生物结合
光电流
材料科学
生物传感器
纳米技术
光电化学
表面改性
检出限
纳米花
纳米结构
线性范围
免疫分析
电化学
化学工程
光电子学
化学
电极
色谱法
抗体
物理化学
免疫学
工程类
生物
作者
Sadman Sakib,Amin Hosseini,Igor Zhitomirsky,Leyla Soleymani
标识
DOI:10.1021/acsami.1c18240
摘要
There is an increasing interest in using photoelectrochemistry for enhancing the signal-to-noise ratio and sensitivity of electrochemical biosensors. Nevertheless, it remains challenging to create photoelectrochemical biosensors founded on stable material systems that are also easily biofunctionalized for sensing applications. Herein, a photoelectrochemical immunosensor is reported, in which the concentration of the target protein directly correlates to a change in the measured photocurrent. The material system for the photoelectrode signal transducer involves using catecholate ligands to modify the properties of TiO2 nanostructures in a three-pronged approach of morphology tuning, photoabsorption enhancement, and facilitating bioconjugation. The catecholate-modified TiO2 photoelectrode is combined with a signal-off direct immunoassay to detect interleukin-6 (IL-6), a key biomarker for diagnosing and monitoring various diseases. Catecholate ligands are added during hydrothermal synthesis of TiO2 to enable the growth of three-dimensional nanostructures to form highly porous photoelectrodes that provide a three-dimensional scaffold for immobilizing capture antibodies. Surface modification by catecholate ligands greatly enhances photocurrent generation of the TiO2 photoelectrodes by improving photoabsorption in the visible range. Additionally, catecholate molecules facilitate bioconjugation and probe immobilization by forming a Schiff-base between their -COH group and the -NH2 group of the capture antibodies. The highest photocurrent achieved herein is 8.89 μA cm-2, which represents an enhancement by a factor of 87 from unmodified TiO2. The fabricated immunosensor shows a limit-of-detection of 3.6 pg mL-1 and a log-linear dynamic range of 2-2000 pg mL-1 for IL-6 in human blood plasma.
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