Electrochemical optical waveguide lightmode spectroscopy (EC-OWLS):: A pilot study using evanescent-field optical sensing under voltage control to monitor polycationic polymer adsorption onto indium tin oxide (ITO)-coated waveguide chips
Electrochemical optical waveguide lightmode spectroscopy (EC-OWLS):: A pilot study using evanescent-field optical sensing under voltage control to monitor polycationic polymer adsorption onto indium tin oxide (ITO)-coated waveguide chips
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DOI：
10.1002/bit.10591
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发表时间：
2003-05-20
影响因子：
3.8
通讯作者：
Textor, M
中科院分区：
文献类型：
--
作者：
Bearinger, JP;Vörös, J;Textor, M
一种新的技术已经开发，结合渐逝场光学传感与表面吸附过程的电化学控制。这种新的技术，被称为“电化学光波导光模式光谱”（EC-OWLS），证明有效的监测分子表面吸附和层厚度的变化的吸附聚合物层原位检查作为一个功能的潜在的应用到波导中的试点研究。对于光学传感，氧化铟锡（ITO）层既充当高折射率波导又充当导电电极。此外，提供了一种电化学流通式流体电池，其包括工作电极、参比电极和对电极，并且与光学感测的约束相容。以聚赖氨酸接枝聚乙二醇（PLL-g-PEG）为模型材料，研究了PLL-g-PEG对聚阳离子吸附的影响。PLL-g-PEG从缓冲水溶液中的吸附量随着相对于Ag参比电极在0 - 1.5 V之间的电位增加而沿着S形路径从125 ng/cm（2）增加到475 ng/cm（2）。缓冲液冲洗后，吸附是部分可逆的，当电位大于或等于0.93 V，维持在ITO波导。然而，在冲洗之前将施加的电势降低回0 V导致不可逆的聚合物吸附。用生物素修饰的PLL-g-PEG表现出类似的吸附特性，但随后的链霉亲和素结合与生物素浓度无关。施加正电位导致吸附质量增加，这可能是由于分子吸附层中的聚合物链延伸和重组。(C)2003 Wiley Periodicals，Inc.
A new technique has been developed that combines evanescent-field optical sensing with electrochemical control of surface adsorption processes. This new technique, termed "electrochemical optical waveguide lightmode spectroscopy" (EC-OWLS), proved efficient in monitoring molecular surface adsorption and layer thickness changes of an adsorbed polymer layer examined in situ as a function of potential applied to a waveguide in a pilot study. For optical sensing, a layer of indium tin oxide (ITO) served as both a high-refractive-index waveguide and a conductive electrode. In addition, an electrochemical flow-through fluid cell was provided, which incorporated working, reference, and counter electrodes, and was compatible with the constraints of optical sensing. POIY(L-lysine)-grafted-poly(ethylene glycol) (PLL-g-PEG) served as a model, polycation adsorbate. Adsorption of PLL-g-PEG from aqueous buffer solution increased from 125 to 475 ng/cm(2) along a sigmoidal path. as a function of increasing potential between 0 and 1.5 V versus the Ag reference electrode. Upon buffer rinse, adsorption was partially reversible when a potential of greater than or equal to0.93 V was maintained on the ITO waveguide. However, reducing the applied potential back to 0 V before rinsing resulted in irreversible polymer adsorption. PLL-g-PEG modified with biotin demonstrated similar adsorption characteristics, but subsequent streptavidin binding was independent of biotin concentration. Applying positive potentials resulted in increased adsorbed mass, presumably due to polymer chain extension and reorganization in the molecular adlayer. (C) 2003 Wiley Periodicals, Inc.