Meng Linghua, Gan Ning, Li Tianhua, Cao Yuting, Hu Futao, Zheng Lei
The State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China; E-Mails:
Int J Mol Sci. 2011 Jan 14;12(1):362-75. doi: 10.3390/ijms12010362.
A novel electrochemical immunosensor for tumor biomarker detection based on three-dimensional, magnetic and electroactive nanoprobes was developed in this study. To fabricate the nanoprobes, negatively charged Fe(3)O(4) nanoparticles (Fe(3)O(4) NPs) and gold nanoparticles (Au NPs) were first loaded on the surface of multiple wall carbon nanotubes (MCNTs) which were functioned with redox-active hemin and cationic polyelectrolyte poly(dimethyldiallylammonium chloride) (PDDA). Using alpha fetoprotein (AFP) as a model analyte, AFP antibody (anti-AFP) was absorbed on the surface of Au NPs, bovine serum albumin (BSA) was then used to block sites against non-specific binding, and finally formed anti-AFP/Au NPs/Fe(3)O(4)/hemin/MCNTs named anti-AFP nanoprobes. When the target antigen AFP was present, it interacted with anti-AFP and formed an antigen-antibody complex on the nanoprobe interface. This resulted in a decreased electrochemical signal of hemin for quantitative determination of AFP when immobilized onto the screen-printed working electrode (SPCE). The results showed that the nanoprobe-based electrochemical immunosensor was sensitive to AFP detection at a concentration of 0.1 to 200 ng·mL(-1) with a detection limit of 0.04 ng·mL(-1), it also demonstrated good selectivity against other interferential substances. The electroactive nanoprobes can be massively prepared, easily immobilized on the SPCE for target detection and rapidly renewed with a magnet. The proposed immunosensor is fast, simple, sensitive, stable, magnet-controlled, nontoxic, label-free and reproducible.
本研究开发了一种基于三维磁性和电活性纳米探针的新型电化学免疫传感器用于肿瘤生物标志物检测。为制备纳米探针，首先将带负电荷的四氧化三铁纳米颗粒（Fe(3)O(4) NPs）和金纳米颗粒（Au NPs）负载在经氧化还原活性血红素和阳离子聚电解质聚二甲基二烯丙基氯化铵（PDDA）功能化的多壁碳纳米管（MCNTs）表面。以甲胎蛋白（AFP）作为模型分析物，将AFP抗体（抗AFP）吸附在Au NPs表面，然后用牛血清白蛋白（BSA）封闭非特异性结合位点，最终形成抗AFP/Au NPs/Fe(3)O(4)/血红素/MCNTs，命名为抗AFP纳米探针。当目标抗原AFP存在时，它与抗AFP相互作用并在纳米探针界面形成抗原-抗体复合物。当固定在丝网印刷工作电极（SPCE）上时，这导致血红素的电化学信号降低，用于AFP的定量测定。结果表明，基于纳米探针的电化学免疫传感器对浓度为0.1至200 ng·mL(-1)的AFP检测敏感，检测限为0.04 ng·mL(-1)，对其他干扰物质也表现出良好的选择性。电活性纳米探针可大量制备，易于固定在SPCE上进行目标检测，并可通过磁铁快速更新。所提出的免疫传感器快速、简单、灵敏、稳定、可磁控、无毒、无标记且可重复。
