Amyloid Beta Detection by Faradaic Electrochemical Impedance Spectroscopy Using Interdigitated Microelectrodes

作者：Park Jin Soo; Kim Hye Jin; Lee Ji Hoon; Park Jung Ho; Kim Jinsik; Hwang Kyo Seon^*; Lee Byung Chul^*

来源：Sensors (Switzerland), 2018, 18(2): 426.

DOI：10.3390/s18020426

• amyloid beta
• redox reagent
• [Fe(CN)(6)](3-/4-)
• faradaic electrochemical impedance spectroscopy
• biosensor
• high sensitivity

Faradaic electrochemical impedance spectroscopy (f-EIS) in the presence of redox reagent, e.g., [Fe(CN)(6)](3/4), is widely used in biosensors owing to its high sensitivity. However, in sensors detecting amyloid beta (A beta), the redox reagent can cause the aggregation of A beta, which is a disturbance factor in accurate detection. Here, we propose an interdigitated microelectrode (IME) based f-EIS technique that can alleviate the aggregation of A beta and achieve high sensitivity by buffer control. The proposed method was verified by analyzing three different EIS-based sensors: non-faradaic EIS (nf-EIS), f-EIS, and the proposed f-EIS with buffer control. We analyzed the equivalent circuits of nf-EIS and f-EIS sensors. The dominant factors of sensitivity were analyzed, and the impedance change rates via A beta reaction was compared. We measured the sensitivity of the IME sensors based on nf-EIS, f-EIS, and the proposed f-EIS. The results demonstrate that the proposed EIS-based IME sensor can detect A beta with a sensitivity of 7.40-fold and 10.93-fold higher than the nf-EIS and the f-EIS sensors, respectively.

• 出版日期2018-2