介电谱
生物传感器
铁氰化物
胰岛素
循环伏安法
材料科学
电阻抗
分析化学(期刊)
化学
共价键
电化学
电极
色谱法
纳米技术
生物化学
医学
有机化学
物理化学
内分泌学
工程类
电气工程
作者
Mukund Khanwalker,Rinko Fujita,Jin‐Hee Lee,Ellie Wilson,Kohei Ito,Ryutaro Asano,Kazunori Ikebukuro,Jeffrey T. La Belle,Koji Sode
标识
DOI:10.1016/j.bios.2021.113901
摘要
To improve glycemic control managed through insulin administration, recent studies have focused on developing hand-held point-of-care testing (POCT) electrochemical biosensors for insulin measurement. Amongst them, anti-insulin IgG-based sensors show promise in detecting insulin with high specificity and sensitivity. However, fabrication of electrochemical sensors with IgG antibodies can prove challenging because of their larger molecular size. To overcome these limitations, this study focuses on utilizing the anti-insulin single chain variable fragment (scFv) as a biosensing molecule with single-frequency faradaic electrochemical impedance spectroscopy (EIS). By comparing two different immobilization methods, covalent conjugation via succinimidyl ester and non-covalent poly-histidine chelation, we demonstrated effective modification of the electrode surface with anti-insulin scFv, while retaining its specific recognition toward insulin. Sensor performance was confirmed via the concentration-dependent faradaic electrochemical impedance change using potassium ferricyanide as a redox probe. The optimal frequency for measurement was determined to be the peak slope of the calculated impedance correlation with respect to frequency. Based on the identified optimized frequency, we performed single-frequency measurement of insulin within a concentration range of 10 pM-100 nM. This study can aid in developing a future point-of-care sensor which rapidly and sensitively measures insulin across a dynamic range of physiological concentrations, with label-free detection.
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