以共聚物Pluronic F127修飾網版印刷式鈉離子選擇電極之研究

Abstract

人體血液內的電解質監測在臨床醫學上一向是不可或缺的指數，在許多偵測方式中離子選擇電極扮演極關鍵的要角。但在實際應用中，若能將離子選擇電極化為貼片或是可植入人體形式以達連續監測，對於一些重症患者可以減少高頻率地抽血分析離子強度。然而當感測器長時間與血液接觸時，血液中蛋白質會吸附於表面，並且根據不同的蛋白質特性會引發不同的後續生物反應，此些吸附過程將大幅影響感測器之穩定度。是故為實踐貼片或可植入式之應用，本篇論文提出以Pluronic F127作為離子選擇薄膜之添加物以增加電極之生物相容性減少表面的蛋白質吸附，進而降低後續不利感測器之生物反應。除此之外，為建立此全固態網印式鈉離子選擇電極，必須在電極與離子選擇薄膜之間引入一離子電子傳導層以穩定訊號。整體而言本論文將分為二部分深入討論：第一部分為離子電子轉換層之討論，屬於電極系統的建立。本論文所採用之全固態網印式離子選擇電極雖可大幅減少電極之體積，然而移除傳統電極之內溶液將造成離子與電子之間轉換發生障礙，進而導致電極訊號之不穩定。是故，必須要導入一層離子電子轉換層（例如導電高分子）以取代內溶液之角色維持其轉換效率並穩定訊號。本論文針對三種導電高分子（PANI: DiOHP、PEDOT: PSS和PPy: DEHESSA）分析電化學特性並比較其應用於此電極系統之可行性。第二部分根據建立之系統，進一步針對電極表面離子選擇薄膜討論抗蛋白質吸附修飾，本篇論文係首次提出以Pluronic F127作為離子選擇薄膜之添加物可降低蛋白質吸附並且詳細分析其修飾對電化學特性影響。在人類血清白蛋白的吸附實驗中，修飾過之電極比起原先未處理可大幅減少96%的蛋白質吸附量。此外，在模擬人類血液的蛋白質溶液中，其電極穩定度可提升78%。儘管結果顯示在薄膜內加入過多的Pluronic F127 會改變薄膜的微結構使其孔隙變得緻密，因而部分妨礙離子及電子的轉移過程，但是電極之選擇性及電位響應比起未修飾電極都沒有明顯的下降，尤其是選擇性依然符合臨床使用之要求，此亦說明了Pluronic F127並不會妨礙薄膜內離子載體與其特定離子之結合。

In vivo monitoring of electrolyte in human blood is important for clinical use. Among this detection, ion-selective electrodes (ISEs) have played a vital role. From the practical use, especially for serious illness, it is pleasing to make ISEs implantable for continuously monitoring physiological analytes. However, it is generally believed that if sensors had long-term contact with protein in human blood, it would cause adverse effect because protein would first adhere on the surface of sensors, and following sequences depended on the properties of the protein. In this work, pluronic F-127 was utilized as an additive to enhance biocompatibility of poly(vinyl chloride) (PVC)-based screen-printed sodium-selective electrodes by reducing levels of protein adsorption. What’s more, to make all-solid-state screen-printed sodium-selective electrodes realized, it is needed to introduce an ion-to-electron transducer (IET) between ion-selective membrane and carbon electrode. Generally, this thesis can be separated into two sections to discuss. First section is to verify the electrode system. To minimize the size of ISEs, this work adopted screen-printed ISEs. However, without inner solution, the process of ion-to-electron transfer would be hindered and the signal is going to be unstable. Therefore, it is needed to introduce an IET such as conducting polymer to facilitate the transfer process. This work compared electrochemical properties of PANI:DiOHP, PEDOT:PSS, and PPy: DEHESSA and chose an adequate material as an IET. Second, based on the electrode system with IET, this thesis further discussed the ion-selective membrane modification against protein adsorption. Biocompatibility of Pluronic F-127 modified sodium-selective electrodes was evaluated by a human serum albumin (HSA) adsorption study. Such modification was able to decrease protein-adsorption by 96% compared to the unmodified PVC membrane, resulting in a signal stability that substantially increased by 78% in human fluids. Although the Pluronic F-127 did somewhat hinder the process of ion-to-electron transfer due to its influence on surface structure, the potentiometric response and the selectivity of modified sodium-selective electrodes were found to be comparable to the untreated sodium-selective electrodes. Selectivity of the modified sodium-selective electrodes still met the requirement for sodium analysis in physiological fluids. These results indicate that Pluronic F-127 did not alter the binding behavior between the ions and ionophores.