Abstract Numerous advantages of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT-PSS) hydrogel make this material appropriable for biosensors developing. Among many of them, it may be exploited as an immobilization matrix for binding bioreceptors. Porous 3-D structure facilitates high loading of the enzyme and extends surface area, what results in better biosensor performance and signal increase. High water content generates hydrophilic environment, thus biocompatibility is greatly enhanced. Citrate or phosphate buffers are typically used to provide optimal pH for the immobilized enzyme. The present work reports on the development of the PEDOT-PSS hydrogels synthesized in phosphate buffer or citrate buffer solutions at pH = 5 to verify the influence of the anion present in the polymerization environment on the molecular structure and electrochemical properties of the hydrogel. The water content in each hydrogel sample is estimated by weighting the swelled and dried samples and termogravimetric analysis. It is shown that PEDOT-PSS obtained in phosphate buffer solution comprises much more water than hydrogel synthesized in citrate buffer. This property is of great importance for the electrocatalytic properties of immobilized horseradish peroxidase (HRP). Wherefore, the PEDOT-PSS/HRP modified electrode has been used for the amperometric detection of H2O2 at pH = 6. The phosphate containing ph-PEDOT-PSS/HRP biosensor is characterized by a good linear relation with the concentrations of H2O2 with a linear range from 0.0088 to 0.15 mM and from 0.4 to 10 mM and a low detection limit of 9.4∙10-7 M and 4.5∙10−5 M (S/N = 3), respectively. While the citrate containing cit-PEDOT-PSS/HRP sensor shows worse analytical parameters - linear range from 0.05 to 0.25 mM and detection limit of 1∙10−5 M (S/N = 3).

中文翻译：

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缓冲溶液对聚（3,4-乙撑二氧噻吩）/聚（苯乙烯磺酸盐）水凝胶结构和电化学性能的影响

摘要 聚（3,4-亚乙基二氧噻吩）/聚（苯乙烯磺酸盐）（PEDOT-PSS）水凝胶的众多优点使该材料适用于生物传感器的开发。其中，它可以用作结合生物受体的固定基质。多孔 3-D 结构有利于酶的高负载并扩大表面积，从而提高生物传感器的性能和信号增加。高含水量产生亲水环境，从而大大提高生物相容性。柠檬酸盐或磷酸盐缓冲液通常用于为固定化酶提供最佳 pH 值。目前的工作报告了在 pH = 5 的磷酸盐缓冲液或柠檬酸盐缓冲溶液中合成的 PEDOT-PSS 水凝胶的开发，以验证聚合环境中存在的阴离子对水凝胶的分子结构和电化学性能的影响。每个水凝胶样品中的水含量是通过对溶胀和干燥的样品进行称重和热重分析来估计的。结果表明，在磷酸盐缓冲液中获得的 PEDOT-PSS 比在柠檬酸盐缓冲液中合成的水凝胶包含更多的水。这种特性对于固定化辣根过氧化物酶 (HRP) 的电催化特性非常重要。因此，PEDOT-PSS/HRP 修饰电极已用于在 pH = 6 时对 H2O2 进行电流检测。含磷酸盐的 ph-PEDOT-PSS/HRP 生物传感器的特点是与 H2O2 的浓度呈良好的线性关系，线性范围为 0.0088 至 0.15 mM 和 0.4 至 10 mM，检测下限为 9.4∙10-7 M和 4.5∙10−5 M (S/N = 3)，分别。而含有柠檬酸盐的 cit-PEDOT-PSS/HRP 传感器显示出较差的分析参数 - 线性范围为 0.05 至 0.25 mM，检测限为 1∙10−5 M (S/N = 3)。