利用雙閘極敏感場效應電晶體結合多離子選擇膜以及溝槽濾膜流道進行全血處理與血液離子濃度檢測

Abstract

血液離子濃度檢測為現今常用來作為免疫狀態監測及提供疾病診斷的方法之一。但傳統做法需要醫護人員進行冗長的樣本前處理並搭配大型儀器量測，導致量測結果無法即時反應病人當前的身體健康狀況。為解決上述問題，我們開發一個整合雙閘極離子敏感場效電晶體 (Dual-gate ion-sensitive field-effect transistor, DG-ISFET)的微流道裝置進行全血處理，並進行原位的血液離子濃度分析。本裝置主要分兩個部分進行。第一部分使用表面添加血球凝集因子(Anti-D)的凹槽陣列進行紅血球沉降，並搭配微米(μm)濾透膜進行高純度且快速的血清萃取。第二部分則使用DG-ISFET結合離子選擇膜 (Ion selective membrane, ISM) 進行血清中特定離子的濃度量測。為驗證上述構想，我們首先使用不同有機鹽類的標準液來最佳化ISM的厚度，接著進行DG-ISFET的血清離子濃度測試，此外也針對陣列凹槽所萃取出的血清進行溶血測試，並使用螢光珠模擬紅血球以探討濾透膜的攔截效果，一旦將上述的ISM參數及流道性能最佳化後，我們注入臨床血液樣本到流道晶片中進行血清的萃取及原位的鈉/鉀離子濃度量測。此實驗驗證了我們可在輸入500 μL的血液當中萃取200 μL的血清並在10分鐘內達到多離子的濃度量測目標，經由上述的結果我們證明此可攜式的檢測系統可用於即時且連續性的血液離子濃度檢測，並在未來將其應用在重症監護病房 (ICU)或是定點照護(POC) 的環境中。

Blood ion testing is commonly used to monitor immune status and physiological information for disease diagnosis. However, traditional methods often require well-trained medical operators to frequently conduct the tedious sample preparation procedures using bulky instruments, which means the results may not be able to reflect the patient's physical conditions in real-time. To solve these problems, we develop a microfluidic device that integrates a dual-gate ion-sensitive field-effect transistor (DG-ISFET) for whole blood pre-treatment and in situ ion concentrations analysis in blood. The system is made of serum extraction section and ion sensing section. In the first section, we used the trench array, coating with RBC agglutination reagent for red blood cells (RBCs) sedimentation, and integrated with a micrometer (μm) filter membrane for rapid and high purity serum extraction. In the second section, we combined DG-ISFET and ion-selective membrane (ISM) for specific ion concentrations sensing in the serum. For proof of concept, we used different standard organic salts solutions to optimize the thickness of ISM. Next, DG-ISFET ion concentrations measurement in serum was conducted. We also performed serum hemolysis tests extracted from the trench array and used fluorescent beads to simulate RBCs to investigate the trapping efficiency of the filter membrane. Once the above ISM parameters and flow channel performance were optimized, we injected the clinical blood sample into the microfluidic chip for serum extraction and in situ sodium/potassium ion concentrations test. This experiment verified that we could extract 200 μL serum from 500 μL of untreated whole blood and achieve the goal of multi-ion concentration measurement in 10 min. From the above results, we proved that this portable DG-ISFET system could be used for real-time and continuous blood ion concentration detection and application in an intensive care unit (ICU) or point-of-care (POC) environments in the future.