Sandwich-type electrochemical immunosensor based on Au@Pt DNRs/NH2-MoSe2 NSs nanocomposite as signal amplifiers for the sensitive detection of alpha-fetoprotein

Authors：Shuan Zhang; Chunyan Zhang; Yilei Jia; Xiaobo Zhang; Yunhui Dong; Xinjin Li; Qing Liu; Yueyun Li; Zengdian Zhao

Source：Bioelectrochemistry, 2019, 128: 140-147.

DOI：10.1016/j.bioelechem.2019.03.012

• Sandwich-type electrochemical immunosensor
• Alpha fetoprotein
• Signal amplification strategy
• [email&#160
• protected] dendritic nanorods
• Functionalized graphene

A sandwich-type electrochemical immunosensor was fabricated for the quantitation of alpha fetoprotein (AFP). To this end, the [email protected] dendritic nanorods loaded with amino functionalized molybdenum selenide nanosheets ([email protected] 41 DNRs/NH2-MoSe2 NSs) with enhanced peroxidase-like properties were selected as the secondary antibody label (Ab2) to achieve signal amplification. The as-obtained [email protected] DNRs/NH2-MoSe2 NSs exhibited better catalytic activity toward hydrogen peroxide reduction and offered rich anchors for bioconjugation. Meanwhile, gold nanoparticles anchored on an amino functionalized graphene (Au NPs/NH2-GS) composite with admirable conductivity and biocompatibility was used as the matrix material to improve sensitivity. Under optimal conditions, amperometric current responses had a good linear relationship with the logarithm values of AFP concentration in the range 10 fg mL–1 to 200 ng mL–1 with a detection limit of 3.3 fg mL–1 (S/N = 3). Additionally, the immunosensor had excellent reproducibility, selectivity, and stability, which indicated superior performance for AFP detection compared with previous reports. The satisfactory results of human serum samples analysis showed that the designed immunosensor has potential applicability for the sensitive detection of other tumor markers.