Key Laboratory for Analytical Science of Food Safety and Biology (MOE and Fujian Province), State Key Laboratory of Photocatalysis on Energy and Environment, Department of Chemistry , Fuzhou University , Fuzhou 3501116 , People's Republic of China.
Anal Chem. 2018 Aug 7;90(15):9568-9575. doi: 10.1021/acs.analchem.8b02421. Epub 2018 Jul 9.
A novel photoelectrochemical (PEC) enzyme immunoassay was designed for the ultrasensitive detection of alpha-fetoprotein (AFP) based on near-infrared (NIR) light-excited core-core-shell UCNP@Au@CdS upconversion nanospheres. Plasmonic gold (Au) between the sandwiched layers was not only utilized as an energy harvester for the collection of the incident light but also acted as an energy conveyor to transfer the energy from upconversion NaYF:Yb,Er (UCNP) to semiconductor CdS, thus exciting the efficient separation of electron-hole pairs by the generated HO of enzyme immunoreaction under the irradiation of a 980 nm laser. By virtue of high catalytic activity of natural enzymes, gold nanoparticles heavily functionalized with glucose oxidase (GOx) and polyclonal anti-AFP antibody were utilized to generate HO. A sandwiched immunoreaction was first carried out in a monoclonal anti-AFP antibody-coated microplate by using an antibody-labeled gold nanoparticle as secondary antibody. Accompanying the gold nanoparticle, the carried GOx oxidized glucose in HO, thereby resulting in the enhanced photocurrent via capturing holes on the valence band of CdS to promote the separation of electron-hole pairs. Under optimum conditions, the NIR light-based PEC immunosensing system exhibited good photocurrent responses toward target AFP within the dynamic working range of 0.01-40 ng mL at a detection limit of 5.3 pg mL. Moreover, the NIR light-based sensing platform had good reproducibility and high selectivity. Importantly, good well-matched results obtained from NIR light-based PEC immunoassay were acquired for the analysis of human serum specimens by using AFP ELISA kit as the reference.
基于近红外（NIR）光激发的核-壳-壳 UCNP@Au@CdS 上转换纳米球，设计了一种新颖的光电化学（PEC）酶免疫分析方法，用于超灵敏检测甲胎蛋白（AFP）。夹在层间的等离子体金（Au）不仅用作收集入射光的能量收集器，而且还用作能量传递器，将能量从上转换 NaYF:Yb,Er（UCNP）传递到半导体 CdS，从而在 980nm 激光照射下，通过酶免疫反应产生的 HO 激发电子-空穴对的有效分离。由于天然酶具有高催化活性，因此大量功能化的金纳米颗粒与葡萄糖氧化酶（GOx）和多克隆抗 AFP 抗体一起用于产生 HO。夹心免疫反应首先在涂有单克隆抗 AFP 抗体的微孔板中进行，使用抗体标记的金纳米颗粒作为二级抗体。伴随着金纳米颗粒，携带的 GOx 在 HO 中氧化葡萄糖，从而通过捕获 CdS 价带上的空穴来增强光电流，从而促进电子-空穴对的分离。在最佳条件下，基于 NIR 光的 PEC 免疫传感系统在 0.01-40ng mL 的动态工作范围内对目标 AFP 表现出良好的光电流响应，检测限为 5.3pg mL。此外，该基于 NIR 光的传感平台具有良好的重现性和高选择性。重要的是，通过使用 AFP ELISA 试剂盒作为参考，通过基于 NIR 光的 PEC 免疫分析对人血清标本进行分析，获得了良好的匹配结果。
