磁性捕获用于快速、简单和可逆的碳纳米管电极修饰:在多巴胺检测中的应用。
Magnetic entrapment for fast, simple and reversible electrode modification with carbon nanotubes: application to dopamine detection.
机构信息
Institut de Microelectrònica de Barcelona (IMB-CNM), CSIC, Campus Universitat Autònoma de Barcelona, Barcelona 08193, Spain.
出版信息
Biosens Bioelectron. 2011 Jan 15;26(5):1876-82. doi: 10.1016/j.bios.2010.03.020. Epub 2010 Mar 20.
Carbon nanotubes (CNT) have been exploited for an important number of electroanalytical and sensing purposes. Specifically, CNT incorporation to an electrode surface coating increases its roughness and area, provides electrocatalytic activity towards a variety of molecules, and improves electron transfer. This modification is generally based on the irreversible deposition of CNT on surface. Nevertheless, CNT are highly porous materials that might promote molecule non-specific adsorption and/or electrodeposition, which could induce sample-to-sample cross-contamination and affect measurement specificity and reproducibility. This drawback has been often circumvented by combining CNT with charged polymers able to repel molecules of opposed charge. We demonstrate that single-walled CNT (SWCNT) have a strong tendency to non-specifically adsorb onto the surface of protein-coated magnetic particles (MP). Magnetic capture of those MP generates CNT coentrapment and allows extremely fast, simple and reversible production of SWCNT electrodes. We have exploited this phenomenon for the production of modified screen-printed electrodes (MP/CNT-SPE), which have been characterized by Scanning Electron Microscopy. The surface has been additionally optimized by evaluating the electrochemical performance of SPE modified with different amounts and proportions of MP and CNT. The modified devices have then been used for dopamine detection. MP/CNT-SPE generated improved assay sensitivity, lower limit of detection, and up to 500% higher current signals than bare electrodes. Magnetic entrapment is proposed as a promising strategy for the fast, simple and reversible generation of nanostructured electrodes of enhanced performance within a few minutes and electrode re-utilisation by simple magnet removal and surface washing.
碳纳米管 (CNT) 在电化学分析和传感领域得到了广泛应用。具体来说,将 CNT 掺入电极表面涂层中可以增加其粗糙度和表面积,提供对多种分子的电催化活性,并促进电子转移。这种修饰通常基于 CNT 在表面的不可逆沉积。然而,CNT 是高度多孔的材料,可能会促进分子的非特异性吸附和/或电沉积,从而导致样品间的交叉污染,并影响测量的特异性和重现性。为了克服这一缺点,通常将 CNT 与带相反电荷的带电聚合物结合使用,以排斥相反电荷的分子。我们证明了单壁 CNT (SWCNT) 具有强烈的非特异性吸附到蛋白质涂层磁性颗粒 (MP) 表面的趋势。这些 MP 的磁性捕获会产生 CNT 共捕获,并允许非常快速、简单和可逆地制备 SWCNT 电极。我们利用这种现象来制备经过修饰的丝网印刷电极 (MP/CNT-SPE),并用扫描电子显微镜对其进行了表征。通过评估不同数量和比例的 MP 和 CNT 修饰的 SPE 的电化学性能,进一步优化了表面。然后,将修饰后的器件用于多巴胺检测。与裸电极相比,MP/CNT-SPE 产生了更高的检测灵敏度、更低的检测限和高达 500%的电流信号。磁性捕获被提出作为一种很有前途的策略,用于在几分钟内快速、简单和可逆地生成具有增强性能的纳米结构电极,并通过简单的磁铁去除和表面清洗实现电极的再利用。