College of Materials & Energy, South China Agricultural University, Guangzhou 510642, China.
Shenzhen Water Quality Center, Shenzhen, 518055, China.
Anal Chim Acta. 2017 Nov 22;994:82-91. doi: 10.1016/j.aca.2017.09.035. Epub 2017 Sep 28.
An ultrasensitive photoelectrochemical (PEC) immunoassay based on multiple signal amplification strategy was fabricated for the detection of microcystin-LR (MC-LR). The CdS/TiO nanorod arrays (CdS/TiO NRAs) modified FTO electrode, which can weaken the self-oxidation by photogenerated holes of CdS nanoparticles, and limit the recombination of electron-hole pairs and broaden optical absorption of TiO NRAs, was used as a visible-light driven material to immobilize antigens. Then, FeO nanoparticles/polydopamine (FeO@PDA) was used as the carrier to load secondary antibody (Ab) and horseradish peroxidase (HRP), where FeO nanoparticles and HRP can synergistically accelerate the oxidation of 4-chloro-1-naphthol (4-CN) by HO to produce biocatalytic precipitation (BCP) on the surface of modified electrode. Due to the catalytic activity of FeO nanoparticles and HRP, the nonproductive absorption of HRP and the steric hindrance by BCP, the photocurrent change was amplified. The proposed PEC immunosensor can detect MC-LR in a range of 0.005-500 μg/L with a detection limit of 0.001 μg/L. Meanwhile, the PEC immunosensor exhibited high sensitivity, good stability, acceptable selectivity and reproducibility, indicating its potential application in environmental monitoring.
基于多重信号放大策略的超灵敏光电化学（PEC）免疫分析用于检测微囊藻毒素-LR（MC-LR）。CdS/TiO 纳米棒阵列（CdS/TiO NRAs）修饰的 FTO 电极被用作可见光驱动材料来固定抗原，该电极可以削弱 CdS 纳米颗粒光生空穴的自氧化，并限制电子-空穴对的复合，拓宽 TiO NRAs 的光吸收。然后，FeO 纳米粒子/聚多巴胺（FeO@PDA）被用作载体来负载二抗（Ab）和辣根过氧化物酶（HRP），其中 FeO 纳米粒子和 HRP 可以协同加速 HO 对 4-氯-1-萘酚（4-CN）的氧化，在修饰电极表面产生生物催化沉淀（BCP）。由于 FeO 纳米粒子和 HRP 的催化活性、HRP 的非生产性吸收以及 BCP 的空间位阻，光电流变化被放大。所提出的 PEC 免疫传感器可以在 0.005-500μg/L 的范围内检测 MC-LR，检测限为 0.001μg/L。同时，PEC 免疫传感器表现出高灵敏度、良好的稳定性、可接受的选择性和重现性，表明其在环境监测中的潜在应用。
