快速交流電動力輔助抗體固定化之阻抗式生醫感測器研究

Abstract

傳統的免疫分析法中，感測器表面修飾抗體僅利用擴散將抗體送到感測器表面反應，造成反應速度太慢且修飾時間太久(通常需要好幾個小時)。本研究利用半導體製程製作阻抗式生醫感測器，利用外圓電極對內圓指叉狀電極產生交流電滲流及介電泳力，達到快速聚集抗體的能力。利用指叉狀電極當作工作電極，除了製程簡單、量測方便、免螢光標定外，檢體體積僅需40 μL就可完成檢測。為了縮短抗體固定化的反應時間，本研究施加交流電動力將mouse IgG聚集於工作電極上，並利用帶有螢光的anti-mouse IgG驗證抗體固定化效果。施加交流電動力的操作時間僅需10分鐘，與傳統靜置法相比，縮短了超過72倍的反應時間。本研究比較施加交流電動力與否的阻抗變化，發現施加交流電動力(500 Hz, 2Vpp)之阻抗變化比傳統靜置方法大了4倍以上，代表抗體捕捉效率增強了4倍以上，且最低偵測濃度為10 ng/mL。本研究利用阻抗分析儀建立等效電路模型，成功擬合實驗結果，並證實修飾和抗體接合的阻抗變化是由電極表面上的法拉第阻抗和電雙層電容主導。

In immunoassays, the conventional surface immobilization typically utilize the diffusion dominated transport of analytes, which causes slow reaction rate and long modification time (several hours). In order to simplify the device preparation and achieve label-free detection, we adopt interdigitated electrodes as our working electrodes. The miniaturized device can reduce the volume of analytes and need just 40 μL sample for detection in this study. We utilize AC electrokinetics to manipulate and concentrate mouse IgG on gold electrodes in 10 min. Compared to the conventional process, surface modification via AC electrokinetics-enhanced is over 72 times faster in time for mouse IgG immobilization. The measured impedance change after optimal AC electrokinetics is higher than the conventional method, and the detection limit is able to reach 10 ng/mL. Finally, an equivalent circuit model has also been constructed to outline the key parameters that dominate the surface reactions before and after modifications.