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

利用UV-Vis-NIR光谱电化学方法，研究了复合聚合物中PEDOT与邻苯二酚结合的醌类化合物在氧化还原循环中的相互作用。在氧化和还原过程中，PEDOT的吸收带分别从可见光（550 nm）转移到IR（> 900 nm）波长，而醌的吸收带则从可见光（400 nm）转移到UV（280 nm）。因此，可以原位跟踪氧化还原活性组分的氧化态及其相对比例。在生理缓冲液条件下的重复循环发现了一个意想不到的积累氧化PEDOT和减少邻苯二酚，这表明形成的电荷转移复合物之间的两个species.Using灵活的聚酰亚胺基板，我们成功地制造了设备与悬浮通道。从水凝胶的顶侧和底侧进入电解质使有效厚度减少一半，从而改善质量传递。因此，水凝胶晶体管放大器响应的截止频率加倍，并且电催化氧还原反应的速率提高。这种新的器件结构有利于使用交流阻抗谱来控制电化学传感信号演变中涉及的动力学。

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.