การตรวจวัดทรานสเฟอรินด้วยเทคนิคการวัดสภาพนาไฟฟ้าแบบคู่ควบด้วยตัวเก็บประจุชนิดไร้สัมผัสในอุปกรณ์ไมโครฟลูอิดิกส์อิเล็กโตรโฟรีซิสเพื่อประยุกต์ใช้ในการคัดกรองภาวะเหล็กเกิน

Abstract

For patients who suffer from iron overload, it is essential to monitor iron level in the body as too much iron can be lethal if not timely treated. Transferrin saturation is one of many biomarkers that can be used to determine iron overload condition from concentration of its 2 main forms: ion-free transferrin (apo transferrin: Apo-Tf) and saturated iron-bound transferrin (diferric transferrin: Diferric-Tf). In this thesis, detections of Apo-Tf and Diferric-Tf were performed using capacitively coupled contactless conductivity detection (C4D) in order to study the feasibility of separating the 2 forms of transferrin using microfluidic electrophoretic device. The 200 μm width, 30 μm height and 7 cm separation length microchannel device was fabricated as a cross shape for pinched injection sample introduction. Applied voltages in each reservoir for designed electric field strength in driving sample with generated electroosmotic flow were determined using COMSOL Multiphysics program. When performing C4D detection with 950 kHz excitation signal and 10,000 V/m separation electric field strength to drive Apo-Tf and Diferric-Tf separately, it was found that the average peak positions of Apo-Tf and Diferric-Tf were 144.634 s and 153.011s, respectively. However, when perform electrophoretic separation of mixture of both forms, only one peak was detected at 147.568 s. The single peak detection could be due to band broadening resulting in inseparable of 2 transferrin forms. To minimized band broadening effect, further study of the effect of electric field strength on Joule heating in microfluidic device is needed.