any catalyst modification on the surface of the material. After drug stimulation, the degree of response of the array electrodes of different curvatures to the active substance H2O2 released by the cells was different. In the same condition, when the electrode bends inward (curvature k0), as the curvature increases, the electrode detection performance is improved; and when the electrode outer bend (curvature k0) increases with the curvature, the measurement result is substantially the same. This result is due to increased potential line density, increased electric field strength, increased cell cross-membrane voltage, and enhanced electrochemical catalytic activity of microarray electrodes due to the increase in potential line density near the array electrodes at the time of internal bending.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71;O657.1
本文编号：2278431
[Abstract]:Graphene is a two-dimensional (2D) periodic honeycomb lattice structure consisting of carbon six-membered rings, such as curling, warping or stacking, can form a zero dimension (0D) fullerene, one-dimensional (1D) carbon nanotubes, cnts) or three-dimensional (3d) graphite. As a novel 2D planar carbon material, graphene is attracted to the outside world due to its excellent mechanical, thermal, optical and electrical properties. and the special structure of graphene has wide application in the field of electrochemistry. Graphene (rGO) obtained by reduction of graphene derivative _ graphene oxide (GO) has good conductivity, and a small amount of functional groups on the surface is an ideal electrochemical electrode material. In addition, GO is easy to disperse, has good surface modification and good biocompatibility, and has unique advantages in cell regulation and electrochemical biosensor construction. In order to meet the needs of special environment and special structural test of human body, the development of new and high-quality flexible devices has attracted more and more attention. A flexible sensor is a very important component of a flexible device, and the performance of the sensor directly determines the performance of the flexible device. With the more and more extensive application of flexible devices, graphene-based flexible sensor has been developed, which has become the direction of joint efforts of many researchers. Compared with the rigid substrate, the graphene flexible electrode prepared based on the high flexibility and mechanical strength of the graphene can make the electrode contact with the target tissue in good contact, so that the mismatching of mechanical strength between the electrode and the tissue can be reduced, and mechanical damage and immune reaction generated in clinical application can be reduced. As a result, extensive attention has been given. In this paper, a patterned GO array and GO/ rGO micro-array were constructed on different rigid substrates by soft lithography transfer and UV lithography. The selective adhesion of PC12 cells on different rigid substrates and the adhesion and proliferation of PC12 cells on the surface of GO/ rGO microarray were investigated. The electrochemical properties of GO/ rGO disk array electrodes under different bending curvature were studied, and the release of PC12 cells (H2O2) was investigated. The specific research contents are as follows: 1. Using soft lithography micro-contact printing technology, a patterned GO film is prepared on different rigid substrate surfaces by using polydimethylsiloxane (PDMS) with micro structure as transfer seal. The film forming quality is controlled by adjusting the number of spin coating GO solutions and the spin coating speed. The influences of different pressures (0. 10N, 0. 20N, 0. 25N, 0. 35N, 0. 45N, 0. 50N, 0. 55N, 1N) on the film forming quality were investigated. The results show that the pressure on the surface of the seal is 0. 5N. When maintaining 12h, the uniform and regular GO pattern is obtained. The thickness is about 10nm. The GO surface contains rich functional groups, has good hydrophilicity, and is convenient for cell adhesion and proliferation. After the transfer of GO arrays on the surface of different rigid substrates and inoculation of PC12 cells, it was found that nerve cells were more likely to adhere to the lower stiffness GO array surface. 2. The GO/ rGO microarray matching the lithography dimension was prepared on the flexible substrate by micro-processing and electrochemical reduction techniques. The surface morphology and microstructure of microarray were characterized. The effects of different shapes and micro patterns on adhesion and proliferation of PC12 cells were studied. It was found that after inoculation of cells on the surface of GO/ rGO microarray, cells tended to adhere to the GO surface and extend along the GO/ rGO boundary. This behavior is beneficial to the rapid diffusion of the active substance released by drug stimulation to the surface of the electrode. The results show that the optimal size of the microarray electrode is 20. m u.m in diameter and 60. m u.m in pitch by means of cyclic voltammetry. Under the condition of 0. 6V, the microarray electrode showed good catalytic oxidation of H2O2 and realized the detection of low content of H2O2 under different curvature conditions without any catalyst modification on the surface of the material. After drug stimulation, the degree of response of the array electrodes of different curvatures to the active substance H2O2 released by the cells was different. In the same condition, when the electrode bends inward (curvature k0), as the curvature increases, the electrode detection performance is improved; and when the electrode outer bend (curvature k0) increases with the curvature, the measurement result is substantially the same. This result is due to increased potential line density, increased electric field strength, increased cell cross-membrane voltage, and enhanced electrochemical catalytic activity of microarray electrodes due to the increase in potential line density near the array electrodes at the time of internal bending.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71;O657.1
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