A simple, low-cost paper-based potassium ion-selective optode that exhibits fully reversible sensing properties is presented. A classic optode formulation consisting of valinomycin as the ionophore and a lipophilic pH indicator has been successfully transferred to a paper substrate and characterised in a flow-through cell with reflectometric optical detection. The optode exhibits high repeatability, reversibility, and stability and can detect potassium in the physiologically relevant concentration range from 10⁻⁴ to 10⁻¹ M. This new paper-based optode shows high potential for general application in paper microfluidic systems and for integration into wearable systems for perspiration monitoring due to its reversible and repeatable response. In general, we have demonstrated that ionophore-based optical sensors on paper can successfully be used for continuous ion-concentration monitoring.

提出了一种简单的低成本纸基钾离子选择性光电二极管，该光电二极管具有完全可逆的传感特性。由缬氨霉素作为离子载体和亲脂性pH指示剂组成的经典optode配方已成功转移到纸质基材上，并在具有反射光学检测功能的流通池中进行了表征。该光电二极管具有很高的重复性，可逆性和稳定性，并且可以检测到生理相关浓度范围为10 ^-4到10 ^-1的钾M.这种新型的纸基光电二极管由于其可逆和可重复的响应，在纸质微流控系统中具有广泛的应用潜力，并可以集成到可穿戴系统中以进行汗液监测。通常，我们已经证明，纸上基于离子载体的光学传感器可以成功地用于连续离子浓度监测。