Investigation and biosensing application of novel switching function in conductive polymer hydrogels

利用UV-VIS-NIR光谱电化学方法，研究了苯二酚与邻苯二酚结合官能团在复合聚合物中氧化还原循环过程中PEDOT的相互作用。在氧化和还原过程中，PEDOT的吸收峰分别从可见(550 Nm)到红外(&gt；900 nm)，而苯二酚的吸收峰从可见(400 Nm)到紫外光(280 Nm)。因此，可以原位跟踪氧化还原活性组分的氧化状态及其相对比例。在生理缓冲条件下重复循环，发现氧化的PEDOT和还原的邻苯二酚意外积累，这表明这两个物种之间形成了电荷转移络合物。利用柔性聚酰亚胺衬底，我们成功地制造了具有悬浮沟道的器件。从水凝胶的顶部和底部接触到电解液，将有效厚度减少了一半，从而改善了质量传输。相应地，水凝胶晶体管放大器的响应截止频率提高了一倍，提高了电催化氧还原反应的速度。这种新的器件结构便于使用交流阻抗谱来控制电化学传感信号演变过程中涉及的动力学。

Using UV-Vis-NIR spectroelectrochemistry, we studied the interaction of PEDOT during redox cycling of quinones from bound catechol functional groups in a composite polymer. Whereas PEDOT absorbance band shifts from visible (550 nm) to IR (>900nm) wavelengths during oxidation and reduction, respectively, quinone bands shift from visible (400 nm) to UV (280 nm). Thus, the oxidation state of redox active components and their relative proportions can be followed in-situ. Repeated cycling in physiological buffer conditions found an unexpected accumulation of oxidized PEDOT and reduced catechol, suggesting the formation of a charge-transfer complex between the two species.Using flexible polyimide substrates, we successfully fabricated devices with suspended channels. Access to electrolyte from top and bottom sides of the hydrogel reduced the effective thickness by half resulting in improved mass transport. Accordingly, the cut-off frequency in the response of a hydrogel transistor amplifier was doubled and the rate of electrocatalyzed oxygen reduction reaction was improved. This new device structure facilitates the use of AC impedance spectroscopy to control the kinetics involved in the evolution of an electrochemical sensing signal.