Carbohydrate-Based Label-Free Detection of Escherichia coli ORN 178 Using Electrochemical Impedance Spectroscopy
Carbohydrate-Based Label-Free Detection of Escherichia coli ORN 178 Using Electrochemical Impedance Spectroscopy
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DOI：
10.1021/ac202419u
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发表时间：
2012-01-03
影响因子：
7.4
通讯作者：
Heineman, William R.
中科院分区：
文献类型：
--
作者：
Guo, Xuefei;Kulkarni, Ashish;Heineman, William R.
基于法拉第电化学阻抗谱（EIS）开发了一种用于大肠杆菌ORN 178的无标记生物传感器。通过末端带有巯基官能团的间隔物，利用自组装单分子层（SAM）将α -甘露糖苷或β -半乳糖苷固定在金圆盘电极上。阻抗测量（奈奎斯特图）显示，由于大肠杆菌ORN 178与α -甘露糖苷特异性结合而发生了偏移。对于不与α -甘露糖苷结合的大肠杆菌ORN 208，未观察到阻抗有显著变化。随着大肠杆菌ORN 178浓度的增加，在传感器饱和之前，电子转移电阻（R - et）增大。对大肠杆菌/混合SAM/金电极的奈奎斯特图进行建模后，发现在细菌浓度为10²到10³ CFU/mL的范围内，归一化的R - et与大肠杆菌浓度的对数值之间存在线性关系。将稳定的碳水化合物配体与EIS相结合，提供了一种无标记、灵敏、特异、用户友好、稳定且便携的生物传感系统，该系统有可能用于即时检测或连续环境监测环境。
A label-free biosensor for Escherichia coli (E. coli) ORN 178 based on faradaic electrochemical impedance spectroscopy (EIS) was developed. alpha-Mannoside or beta-galactoside was immobilized on a gold disk electrode using a self-assembled monolayer (SAM) via a spacer terminated in a thiol functionality. Impedance measurements (Nyquist plot) showed shifts due to the binding of E. coli ORN 178, which is specific for alpha-mannoside. No significant change in impedance was observed for E. coli ORN 208, which does not bind to alpha-mannoside. With increasing concentrations of E. coli ORN 178, electron-transfer resistance (R-et) increases before the sensor is saturated. After the Nyquist plot of E. coli/mixed SAM/gold electrode was modeled, a linear relationship between normalized R-et and the logarithmic value of E. coli concentrations was found in a range of bacterial concentration from 10(2) to 10(3) CFU/mL. The combination of robust carbohydrate ligands with EIS provides a label-free, sensitive, specific, user-friendly, robust, and portable biosensing system that could potentially be used in a point-of-care or continuous environmental monitoring setting.