Switching of directions of bioelectrocatalytic currents and photocurrents at electrode surfaces by using hydrophobic magnetic nanoparticles.
Switching of directions of bioelectrocatalytic currents and photocurrents at electrode surfaces by using hydrophobic magnetic nanoparticles.
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DOI：
10.1002/anie.200501126
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发表时间：
2005-07
影响因子：
--
通讯作者：
E. Katz;I. Willner
中科院分区：
文献类型：
--
作者：
E. Katz;I. Willner
磁性颗粒——微球、纳米球和铁磁流体——被广泛研究和应用于生物学和医学的各个领域，如磁性靶向（药物、基因、放射性药物）、磁共振成像、诊断、免疫测定、RNA和DNA纯化、基因克隆、细胞分离和纯化近年来，广泛的研究工作集中在功能化磁颗粒的应用上，以控制电极界面的电化学转化或固体载体的化学反应性氧化还原单元功能化的磁性粒子对电极表面的磁性吸引或收缩被用来开关氧化还原过程的“开启”和“关闭”，并随后激活/灭活生物电催化转化类似地，催化磁性颗粒（如镍纳米颗粒）通过使用外部磁铁在电极支架上开启和关闭电催化过程据报道，电极支架上的磁性颗粒的旋转通过反应底物向电极的流体动力学传输来增强电催化和生物电催化过程据报道，在旋转磁颗粒[6]存在下，电化学产生的化学发光增强，该系统被用于DNA、[6,7]抗原抗体复合物、[6]和癌细胞[8]的扩增检测最近，具有疏水覆盖层的磁性纳米颗粒被用于在电极上可逆地分离表面约束和扩散氧化还原过程。[9,10]通过将疏水磁性纳米颗粒溶解在有机相中，磁性纳米颗粒被一层疏水溶剂输送到电极表面。这一层使得电极受限物质的电化学过程从水相型转变为有机相型，疏水底物到电极表面的共输运使电催化成为可能
Magnetic particles—microspheres, nanospheres, and ferrofluids—are widely studied and applied in various fields of biology and medicine, such as magnetic targeting (drugs, genes, radiopharmaceuticals), magnetic resonance imaging, diagnostics, immunoassays, RNA and DNA purification, gene cloning, and cell separation and purification.[1] Extensive research efforts were recently directed towards the application of functionalized magnetic particles for controlling electrochemical transformations at electrode interfaces or chemical reactivity at solid supports.[2] The magnetic attraction or retraction of magnetic particles that are functionalized with redox units to and from electrode surfaces was used to switch “on” and “off” redox processes and subsequently activate/deactivate bioelectrocatalytic transformations.[3] Similarly, catalytic magnetic particles such as nickel nanoparticles were used to switch on and off electrocatalytic processes at electrode supports by using an external magnet.[4] The rotation of magnetic particles on electrode supports was reported to enhance electrocatalytic and bioelectrocatalytic processes by the hydrodynamic transport of the reacting substrates to the electrode.[5] Enhanced electrochemically generated chemiluminescence was reported in the presence of rotating magnetic particles,[6] and the system was employed for the amplified detection of DNA,[6, 7] antigen–antibody complexes,[6] and cancer cells.[8] Recently, magnetic nanoparticles with a hydrophobic capping layer were employed to reversibly separate surfaceconfined and diffusional redox processes at electrodes.[9, 10] By dissolving the hydrophobic magnetic nanoparticles in an organic phase, the magnetic nanoparticles were transported to the electrode surface with a colayer of hydrophobic solvent. This layer enabled a change of electrochemical processes of the electrode-confined species from aqueous type to organic-phase type, and the co-transport of hydrophobic substrates to the electrode surfaces allowed switchable electrocatalysis.[10]